10-K
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 10-K
(Mark One)
For the fiscal year ended December 31, 2023
OR
Commission File Number 001-39409
ALLOVIR, INC.
(Exact name of Registrant as specified in its Charter)
(Address of principal executive offices) (Zip Code)
Registrant’s telephone number, including area code: (617) 433-2605
Securities registered pursuant to Section 12(b) of the Act:
Title of each class TradingSymbol(s) Name of each exchange on which registered
Common Stock, par value $0.0001 per share ALVR The Nasdaq Global Select Market
Securities registered pursuant to Section 12(g) of the Act: None
Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐ No ☒
Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ☐ No ☒
Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐
Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the @Exchange Act.
Large accelerated filer ☐ Accelerated filer ☐
Non-accelerated filer ☒ Smaller reporting company ☒
Emerging growth company ☒
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐
If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐
Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐
Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No☒
The aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrant was $265.4 million based on the closing price of the shares of common stock on The Nasdaq Global Select Market on June 30, 2023, the last business day of the registrant's most recently completed second quarter. In determining the market value of non-affiliate common stock, shares of the Registrant’s common stock beneficially owned by officers, directors and affiliates have been excluded. This determination of affiliate status is not necessarily a conclusive determination for other purposes.
The number of shares of Registrant’s Common Stock, par value $0.0001 per share, outstanding as of March 8, 2024 was 114,869,175.
DOCUMENTS INCORPORATED BY REFERENCE
Portions of the Proxy Statement for the registrant’s 2024 Annual Meeting of Stockholders, or the Proxy Statement, which the Registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the Registrant’s fiscal year end of December 31, 2023, are incorporated by reference into Part III of this Annual Report on Form 10-K.
Table of Contents
Page
SUMMARY OF MATERIAL RISKS ASSOCIATED WITH OUR BUSINESS 1
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS 2
PART I 4
Item 1. Business 4
Item 1A. Risk Factors 52
Item 1B. Unresolved Staff Comments 98
Item 1C. Cybersecurity 98
Item 2. Properties 99
Item 3. Legal Proceedings 99
Item 4. Mine Safety Disclosures 99
Item 6. Selected Financial Data 101
Item 7A. Quantitative and Qualitative Disclosures About Market Risk 112
Item 8. Financial Statements and Supplementary Data 112
Item 9A. Controls and Procedures 112
Item 9B. Other Information 113
Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 113
Item 10. Directors, Executive Officers and Corporate Governance 114
Item 11. Executive Compensation 114
Item 14. Principal Accounting Fees and Services 114
Item 15. Exhibits, Financial Statement Schedules 115
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Summary of Material Risks Associated with Our Business
Our business is subject to numerous risks and uncertainties that you should be aware of before making an investment decision, including those highlighted in the section entitled “Risk Factors.” These risks include, but are not limited to, the following:
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We may not be successful in identifying and implementing any strategic transaction and any strategic transactions that we may consummate in the future could have negative consequences.
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Even if we successfully consummate any transaction from our strategic assessment, including, but not limited to, in-licensing and/or out-licensing, a merger, sale, and/or divestiture of assets, we may fail to realize all of the anticipated benefits of the transaction, those benefits may take longer to realize than expected, or we may encounter integration difficulties.
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If we are successful in completing a strategic transaction, we may be exposed to other operational and financial risks.
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If a strategic transaction is not consummated, our board of directors may decide to pursue a dissolution and liquidation. In such an event, the amount of cash available for distribution to our stockholders will depend heavily on the timing of such liquidation as well as the amount of cash that will need to be reserved for commitments and contingent liabilities.
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We are a clinical-stage cell therapy company and we have incurred net losses since our inception. We anticipate that we will continue to incur significant losses for the foreseeable future and may never achieve or maintain profitability.
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We depend substantially on intellectual property licensed from third parties, including Baylor College of Medicine, or BCM, and termination of any of these licenses could result in the loss of significant rights, which would harm our business.
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If we are unable to obtain and maintain sufficient intellectual property protection for our product candidates and manufacturing process, or if the scope of the intellectual property protection is not sufficiently broad, our ability to commercialize our product candidates successfully and to compete effectively may be adversely affected.
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We will need substantial additional funding, and if we are unable to raise capital when needed, we could be forced to delay, reduce or eliminate our product discovery and development programs or commercialization efforts.
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We have a limited operating history, which may make it difficult to evaluate the success of our business to date and to assess our future viability.
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We are early in our development efforts and have only a small number of product candidates in clinical development. All of our other product candidates are still in preclinical development. If we or our collaborators are unable to successfully develop and commercialize product candidates or experience significant delays in doing so, our business may be materially harmed.
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Clinical drug development involves a lengthy and expensive process with an uncertain outcome, and the inability to successfully and timely conduct clinical trials and obtain regulatory approval for our product candidates would substantially harm our business.
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The results of preclinical studies or earlier clinical trials are not necessarily predictive of future results. Our existing product candidates in clinical trials, and any other product candidate we advance into clinical trials, may not have favorable results in later clinical trials or receive regulatory approval.
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Our product candidates, the methods used to deliver them or their dosage levels may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit the commercial profile of an approved label or result in significant negative consequences following any regulatory approval.
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We face substantial competition, which may result in others discovering, developing or commercializing products before or more successfully than we do.
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We and our third-party partners are subject to a multitude of manufacturing risks, any of which could substantially increase our costs and limit supply of our product candidates.
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We intend to develop an efficient and highly productive manufacturing supply chain for our allogeneic, off-the-shelf single- and multi-virus specific T, or VST, cell therapies. Delays in process performance qualification to validate the drug product manufacturing process could delay regulatory approvals, our development plans and thereby limit our ability to generate revenues.
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We are highly dependent on our key personnel and anticipate hiring new key personnel. If we are not successful in attracting and retaining highly qualified personnel, we may not be able to successfully implement our business strategy.
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The trading price of our common stock may be volatile.
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Our business could be adversely affected by the effects of health epidemics, like the COVID-19 pandemic, in regions where our contracted third parties, including contract research organizations, or CROs, and contract development and manufacturing organizations, or CMOs or CDMOs, have significant research, development or manufacturing facilities, concentrations of clinical trial sites or other business operations, causing disruption in supplies and services.
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The summary risk factors described above should be read together with the text of the full risk factors below, in the section entitled “Risk Factors” and the other information set forth in this Annual Report on Form 10-K, including our consolidated financial statements and the related notes, as well as in other documents that we file with the SEC. The risks summarized above or described in full below are not the only risks that we face. Additional risks and uncertainties not precisely known to us, or that we currently deem to be immaterial may also materially adversely affect our business, financial condition, results of operations and future growth prospects.
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
This Annual Report on Form 10-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements other than statements of historical facts contained in this Annual Report on Form 10-K are forward-looking statements, including but not limited to, statements about:
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our plans and expectations regarding our strategic alternative review process and the timing and success of such process regarding a potential transaction;
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timing of and costs or charges associated with our restructurings, and the savings benefits we expect to receive from those restructurings;
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success in retaining, or changes required in, our officers, key employees or directors;
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should we resume development of our product candidates, the success, cost, timing and potential indications of our product development activities and clinical trials, including the future clinical trials of posoleucel and ALVR106;
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the timing of our planned Investigational New Drug, or IND, submissions to the U.S. Food and Drug Administration, or FDA, for our product candidates, including ALVR107;
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the timing of the initiation, enrollment and completion of planned clinical trials;
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should we resume development of our product candidates, our plans to research, develop and commercialize our product candidates, including posoleucel, ALVR106, and ALVR107;
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the timing of the initiation, completion and outcomes of our preclinical studies;
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the costs of development of any of our product candidates or clinical development programs and our ability to obtain funding for our operations, including funding necessary to complete the clinical trials of any of our product candidates;
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our ability to successfully manufacture and distribute posoleucel, ALVR106 or any other future product or product candidate, should we resume development of our product candidates;
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the potential benefits of and our ability to maintain our collaboration with our existing collaborators, including BCM, and establish or maintain future collaborations or strategic relationships or obtain additional funding;
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the ability to maintain our existing license agreements, including Baylor College of Medicine, or BCM, and to license additional intellectual property relating to any future product candidates and to comply with our existing license agreements;
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our ability to attract and retain collaborators with development, regulatory and commercialization expertise;
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risks associated with a health epidemic like the COVID-19 pandemic, including the emergence of new COVID-19 variants, which may adversely impact our business and clinical trials;
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the size of the markets for our VST product candidates, and our ability to serve those markets;
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whether the results of our clinical trials will be sufficient to support domestic or foreign regulatory approvals for any of our product candidates;
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should we resume development of our product candidates, our ability to successfully commercialize our product candidates, including posoleucel and ALVR106;
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should we resume development of our product candidates, the rate and degree of market acceptance of our product candidates, including posoleucel and ALVR106;
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our ability to obtain and maintain regulatory approval of our product candidates in any of the indications for which we plan to develop them, and any related restrictions, limitations or warnings in the label of any approved product we develop;
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our ability to develop and maintain sales and marketing capabilities, whether alone or with potential future collaborators;
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regulatory developments in the United States and foreign countries with respect to our product candidates or our competitors’ products and product candidates;
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our reliance on third-party contract manufacturers and the performance of our third-party suppliers and manufacturers to manufacture and supply our product candidates for us;
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the success of competing therapies that are or become available;
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our ability to attract and retain key scientific or management personnel;
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our expectation about the period of time over which our existing capital resources will be sufficient to fund our operating expenses and capital expenditures;
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our expectations regarding the time during which we will be an emerging growth company under the Jumpstart Our Business Startups Act of 2012, or the JOBS Act;
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our financial performance;
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the impact of laws and regulations;
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developments and projections relating to our competitors or our industry;
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the accuracy of our estimates regarding expenses, future revenues, capital requirements and needs for additional financing; and
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our expectations regarding our ability to obtain and maintain intellectual property protection for our product candidates and our ability to operate our business without infringing on the intellectual property rights of others.
In some cases, you can identify forward-looking statements by the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “objective,” “ongoing,” “plan,” “predict,” “project,” “potential,” “should,” “will,” or “would,” or the negative of these terms, or other comparable terminology intended to identify statements about the future. These statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from the information expressed or implied by these forward-looking statements.
In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this report, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and investors are cautioned not to unduly rely upon these statements.
You should read the section titled “Risk Factors” set forth in Part I, Item 1A of this Annual Report on Form 10-K for a discussion of important factors that may cause our actual results to differ materially from those expressed or implied by our forward-looking statements. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. As a result of these factors, we cannot assure you that the forward-looking statements in this Annual Report on Form 10-K will prove to be accurate. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise.
You should read this Annual Report on Form 10-K, completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of our forward-looking statements by these cautionary statements.
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PART I
Item 1. Business.
Overview
We are a cell therapy company developing highly innovative allogeneic T cell therapies to treat and prevent devastating viral diseases. Our innovative and proprietary virus-specific T cell, or VST, therapy platform allows AlloVir to generate off-the-shelf VSTs designed to restore immunity in patients with T cell deficiencies who are at risk from the life-threatening consequences of viral diseases. There is an urgent medical need for therapies to treat a large number of patients suffering from viral diseases who currently have limited or no treatment options. Our platform includes three innovative, allogeneic, off-the-shelf VST therapy candidates targeting 11 different devastating viruses. Our lead product candidate, posoleucel (previously referred to as Viralym-M or ALVR105), is a multi-VST therapy that targets six viruses: adenovirus, or AdV, BK virus, or BKV, cytomegalovirus, or CMV, Epstein-Barr virus, or EBV, human herpesvirus 6, or HHV-6 and JC virus, or JCV.
In December 2023, we announced the discontinuation of three Phase 3 registrational trials of posoleucel following separate, pre-planned Data Safety Monitoring Board, or DSMB, futility analyses that concluded the studies were unlikely to meet their primary endpoints. Specifically, we discontinued a multicenter, randomized, double-blind, placebo-controlled Phase 3 trial comparing posoleucel to placebo for the prevention of infection or disease due to AdV, BKV, CMV, EBV, HHV-6, or JCV in high-risk adult and pediatric patients after undergoing an allogeneic hematopoietic stem cell transplant. We also discontinued two multicenter, randomized, double-blind, placebo-controlled Phase 3 trials of posoleucel – one for the treatment of virus-associated hemorrhagic cystitis and the second for the treatment of adenovirus infection - both after allogeneic hematopoietic cell transplant.
In December 2023, we also announced that we would review the detailed datasets from those Phase 3 trials and launch a comprehensive review of strategic alternatives focused on maximizing stockholder value, including, but not limited to, a merger, sale, divestiture of assets, licensing, or other strategic transaction. We expect to devote substantial time and resources to exploring strategic alternatives that our board of directors believes will maximize stockholder value. Despite devoting significant efforts to identify and evaluate potential strategic alternatives, there can be no assurance that this strategic review process will result in us pursuing any transaction or that any transaction, if pursued, will be completed on attractive terms or at all. We have not set a timetable for completion of this strategic review process, and our board of directors has not approved a definitive course of action. Additionally, there can be no assurances that any particular course of action, business arrangement or transaction, or series of transactions, will be pursued, successfully consummated or lead to increased stockholder value, or that we will make any cash distributions to our stockholders.
