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Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis are meant to provide material information relevant to an assessment of the financial condition and results of operations of our Company, including an evaluation of the amounts and certainty of cash flows from operations and from outside sources, so as to allow investors to better view our Company from management’s perspective. You should read the following discussion and analysis of our financial condition and results of operations together with our audited consolidated financial statements and related notes appearing elsewhere in this Annual Report on Form 10-K. In addition to historical information, this discussion and analysis contains forward-looking statements that involve risks, uncertainties and assumptions. Our actual results may differ materially from those anticipated in these forward-looking statements as a result of certain factors. We discuss factors that we believe could cause or contribute to these differences below and elsewhere in this report, including those set forth under Item 1A. “Risk Factors” in this Annual Report on Form 10-K.

Overview and Recent Developments

We are a clinical stage biopharmaceutical company focused on developing novel therapies for the treatment of orphan pulmonary and fibrosis indications with no approved or limited effective treatments. We currently have two product candidates in clinical development, LTI-03 and LTI-01, and multiple candidates in preclinical development focused on fibrosis indications. Our pipeline includes:

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LTI-03, a peptide, for which we conducted a Phase 1b dose-ranging, placebo-controlled safety, tolerability, and pharmacodynamic biomarker activity trial in development for the treatment of Idiopathic Pulmonary Fibrosis, or IPF, that has demonstrated the ability to protect healthy lung epithelial cells and reduce pro-fibrotic signaling;

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LTI-01, a proenzyme that completed a Phase 2a dose-ranging, placebo-controlled trial and a Phase 1b safety, tolerability and proof of mechanism trial in loculated pleural effusion, or LPE, patients, an indication that has no approved drug treatment; and

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preclinical programs targeting cystic fibrosis and a peptide program focused on the Cav1 protein for systemic fibrosis indications.

In June 2024, we decided to temporarily delay clinical development of LTI-01 in an effort to focus our resources on clinical development of LTI-03 and until additional funds are raised. In the fourth quarter of 2024, we determined that the temporary delay of further clinical development of LTI-01 may not be a short-term measure.

We have not completed the development of any of our product candidates, have not generated any revenue from product sales and have never generated an operating profit.

To date, we have financed operations primarily through $145.5 million in net proceeds from sales of common stock and warrants, $0.7 million in net proceeds from sales of common stock under our “at-the-market” offering program, $131.2 million from sales of preferred stock prior to our initial public offering, or IPO, $34.9 million from a collaboration agreement in 2010, $17.5 million in net proceeds in connection with a private placement following the Lung Acquisition (as defined below) in 2023, and $17.7 million in net proceeds in connection with the issuance and sale of shares and accompanying warrants in our public offering in May 2024.

Since our inception, we have incurred significant losses on an aggregate basis. Our net losses were $62.9 million and $15.7 million for the years ended December 31, 2024 and 2023, respectively. As of December 31, 2024, we had an accumulated deficit of $351.4 million. These losses have resulted primarily from costs incurred in connection with research and development activities, licensing and patent investment and general and administrative costs associated with our operations as well as the impairment loss on intangible assets identified in the fourth quarter of 2024. We expect to continue to incur operating losses for the foreseeable future.

As of December 31, 2024, we had cash and cash equivalents of $12.9 million. Based on our current operating plan, we believe that our existing cash and cash equivalents will enable us to fund our planned operating expense and capital expenditure requirements into August 2025. These funds are not sufficient to enable us to complete our planned Phase 2 clinical trial of LTI-03 and we will need to obtain additional funding prior to initiating the trial. Our future

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viability is dependent on our ability to raise additional capital to finance our operations. Our estimate as to how long we expect our existing cash and cash equivalents to be able to continue to fund our operations is based on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we currently expect. In addition, our existing cash and cash equivalents will not be sufficient to fund all of the efforts that we plan to undertake or to fund the completion of development of our product candidates. Accordingly, we will be required to obtain further funding through public or private equity offerings, debt financings, collaborations and licensing arrangements or other sources. There is no assurance that we will be successful in obtaining sufficient funding on terms acceptable to us to fund continuing operations, or at all.

Exclusive Option Agreement with Advancium

On October 31, 2024, we entered into an exclusive option agreement, or the Option Agreement, with Advancium Health Network, or Advancium, for the sale of ALRN-6924, a clinical stage oncology agent that we were development prior to the Lung Acquisition (as defined below). During the option period, Advancium intends to evaluate ALRN-6924 as a potential therapy for retinoblastoma. Under the terms of the option agreement Advancium paid us a non-refundable fee of $0.1 million for the exclusive option to acquire ALRN-6924 and related assets. If Advancium exercises its option, we will receive an exercise payment with potential for additional development, regulatory and commercial milestone payments and sales royalties.

Equity Distribution Agreement

On July 26, 2024, we entered into an Equity Distribution Agreement with Citizens JMP Securities, LLC, or Citizens JMP, as agent and/or principal, under which we may offer and sell up to $50.0 million of shares of our common stock from time to time through or to Citizens JMP. Sales of common stock through or to Citizens JMP may be made by any method that is deemed an “at the market” offering as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended, including sales made directly on or through the Nasdaq Capital Market. There have been no sales on the "at the market" offering through December 31, 2024, however, in January 2025, we issued and sold 317,772 shares of common stock for total net proceeds of $0.7 million.

Follow-on public offering

In May 2024, we completed an underwritten follow-on public offering, or the Offering, pursuant to which we issued and sold 4,273,505 shares of our common stock, or the Offering Shares, and accompanying warrants, or the Offering Warrants, to purchase 4,273,505 shares of common stock, or the Offering Warrant Shares. We sold all of the Offering Shares and Offering Warrants. Each Offering Share was offered and sold together with an accompanying Offering Warrant at a combined offering price of $4.68, and the underwriter purchased each Offering Share with an accompanying Offering Warrant at a combined price of $4.35. Net proceeds from the Offering were $17.7 million, after deducting underwriting discounts and commissions and offering expenses, and excluding any proceeds that may be received from exercise of the Offering Warrants.

The Lung Acquisition

On October 31, 2023, we acquired Lung Therapeutics, Inc., or Lung, pursuant to an Agreement and Plan of Merger, or the Lung Acquisition Agreement. Following our acquisition of Lung, Lung became our wholly owned subsidiary, or the Lung Acquisition. Following the Lung Acquisition, the business conducted by Lung became the business primarily conducted by us and we shifted our operating disease focus to advancing a pipeline of first-in-class medicines to address significant unmet medical needs in orphan pulmonary and fibrosis indications.

Under the terms of the Lung Acquisition Agreement, at the closing of the Lung Acquisition, we issued to the stockholders of Lung 344,345 shares of our common stock and 19,903 shares of our newly designated Series X Preferred Stock. Each share of Series X Preferred Stock is convertible into 1,000 shares of common stock. In addition, we assumed (i) all Lung stock options and all warrants exercisable for Lung common stock immediately outstanding prior to the closing of the Lung Acquisition, each subject to adjustment pursuant to the terms of the Lung Acquisition Agreement.

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Immediately following the closing of the Lung Acquisition, we entered into the Purchase Agreement, with the Investors, led by Bio Partners, the majority stockholder of Lung prior to the closing of the Lung Acquisition, and including Nantahala Capital, as well as additional undisclosed investors, pursuant to which we issued and sold (i) an aggregate of 4,707 shares of Series X Preferred Stock, and (ii) warrants to purchase up to an aggregate of 2,353,500 shares of common stock, or the PIPE Warrant Shares, for an aggregate purchase price of approximately $18.4 million, which included the conversion of certain convertible promissory notes in the aggregate principal amount of approximately $1.6 million issued by Lung to Bios Partners prior to the closing of the Lung Acquisition at a 10% discount to the per share price of the Series X Preferred Stock, or the PIPE Financing, and collectively with the Lung Acquisition, the Transactions. The PIPE Financing closed on November 2, 2023.

On February 28, 2024, we held our 2023 annual meeting of stockholders in which our stockholders approved the issuance, in accordance with Nasdaq Listing Rule 5635(a), of shares of common stock, upon conversion of our outstanding Series X Preferred Stock. Following approval of the conversion of outstanding Series X Preferred Stock, the Company had approximately 29,495,512 shares of common stock issued and outstanding on a pro forma basis, which gives effect to the full conversion of the Series X Preferred Stock as of the date of our 2023 annual meeting of stockholders, without regard to beneficial ownership limitations that may limit the ability of certain holders of Series X Preferred Stock to convert such shares to common stock as such time. On March 5, 2024, subject to then existing beneficial ownership limitations, 11,957 shares of Series X Preferred Stock were automatically converted into 11,957,000 shares of common stock.

Components of Rein’s Results of Operations

Revenue

We have not generated any revenue from product sales and we do not expect to generate any revenue from the sale of products in the foreseeable future.

Operating Expenses

Our expenses since inception have consisted solely of research and development costs, general and administrative, and restructuring costs.

Research and Development Expenses

For the periods presented in this Annual Report on Form 10-K, research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts, and the development of our product candidates, and include:

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salaries, benefits and other related costs, including stock-based compensation expense, for personnel engaged in research and development functions;

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expenses incurred in connection with the clinical development of our product candidates, including under agreements with third parties, such as consultants and contract research organizations, or CROs;

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the cost of manufacturing product candidates for use in our clinical trials and preclinical studies, including under agreements with third parties, such as consultants and contract manufacturing organizations, or CMOs;

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expenses incurred in connection with the preclinical development of our product candidates, including outsourced professional scientific development services, consulting research fees and payments made under sponsored research arrangements with third parties;

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the costs of laboratory supplies and acquiring, developing and manufacturing preclinical study and clinical trial materials;

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third-party license fees;

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costs related to compliance with regulatory requirements; and

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facility-related expenses, which included direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expense research and development costs as incurred. We recognize costs for certain development activities, such as clinical trials, based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations or information provided to us by our vendors and our clinical investigative sites. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our financial statements as prepaid or accrued research and development expenses.