In connection with the evaluation of strategic alternatives and in order to maximize capital preservation, we have implemented a plan to reduce our workforce by approximately 95%. This workforce reduction plan was approved in January 2024, and will take place primarily during the first quarter of 2024 and is expected to be substantially completed by April 15, 2024. In clinical trials conducted to date, we have treated more than 500 transplant patients with either single or multi-virus targeted allogeneic VSTs, and our product candidates have been generally well-tolerated and have been associated with clinical benefit. We believe that our allogeneic, off-the-shelf VSTs can benefit patients with other conditions characterized by T-cell deficiencies who are at high risk for life-threatening viral diseases, including immunocompromised cancer patients, the elderly and young children with immature immune systems.
Our proprietary VST manufacturing platform enables the rapid, robust and reproducible generation of single-virus and multi-virus specific cell therapeutic candidates for clinical use. Our VST production process selectively expands polyclonal (CD4+ helper and CD8+ cytotoxic) virus-targeted T-cell populations. The critical components of our off-the-shelf VST platform, for which patents are issued and/or pending, include:
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Methods of identifying immunodominant viral antigens in target viruses;
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CytokinTM, our selection algorithm to identify healthy donors from whom to generate VSTs that provide coverage to over 95% of patients in our targeted populations;
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Methods of rapidly and selectively expanding polyclonal VSTs ex vivo; and
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CytomatchTM, our algorithm to choose the appropriate partially HLA-matched off-the-shelf VST therapy to deliver to each patient.
We have applied this expertise in the development of additional product candidates that may benefit high-risk individuals:
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ALVR106 is our second off-the-shelf, multi-VST product candidate that we developed to target devastating respiratory diseases caused by human metapneumovirus, or hMPV, influenza, parainfluenza virus, or PIV, and respiratory syncytial virus, or RSV. A Phase 1b/2 proof of concept clinical study of ALVR106 has completed enrollment of patients in Part A of the trial. We have paused development of ALVR106, including discontinuing the trial pending the outcome of our review of strategic alternatives.
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ALVR107 is our preclinical stage product candidate designed to target hepatitis B, or HBV, infected cells and with the aim of curing chronic HBV infections. Preclinical and IND-enabling studies of ALVR107 to treat and cure HBV were completed
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in 2022 to support advancement into a POC study. Clinical development of ALVR107 is currently paused pending the outcome of our review of strategic alternatives.
Our management team has significant experience in successfully advancing products from early-stage discovery through commercialization. Our Chief Executive Officer, Diana Brainard, has more than 20 years of experience in the biopharmaceutical industry and academic medicine. During her 10-year tenure at Gilead Sciences, Dr. Brainard served as the head of the virology therapeutic area, leading the development and launch of some of the most successful drugs of the last decade, including Sovaldi, Harvoni, Epclusa and Biktarvy. In 2020, she led the company-wide initiative to rapidly advance Veklury (remdesivir) to become the first and only antiviral to receive regulatory approval for the treatment of SARS-CoV-2, which earned her global recognition as one of the most influential people in the fight against SARS-CoV-2. Her industry career began at Merck, where she held positions in clinical pharmacology and experimental medicine. Dr. Brainard also serves as an Independent Director of Nektar Therapeutics and Affinia Therapeutics.
Vikas Sinha, our President and Chief Financial Officer, brings more than 25 years of experience in executive finance roles within the biopharmaceutical industry. He served as the Chief Financial Officer of Alexion Pharmaceuticals for more than 11 years, where he oversaw the global expansion of the company across 50 countries and revenue growth to more than $3 billion. Prior to joining Alexion, Mr. Sinha held various positions with Bayer AG across the world, including CFO, Bayer Pharma, North America and CFO, Bayer Yakuhin, Japan. He also serves as Chief Financial Officer of ElevateBio and an Independent Director and Audit Committee Chair at Verona Pharma.
To date, we have raised $156.9 million in aggregate gross proceeds through private financings, $317.7 million in aggregate gross proceeds through our IPO, which closed in August 2020, $126.6 million in aggregate gross proceeds through a registered direct offering in July 2022, and $75.0 million in aggregate gross proceeds through an underwritten public offering July 2023.
Our Pipeline
Our pipeline is comprised of three allogeneic off-the-shelf VST therapy candidates targeting 11 different viruses to treat and prevent life-threatening viral diseases. For each of these pipeline therapies, we have global development and commercialization rights. The chart below summarizes key information about our programs. As noted above, in December 2023, we announced the discontinuation of all three Phase 3 registrational trials of posoleucel.
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Posoleucel. An allogeneic, off-the-shelf VST therapy candidate targeting six common viruses: AdV, BKV, CMV, EBV, HHV-6 and JCV, which can lead to devastating viral disease in the allogeneic HCT population. Given that posoleucel is multi-VST product candidate, the therapy has multiple potential applications.
Promising efficacy and safety results from the completed Phase 2 treatment and prevention trials in allogeneic HCT patients enabled the rapid progression of posoleucel into Phase 3 development. In the CHARMS Phase 2 POC treatment trial, 95% of allogeneic HCT patients with infections from one or more of the target viruses and who previously failed or were intolerant to conventional antiviral treatments, achieved a clinical response when treated with posoleucel therapy. In the Phase 2 multi-virus prevention trial, posoleucel demonstrated a substantial reduction in the expected rate of clinically significant viral infections or diseases, with 88% of patients remained free of clinically significant infections caused by any of the six viruses that posoleucel targets through the Week 14 primary endpoint.
A Phase 2 POC trial of posoleucel to treat BK viremia in kidney transplant patients completed in 2022. Positive topline data from the BKV study were reported in February 2023, showing balanced safety across posoleucel and placebo groups and clinically meaningful greater viral load declines with posoleucel versus placebo.
Based on the totality of supportive evidence in the allo-HCT patient population, we initiated three Phase 3 registrational trials of posoleucel – one for the treatment of virus-associated HC, one for the treatment of adenovirus infection and one for multi-virus prevention, all in HCT patients. In December 2023, we announced the discontinuation of all three Phase 3 registrational trials of posoleucel following separate, pre-planned DSMB futility analyses concluded the studies were unlikely to meet their primary endpoints based on the interim data reviewed by each DSMB.
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ALVR106. An allogeneic, off-the-shelf VST therapy candidate developed to target devastating diseases caused by four respiratory viruses: hMPV, influenza, PIV and RSV. A Phase 1b/2 proof of concept clinical study of ALVR106 has completed enrollment of patients in Part A of the trial. In December 2023, we paused development of ALVR106, including discontinuing the trial pending the outcome of our review of strategic alternatives.
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ALVR107. An allogeneic, off-the-shelf VST therapy candidate designed to target HBV-infected cells with the aim of curing chronic HBV infections. Preclinical and IND-enabling studies of ALVR107 to treat and cure HBV were completed in 2022 to support advancement into a proof of concept study. Clinical development of ALVR107 is currently paused pending the outcome of our review of strategic alternatives.
Our Strategy
As announced in December 2023, we have discontinued the three Phase 3 registrational trials of posoleucel following separate, pre-planned DSMB futility analyses concluded the studies were unlikely to meet their primary endpoints.
As also announced in December 2023, we are completing a comprehensive review of strategic alternatives focused on maximizing stockholder value, including, but not limited to, a merger, sale, divestiture of assets, licensing, or other strategic transaction. We expect to devote substantial time and resources to exploring strategic alternatives that our board of directors believes will maximize stockholder value. Despite devoting significant efforts to identify and evaluate potential strategic alternatives, there can be no assurance that this strategic review process will result in us pursuing any transaction or that any transaction, if pursued, will be completed on attractive terms or at all. We have not set a timetable for completion of this strategic review process, and our board of directors has not approved a definitive course of action. Additionally, there can be no assurances that any particular course of action, business arrangement or transaction, or series of transactions, will be pursued, successfully consummated or lead to increased stockholder value, or that we will make any additional cash distributions to our stockholders.
In connection with the evaluation of strategic alternatives and in order maximize capital preservation, we have implemented a plan to reduce our workforce by approximately 95%. This workforce reduction will take place primarily during the first quarter of 2024 and is expected to be substantially completed by April 15, 2024.
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The Immune System and the Role of T Cells
In healthy individuals, the adaptive immune response forms a critical component of the body’s natural defense system and provides protection against numerous disease-causing viruses, as depicted in the figure below. Certain types of T cells have an essential role in driving the immune response to viruses. The major role of CD8+ “cytotoxic” T cells is to kill virus-infected or otherwise diseased cells, while the major role of CD4+ “helper” T cells is to produce soluble proteins, known as cytokines, which produce direct antiviral effects and support CD8+ T-cell survival. CD4+ T cells can also signal other immune cell types, including antibody-producing B cells, thereby influencing the broader antiviral immune response. CD8+ and CD4+ T cells are vital components in maintaining adaptive immunity against many devastating viruses.
Figure 1. T cells play a central role in response to viral infection
T cells recognize viruses via their T-cell receptors, or TCRs, which selectively recognize “foreign” viral peptides displayed by a compatible “self” human leukocyte antigen, or HLA, proteins present on the surface of virus-infected cells or antigen presenting cells. Once T cells bind to the peptide-HLA complex, they become activated and start to multiply as the body mounts an immune response to control or eliminate the virus. In contrast, if the peptide displayed by the HLA allele is not “foreign” but instead from a “self” antigen, then T cells do not bind to the cell and no immune response is generated.
To be clinically effective, at least a portion of the infused, allogeneic, off-the-shelf VSTs must be compatible, or partially HLA matched, with the patient so that some of the infused T cells can bind to viral peptide-HLA complexes, resulting in selective antiviral effects against virus-infected cells.
While HLA alleles provide a defining feature of an individual’s biology, there are only a limited number of unique HLA types among humans. This important characteristic has allowed us to develop allogeneic VSTs from donors who are carefully chosen to provide HLA coverage to the broad patient population at risk of devastating viral infections.
VST therapies are specifically designed to enhance and restore T-cell function. In patients with T-cell deficiencies, uncontrolled viral infection, replication and expansion can result in severe and devastating consequences.
Transplantation and Immunosuppression
There are two major types of transplant procedures: HCTs and SOTs. In each procedure, the immune system of the patient is suppressed or eliminated to prevent rejection of the transplanted cells or organs. In the case of HCT, this immunocompromised state is
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typically temporary and resolves once the transplanted donor stem cells begin to replenish the cells of the immune system. In SOT, most patients require a high dose of immunosuppressive drugs for the first six months post-transplant and some degree of immunosuppressive treatment for the rest of their lives.
HCTs are clinical procedures used in the treatment of severe and life-threatening diseases primarily of the blood and immune systems, including some forms of leukemia and lymphoma, genetic diseases and other blood-based diseases. In HCTs, physicians remove diseased or, in the case of some genetic diseases, missing blood cells, along with the stem cells that lead to their formation. The physician then replaces the diseased or missing blood cells with healthy red and white blood cell-forming stem cells from donors. The process of destroying the defective cells, known as conditioning, also leads to the depletion of the patient’s immune cells, leaving patients highly vulnerable to disease-causing viruses, which can become life-threatening due to their weakened immune systems. Patients can remain vulnerable for an extended period until the donor stem cells take up residence and begin to reconstitute a functional immune system. A key challenge in HCT is the identification of transplant material that is immunologically compatible with the patient. The selection of donors for HCT procedures requires that the donor’s HLA antigens comprise a close match to those of the patient, as an exact match is not often available. Procedures using more stringent conditioning enable these patients to receive partially matched stem cells from allogeneic donors. This more stringent conditioning, known as myeloablative conditioning, leaves the patient extremely immunosuppressed and highly prone to potentially deadly viral diseases.
In up to 90% of allogeneic HCT patients, the suppressed immune system allows viruses that were previously in a latent, quiescent state to reactivate and more than 60% of allogeneic HCT patients experience a reactivation of more than one virus, including BKV, CMV, AdV, EBV and HHV-6, as depicted in the figure below. In healthy, immunocompetent individuals, these viruses typically lead to mild, self-limiting infections. However, in immunocompromised patients, once reactivated, each of these viruses has the potential to cause significant morbidity and even mortality. It is estimated that more than 20% of all deaths associated with HCTs are due to infections.
Figure 2. Approximately 90% of patients undergoing allogeneic HCT have at least one viral infection and 62% have more than one. Multiple viruses contribute to significant mortality
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SOT has been established as a definitive treatment option for patients with organ failure. Over the past few decades, SOT procedures have rapidly progressed and now include a variety of solid organs, including the kidney, lung, liver, heart, intestine and pancreas. The increase in organ transplants has been matched by improved short- and long-term graft survival. This is due, in large part, to the use of immunosuppressive drugs that prevent the immune system from rejecting the transplanted organ. However, typically SOT patients require some degree of immunosuppressive therapy life-long, which leaves them vulnerable to viral infections and disease for a longer duration than HCT patients. In addition, high-risk SOT patients, including recipients of organs mismatched at a high number of HLA antigens, highly sensitized recipients, or ABO blood type incompatible recipients, tend to receive more rigorous immunosuppressive induction treatment, further increasing the risk of these patients contracting potentially deadly viral diseases. Further, SOT patients with the viral infections and diseases our product candidates aim to treat or prevent, suffer from worse outcomes, including graft failure, despite current standard of care treatment, as depicted in the figure below.
Figure 3. BKV in kidney transplant recipients leads to decreased graft survival despite standard of care
We believe transplant patients represent one segment of the large number of immunocompromised patients suffering from devastating viral infections who could potentially benefit from allogeneic, off-the-shelf VST therapies. Other individuals with weakened immune systems, including those with primary immunodeficiencies, the elderly and very young and patients who have compromised immune systems due to cancer or the treatment of their cancer are all at high risk of the life-threatening consequences of viral diseases and infections. Each of these target patient populations represents a large potential market that is currently untapped or underserved by existing therapies.