In addition, we typically use our employee and infrastructure resources across our development programs. We track outsourced development costs and milestone payments made under our licensing arrangements by product candidate or development program, but we do not allocate personnel costs, license payments made under our licensing arrangements or other internal costs to specific development programs or product candidates because these costs are deployed across multiple programs and, as such, are not separately classified.

Research and development activities are central to our business model. The duration, costs and timing of clinical trials and development of a product candidate will depend on a variety of factors, including:

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the scope, rate of progress, expense and results of clinical trials of the product candidates that we are developing and other research and development activities that we have conducted;

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uncertainties in clinical trial design and patient enrollment rates;

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significant and changing government regulation and regulatory guidance;

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the timing and receipt of any marketing approvals; and

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the expense of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights.

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of that product candidate. For example, if the U.S. Food and Drug Administration, or the FDA, or another regulatory authority were to require us to conduct clinical trials beyond those that we anticipated would be required for the completion of clinical development of a product candidate, or if we experience significant trial delays due to patient enrollment or other reasons, we could be required to expend significant additional financial resources and time on the completion of clinical development.

General and Administrative Expenses

General and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance and corporate and administrative functions. General and administrative expenses are comprised of professional fees associated with being a public company including costs of accounting, auditing, legal, regulatory, tax and consulting services associated with maintaining compliance with exchange listing and SEC requirements, director and officer insurance costs; and both public and investor relations costs. General and administrative expenses also include legal fees relating to patent and corporate matters; legal and other professional fees relating to our strategic process; other insurance costs; travel expenses; and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

Impairment Loss on Intangible Assets

Impairment loss on intangible assets was identified in the fourth quarter of 2024 when the carrying value of LTI-01 exceeded its fair value as of December 31, 2024.

Restructuring Costs

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Restructuring-related charges are comprised of one-time termination costs in connection with our reduction-in-workforce in 2023, including severance, benefits, and related costs.

Other Income, net

Interest and Other Income

Interest income consists of interest income earned on our cash and cash equivalents. Historically, our interest income had not been significant due to low investment balances and low interest earned on those balances. We anticipate that our interest income will fluctuate in the future in response to our cash and cash equivalents and the interest rate environment.

Other income, net consists of the income recognized under the Option Agreement with Advancium, gains or losses recognized from non-routine items such as accretion on short-term investments, and gains or losses recognized from foreign currency transactions, and the disposal of fixed assets.

We anticipate that our interest income and investment accretion will fluctuate in the future in response to our then-current cash and cash equivalents, and then-current interest rates.

Results of Operations

Comparison of the Years Ended December 31, 2024 and 2023

The following tables summarize our results of operations for the years ended December 31, 2024 and 2023 in thousands:

Year Ended December 31, Increase

(in thousands)

Operating expenses:

Impairment loss on intangible assets 37,000 — 37,000

Restructuring and Other Costs — 928 (928 )

Research and Development Expenses

Year Ended December 31, Increase

Professional fees for services 34 324 (290 )

Facilities and other expenses 47 47 —

Research and development expenses for the year ended December 31, 2024 were $14.2 million, compared to $4.0 million for the year ended December 31, 2023. The increase of $10.3 million of research and development expenses was primarily a result of the termination of ALRN-6924 in 2023 and new clinical programs acquired as part of the Lung Acquisition in October 2023. During the year ended December 31, 2024, we incurred expenses of $5.9 million on clinical trials and preclinical studies, $5.5 million on manufacturing including $3.2 million write-offs due

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to the expiration of clinical materials and the temporary delay of clinical development of LTI-01, and $0.6 million on regulatory and development consulting as well as $2.2 million on employee and related expenses associated with clinical programs acquired in the Lung Acquisition. These programs and related activities were not included in our financial results for periods prior to the Lung Acquisition. There were $2.1 million on research and development expenses related to ALRN-6924 and $1.9 million on research and development expenses related to LTI-03, LTI-01 and other preclinical programs including $1.2 million on clinical trials and preclinical studies, $0.2 million on manufacturing, $0.1 million on regulatory and development consulting as well as $0.5 million on employee and related expenses during the year ended December 31, 2023.

General and Administrative Expenses

Year Ended December 31, Increase

General and administrative expenses were $13.9 million for the year ended December 31, 2024, compared to $11.4 million for the year ended December 31, 2023. The increase of $2.5 million in general and administrative expenses was primarily due to increased employee and related expenses of $2.7 million as a result of increased headcount associated with the Lung Acquisition and severance expense recognized due to departure of former employees, and increased facilities and other expenses of $0.6 million as a result of the Lung Acquisition, offset by a decrease of $0.8 million in professional fees as a result of no acquisition related events during the year ended December 31, 2024 as compared to the year ended December 31, 2023.

Impairment Loss on Intangible Assets

We incurred impairment loss on intangible assets of $37.0 million for the year ended December 31, 2024 in connection with the temporary delay of further clinical development of LTI-01 until additional funds are raised. In the fourth quarter of 2024, we determined that the temporary delay of further clinical development of LTI-01 may not be a short-term measure. There was no impairment loss on goodwill during the year ended December 31, 2024. There was no impairment loss on goodwill or intangible assets incurred during the year ended December 31, 2023.

Restructuring and Other Costs

There were no restructuring-related expenses incurred during the year ended December 31, 2024. We incurred restructuring-related charges of $0.9 million for the year ended December 31, 2023 in connection with our February 2023 restructuring. Restructuring-related charges were comprised of one-time termination costs in connection with the reduction-in-workforce, including severance, benefits, and related costs. All restructuring-related expenses were incurred and paid in 2023.

Other Income, net

Other income, net of $0.7 million for the year ended December 31, 2024 consisted of interest income of $0.4 million, investment accretion of $0.3 million, and other income of $0.1 million recognized from the Option Agreement with Advancium. Other income, net of $0.5 million for the year ended December 31, 2023 consisted of interest income of $0.4 million and investment accretion of $0.2 million. We anticipate that our interest income and investment accretion will fluctuate in the future in response to our then-current cash and cash equivalents, and then-current interest rates.

Income Taxes

As of December 31, 2024, we had federal and state net operating loss carryforwards of $77.3 million and $18.8 million, respectively, which begin to expire in 2036 and 2043, respectively. As of December 31, 2024, we also had

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federal research and development tax credit carryforwards of $2.4 million, which begin to expire in 2035. We also have federal orphan drug tax credit carryforwards of $5.8 million which begin to expire in 2039.

Utilization of the net operating loss carryforwards and research and development tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986 due to ownership changes that have occurred previously or that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50% over a three-year period. As a result of the Lung Acquisition, the tax attributes have been limited under Section 382. We have reflected the reduction of these tax attributes within the income tax footnote at December 31, 2024 and 2023, respectively.

On October 31, 2023, we acquired, in accordance with the terms of the Lung Acquisition Agreement, the stock of Lung. In accordance with Accounting Standards Codification, or ASC, 805-740-25-3, recognition of deferred tax assets and liabilities is required for substantially all temporary differences and acquired tax carryforwards and credits. We have computed estimated temporary differences and acquired tax carryforwards and credits as of the transaction date. We will not have tax basis in intangible assets recorded as part of the purchase. For accounting purposes, the intangible assets will not be amortized and subject to impairment review and testing. Though the tax effects may be delayed indefinitely, ASC 740-10-55-63 states that “deferred tax liabilities may not be eliminated or reduced because a reporting entity may be able to delay the settlement of those liabilities by delaying the events that would cause taxable temporary differences to reverse.” As such, we have recorded a deferred tax liability for the portion of the liability that cannot be offset with indefinite lived deferred tax assets.

Liquidity and Capital Resources

Since inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from operations. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we advance the clinical development of our lead product candidates, LTI-03 and LTI-01, or any future product candidates. We expect that our research and development and general and administrative costs will continue to increase significantly, including in connection with conducting clinical trials and manufacturing for our lead product candidates or any future product candidates to support potential future commercialization and providing general and administrative support for our operations, including the costs associated with operating as a public company.

As of December 31, 2024, we had cash and cash equivalents of $12.9 million. Based on our current operating plan, we believe that our existing cash and cash equivalents as of December 31, 2024 will be sufficient to enable us to fund our operating expenses and capital expenditure requirements into August 2025. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. As a result, we will need additional capital to fund our operations, which we may obtain from additional equity or debt financings, strategic collaborations, licensing arrangements or other sources. See the section titled “Risk Factors” found elsewhere in this Annual Report on Form 10-K for risks associated with our substantial capital requirements.

To date, we have funded our operations through sales of common stock in our initial public offering, sales of common stock and warrants in follow-on public offerings, sales of common stock and warrants in a private placement, sales of common stock in “at-the-market” offerings, sales of preferred stock prior to our initial public offering, payments received under a collaboration agreement, sales of common stock, preferred stock and warrants in connection with the Lung Acquisition and the PIPE Financing and sales of common stock upon option exercises.

In July 2024, we entered into an Equity Distribution Agreement with Citizens JMP, as agent and/or principal, under which we may offer and sell up to $50.0 million of our common stock from time to time through or to Citizens JMP. Sales of common stock through or to Citizens JMP may be made by any method that is deemed an “at the market” offering as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended, including sales made directly on or through the Nasdaq Capital Market. Under General Instruction I.B.6 to Form S-3, or the Baby Shelf Rule, the amount of funds we can raise through primary public offerings of securities in any 12-month period using our registration statement on Form S-3 is limited to one-third of the aggregate market value of our common stock held

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by non-affiliates. As of March 27, 2025, the aggregate market value of our outstanding shares of common stock held by non-affiliates was approximately $35.2 million, which was calculated based on 19,889,930 shares held by non-affiliates on such date and a price per share of $1.77, which was the closing price of our common stock on the Nasdaq Capital Market on March 27, 2025. We therefore are limited by the Baby Shelf Rule as of the filing of this Annual Report on Form 10-K, until such time as our public float exceeds $75.0 million.