Limitations of Current Therapies for Immunocompromised Patients
There are no FDA- or EMA-approved antiviral drugs to treat the majority of the diseases and patients we are planning to target using our allogeneic off-the-shelf VSTs. When used clinically, available antivirals are often ineffective, toxic, can lead to emergence of virus escape mutants that are treatment-refractory and despite their use patients often succumb to their infections.
Similarly, there are limitations to prophylactic approaches, such as vaccines, in immunosuppressed patients, the elderly, and the very young who may be unable to mount an effective immune response that protects against the target viruses.
In contrast, the adoptive transfer of ex vivo expanded VSTs to HCT patients has generated promising preliminary disease outcome measures and safety data in treating a range of viral diseases in clinical trials. We designed an approach whereby VSTs could be prospectively generated from healthy, third-party donors expressing common HLA polymorphisms who were seropositive for all of the
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targeted viruses. These VSTs were prepared by stimulating peripheral blood mononuclear cells, or PBMCs, with viral antigens followed by ex vivo expansion and cryopreservation to enable utilization when needed by patients. We then clinically assessed whether such allogeneic VSTs, when administered as a partially HLA-matched off-the-shelf therapy could still provide clinical benefit in a safe manner. We have treated more than 500 allogeneic HCT patients with either single or multi-virus targeted allogeneic VSTs. These off-the-shelf VSTs have been generally well-tolerated and were associated with clinical benefit as indicated by the high response rate demonstrated in immunocompromised patients with drug-refractory infections and diseases.
Our Approach to Allogeneic Off-the-Shelf T-Cell Immunotherapy
There is an urgent medical need for therapies to treat a large number of patients suffering from devastating viral diseases who currently have limited or no treatment options. Our approach involves the restoration of viral immunity through the adoptive transfer of VSTs, which have been prospectively generated from healthy, eligible donors. These cells are immediately available for “off-the-shelf” administration to patients at risk from the devastating consequences of viral diseases due to T-cell deficiencies, as depicted in the figure below. The partial HLA match between the allogeneic VST therapy and infected patient allows the infused T cells to recognize and selectively kill virus-infected cells while leaving non-virus-infected host cells intact, thereby minimizing the risk of therapy-associated graft-versus-host disease, or GVHD.
Figure 4. Adoptive transfer of off-the-shelf VSTs kill virus-infected cells and restore virus-specific T-cell immunity
Our VSTs are generated from a panel of healthy, third-party blood donors that collectively express a diverse array of HLA allele subtypes. Collectively, these VSTs, which therefore recognize viral peptides displayed by an array of different HLA alleles, form a mini-bank of product candidates that provide coverage to more than 95% of patients in our targeted populations. These VSTs can be stored in a cryopreserved state and thus supplied rapidly and globally as an off-the-shelf therapy for patients suffering from, or at risk for contracting, one or more viral diseases.
Using our versatile and robust off-the-shelf VST platform, we are able to rapidly generate VST therapies for the treatment of a spectrum of viral diseases. This is demonstrated by our pipeline of innovative, allogeneic off-the-shelf VST therapy candidates targeting both multi-virus (posoleucel and ALVR106) and single-virus indications (ALVR107).
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Figure 5. Schematic depicting how AlloVir’s versatile off-the-shelf VST manufacturing platform is used to generate Posoleucel
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Our Proprietary Allogeneic VST Therapy Process
We are uniquely positioned to rapidly develop and deploy T-cell therapies to treat and/or prevent a range of viral diseases, given our team’s extensive experience in the fields of virology, immunology and cell therapy. We have leveraged this expertise to design the robust and reproducible allogeneic VST therapy production process depicted in the figure below. This process is comprised of three steps that enable the reliable generation of allogeneic, off-the-shelf, single or multi-virus-specific T cells: (1) our virus-specific T-cell profiling and targeted donor selection process, CytokinTM; (2) rapid and scalable off-the-shelf VST manufacturing; and (3) our proprietary, customized VST-cell line selection process, CytomatchTM, which allows for rapid patient access to our allogeneic VST therapy.
Figure 6. Key advantages of AlloVir’s patented, highly efficient and industrialized VST platform
Step 1: Profiling T-Cell Responses to Viruses and Donor Selection
Identifying immunodominant viral antigens and selecting targeted donors, using CytokinTM, from whom to generate VSTs specific for these immunodominant viral antigens.
To define a hierarchy of immunodominance, we first analyze the T-cell immune response present in healthy individuals who have naturally controlled a viral infection. To delineate which viral antigens induce the strongest T-cell immune responses we evaluate two parameters: (1) the number of donors whose T cells recognize each of the expressed viral antigens and (2) the strength of the T-cell response induced by each antigen, as measured using functional assays such as production of cytokines. Using these parameters, we can establish a hierarchy of immunodominance and determine which antigens to select for incorporation into our VST manufacturing process. We identify and advance at least two viral antigens in each target virus. This allows us to generate polyclonal VSTs that recognize multiple parts of each of the target viruses, thereby minimizing the risk of virus immune escape with our product candidates.
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Donor Selection—CytokinTM
We next apply our CytokinTM algorithm, as depicted in the figure below, to select the optimal combination of donors from whom to generate VSTs. CytokinTM compares the HLA types of our targeted patient population with a pool of diverse healthy, eligible seropositive donors and identifies a subset of donors, or a mini-bank, that collectively provide greater than 95% of all patients with an appropriate partially HLA-matched VST line. To ensure redundancy and that each patient has multiple VST line options, we build one or more additional mini-banks using the same strategy. In this way, we can assure both breadth and depth of patient coverage with our VST bank.
Figure 7. Implementing the CytokinTM algorithm to efficiently select donors from whom to generate mini-banks of VSTs
Step 2: Rapid and Scalable Off-the-Shelf VST Manufacturing
Applying our patented manufacturing platform to selectively, efficiently and rapidly expand polyclonal VSTs that are cryopreserved and available as an off-the-shelf therapy
To selectively activate and expand VSTs, we stimulate donor peripheral blood mononuclear cells, or PBMCs, with overlapping peptide libraries spanning immunodominant viral target antigens, in cell culture medium supplemented with growth factors for a period of approximately two weeks. During this timeframe, polyclonal VSTs are stimulated and expand while T cells that could potentially react with non-virus-infected patient cells and cause toxicities such as GVHD are deselected. In addition, for each virus we target at least two viral antigens in order to minimize the risk of virus immune escape. Once generated, these VSTs are stably maintained in a cryopreserved state allowing for immediate patient access. Each manufacturing run from an individual donor yields hundreds of product candidate doses.
Our ability to generate allogeneic, off-the-shelf VSTs in a single expansion step allows us to minimize antigen competition and preserve polyclonality. As a result, our polyclonal VSTs are comprised of both helper (CD4+) and cytotoxic (CD8+) virus-specific T cells that recognize multiple parts of each of our target viral antigens, or viral peptides, presented by different HLA alleles. As a result, we can deliver our product candidate to patients based on partial HLA match. The partial HLA match between the allogeneic VST-cell line and infected patient allows the infused T cells to recognize and selectively kill virus-infected cells.
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To facilitate investigational product supply for our clinical trials, we currently manufacture posoleucel and ALVR106 at external cGMP CMOs and leverage a network of cGLP contract testing laboratories. We are also able to leverage ElevateBio’s cell therapy expertise to develop and manufacture VST therapies for clinical trials and commercialization. ElevateBio has established ElevateBio BaseCamp, Inc., or BaseCamp, a centralized cell and gene therapy development and manufacturing facility dedicated to the production of products for its affiliated companies. Therefore, we have also added ElevateBio BaseCamp to our manufacturing network.
Step 3: CytomatchTM and Immediate Patient Access to Our Allogeneic VST Therapy
Rapidly identifying the appropriate VST line for each patient using the CytomatchTM algorithm, ensuring immediate accessibility to therapy for high-risk patients
The final component of our process relates to the clinical use of our allogeneic off-the-shelf VST therapy. The CytomatchTM algorithm guides the selection of the VST cell line for patient treatment. A specific drug product lot is selected for infusion based on the level of HLA matching between patient and associated VST-cell line, with two HLA allele matches set as a minimum threshold. The “best” VST-cell line is rapidly identified and can be immediately packed and shipped to the treatment center, where it can be thawed and infused to patients without the need for additional manipulation.
Our Highly Innovative Allogeneic VST Therapy Candidates
Our pipeline of allogeneic, off-the-shelf VST therapy candidates is designed to restore virus-specific T-cell immunity in patients suffering from, or at risk for, life-threatening viral diseases. Our proprietary VST therapy platform can be used to generate allogeneic cell therapies targeting single or multiple viruses at commercial scale. We own worldwide development and commercialization rights to all our cell therapies.
Figure 8. AlloVir’s pipeline
Posoleucel
Our lead product candidate, posoleucel, is a multi-VST therapy targeting six viral pathogens: AdV, BKV, CMV, EBV, HHV-6 and JCV, which has the potential to fundamentally transform the treatment landscape for immunocompromised individuals.
Our initial focus was to develop posoleucel in immunocompromised HCT and SOT patients who are at high risk for life-threatening viral infections as follows:
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Treatment of virus-associated HC (BKV and/or AdV) in HCT patients
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Treatment of AdV infections in HCT patients
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Prevention of multi-virus infections (AdV, BKV, CMV, EBV, HHV-6 and JCV) in HCT patients
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Treatment of BKV infections in kidney transplant patients
Based on the strength of the posoleucel Phase 2 data for both treatment and prevention, the FDA has granted posoleucel Regenerative Medicine Advanced Therapy (RMAT) designation for three indications – for the treatment of HC caused by BKV, for the treatment of AdV infection in adults and children following allo-HCT, and for the prevention of clinically significant infections and disease caused by posoleucel’s six target viruses. Similarly, based on data generated from the Phase 2 POC treatment trial and the critical medical need, the European Medicines Agency (EMA) has granted posoleucel PRIority Medicines (PRIME) designation for the treatment of serious infections with AdV, BKV, CMV, EBV and HHV-6. Posoleucel was one of the first seven investigational therapies to receive both PRIME and RMAT designations and, to our knowledge, is the only investigational therapy to receive three RMAT designations. While these designations may not lead to a faster development process and do not increase the likelihood that a product candidate will receive approval from the FDA or EMA, we expect that PRIME and RMAT designations will result in increased EMA and FDA interactions to support our development efforts and may enable an expedited regulatory review process. In addition, the FDA also granted posoleucel Orphan Drug Designation for the treatment of virus-associated HC, and the EMA granted Orphan Medicinal Product designation to posoleucel for its targeted viruses in HCT patients, including for the potential prevention of infections or disease by these viruses.
Posoleucel for Allogeneic HCT Patients
HCT conditioning regimens often require the complete elimination of a patient’s own stem cells, a procedure referred to as myeloablation. These patients are left without a functioning immune system and are consequently in a severely immunocompromised state until their donor stem cells take hold, or engraft, and repopulate the bone marrow. During this period, these patients are highly susceptible to infection. We believe that, as depicted in the figure below, our VST therapy candidates can play the key role of providing bridging immunity between myeloablation, where patients have little-to-no immune function of their own, and reconstitution of their immune systems after the donor stem cells engraft and expand to physiologic levels. We believe that by restoring immunity during this time of severe immune compromise, our VST therapy candidates may substantially reduce or prevent virus-associated morbidity and mortality, thereby dramatically improving patient outcomes.
Figure 9. Posoleucel is designed to treat and prevent viral diseases until the patient’s own immune system recovers
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In approximately 90% of allogeneic HCT patients, the suppressed immune system allows viruses that were previously in a latent, quiescent state to reactivate. Furthermore, more than 60% of allogeneic HCT patients experience a reactivation of more than one virus targeted by posoleucel. These viral infections can cause multi-organ disease and multi-organ failure that may be life-threatening and that typically require hospitalization. It is estimated that more than 20% of all deaths associated with HCTs are due to infections. There are currently no FDA- or EMA-approved therapies for treating most viral infections in the post-transplant setting, and current antiviral therapies are associated with significant toxicity, including renal insufficiency and bone marrow suppression.
Posoleucel Phase 2 POC CHARMS Clinical Results in Allogeneic HCT Patients
We evaluated posoleucel in a Phase 2 open-label POC trial where VSTs were administered to 58 allogeneic HCT patients with treatment-refractory infections. We refer to this trial as CHARMS.
The primary objective of CHARMS, which was not statistically powered for superiority or significance, was to determine the feasibility and safety of administering partially HLA-matched multi-VST therapies targeting six viruses in HCT patients with persistent viral reactivations or infections. Patients were eligible following any type of allogeneic transplant if they had AdV, BKV, CMV, EBV, HHV-6 and/or JCV infections that were relapsed, reactivated or persistent despite standard antiviral therapy.
Figure 10. CHARMS—Phase 2, proof-of-concept, open-label trial design
The treatment schedule encompassed an initial single infusion of 2 x 107 partially HLA-matched multi-VSTs/m2. If the patients had a partial response, or a PR, within 28 days of the first infusion, as defined by a 50% or greater fall in viral load, they were eligible to receive up to four additional doses from day 28 after the initial infusion and at two weekly intervals from day 28.
Efficacy endpoints for CHARMS were resolution of the target infections, as measured by viral load, and resolution of clinical signs and symptoms, as determined by the primary investigator. Clinical and virologic responses were assessed by week 6 per protocol and at additional timepoints where feasible. A complete response, or CR, was defined as return of viral load to normal range and resolution of clinical signs and symptoms. A PR was defined as a decrease in viral load of at least 50% from baseline or 50% improvement in clinical signs and symptoms. No response, or NR, was defined as either stable or progressive disease.