We did not sell any shares of common stock pursuant to the Equity Distribution Agreement during the year ended December 31, 2024. In January 2025, we issued and sold 317,772 shares of common stock for total net proceeds of $0.7 million. Upon entry into the Equity Distribution Agreement, we terminated our prior “at the market offering” pursuant to a Capital on DemandTM Sales Agreement with JonesTrading Institutional Services LLC and William Blair & Company, L.L.C. At the time of termination, we had not sold any shares under the sales agreement prospectus related to the prior sales agreement.

In May 2024, we completed the Offering as described above. We received net proceeds of $17.7 million from the Offering, after deducting underwriting discounts and commissions and offering expenses, and excluding any proceeds that may be received from exercise of the Offering Warrants.

Each Offering Warrant has an exercise price per share of common stock equal to $4.68. Each Offering Warrant may be exercised until May 1, 2027. Each Offering Warrant is exercisable solely by means of a cash exercise, except that an Offering Warrant is exercisable via cashless exercise if at the time of exercise, a registration statement registering the issuance of Offering Warrant Shares is not then effective or the prospectus contained therein is not available for the issuance of such shares.

Cash Flows

The following table summarizes our sources and uses of cash for each of the periods presented:

Year Ended December 31,

(in thousands)

Cash used in operating activities $ (22,291 ) $ (19,808 )

Cash provided by investing activities — 16,196

Cash provided by financing activities 17,818 15,794

Effect of exchange rate changes on cash and cash equivalents — (63 )

Operating Activities

During the year ended December 31, 2024, operating activities used $22.3 million of cash, primarily resulting from our net loss of $62.9 million partially offset by a change in operating assets and liabilities of $2.4 million and non-cash charges of $38.2 million. Non-cash charges resulted primarily from impairment loss on intangible assets of $37.0 million and stock-based compensation expense of $1.1 million. Changes in our operating assets and liabilities during the year ended December 31, 2024 consisted primarily of a decrease of $2.2 million in other assets, and an increase of $1.7 million in accrued expenses and other current liabilities, offset by a decrease of $1.6 million in deferred tax liabilities due to the reduction in the carrying value of our intangible assets.

During the year ended December 31, 2023, operating activities used $19.8 million of cash, primarily resulting from our net loss of $15.7 million and cash provided by the change in operating assets and liabilities of $5.4 million offset by non-cash charges of $1.3 million. Non-cash charges resulted primarily from stock-based compensation expense of $1.2 million. Changes in our operating assets and liabilities during the year ended December 31, 2023 consisted primarily of an increase of $5.0 million in accounts payable, and $0.4 million in accrued expenses and other current liabilities.

Investing Activities

During the year ended December 31, 2024, no cash was provided by investing activities.

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During the year ended December 31, 2023, investing activities provided $16.2 million of cash. We received $16.3 million of proceeds from the maturities of investments, offset by $0.1 million of cash and cash equivalents from the Lung Acquisition.

Financing Activities

During the year ended December 31, 2024, net cash provided by financing activities was $17.8 million primarily due to the Offering in May 2024.

During the year ended December 31, 2023, net cash provided by financing activities was $15.8 million due to the proceeds of $15.8 million from the PIPE Financing in October 2023.

Funding Requirements

Our plan of operation is to continue implementing our business strategy, continue research and development of LTI-03 and LTI-01 and any other product candidates we may acquire or develop and continue to expand our research pipeline and our internal research and development capabilities. We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the preclinical activities and clinical trials of our current and future product candidates. In addition, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or terminate our research and development programs or future commercialization efforts. Our future capital requirements will depend on many factors, including:

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the scope, timing, progress, costs, and results of discovery, preclinical development, and clinical trials for our current and future product candidates;

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the number of clinical trials required for regulatory approval of our current and future product candidates;

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the costs, timing, and outcome of regulatory review of any of our current and future product candidates;

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the cost of manufacturing clinical and commercial supplies of our current and future product candidates;

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the costs and timing of future commercialization activities, including manufacturing, marketing, sales, and distribution, for any of our product candidates for which we receive marketing approval;

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the costs and timing of preparing, filing, and prosecuting patent applications, maintaining and enforcing our intellectual property rights, and defending any intellectual property-related claims, including any claims by third parties that we are infringing upon their intellectual property rights;

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our ability to maintain existing, and establish new, strategic collaborations, licensing, or other arrangements and the financial terms of any such agreements, including the timing and amount of any future milestone, royalty, or other payments due under any such agreement;

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the revenue, if any, received from commercial sales of our product candidates for which we receive marketing approval;

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expenses to attract, hire and retain, skilled personnel;

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the costs of operating as a public company;

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if our product candidates are approved, our ability to establish a commercially viable pricing structure and obtain approval for coverage and adequate reimbursement from third-party and government payors;

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the effect of competing technological and market developments;

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the extent to which we acquire or invest in businesses, products, and technologies; and

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unfavorable global economic conditions, which may exacerbate the magnitude of the factors discussed above.

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of the product candidates.

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As of December 31, 2024, we had cash and cash equivalents of $12.9 million. Based on our current operating plan, we believe that our existing cash and cash equivalents will be sufficient to enable us to fund our operating expenses and capital expenditure requirements into August 2025. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. Our future viability is dependent on our ability to raise additional capital to finance our operations. In addition, our existing cash and cash equivalents will not be sufficient to fund all of the efforts that we plan to undertake or to fund the completion of development of our product candidates. Accordingly, we will be required to obtain further funding through public or private equity offerings, debt financings, collaborations and licensing arrangements or other sources. Although management plans to pursue additional funding, there is no assurance that we will be successful in obtaining sufficient funding on terms acceptable to us to fund continuing operations, or at all.

Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations from the sale of additional equity or debt financings, strategic collaborations, licensing, arrangements or other sources. In the event that additional financing is required, we may not be able to raise it on terms acceptable to us, or at all. If we raise additional funds through the issuance of equity or convertible preferred stock, it may result in dilution to our existing stockholders. Debt financing or preferred equity financing, if available, may result in increased fixed payment obligations, and the existence of securities with rights that may be senior to those of our common stock. If we incur indebtedness, we could become subject to covenants that would restrict our operations.

If we raise funds through strategic collaborations, licensing or other arrangements, we may relinquish significant rights or grant licenses on terms that are not favorable to us. Our ability to raise additional funds may be adversely impacted by potential worsening global economic conditions and the recent disruptions to, and volatility in, the credit and financial markets in the United States and worldwide. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market products or product candidates that we would otherwise prefer to develop and market ourselves.

Off-Balance Sheet Arrangements

As of December 31, 2024 and 2023 and in the periods presented, we did not have any off-balance sheet arrangements, as defined in the rules and regulations of the SEC.

Critical Accounting Estimates

Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs, and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

Accrued Research and Development Expenses

As part of the process of preparing our financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing open contract and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated costs incurred for the services when we have not yet been invoiced or otherwise notified of the actual costs. Some of our service providers invoice us in arrears for services performed, on a pre-determined schedule or when contractual milestones are met; however, some require advanced payments. We make estimates of our accrued expenses as of each balance sheet date in our financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to:

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vendors in connection with preclinical and clinical development activities;

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contract research organizations, or CROs, in connection with performing research activities on our behalf and conducting preclinical studies and clinical trials on our behalf;

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•

investigative sites or other service providers in connection with clinical trials; and

•

contract manufacturing organization, or CMOs, or other vendors in connection with the production of preclinical and clinical trial materials.

We base our expenses related to preclinical studies and clinical trials on our estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CMOs and CROs that supply, conduct and manage clinical trials and preclinical studies on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones. In recording accrued or prepaid service fees, we estimate the time period over which services will be performed, enrollment of patients, number of sites activated and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual or amount of prepaid expense accordingly.

Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in us reporting amounts that are too high or too low in any particular period. To date, we have not made any material adjustments to our prior estimates of accrued research and development expenses.

Stock-Based Compensation

We account for stock-based compensation awards in accordance with ASC Topic 718, Compensation—Stock Compensation, or ASC 718. ASC 718 requires all stock-based payments, including grants of stock options and restricted stock, to be recognized in the statements of operations and comprehensive loss based on their fair values. We measure stock-based awards based on their fair value on the date of grant and recognize compensation expense for those awards over the requisite service period, which is generally the vesting period of the respective award. We apply the straight-line method of expense recognition to all awards with only service-based vesting conditions and apply the graded-vesting method to all awards with performance-based vesting conditions or to awards with both service-based and performance-based vesting conditions.

We estimate the fair value of each stock option grant at the date of grant using the Black-Scholes option pricing model and the fair value of each restricted common stock award is estimated on the date of grant based on the fair value of our common stock on that same date. The Black-Scholes option-pricing model requires inputs based on certain subjective assumptions including the volatility of our common stock, the expected term of our stock options, the risk-free interest rate for a period that approximates the expected term of our stock options and our expected dividend yield. Changes to these assumptions can materially affect the fair value of stock options and ultimately the amount of stock-based compensation expense recognized in our consolidated financial statements.

We account for stock option forfeitures during the period in which they occur.

Impairment on Indefinite-lived Intangible Assets

We review our intangible assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Indefinite-lived intangible assets, including goodwill, are tested for impairment at least annually. The fair value of reporting unit was determined using the income approach with a reconciliation to market capitalization. The fair value of intangible assets was determined using multi-period excess earning method and using Level 3 inputs, which included estimates of forecasted cash flows for each candidate.

Impairment is assessed by comparing the carrying value of the asset to its recoverable amount, which is determined as the higher of its fair value less costs to sell and its value in use. The value in use is estimated based on discounted future cash flows derived from assumptions regarding revenue growth, operating margins, discount rates, and market conditions. These estimates require significant management judgment and are subject to inherent uncertainties.

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Key assumptions used in impairment testing include:

•

Projected cash flows: Based on historical trends, market analysis, and business forecasts.

•

Discount rate: Reflecting the risk-adjusted cost of capital applicable to the asset or cash-generating unit.

•

Growth rate: Used for terminal value calculations, based on long-term industry outlook and economic conditions.

•

Market conditions: Including competitive landscape, industry trends, and macroeconomic factors.