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The demographics and clinical characteristics for the 58 unique patients enrolled and treated in the CHARMS trial are presented in Table 1. These patients were infused with posoleucel therapy matched at one to seven HLA alleles. In this clinical trial, we observed the delivery of partially HLA matched VSTs were generally well-tolerated. These final trial results were published in Clinical Cancer Research in January 2023.
Characteristic Number (%)
Sex (N = 58)a
Age (N = 58)a
Pediatric (18 years of age) 18 (31)
Race (N = 58)a
Black or African American 3 (5)
Asian 3 (5)
Evaluable infections treated (N = 70)
Number of infections per patient at study entry (N = 58)a
Number of infusions per patient (N = 58)a
a The CHARMS trial treated 58 unique patients. One patient was enrolled twice, treated first for AdV and then for JCV. This patient was counted twice for some efficacy and once for safety. One patient with HHV-6 was not evaluable for response rate.
Table 1. CHARMS clinical trial patient demographic and clinical characteristics
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Clinical and Virologic Response
Of the 58 unique patients evaluated for efficacy by six weeks post infusion, 55 had a CR or PR, representing a 95% response rate, as depicted in the figure below. Twelve patients were co-infected with at least two different viruses and of these, ten patients (83%) responded to posoleucel by six weeks post-infusion. This demonstrates the potential for treating patients with multiple viral infections with off-the-shelf posoleucel.
Figure 11. Posoleucel Phase 2 proof-of-concept trial (CHARMS): 95% overall response rate in patients with viral disease by 6 weeks in 58 unique patients
In Vivo VST Persistence
In order to provide bridging immunity to HCT patients, allogeneic off-the-shelf VSTs must persist and provide continued antiviral protection until the transplanted stem cells engraft and the patient’s own immune function is restored. To examine how long our posoleucel cells persisted in patients, we examined the peptide epitope specificity of circulating T cells to discriminate between infused and endogenous virus-specific T cells. Of 16 patients that we tested, we were able to confirm the persistence of allogeneic VSTs in 11 patients for up to 12 weeks.
Safety Profile
The overall analysis of preliminary safety results gathered in the CHARMS trial showed that treatment with posoleucel was generally well-tolerated.
Safety monitoring in the CHARMS trial consisted of several assessments, including assessments of both GVHD and serious adverse events, or SAEs, as reflected in the table below. Overall, 23 deaths occurred during the study; none of these deaths was deemed related to study treatment. Of the 23 deaths, 6 were associated with treatment-emergent AEs (TEAEs), and 5 deaths occurred during the protocol-specified AE reporting period. Treatment-related TEAEs ≥ Grade 3 occurred in 8 (13.8%) participants, however there were no TEAEs leading to interruption or discontinuation of study intervention, there were no dose-limiting toxicities, and no deaths were attributed to treatment-related TEAEs.
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In general, safety findings were consistent with those expected in an allogeneic HCT patient population with persistent and/or refractory viral infections, including the known risks of GVHD. To date, no overt safety signal has been detected above and beyond the safety findings expected to be found in patients who have already undergone allogeneic HCT.
Table 2. Serious adverse events and GVHD in the CHARMS trial
Treatment of Virus-Associated Hemorrhagic Cystitis
HC is the primary clinical manifestation associated with BKV following HCT, occurring in 8-25% and 7-54% of pediatric and adult patients, respectively. HC can also be caused by other viruses, including AdV and CMV. However, up to 90% of cases of HC are caused by BKV.
Between 65-90% of individuals are infected with BKV by the age of ten. Most infections are asymptomatic, but the virus remains latent in the body, primarily in kidney cells throughout life. BKV can reactivate during periods of immune compromise with the virus being detected in the urine of over half of HCT patients.
More than half of patients with HC present with clot formation and/or severe bladder hemorrhage with renal impairment. Bleeding may be life-threatening requiring urologic interventions including the removal of the urinary bladder, or cystectomy. Clinical manifestations of HC include kidney dysfunction or failure, bright red-colored urine due to the presence of blood in the urine, as well as abdominal pain so severe and debilitating that patients often require continuous narcotic infusions.
A recent, prospective, multi-center trial of the natural history of BKV after allogeneic HCT in 193 patients found that:
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22% of patients developed grade 2 or higher HC, and 18% had a high level of BK viremia ( 10,000 copies/mL) in the first three months post-HCT;
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Patients with a high level of BK viremia in the first three months after transplant had a significantly lower estimated glomerular filtration rate, or eGFR, at 12 and 24 months (on average 20mL/min/m2 lower by two years after transplant) and a 6-fold higher risk of receiving dialysis (p=0.004);
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Patients with high levels of BK viremia have been found to have significant reduction in kidney function (17-26% below baseline) as compared to patients with low levels of BK viremia (4-5% below baseline). Additionally, 18% of patients with high levels of BK viremia required dialysis, compared with 3% of patients with low levels of BK viremia;
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A high level of BK viremia was associated with a significantly higher risk of death;
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Virus-associated HC has been associated with increased mortality, with patients with high levels of BK viremia experiencing mortality rates of 44%, compared with 19% in patients with low levels of BK viremia;
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Asymptomatic viremia was common and associated with decreased kidney function, and;
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Patients with detectable BKV-specific T cells were 5-fold more likely to clear viremia, but patients who received off-label cidofovir were not.
There are currently no FDA- or EMA-approved therapies for virus-associated HC. The current standard of care relies on supportive care to address the symptoms and manifestations of HC; urinary bladder irrigation to avoid its obstruction by blood clots; narcotics to alleviate suffering; hyperbaric oxygen therapy; cystectomy in uncontrollable bleeding cases; and dialysis for acute renal failure. The antiviral cidofovir is sometimes used off-label to treat virus-associated HC. However, cidofovir has been associated with kidney toxicity, which may compound the kidney damage caused by virus-associated HC itself.
Posoleucel Clinical Data—BKV
In our Phase 2 proof-of-concept trial for posoleucel, we treated 27 evaluable patients with BKV disease and 100% achieved an overall response by six weeks post-infusion. Overall response rates were defined as achieving either a PR or CR by six weeks post-infusion, as described in the protocol criteria.
In 23 patients infused with posoleucel, HC severity was retrospectively graded using the National Cancer Institute cystitis grading scale. This was performed by three physicians independently based on chart review of clinical and laboratory documentation. These patients treated with posoleucel therapy showed a rapid improvement in disease severity; complete resolution of macroscopic hematuria was observed in 43%, 61% and 74% of patients weeks 2, 4 and 6 post-infusion.
Figure 12. Time to resolution of BKV-HC following treatment with posoleucel
In a retrospective study conducted at BCM, out of 33 pediatric allogeneic HCT patients with an average of Grade 3 BK-HC receiving current standard of care, only 36% had resolved their disease by week 6. Furthermore, less than 10% of the patients had resolved their disease by week 2.
We believe our data provide preliminary evidence demonstrating that posoleucel has the potential to meet unmet medical needs in allogeneic HCT patients with virus-associated HC.
Clinical Development Plan
We initiated a multicenter, randomized, double-blind, placebo-controlled Phase 3 trial to assess the safety and efficacy of posoleucel therapy compared to placebo for the treatment of patients with virus-associated HC following allogeneic HCT. The primary
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endpoint was the time to resolution of macroscopic hematuria. As these HCT patients often experience multiple viral infections, secondary endpoints included the reduction in viral load for AdV, CMV, EBV, HHV-6 and JCV.
Figure 13. Phase 3, multicenter, randomized, double-blind, placebo-controlled virus-associated HC trial design
In December 2023 the DSMB monitoring the trial met and recommended stopping the trial due futility because the interim data reviewed suggested the trial was unlikely to meet its primary endpoint. As such, we discontinued the trial and have stopped all clinical development of posoleucel for the treatment of virus-associated HC.
Treatment of Adenovirus Infections
AdV viremia occurs in 32% of pediatric allogeneic HCT patients and 6% of adult allogeneic HCT patients. In the HCT setting, patients can present with AdV disease due either to reactivation or de novo exposure. Infection usually occurs between two and three months post-transplant and is a significant cause of morbidity and mortality. The spectrum of AdV-associated disease in HCT patients ranges from mild gastroenteric or respiratory symptoms to severe hemorrhagic enteritis, hemorrhagic cystitis, nephritis, hepatitis, pneumonia, encephalitis, myocarditis, and potentially lethal multiple organ involvement, frequently associated with hepatic failure. Off-label use of cidofovir has been established as the current standard of care treatment to control the replication of virus and prevent disseminated viremia. However, it has limited efficacy irrespective of dose and its use is limited due to toxicity to the kidneys and poor bioavailability. To date, no adequately powered, randomized well-controlled trials demonstrating significant efficacy of cidofovir use for adenoviral disease versus control have been performed.
Posoleucel Clinical Data—AdV
In our CHARMS trial, 83% of patients with AdV infection achieved a response by six weeks post-infusion.
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Clinical Development Plan
We initiated a multicenter, randomized, double-blind, placebo-controlled Phase 3 trial to assess the safety and efficacy of posoleucel therapy for the treatment of pediatric and adult allogeneic HCT patients with AdV infection at the end of 2021.
Figure 14. Phase 3, randomized, double-blind, placebo-controlled adenovirus treatment trial design
In December 2023, the DSMB monitoring the trial met and recommended stopping the trial due futility because the interim data reviewed suggested the trial was unlikely to meet its primary endpoint. As such, we discontinued the trial and have stopped all clinical development of posoleucel for the treatment of AdV.
Prevention of Multi-Virus Infection and Associated Disease in HCT Patients
Approximately 90% of all allogeneic HCT patients experience at least one infection associated with BKV, CMV, AdV, EBV or HHV-6 and more than 60% of patients experience infections caused by two or more of these five viruses within 100 days post-allogeneic HCT. Because of the increased morbidity and mortality associated with viral infections in transplant patients, prevention of viral disease is important for the overall health and survival of patients. Prophylactic therapy, which is a treatment administered to patients at risk for developing viral disease, and preemptive therapy, a treatment of patients with evidence of virus replication in blood, are the two major strategies used for disease prevention. Clinical guidelines recommend that allogeneic HCT patients infected with CMV or AdV should be monitored weekly for virus replication with a sensitive diagnostic technique for at least the first three months after HCT. There are currently no FDA- or EMA-approved antiviral therapies for prevention of multiple viral diseases or infections in transplant patients with one single therapy. For CMV alone, letermovir is approved for CMV in seropositive patients. However, drug resistant CMV has emerged with the use of letermovir, which may limit or restrict its utility.
Posoleucel Clinical Data—Multi-Virus Prevention in HCT Patients
Out of 26 high-risk allo-HCT patients who received posoleucel in this open-label study, 22 (85%) patients experienced reactivation of at least one of posoleucel’s target viruses. Despite these expected high rates of viral reactivation, only three clinically significant infections were observed through Week 14. These results represent a substantial reduction in the expected rate of clinically significant viral infections or diseases in this high-risk patient population. Biomarker analyses demonstrated that viral control was associated with expansion of functional VSTs, and the presence of posoleucel was confirmed both during the infusion period and up to 14 weeks after
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the last infusion.
Treatment with up to seven doses of posoleucel over 12 weeks was generally well tolerated with no unanticipated safety signals. Rates of GVHD were similar in frequency and severity to those expected in this high-risk allo-HCT population. Three (12%) treatment-related serious adverse events were reported. No episodes of cytokine release syndrome were reported.
Clinical Development Plan
Based on preliminary data from the open-label, Phase 2 POC study for multi-virus prevention, we initiated a global, registrational Phase 3 multicenter, randomized, double-blind, placebo-controlled clinical trial of posoleucel for multi-virus prevention.
Figure 15. Phase 3, randomized, double-blind, placebo-controlled multi-virus prevention trial design
In December 2023, the DSMB monitoring the trial met and recommended stopping the trial due futility because the interim data reviewed suggested the trial was unlikely to meet its primary endpoint of the number of clinically significant infections or episodes of end organ disease through week 14. As such, we discontinued the trial and have stopped all clinical development of posoleucel for the prevention of viral infection and disease.
Treatment of BKV Infections in Kidney Transplant Patients
BK virus reactivation in KT patients is due to T-cell immune deficiencies caused by intensive immunosuppressive induction therapy followed by maintenance immunosuppressive treatment. BKV reactivation causes interstitial nephritis and progressive allograft injury. Routine screening for BKV reactivation after transplantation has been widely recommended and is performed at most transplant centers. The goal of diagnosing and managing BK viremia early in the course of active infection is to prevent allograft failure that is associated with BKV-associated nephropathy. BK viremia is detected in up to 20% of KT patients and up to 50% of patients with BK viremia progresses to BK nephropathy, resulting in decreased graft function and graft survival. Nearly half of all patients who develop BK nephropathy experience allograft failure. Because KT patients remain on immunosuppression for life, BK viremia and BK nephropathy onset is not restricted to the first year post-transplant. There are currently no FDA- or EMA-approved therapies for the treatment of BK viremia or BK nephropathy in KT patients. Treatment primarily involves reduction of immunosuppression. However, this results in patients being at increased risk of immune mediated acute allograft rejection.
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Posoleucel Clinical Data— BKV Treatment in Kidney Transplant Patients
In February 2023, we announced positive data from a proof-of-concept, multi-center, randomized, double-blind, placebo-controlled, Phase 2 trial evaluating posoleucel for the treatment of BKV in KT patients.