Changes in these assumptions, particularly in discount rates or expected future cash flows, could result in significant adjustments to the impairment calculation and may lead to impairment losses recognized in the financial statements.

During the year ended December 31, 2024, we conducted an impairment assessment and determined that an impairment loss of $37.0 million was recognized for our LTI-01 intangible asset in connection with the temporary delay of further clinical development of LTI-01 until additional funds are raised. In the fourth quarter of 2024, we determined that the temporary delay of further clinical development of LTI-01 may not be a short-term measure.

Management continues to monitor these estimates and will adjust them as necessary to reflect changing economic conditions and business performance.

Income Taxes

We account for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in our tax returns. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse.

We assess the likelihood that our deferred tax assets will be recovered from future taxable income and, to the extent we believe, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Changes in valuation allowances from period to period are included in our tax provision in the period of change. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

We account for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.

The recognition and measurement of tax benefits requires significant judgment, especially in assessing uncertain tax positions. Judgments concerning the recognition and measurement of our tax benefits, as well as limitations surrounding their realizability, might change as new information becomes available.

Contractual Obligations

Our wholly owned subsidiary, Lung, leased a facility containing 6,455 square feet of office space located at 3801 S. Capital of Texas Hwy, Suite 330, Austin, Texas, which expired on March 31, 2024. We did not renew the lease. Following expiration of the lease, we are operating virtually, and expect to do so for the foreseeable future.

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Our remaining contractual rent commitment under this lease was $0 million and less than $0.1 million as of December 31, 2024 and December 31, 2023, respectively. For a description of our lease obligations, refer to Note 14 to our consolidated financial statements appearing in this Annual Report on Form 10-K.

Smaller Reporting Company Status

We are a “smaller reporting company” as defined in Rule 12b-2 under the Securities Exchange Act of 1934, as amended, or the Exchange Act. We may continue to be a smaller reporting company if either (i) the market value of our shares held by non-affiliates is less than $250.0 million or (ii) our annual revenue was less than $100.0 million during the most recently completed fiscal year and the market value of our shares held by non-affiliates is less than $700.0 million. For so long as we continue to be a smaller reporting company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies.

Recently Issued Accounting Pronouncements

We have reviewed all recently issued standards and have determined that, other than as disclosed in Note 2 to our consolidated financial statements appearing at the end of this Annual Report on Form 10-K, such standards will not have a material impact on our consolidated financial statements or do not otherwise apply to our operations.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

We are a smaller reporting company, as defined in Rule 12b-2 under the Exchange Act for this reporting period and are not required to provide the information required under this item.

Item 8. Financial Statements and Supplementary Data

The consolidated financial statements required to be filed pursuant to this Item 8 are appended to this Annual Report on Form 10-K. An index of those consolidated financial statements is found in Item 15 of Part IV of this Annual Report on Form 10-K.

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

None.

Item 9A. Controls and Procedures

Limitations on Effectiveness of Controls and Procedures

The term “disclosure controls and procedures”, as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, refers to controls and procedures that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the company’s management, including its principal executive and principal financial officers, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

In designing and evaluating our disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives. In addition, the design of disclosure controls and procedures must reflect the fact that there

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are resource constraints and that management is required to apply judgment in evaluating the benefits of possible controls and procedures relative to their costs.

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our Chief Executive Officer and our interim Chief Financial Officer, evaluated, as of the end of the period covered by this Annual Report on Form 10-K, the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act). Based on that evaluation, our Chief Executive Officer and our interim Chief Financial Officer concluded that our disclosure controls and procedures were not effective at the reasonable assurance level as of December 31, 2024, because of the identified material weaknesses in our internal control over financial reporting described below.

Management’s Annual Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting. Internal control over financial reporting is defined in Rules 13a-15(f) and 15d-15(f) promulgated under the Exchange Act as a process designed by, or under the supervision of, the company’s principal executive and principal financial officers and effected by the company’s board of directors, management and other personnel, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and includes those policies and procedures that:

•

Pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of the assets of the company;

•

Provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and

•

Provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Therefore, even those systems determined to be effective can provide only reasonable assurance with respect to financial statement preparation and presentation. Projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Management conducted an evaluation of the effectiveness of our internal control over financial reporting based on the Internal Control-Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on this evaluation, management concluded that our internal control over financial reporting was not effective as of December 31, 2024 as a result of the material weaknesses discussed below.

Material Weaknesses

We identified material weaknesses in our internal control over financial reporting. A material weakness is a deficiency, or combination of deficiencies, in internal control over financial reporting such that there is a possibility that a material misstatement of our financial statements will not be prevented or detected on a timely basis. Management identified material weaknesses related to the (i) lack of sufficient accounting and supervisory personnel to maintain appropriate segregation of duties relating to user access of the financial accounting system and who have the appropriate level of technical accounting experience and training, (ii) lack of evidence over reviews of account reconciliations and supporting schedules, and (iii) lack of adequate procedures and controls to ensure that accurate financial statements could have been prepared and reviewed on a timely basis for annual reporting purposes. In the year ended December 31, 2023, management identified material weaknesses related to the accounting for the Lung Acquisition, including a lack of sufficient precision in the performance of reviews supporting the purchase price

117

allocation accounting, and a lack of timely oversight over third-party specialists and the reports they produced to support the accounting for the Lung Acquisition.