Figure 16. Phase 2, randomized, double-blind, placebo-controlled BK virus treatment in kidney transplant trial design
The primary endpoint of the posoleucel Phase 2 BKV treatment study in kidney transplant patients with BK viremia was the safety and tolerability of posoleucel versus placebo. Posoleucel was generally well tolerated in the study, with balanced safety across posoleucel dosing groups and placebo, and adverse events rates and severity consistent with the underlying patient population and background immunosuppression. Low rates of infusion reactions were observed in patients receiving posoleucel (2%) and those receiving placebo (5%). There were no deaths or reports of graft versus host disease or cytokine release syndrome. Emergence of donor-specific antibodies was uncommon and occurred with similar frequency in patients receiving posoleucel (7%) or placebo (5%). Three patients who received posoleucel were reported to have acute rejection per biopsy report by a central reader; none of these cases were assessed by the investigator as related to study drug.
The key secondary endpoint of the study was the change in BK viral load in patients receiving posoleucel versus those receiving placebo. The efficacy analysis excluded six patients in whom significant reductions in immunosuppression were made immediately prior to study entry. Posoleucel achieved greater viral load reductions versus placebo across all BK viral load measures. Antiviral responses among posoleucel patients increased over time, with maximal responses observed at Week 24. This clinically meaningful treatment effect was strongest among patients receiving posoleucel every two weeks and among those with high viral loads at study screening.
Clinical Development Plan
The topline data described above will inform next steps for this potential indication as well as a broader strategy in solid organ transplant patients.
Prevention of Multi-Virus Infection and Associated Disease in SOT Patients
Similar to HCT patients, the prevention of viral disease in SOT patients is important for both graft survival and the overall health and survival of patients. Published clinical guidelines recommend that all high and intermediate risk SOT patients, which account for nearly 90% of all SOT patients, should receive prophylactic therapy for CMV, which is only one of six viruses that posoleucel targets.
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There are currently no FDA- or EMA-approved antiviral therapies for prevention of multiple viral diseases or infections in SOT patients with one single therapy. Learnings from our discontinued multi-virus prevention study in allogeneic HCT patients and our Phase 2 study of kidney transplant patients with BK viremia will inform the potential for a POC study of posoleucel for multi-virus prevention in SOT patients.
Other Viruses Targeted by Posoleucel
Epstein-Barr Virus
Epstein-Barr virus is a latent herpesvirus that infects more than 90% of humans worldwide and establishes life-long latency after primary infection. During a primary infection, an immunocompetent host will mount vigorous CD4+ and CD8+ cellular immune responses and these T cells control both the primary infection and any periodic EBV reactivations. However, EBV reactivation can cause significant morbidity and mortality in immunocompromised patients and uncontrolled EBV reactivation can lead to fulminant viremia and progress to life-threatening post-transplantation lymphoproliferative disorder, or PTLD.
PTLD can occur at any age and after all types of transplants, though allogeneic HCT patients are at particular risk. The median time to development of EBV-associated PTLD, or EBV-PTLD, after HCT is two to four months. Fever and lymphadenopathy are the most common symptoms and signs of EBV-PTLD and, if not treated, PTLD generally progresses rapidly to multi-organ failure and death. Off-label rituximab has been used to treat EBV-PTLD. However, response to rituximab is not universal and mortality remains high in rituximab-refractory patients. In December 2022, tabelecleucel received marketing authorization in Europe to treat patients with relapsed or refractory EBV-PTLD who have received at least one prior therapy; the cell therapy has not been approved in other regions at this time.
In our CHARMS trial, two evaluable patients with EBV infections were treated with posoleucel; the overall response rate to EBV by six weeks post-infusion was 100%.
Human Herpesvirus Type 6
There are two variants of HHV-6: HHV-6A and HHV-6B, both infect and establish latency in different cell types including CD4+ T lymphocytes, monocytes, and other epithelial, fibroblastic and neuronal cells. No disease has been causally linked to HHV-6A, and its natural history is unknown. In contrast, HHV-6B primary infection is ubiquitous in the first two years of life, sometimes causing exanthema subitum (also known as roseola infantum and sixth disease). Subsequent viral latency gives the potential for reactivation and disease.
HHV-6 reactivation is the most frequent cause of encephalitis after HCT. Disease onset is typically two to six weeks post-transplant. Initial signs and symptoms include confusion, delirium, short-term memory loss, syndrome of inappropriate antidiuretic hormone secretion and seizures. Long-term outcomes can result in brain damage, memory defects and death. HHV-6 is also associated with delayed engraftment, allograft failure, acute GVHD and CMV reactivation. There are currently no FDA-approved treatments for HHV-6. The use of off-label antivirals is limited by several factors. Ganciclovir is associated with dose-limiting bone marrow toxicity which may delay HCT engraftment, cidofovir is associated with kidney toxicity and foscarnet is also associated with kidney toxicity, as well as the risks of infection and deep vein clots stemming from its required route of administration.
In our CHARMS trial, three evaluable patients with HHV-6 infections were treated with posoleucel; the overall response rate by six weeks post-infusion was 100% (3/3). One additional patient was found to have chromosomal integration of HHV-6 and was excluded from the efficacy analyses.
ALVR106: VST Therapy for the Treatment of Patients with Respiratory Viruses
Acute respiratory tract infections due to respiratory viruses including RSV, influenza, PIV, hMPV and coronaviruses such as SARS-CoV-2, the virus that causes COVID-19, are a major public health concern. For example, RSV-induced bronchiolitis is the most common reason for hospital admission in children less than one year of age. The lack of approved antiviral agents to treat many respiratory viruses underscores the need for alternative treatment and prevention strategies.
ALVR106 is an allogeneic, off-the-shelf VST therapy designed to treat or prevent four common respiratory viruses, RSV, influenza, PIV, and hMPV. A Phase 1/2 proof of concept clinical trial of ALVR106 to target severe respiratory diseases in high-risk populations was initiated in 2022. Part A of the trial has now completed enrollment, but we have discontinued this trial pending the outcome of our review of strategic alternatives.
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Figure 17. Consequences to high-risk patients with respiratory virus infections
Preclinical Data
As illustrated below, our preclinical in vitro data demonstrates that ALVR106 can be reproducibly generated from healthy seropositive donors and reactive cells have potent antiviral activity against each of the target viruses. Additionally, these cells do not target non-virus-infected autologous or allogeneic cells. We believe this data supports the potential for antiviral benefit and safety of ALVR106 when administered to patients.
Figure 18. ALVR106 has selective antiviral activity against target viruses, leaving non-virus infected targets intact
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Respiratory Virus Infections in HCT Patients
Respiratory tract infections due to RSV, influenza, PIV and hMPV, are detected in up to 40% of allogeneic HCT patients. In approximately half of these patients, these viral infections progress from less serious upper respiratory tract infections, with symptoms similar to those of a common cold, to far more serious lower respiratory tract infections, with severe symptoms including pneumonia and bronchiolitis. These more serious infections are associated with mortality rates between 20-45%.
RSV
RSV is a common infectious complication of transplantation, with an incidence of up to 12% in HCT patients. In immunocompetent adults, infections from RSV typically result in upper respiratory tract infections characterized by cough, fever and runny nose. However, in approximately two-thirds of infected HCT patients, an RSV infection develops into a lower respiratory tract infection characterized by severe symptoms including pneumonia and bronchiolitis. These infections are associated with morbidity and mortality rates of up to 28%. Therapy for RSV infections in HCT patients consists primarily of supportive care. Aerosolized ribavirin, or RBV, is FDA-approved for the treatment of RSV but is logistically difficult to administer, as it requires a specialized nebulization device that connects to an aerosol tent surrounding the patient.
Influenza
Influenza infections have been found in up to 46% of allogeneic HCT patients. Approximately 20% of HCT patients with influenza infections progress to develop pneumonia which has been associated with a 30-day mortality rate of 28%. Influenza infections are a major cause of morbidity and mortality in individuals who have weakened immune systems, the elderly and patients with chronic diseases. While there are preventative vaccines for influenza, they are only partially effective in HCT patients. Available antiviral drugs are associated with the development of drug resistance at high rates in HCT patients.
PIV
PIV primarily affects young children and can cause upper respiratory tract infections and lower respiratory tract infections including conditions such as the common cold, croup, bronchitis, bronchiolitis and pneumonia. In immunocompetent individuals the course of these infections is limited due to antiviral responses from both the innate and adaptive immune systems. Up to 18% of immunocompromised HCT patients develop PIV infections, which can lead to decreased lung function, multiorgan failure and graft loss. Mortality rates of HCT patients with PIV infections can be as high as 60%. There are currently no FDA- or EMA-approved vaccines or treatments for PIV infections.
hMPV
Between 5-9% of HCT patients develop hMPV infections. hMPV is a ubiquitous virus to which nearly the entire population globally has been exposed by age five. In the majority of cases, hMPV results in upper respiratory infections with symptoms similar to that of the common cold. In 21-40% of hMPV infections in HCT patients, however, the viral infection progresses from a mild upper respiratory disease to a serious lower respiratory disease that is associated with fatality rates of up to 80%. There are currently no FDA- or EMA-approved therapies or vaccines for hMPV.
Clinical Development Plan
A Phase 1/2 clinical trial of posoleucel in autologous and allogeneic HCT patients with respiratory viral diseases was initiated in 2022. This proof of concept trial was designed as a Phase 1/2, double-blind, placebo-controlled, dose escalation and expansion trial of ALVR106 in addition to standard of care to assess safety and efficacy of ALVR106. Part A of the trial has now completed enrollment, but we have paused development of ALVR106, including discontinuing the trial pending the outcome of our review of strategic alternatives.
Respiratory Virus Infections in High-risk Populations: Elderly, Young, Cancer Patients
In developed countries, there are well-defined high-risk populations in whom RSV infection is more likely to progress into a severe lower respiratory tract infection, including infants less than three months of age or born prematurely, the elderly and immunosuppressed patients. In children, bronchiolitis and pneumonia are the most common clinical manifestations. RSV is responsible for between approximately 66,000 and 199,000 deaths each year. In adults, RSV infections develop annually in 3-7% of elderly individuals and in 4-10% of high-risk adults, where they can cause pneumonia and bronchitis and may lead to death. Importantly, previous infection does not confer immunity. To date, there is no FDA- or EMA-approved vaccine and no clear evidence that treatment with antiviral agents or anti-inflammatory agents reduces the length of infection or the duration of hospital stay in any population. A neutralizing monoclonal antibody, palivizumab, has been developed as immunoprophylaxis to prevent RSV infection; however, its use is limited to high-risk infants because evidence of its effectiveness is limited in broader patient populations.
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Influenza
Influenza virus infection causes substantial morbidity and mortality. The World Health Organization, or WHO, estimates that annual epidemics cause 3-5 million cases of severe illness worldwide, and influenza-associated respiratory deaths are estimated to be between approximately 290,000 and 650,000 persons annually. Of these, the highest mortality rates are observed in people aged 75 years and older (51.3 to 99.4 individuals per 100,000). The overall rate of respiratory-associated deaths is also relatively high in patients less than five years of age (2.1 to 23.8 per 100,000). These events occur despite the availability of vaccines and antiviral therapies for influenza. A recent study in the United States demonstrated that vaccination was only 38% effective for influenza A or B viral infections. In the event of infection, patients may be treated with neuraminidase inhibitors, such as oseltamivir and zanamivir. However, not only must these antivirals be administered early in the disease course, they may induce resistance to the influenza virus.
PIV
PIV is among the most common respiratory tract infection worldwide and is associated with both upper and lower respiratory tract infections in both children and adults. Progression from upper to lower respiratory tract infection is most common in children less than five years old and in immunocompromised adults, including the elderly and those with hematologic malignancies. In children, seasonal epidemics account for 40% of hospitalizations for lower respiratory tract illness and 75% of croup cases. Overall, 7% of pediatric hospitalizations for febrile respiratory illness in children less than 5 years old are due to PIV. The estimated annual cost of pediatric hospitalization and emergency room visits due to PIV is greater than $200 million, according to a 2016 study. PIV accounts for 15% of respiratory illness in adults and most commonly manifests as upper respiratory tract infections or pneumonia. Approximately 2.0-11.5% of adult hospitalizations for respiratory illnesses are due to PIV. Currently there are no FDA- or EMA-approved vaccines or antiviral therapies for PIV, and treatment of infection consists of supportive care.
hMPV
Similar to other respiratory pathogens, hMPV causes both upper and lower respiratory tract infections with the most severe disease observed in infants, young children, the elderly, and immunocompromised patients. The most common diagnoses associated with hMPV are bronchiolitis and pneumonia. Studies in children either in the hospital or seen in the outpatient setting show that hMPV is associated with between 6% and 40% of acute respiratory illness. Similar to other respiratory viruses, exposure does not confer immunity, and despite almost all people having been infected with hMPV by age five, re-infection occurs throughout adulthood and is associated with morbidity and mortality in the elderly population. In one study, 46% of hMPV cases were seen in patients greater than 65 years of age and 60% of these patients were hospitalized. In a separate study in an elderly care center, 50% of infected patients developed bronchitis or pneumonia, which led to 50% mortality. Currently there are no FDA- or EMA-approved vaccines or antiviral therapies for hMPV, and treatment of infection consists of supportive care.
Clinical Development Plan
We have paused clinical development of ALVR106, which includes discontinuing the trial pending the outcome of our review of strategic alternatives.
Commercial Opportunity
ALVR106 is an allogeneic, off-the-shelf VST therapy candidate designed to target four common respiratory viruses that represent important causes of morbidity and mortality in HCT and SOT patients, as well as other high-risk patient populations.
ALVR106 for Transplant Patients
In HCT patients, respiratory viral infections occur in both allogeneic HCT and autologous HCT patients. Respiratory viruses infect patients both within the first year post-transplant and beyond. Our target population for ALVR106 includes patients who have undergone allogeneic and autologous HCTs and who have lower respiratory tract infections and upper respiratory tract infections at medium or high risk of progressing to lower respiratory tract infections.
We project the number of allogeneic and autologous HCT procedures to grow 3% annually to approximately 42,000 and 51,000 procedures annually, respectively, by 2025 in our target markets in North America, Europe, Asia Pacific and Latin America. By 2025, we estimate there will be nearly 16,000 HCT patients annually infected with one of the four respiratory viruses targeted by ALVR106. We believe that ALVR106 will be effective for treating infections in HCT patients with one or more of the targeted respiratory viruses.
Respiratory viruses can infect patients of all types of SOTs, although the majority of the literature describes devastating consequences in lung transplant patients. Our initial target population will include lung transplant patients hospitalized for respiratory viruses.
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We project the number of new lung transplants to grow 2% annually to approximately 7,000 new lung transplants annually by 2025 in our target markets. We estimate the size of the prevalent lung transplant population to be nearly 56,000 patients in our target markets. By 2025, we estimate that there are annually over 12,000 lung transplant patients that are infected with one of the four respiratory viruses targeted by ALVR106.
ALVR106 for High-risk Populations: Elderly, Young, Cancer Patients
We believe transplant patients represent only a small fraction of the large number of patients suffering from devastating respiratory infections who could potentially benefit from ALVR106. Other individuals with weakened immune systems, including those with primary immunodeficiencies, the elderly and very young and patients who have compromised immune systems due to cancer or the treatment of their cancer are all at high risk of the severe consequences of respiratory infections. Each of these target patient populations represents a large potential market that is currently untapped or underserved by existing therapies.
ALVR107: VST Therapy for the Treatment of Hepatitis B Virus
Hepatitis B Virus
The global prevalence of HBV has been estimated to be between 292 and 360 million people with approximately 260 million people living with chronic HBV infection. HBV is most common in the Western Pacific and African regions, where approximately 6% of the adult population is infected. In contrast, only approximately 1.6% and 0.7% of the European and Americas regions, respectively, are infected. About 30% of patients with chronic HBV develop liver cirrhosis, and nearly 23% of these die within five years of developing cirrhosis.
Current treatment options for chronic HBV consist of life-long antiviral therapy to suppress virus replication. This can slow the progression of liver cirrhosis and reduce the incidence of liver cancer. However, there are no curative therapies available.
Chronic HBV infection is associated not only with significant morbidity and mortality as noted above, but also with weak or absent endogenous HBV-specific T-cell reactivity. In contrast, clinical recovery and effective antiviral therapy are associated with sustained viral control by HBV-specific T cells. Therefore, an off-the-shelf VST therapy that could cure HBV would meet a critical unmet medical need.
POC for the potential of adoptive T cell therapy to achieve functional HBV cure has already been established. A Taiwanese study published in Blood in 2005 demonstrated that 65% of chronic hepatitis B patients who underwent allogeneic HCT transplantation and received cells from a donor with natural HBV immunity, achieved functional HBV cure post-transplant.
ALVR107
ALVR107 is an allogeneic, off-the-shelf VST therapy designed to cure patients with HBV. ALVR107 is comprised of a bank of VSTs manufactured from eligible third-party healthy donors who are pre-screened for infectious agents and disease risk factors. These donors are chosen to reflect and accommodate the HLA diversity of the patient population.
Clinical Development Plan
Preclinical and IND-enabling studies of ALVR107 to treat and cure HBV were completed in 2022 to support advancement into a POC study. Clinical development of ALVR107 is currently paused pending the outcome of our review of strategic alternatives.
Competition
The biopharmaceutical industry is characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe that our innovative and proprietary technology, the expertise of our executive and scientific team, and our access to cell therapy process development and manufacturing expertise at ElevateBio and BaseCamp provide us with competitive advantages, we face potential competition from many different sources, including pharmaceutical and biotechnology companies, academic institutions and public and private research institutions. VST therapies that we successfully develop and intend to commercialize may compete with existing therapies and new therapies that may become available in the future.
Many of our competitors, either alone or with their collaborators, may have a more established presence in the market and significantly greater financial, technical and human resources than we have. The competitors also compete with us in recruiting and retaining qualified scientific, sales, marketing and management personnel. Smaller or early-stage companies may also prove to be significant competitors through collaborative arrangements with large and established companies.
Our commercial potential could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, or are less expensive than any products that we may develop. Our competitors
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may also obtain FDA or other regulatory approval for their products faster than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market or make our development more complicated.
If approved, our VST therapies would compete with cell therapies and antivirals used to treat and prevent the viral diseases our VST therapies target.
Cell Therapies
There are currently no FDA-approved cell therapies for treating or preventing the viral diseases and infections we are targeting. Atara Biotherapeutics, Inc.’s EbvalloTM (tabelecleucel), an off-the-shelf, allogeneic T-cell immunotherapy, for HCT and SOT patients with EBV+PTLD (EBV-associated post-transplant lymphoproliferative disease), received European marketing authorization in December 2022.
Antivirals
There are currently no FDA or EMA-approved antiviral therapies for treating most viral diseases and infections in the post-transplant setting, and current antiviral therapies are associated with significant toxicity, including renal insufficiency and bone marrow suppression. Despite the availability of antivirals for some of the viral diseases we are targeting, patients continue to experience high levels of morbidity and mortality. Additionally, the effectiveness of these antivirals is limited due to the emergence of drug resistance. Similarly, there are limitations to prophylactic approaches, such as vaccines, which may not work well in immunosuppressed patients, the elderly, and the very young who are unable to mount an effective immune response. The antiviral therapies currently available for the indications we are targeting with our allogeneic, off-the-shelf VST therapy candidates are listed below. Unless otherwise noted, there are no antiviral therapies approved by the FDA for the treatment or prevention of the viral diseases we are targeting:
Posoleucel: With the exception of valganciclovir, ganciclovir and letermovir for the prevention of CMV disease, and maribavir for the treatment of refractory CMV infection/disease, there are no products FDA-approved for the treatment of AdV, EBV, BKV, HHV-6, or CMV infections or their consequent diseases in allogeneic HCT or SOT patients. Furthermore, there are currently no FDA- or EMA-approved antiviral therapies for the prevention of multiple-viral diseases or infections in transplant patients. Cidofovir is sometimes used off-label for the treatment of BKV-associated HC and AdV infections in HCT patients. Additionally, Vera Therapeutics has completed a Phase 2 clinical trial for MAU868 for the treatment of BKV in KT patients and is exploring the development of MAU868 for the treatment of BKV cystitis in HCT recipients. Memo Therapeutics’ AntiBKV, a therapeutic antibody candidate, is in Phase 2 development for the treatment of BKV infection in renal transplant patients. Helocyte, Inc. is conducting Phase 2 clinical trials of its Triplex vaccine to control CMV infections in HCT patients. Rituximab, an approved antiviral treatment for rheumatoid arthritis and B-cell non-Hodgkin’s lymphoma, is used off-label for the treatment of EBV infections in HCT and SOT patients. Brincidofovir, a lipid conjugate of cidofovir, is in clinical development by SymBio Pharmaceuticals for the treatment of adenoviral disease after allogeneic HCT. AiCuris has in early development AIC468 to prevent BK viral infection in transplanted kidneys. Finally, intravenous immunoglobulin (IVIG) has been explored for the prevention and treatment of BKV associated nephropathy in renal transplant patients, but not in HCT patients. Even in renal transplant patients, there is limited efficacy data for IVIG to support routine use.
ALVR106: The FDA has approved two vaccines for the prevention of lower respiratory tract disease caused by RSV in individuals 60 and older: Arexvy and Abrysvo. The FDA has approved ribavirin (aerosol) to treat RSV infections in children and pavilizumab to treat RSV infections in children younger than two years old. Ribavirin is also used off-label for the treatment or prevention of RSV infections in HCT and SOT patients and PIV infections and hMPV infections in HCT patients. The FDA has approved the monoclonal antibody Beyfortus (nirsevimab) to treat RSV infections in immunocompromised children. Certain approved antiviral medications, including oseltamivir, zanamivir, baloxavir and peramivir, are used to treat influenza infections in HCT and SOT patients. Ansun BioPharma, or Ansun, is conducting Phase 3 clinical trials of DAS181 to treat influenza infections. Several vaccines are FDA-approved and in clinical development for the prevention of influenza infections. Ansun is also conducting Phase 3 clinical studies of DAS181 to treat PIV infections in immunocompromised patients.
ALVR107: There are numerous antiviral therapies approved by the FDA and in clinical development for the treatment of chronic HBV infections. However, these current treatment options for chronic HBV consist of life-long antiviral therapy to suppress virus replication. This can slow the progression of liver cirrhosis and reduce the incidence of liver cancer, but there are no curative therapies available.
Intellectual Property
Our intellectual property is critical to our business and we strive to protect it, including by obtaining, maintaining, defending, and enforcing patent protection in the United States and internationally for our proprietary technology, improvements, platforms, product candidates and components thereof, novel biological discoveries, new therapeutic approaches and potential indications, and other inventions that are important to our business. For our product candidates, generally we initially pursue patent protection covering compositions of matter, methods of production, and methods of use. Throughout the development of our product candidates, we will
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seek to identify additional means of obtaining patent protection that would potentially enhance commercial success, including through additional pharmaceutical formulations, methods of use and production.
As of January 18, 2024, our patent portfolio includes ten patent families exclusively in-licensed from Baylor College of Medicine, or BCM, in our field (one of which is co-owned by AlloVir) and one patent family wholly owned by us. These families include issued and pending patents related generally to allogeneic, off-the-shelf, single and multi-VST cell therapies, and specifically to posoleucel, ALVR106 and ALVR109, various potential preclinical product candidates including ALVR107 and ALVR108, and clinical and backup processes for generating VST-cell products and banks. Specifically, we wholly own two pending PCT applications and exclusively in-license at least five issued U.S. patents, 57 patents issued in foreign jurisdictions, and 87 patent applications pending worldwide. Our issued patents are expected to expire between 2030 and 2036, and any patents that may issue from our pending patent applications are expected to expire between 2030 and 2043, absent any patent term adjustments or extensions. As to the patent term extension to restore patent term lost during product development and the FDA regulatory review process, the restoration period cannot be longer than five years and the total patent term including the restoration period must not exceed 14 years following FDA approval.
Our portfolio related to posoleucel includes two patent families exclusively in-licensed from BCM, directed to multi-VST compositions and methods of making and using such compositions therapeutically. The first family includes two issued U.S. patents with claims directed to our clinical and backup methods of making multi-VST cell lines and related patent applications are pending in the U.S. and Europe. Patents in this family are expected to expire in 2030, absent any patent term adjustments or extensions. The second family includes one issued U.S. patent with claims directed to methods of making posoleucel, one issued European patent with claims directed to methods of making multi-VST compositions including posoleucel and ALVR106, and a second issued European patent with claims directed to compositions of multi-VST compositions including posoleucel and ALVR106, made via such methods. The first European patent is validated in 19 European states, and the second in 21 European States, each including Denmark, France, Germany, Spain and the UK. Related patent applications are pending in the U.S. and in Europe. Patents in this family are expected to expire in 2033, absent any patent term adjustments or extensions as noted above. Our portfolio related to posoleucel also includes one patent family wholly owned by us with two pending PCT applications directed to doses and dosing regimens for treating BK viremia and BK disease in subjects, including solid organ transplant patients using VST compositions such as posoleucel. As part of our alternative strategic direction, we are still assessing whether we will proceed with nationalizing and prosecuting these PCT applications. However, if we do, patents in this family are expected to expire between 2042 and 2043, absent any patent term adjustments or extensions.
Our portfolio related to our ALVR106 product candidate includes the two patent families discussed above with respect to posoleucel as well as a patent family directed to the ALVR106 product and methods of making and using the same therapeutically. This patent family includes one U.S. pending patent application and pending patent applications in Australia, Canada, Europe, and Japan. Any patents that may issue from this patent application are expected to expire in 2040, absent any patent term adjustments or extensions. Additionally, our portfolio related to our ALVR106 product candidate includes a patent family with one allowed U.S. patent application and other applications pending in ex-U.S. jurisdictions with claims directed to VSTs targeting ALVR106 antigens hMPV and PIV. The U.S. patent, once issued, and any patents that may issue from the pending patent applications are expected to expire in 2036, absent any patent term adjustments or extensions.
Our portfolio licensed from BCM also includes a patent family related to our ALVR109 product candidate and methods of treating COVID-19 and other coronavirus infections using the same. This patent family includes one U.S. pending patent application, and 1 pending patent applications in Europe. Any patents that may issue from the patent applications in this family are expected to expire in 2041, absent any patent term adjustments or extensions.
Our portfolio licensed from BCM also includes one patent family related to VST compositions, including our ALVR107 and ALVR108 product candidates, and methods of making and using the same therapeutically. This patent family includes one pending PCT application, and one pending application in Taiwan. Any patents that may issue from the patent applications in this family are expected to expire in 2042, absent any patent term adjustments or extensions.
Our portfolio further includes other patent families related to our VST technologies. For example, our portfolio includes one patent family that includes one pending patent application in each of the U.S. and Europe related to our process of selecting donors for VST generation and our methods of matching patients with suitable VST-cell lines; one patent family that includes one pending patent application in each of the U.S. and Europe related to methods for the prophylactic treatment of viral infections; one patent family with one issued U.S. patent, five issued foreign patents, and pending patent applications in the U.S. and foreign jurisdictions including Australia, Canada, Europe, and Japan, directed to methods of identifying peptides that are likely to be immunogenic or, as is discussed already above, directed to VSTs targeting ALVR106 antigens hMPV and PIV; one patent family including one pending patent application in each of the U.S. and Europe directed to universal antigen-specific T cells compositions and methods of making and using the same; and one patent family including 11 issued patents (including a European patent validated in 7 European states) and 4 pending patent applications with claims directed to methods of rapidly expanding T-cells. Patents in the T-cell expansion family are expected to expire in 2032, and any patents that may issue from the immunogenicity family, the donor selection family, the methods for prophylactic treatment family, or the universal antigen-specific T cell family are expected to expire in 2036, 2040, 2040, and 2041, respectively, absent any patent term adjustments or extensions.
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Individual patents extend for varying periods depending on the date of filing of the patent application or the date of patent issuance and the legal term of patents in the countries in which they are obtained. Generally, patents issued for regularly filed applications in the United States are granted a term of 20 years from the earliest effective non-provisional filing date. In addition, in certain instances, a patent term can be extended to recapture a portion of the U.S. Patent and Trademark Office, or the USPTO, delay in issuing the patent as well as a portion of the term effectively lost as a result of the FDA regulatory review period. However, as noted, as to the FDA component, the restoration period cannot be longer than five years and the total patent term including the restoration period must not exceed 14 years following FDA approval.
We also rely on trade secrets relating to product candidates and seek to protect and maintain the confidentiality of proprietary information to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. It is our policy to require our employees, consultants, outside scientific partners, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual during the course of the individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. Our agreements with employees and consultants also provide that all inventions conceived by the employee or consultant in the course of employment or consulting relationships with us or from the employee’s or consultant’s use of our confidential information are our exclusive property and require such employees and consultants to assign their title, right and interest in such inventions to us. Although we take steps to protect our proprietary information and trade secrets, including through such contractual means with our employees and consultants, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets, including through breaches of such agreements with our employees and consultants. Thus, we may not be able to meaningfully protect our trade secrets.
Sponsored Research, Collaboration, License and Other Agreements
Amended and Restated Exclusive License Agreement with BCM
In June 2017, we signed a License Agreement, or the License Agreement, with BCM, whereby we acquired a royalty-bearing, worldwide, exclusive license to BCM’s rights in Subject Technology and related patent rights in the field of viral infection. In May 2020, we entered into an amended and restated exclusive license agreement, or the A&R License Agreement, with BCM, pursuant to which we obtained (a) an exclusive worldwide license, with the right to sublicense, under certain patent rights and other intellectual property rights of BCM, to make, have made, use, market, sell, offer to sell, lease, import and export products in a particular field, except that such license is non-exclusive within a particular subfield, and in addition with respect to certain patent rights such license is limited to two particular subfields, and (b) an exclusive, worldwide sublicense, with the right to further sublicense, under all patent rights and other intellectual property rights that are exclusively licensed to BCM by a certain third party licensor, to make, have made, use, market, sell, offer to sell, lease, import and export products in the same field. Our rights are subject to the rights of the U.S. government and certain rights retained by BCM.
Unless earlier terminated, the A&R License Agreement will expire on a country-by-country basis with respect to a product upon the later of (a) the expiration of the last to expire valid claim of a patent or patent application covering such product in such country or (b) 10 years after the first commercial sale of such product in such country. We may terminate the A&R License Agreement in its entirety at any time for convenience upon a certain number of days’ written notice. BCM may terminate the A&R License Agreement in its entirety for our uncured material default.
BCM maintains control of all filing, prosecution and maintenance of its patent rights licensed by us, and we are responsible for all related costs and expenses during the term of the agreement. We also reimbursed BCM for costs and expenses (including reasonable legal fees and expenses) incurred prior to the effective date of the agreement with respect to the filing, prosecution and maintenance of the patent rights licensed by us. If BCM licenses the patent rights licensed by us to third parties for additional fields of use, our responsibility for patent-related costs and expenses will be reduced on a pro-rata basis.
Under the A&R License Agreement, we must use commercially reasonable efforts to develop and commercialize one or more products in certain countries. As partial consideration for the rights conveyed by BCM under the original agreement executed in June 2017, we paid BCM a non-refundable license fee of $250,000. During the term of the A&R License Agreement, we are obligated to pay BCM a non-refundable annual license maintenance fee of $20,000 on the first through fourth anniversaries of the original agreement date and $40,000 beginning on the fifth anniversary of the original agreement date, but beginning with the fifth anniversary of the original agreement date, license maintenance fees are fully creditable against royalty revenue due in the applicable year. We are required to pay certain milestone payments upon the achievement of specified clinical, regulatory, and sales milestones. In the event that we are able to successfully develop, launch and commercialize a product under the A&R License Agreement, total milestone payments could exceed $40.0 million. BCM is also eligible to receive tiered royalties at percentage rates ranging from less than 1% to the low single-digits, on net sales of any products that are commercialized by us or our sublicensees that incorporate, utilize or are made with the use of, the intellectual property licensed by us. To the extent we sublicense our license rights under the A&R License Agreement, BCM would be eligible to receive tiered sublicense income at percentage rates in the mid-single to low double-digits.
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In November 2020, we entered into the First Amendment, or the License Amendment, to the A&R License Agreement. Under the License Amendment, we assumed responsibility from BCM for the filing, prosecution and maintenance of the patent rights licensed by us from BCM under the A&R License Agreement that are in common with the License Agreement. Further, BCM also transferred to us the right of enforcement against third parties for any suspected infringement of any claims in such patent rights or misuse, misappropriation, theft or breach of confidence of other proprietary rights.
Exclusive License Agreement with BCM
In November 2020, we signed a second License Agreement, or the Second License Agreement, with BCM, whereby we acquired a royalty-bearing, worldwide, exclusive license to BCM’s rights in Subject Technology and related patent rights outside the field of viral infection (all fields other than those covered by the License Agreement Amendment noted above).
Unless earlier terminated, the Second License Agreement will expire on a country-by-country basis with respect to a product upon the later of (a) the expiration of the last to expire valid claim of a patent or patent application covering such product in such country or (b) 10 years after the first commercial sale of such product in such country, provided that the Second License Agreement shall not expire later than March 25, 2040. We may terminate the Second License Agreement in its entirety at any time for convenience upon a certain number of days’ written notice. BCM may terminate the Second License Agreement in its entirety for our uncured material default.
Under the Second License Agreement, BCM transferred to us control of all filing, prosecution and maintenance of the patent rights licensed by us, and we are responsible for all related costs and expenses during the term of the Second License Agreement. BCM also transferred to us the right of enforcement against third parties for any suspected infringement of any claims in the patent rights or misuse, misappropriation, theft or breach of confidence of other proprietary rights. We also reimbursed BCM for costs and expenses (including reasonable legal fees and expenses) incurred prior to the effective date of the Second License Agreement with respect to the filing, prosecution and maintenance of the patent rights licensed by us, to the extent not already paid by us under the A&R License Agreement.
Under the Second License Agreement, we must use commercially reasonable efforts to develop and commercialize one or more products in certain countries. As partial consideration for the rights conveyed by BCM under the Second License Agreement, we paid BCM a non-refundable license fee of $125,000. During the term of the Second License Agreement, we are obligated to pay BCM a non-refundable annual license maintenance fee of (a) $20,000 for the first through fourth anniversary of the effective date of the Second License Agreement, and (b) $40,000 for the fifth anniversary of the effective date and continuing thereafter, but beginning with the fifth year, license maintenance fees are fully creditable against royalty revenue due in the applicable year. We are required to pay certain milestone payments upon the achievement of specified clinical, regulatory, and sales milestones. In the event that we are able to successfully develop, launch and commercialize multiple products under the Second License Agreement, total milestone payments could exceed $30.0 million. BCM is also eligible to receive tiered royalties at percentage rates ranging from less than 1% to the low single-digits, on net sales of any products that are commercialized by us or our sublicensees that incorporate, utilize or are made with the use of, the intellectual property licensed by us. To the extent we sublicense our license rights under the Second License Agreement, BCM would be eligible to receive tiered sublicense income at percentage rates in the mid-single to low double-digits.
Sponsored Research Agreement with BCM
In June 2019, we entered into a sponsored research agreement, or SRA-2, with BCM, under which we agreed to pay BCM for performing certain research activities related to virus specific T-cell manufacturing for a one-year period, renewable for an additional one-year term upon written consent of both parties. SRA-2 requires us to make payments to BCM totaling $1.0 million, payable in four equal installments. SRA-2 was amended in March 2020 to include the discovery and development of allogeneic, off-the-shelf, virus specific T-cell therapies to combat SARS-CoV-2, the virus that causes COVID-19. In June 2020, a second amendment was entered into resulting in a no-cost extension through November 30, 2020, upon which the agreement terminated.
Collaboration Agreement with BCM
In November 2020, we entered into a Research Collaboration Agreement, or the Research Agreement, with BCM, under which we agreed to pay BCM for performing certain research activities under the direction of Dr. Ann Leen commencing on January 1, 2021, and continuing for a three-year period thereafter. The Research Agreement requires us to make payments to BCM totaling approximately $6.0 million over the term of the Research Agreement. In August 2023, the term of the Research Agreement was extended for an additional year, expiring December 31, 2024.
Redeemable Preferred Stock Redemption Agreement
In September 2018, we entered into a redeemable preferred stock redemption agreement, or Redemption Agreement, to redeem shares of our Series A1 convertible preferred stock held by certain investors, including executive officer Ann Leen, director and former executive officer Juan Vera and entities affiliated with director, Malcolm Brenner and former director, John Wilson (or their affiliates).
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Pursuant to the Redemption Agreement, for a period of 20 years from the date of the first commercial sale of Viralym-M by us, we are obligated to make earnout payments to such investors on at least an annual basis. The earnout payments will be 10% of our net sales of Viralym-M, which number will be reduced to a high single-digit percentage if certain events occur. Specifically, royalties due to third parties for the sale of Viralym-M are subtracted from the earnout payments due to the investors. Further, if the investors receive at least $50,000,000 in earnout payments from us during the three-year period after the first commercial sale of Viralym-M, the earnout payment percentage will be reduced.
Manufacturing
Our versatile VST manufacturing platform supports the rapid, robust and scalable generation of single- and multi-virus specific cell therapeutic candidates for clinical use. We leverage CytokinTM, our proprietary algorithm to select donors from whom to generate VSTs such that there is broad patient HLA coverage through an efficient set of donors. Virus-specific T-cells from individual healthy seropositive donors are expanded in a fully good manufacturing practices, or cGMP, compliant process, which is scaled to produce hundreds of patient doses from each manufacturing run. Our VST cell therapies are maintained in a cryopreserved state ready for “off-the-shelf” use. CytomatchTM, our proprietary algorithm for HLA matching, identifies the best VST cell line for each patient. In combination, these elements allow us to efficiently build our global supply chain to serve a growing number of patients who could benefit from our highly innovative off-the-shelf VST therapy candidates.
To facilitate investigational product supply for our posoleucel and ALVR106 clinical trials, we manufacture posoleucel and ALVR106 at external cGMP CMOs and leverage a network of cGLP contract testing laboratories. We believe this approach for our clinical product candidates is most cost-effective at our current clinical phase and production scale and has allowed us to rapidly prepare for clinical trials in accordance with our development plans.
Government Regulation
In the United States, biological products, are subject to regulation under the Federal Food, Drug, and Cosmetic Act, or FD&C Act, and the Public Health Service Act, or PHS Act, and other federal, state, local and foreign statutes and regulations. Both the FD&C Act and the PHS Act and their corresponding regulations govern, among other things, the research, development, clinical trial, testing, manufacturing, quality control, safety, efficacy, labeling, packaging, storage, record keeping, distribution, reporting, marketing, promotion, advertising, post-approval monitoring, and post-approval reporting involving biological products. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources, and we may not be able to obtain the required regulatory approvals.
U.S. Biological Products Development Process
The process required by the FDA before a biological product may be marketed in the United States generally involves the following:
• completion of nonclinical laboratory tests and animal studies according to good laboratory practices, or GLPs, and applicable requirements for the humane use of laboratory animals or other applicable regulations;
• submission to the FDA of an application for an investigational new drug application, or IND, which must become effective before human clinical trials may begin;
• approval of the protocol and related documentation by an independent institutional review board, or IRB, or ethics committee at each clinical trial site before each study may be initiated;
• performance of adequate and well-controlled human clinical trials according to the FDA’s regulations commonly referred to as good clinical practices, or GCPs, and any additional requirements for the protection of human research subjects and their health information, to establish the safety and efficacy of the proposed biological product for its intended use;
• preparation of and submission to the FDA of a biologics license application, or BLA, for marketing approval that includes sufficient evidence of establishing the efficacy, safety, purity, and potency of the proposed biological product for its intended indication, including from results of nonclinical testing and clinical trials;
• satisfactory completion of an FDA inspection of the manufacturing facility or facilities where the biological product is produced to assess compliance with current good manufacturing practices, or cGMPs, to assure that the facilities, methods and controls are adequate to preserve the biological product’s identity, strength, quality and purity and, if applicable, the FDA’s current good tissue practices, or CGTPs, for human cellular and tissue products;
• potential FDA audit of the nonclinical study and clinical trial sites that generated the data in support of the BLA;
• review of the product candidate by an FDA advisory committee, where appropriate and if applicable;
• payment of user fees for FDA review of the BLA (unless a fee waiver applies); and
• FDA review and approval of the BLA, resulting in the licensure of the biological product for commercial marketing.
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Before testing any biological product candidate, in humans, the product candidate enters the preclinical testing stage. Preclinical tests, also referred to as nonclinical studies, may include laboratory evaluations of product biological characteristics, chemistry, toxicity and formulation, as well as animal studies to assess the potential safety and activity of the product candidate. The conduct of the preclinical tests must comply with federal regulations and requirements including GLPs, if applicable.
Prior to beginning the first clinical trial with a product candidate in the United States, an IND must be submitted to the FDA and the FDA must allow the IND to proceed. An IND is an exemption from the FD&C Act that allows an unapproved product candidate to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA allowance that such investigational product may be administered to humans in connection with such trial. Such authorization must be secured prior to interstate shipment and administration. In support of a request for an IND, applicants must submit a protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. In addition, the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, must be submitted to the FDA as part of an IND. An IND must become effective before human clinical trials may begin. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, raises safety concerns or questions about the proposed clinical trial. In such a case, the IND may be placed on clinical hold or partial clinical hold. In this case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin. Submission of an IND therefore may or may not result in FDA allowance to begin a clinical trial.
In addition to the submission of an IND to the FDA before initiation of a clinical trial in the United States, certain human clinical trials involving recombinant or synthetic nucleic acid molecules are subject to oversight of institutional biosafety committees, or IBCs, as set forth in the NIH Guidelines for Research Involving Recombinant or Synthetic Nucleic Acid Molecules, or NIH Guidelines. Under the NIH Guidelines, recombinant and synthetic nucleic acids are defined as: (i) molecules that are constructed by joining nucleic acid molecules and that can replicate in a living cell (i.e., recombinant nucleic acids); (ii) nucleic acid molecules that are chemically or by other means synthesized or amplified, including those that are chemically or otherwise modified but can base pair with naturally occurring nucleic acid molecules (i.e., synthetic nucleic acids); or (iii) molecules that result from the replication of those described in (i) or (ii). Specifically, under the NIH Guidelines, supervision of human gene transfer trials includes evaluation and assessment by an IBC, a local institutional committee that reviews and oversees research utilizing recombinant or synthetic nucleic acid molecules at that institution. The IBC assesses the safety of the research and identifies any potential risk to public health or the environment, and such review may result in some delay before initiation of a clinical trial. While the NIH Guidelines are not mandatory unless the research in question is being conducted at or sponsored by institutions receiving NIH funding of recombinant or synthetic nucleic acid molecule research, many companies and other institutions not otherwise subject to the NIH Guidelines voluntarily follow them.
Clinical trials involve the administration of the biological product candidate to healthy volunteers or patients under the supervision of qualified investigators who generally are physicians not employed by, or under, the control of, the trial sponsor. Clinical trials are conducted under written study protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria and the parameters to be used to monitor subject safety, including stopping rules that assure a clinical trial will be stopped if certain adverse events should occur.
An IRB representing each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution, and the IRB must conduct continuing review and reapprove the study at least annually. The IRB must review and approve, among other things, the study protocol and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. An IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the product candidate has been associated with unexpected serious harm to patients.
Some trials are overseen by an independent group of qualified experts organized by the trial sponsor, known as a data safety monitoring board or committee, or DSMB. This group provides authorization as to whether or not a trial may move forward at designated check points based on data from the ongoing study that are available to the DSMB members.
Certain information about certain clinical trials must also be submitted within specific timeframes to the NIH for public dissemination on its ClinicalTrials.gov website.
Clinical trials typically are conducted in three sequential phases that may overlap or be combined:
• Phase 1. The investigational product is initially introduced into healthy human subjects and tested for safety. In the case of some products for severe or life-threatening diseases, especially when the product may be too inherently toxic to ethically administer to healthy volunteers, the initial human testing is often conducted in patients.
• Phase 2. The investigational product is evaluated in a limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance, optimal dosage and dosing schedule.
• Phase 3. The investigational product is administered to an expanded patient population to further evaluate dosage, clinical efficacy, potency, and safety in an expanded patient population at geographically dispersed clinical trial sites. These clinical
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trials are intended to establish the overall risk/benefit ratio of the product and provide an adequate basis for approval and product labeling.
In some cases, FDA may require, or firms may voluntarily pursue, post-approval clinical trials, sometimes referred to as Phase 4 clinical trials, after initial marketing approval. These clinical trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication, particularly for long-term safety follow-up. During all phases of clinical development, regulatory agencies require extensive monitoring and auditing of all clinical activities, clinical data, and clinical trial investigators. Annual progress reports detailing the results of the clinical trials must be submitted to the FDA. Written IND safety reports must be promptly submitted to the FDA and the investigators for serious and unexpected adverse events, any findings from other studies, tests in laboratory animals or in vitro testing that suggest a significant risk for human subjects, or any clinically important increase in the rate of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. The sponsor must submit an IND safety report within 15 calendar days after the sponsor determines that the information qualifies for reporting. The sponsor also must notify the FDA of any unexpected fatal or life-threatening suspected adverse reaction within seven calendar days after the sponsor’s initial receipt of the information. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, if at all. The FDA or the sponsor, acting on its own or based on a recommendation from the sponsor’s data safety monitoring board, may suspend a clinical trial at any time on various grounds, including a finding that the research subjects or patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the biological product has been associated with unexpected serious harm to patients.
Concurrent with clinical trials, companies may complete additional animal studies and also must develop additional information about the physical characteristics of the biological product as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP and as applicable CGTP requirements. To help reduce the risk of the introduction of adventitious agents with use of biological products, the PHS Act emphasizes the importance of manufacturing control for products whose attributes cannot be precisely defined. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, the sponsor must develop methods for testing the identity, strength, quality, potency and purity of the final biological product. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the biological product candidate does not undergo unacceptable deterioration over its shelf life.
U.S. Review and Approval Processes
Assuming successful completion of all required testing in accordance with all applicable regulatory requirements, the results of product development, nonclinical studies and clinical trials are submitted to the FDA as part of a BLA requesting approval to market the product for one or more indications. The BLA must include results of product development, laboratory and animal studies, human studies, information on the manufacture and composition of the product, proposed labeling and other relevant information.
Within 60 days following submission of the application, the FDA reviews a BLA submitted to determine if it is substantially complete before the FDA accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional information. The resubmitted application also is subject to review to determine if it is substantially complete before the FDA accepts it for filing. In most cases, the submission of a BLA is subject to a substantial application user fee, although the fee may be waived under certain circumstances. Under the performance goals and policies implemented by the FDA under the Prescription Drug User Fee Act, or PDUFA, for original BLAs, the FDA targets ten months from the date FDA files the application (i.e., the filing date) in which to complete its initial review of a standard application and respond to the applicant, and six months from the filing date for an application granted priority review by FDA. The FDA does not always meet its PDUFA goal dates, and the review process is often significantly extended by FDA requests for additional information or clarification.
Once the submission is accepted for filing, the FDA begins an in-depth substantive review of the BLA. The FDA reviews the BLA to determine, among other things, whether the proposed product is safe, pure and potent, for its intended use, and whether the product is being manufactured in accordance with cGMP to ensure its continued safety, purity and potency. The FDA may refer applications for novel biological products or biological products that present difficult or novel questions of safety, efficacy, or quality to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. During the biological product approval process, the FDA also will determine whether a Risk Evaluation and Mitigation Strategy, or REMS, is necessary to assure the safe use of the biological product. If the FDA concludes a REMS is needed, the sponsor of the BLA must submit a proposed REMS; the FDA will not approve the BLA without a REMS, if required.
Before approving a BLA, the FDA typically will inspect the facilities at which the product is manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Where applicable, the FDA also will not approve
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the product if the manufacturer is not in compliance with the CGTPs. These are FDA regulations that govern the methods used in, and the facilities and controls used for, the manufacture of human cells, tissues, and cellular and tissue-based products, or HCT/Ps, which are human cells or tissue intended for implantation, transplant, infusion, or transfer into a human patient. The primary intent of the CGTP requirements is to ensure that cell and tissue-based products are manufactured in a manner designed to prevent the introduction, transmission and spread of communicable disease. FDA regulations also require tissue establishments to register and list their HCT/Ps with the FDA and, when applicable, to evaluate donors through appropriate screening and testing. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure that the clinical trials were conducted in compliance with IND study requirements and GCP requirements. To ensure cGMP, CGTP and GCP compliance, an applicant must incur significant expenditure of time, money and effort in the areas of training, record keeping, production and quality control.
Under the Pediatric Research Equity Act, or PREA, a BLA or supplement to a BLA for a novel product (e.g., new active ingredient, new indication, etc.) must contain data to assess the safety and effectiveness of the biological product for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may grant deferrals for submission of data or full or partial waivers. Unless otherwise required by regulation, PREA does not apply to any biological product for an indication for which orphan designation has been granted.
After the FDA evaluates a BLA and conducts inspections of manufacturing facilities where the investigational product and/or its drug substance will be produced, the FDA may issue an approval letter or a Complete Response Letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A Complete Response Letter will describe all of the deficiencies that the FDA has identified in the BLA, except that where the FDA determines that the data supporting the application are inadequate to support approval, the FDA may issue the Complete Response Letter without first conducting required inspections, testing submitted product lots, and/or reviewing proposed labeling. In issuing the Complete Response Letter, the FDA may recommend actions that the applicant might take to place the BLA in condition for approval, including requests for additional information or clarification. The FDA may delay or refuse approval of a BLA if applicable regulatory criteria are not satisfied, require additional testing or information and/or require post-marketing testing and surveillance to monitor safety or efficacy of a product.
If a product receives regulatory approval, the approval may be significantly limited to specific diseases and dosages or the indications for use may otherwise be limited, including to subpopulations of patients, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings precautions or interactions be included in the product labeling. The FDA may impose restrictions and conditions on product distribution, prescribing, or dispensing in the form of a REMS, or otherwise limit the scope of any approval. The FDA also may condition approval on, among other things, changes to proposed labeling or the development of adequate controls and specifications. Once approved, the FDA may withdraw the product approval if compliance with pre- and post-marketing requirements is not maintained or if problems occur after the product reaches the marketplace. The FDA may require one or more Phase IV post-market studies and surveillance to further assess and monitor the product’s safety and effectiveness after commercialization, and may limit further marketing of the product based on the results of these post-marketing studies.
Orphan Drug Designation
Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biological product intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States and for which there is no reasonable expectation that the cost of developing and making a drug or biological product available in the United States for this type of disease or condition will be recovered from sales of the product. Orphan product designation must be requested before submitting a BLA. After the FDA grants orphan product designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan product designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.
If a product that has orphan drug designation subsequently receives the first FDA approval for a particular active ingredient for the disease for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications, including a full BLA, to market the same biologic for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the drug was designated. Orphan drug exclusivity does not prevent the FDA from approving a different drug or biologic for the same disease or condition, or the same drug or biologic for a different disease or condition. Among the other benefits of orphan drug designation are tax credits for certain research and a waiver of the BLA application user fee.
A designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or, as noted above, if the second applicant demonstrates that its product is clinically superior to the approved product with orphan exclusivity or the manufacturer of the approved product is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.
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Orphan drug designation may also entitle a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers.
Expedited Development and Review Programs
The FDA has various programs, including Fast Track designation, breakthrough therapy designation, accelerated approval and priority review, that are intended to expedite or simplify the process for the development and FDA review of drugs and biologics that are intended for the treatment of serious or life-threatening diseases or conditions. To be eligible for fast track designation, new drugs and biological product candidates must be intended to treat a serious or life-threatening condition and demonstrate the potential to address unmet medical needs for the condition. Fast Track designation applies to the combination of the product and the specific indication for which it is being studied. The sponsor of a new drug or biologic may request the FDA to designate the drug or biologic as a fast track product at any time during the clinical development of the product. One benefit of fast track designation, for example, is that the FDA may consider for review sections of the marketing application on a rolling basis before the complete application is submitted if certain conditions are satisfied, including an agreement with the FDA on the proposed schedule for submission of portions of the application and the payment of applicable user fees before the FDA may initiate a review.
Under the FDA’s breakthrough therapy program, a sponsor may seek FDA designation of its product candidate as a breakthrough therapy if the product candidate is intended, alone or in combination with one or more other drugs or biologics, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that it may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. Breakthrough therapy designation comes with all of the benefits of fast track designation, which means that the sponsor may file sections of the BLA for review on a rolling basis if certain conditions are satisfied, including an agreement with the FDA on the proposed schedule for submission of portions of the application and the payment of applicable user fees before the FDA may initiate a review. The FDA may take other actions appropriate to expedite the development and review of the product candidate, including holding meetings with the sponsor and providing timely advice to, and interactive communication with, the sponsor regarding the development program.
A product candidate is eligible for priority review if it treats a serious or life-threatening disease or condition and, if approved, would provide a significant improvement in the safety or effectiveness of the treatment, diagnosis or prevention of a serious disease or condition. The FDA will attempt to direct additional resources to the evaluation of an application for a new drug or biological product designated for priority review in an effort to facilitate the review. Under priority review, the FDA’s goal is to review an application in six months once it is filed, compared to ten months for a standard review. Priority review designation does not change the scientific/medical standard for approval or the quality of evidence necessary to support approval.