Management’s Plan to Remediate the Material Weaknesses

We have implemented and are continuing to implement procedures to remediate these material weaknesses, including the hiring of a Controller with the requisite supervisory background and knowledge in financial reporting, integration into one accounting system, engaging third party accounting specialists and building a more streamlined process in order to prepare and review financial information, however, our control environment needs improvement, and as a result we may be exposed to errors. Our remediation plan also includes the hiring of additional accounting employees and/or consultants with the specific technical accounting experience necessary to assist with complex, non-routine transactions and to support the timely completion of financial close procedures, the implementation of robust processes, and to assist with the preparation of financial statements and our compliance with SEC reporting obligations. Management has engaged a third-party to assist in evaluating and documenting the design and operating effectiveness of our internal control over financial reporting, and their work is ongoing. With the help of third-party consultants, we have nearly completed the integration of the acquired systems from the Lung Acquisition into our financial and accounting systems. Additionally, we intend to develop and implement consistent accounting policies and internal control procedures and provide additional training to our accounting and financial reporting personnel.

The below are actions that we have taken to date to remediate the above-mentioned material weaknesses:

•

Enhanced the execution of our risk assessment activities by evaluating whether the design of our internal controls appropriately addresses changes in the business (including changes to people, processes and systems) that could impact our system of internal controls.

•

Substantially completed the integration of the acquired systems from the Lung Acquisition into our financial and accounting systems to allow for systematic segregation of duties, and to enhance the accurate and timely preparation and review of financial statements and supporting schedules.

•

Engaged a third-party to assist in assessing the design and implementation of controls and develop remediation plans for identified control gaps related to our timely preparation and review of account reconciliations, financial statements and supporting schedules.

•

Reported regularly to the audit committee on the progress and results of the remediation plan, including the identification, status and resolution of internal control deficiencies.

In addition to implementing and executing the aforementioned activities, the following activities are expected to be completed in fiscal year 2025:

•

Continue to reassess staffing and add additional resources, as required, with the requisite technical accounting experience and training, to further allow for segregation of duties and to support our system of internal control.

•

Implement remediation plans for identified control design and implementation gaps.

•

Define user roles within our ERP system to ensure proper segregation of duties within our accounting systems.

•

Perform testing of operating effectiveness of identified controls over financial reporting including IT General Controls.

•

As needed, we will also supplement our internal resources with additional third-party resources to enhance our corporate oversight and monitoring over process-level controls and structures to ensure that there is appropriate assignment of authority, responsibility, and accountability.

The material weaknesses will not be considered remediated until management completes the design and implementation of the measures described above and the controls operate for a sufficient period of time and management has concluded, through testing, that these controls are effective. Management believes that the remediation measures described above will be implemented in a manner such that the controls can be tested, and the

118

identified material weaknesses can be determined to be remediated, however, no assurance can be made that such remediation will occur or that additional material weaknesses will not be identified.

Changes in Internal Control Over Financial Reporting

Except for the above noted and previously reported material weaknesses and the related ongoing remediation activities described above, no change in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) has occurred during the year ended December 31, 2024 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

Item 9B. Other Information

Rule 10b5-1 Trading Plans

During the fourth quarter of 2024, none of our directors or officers adopted or terminated a Rule 10b5-1 trading arrangement or non-Rule 10b5-1 trading arrangement, as each term is defined in Item 408(a) of Regulation S-K.

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

None.

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PART III

Item 10. Directors, Executive Officers and Corporate Governance

The information required by this Item 10 will be included in our definitive proxy statement to be filed with the Securities and Exchange Commission, or SEC, with respect to our 2025 Annual Meeting of Stockholders, which is expected to be filed no later than 120 days after the end of our last fiscal year ended December 31, 2024 and is incorporated herein by reference.

We have adopted a Code of Business Conduct and Ethics that applies to our officers, including our principal executive, financial and accounting officers, and our directors and employees. We have posted the text of our Code of Business Conduct and Ethics under the “Investors & Media — Governance” section of our website, www.reintx.com. We intend to disclose on our website any amendments to, or waivers from, the Code of Business Conduct and Ethics that are required to be disclosed pursuant to the disclosure requirements of Item 5.05 of Form 8-K.

Item 11. Executive Compensation

The information required by this Item 11 will be included in our definitive proxy statement to be filed with the SEC with respect to our 2025 Annual Meeting of Stockholders, which is expected to be filed no later than 120 days after the end of our last fiscal year ended December 31, 2024 and is incorporated herein by reference.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

The information required by this Item 12 will be included in our definitive proxy statement to be filed with the SEC with respect to our 2025 Annual Meeting of Stockholders, which is expected to be filed no later than 120 days after the end of our last fiscal year ended December 31, 2024 and is incorporated herein by reference.

Item 13. Certain Relationships and Related Transactions, and Director Independence

The information required by this Item 13 will be included in our definitive proxy statement to be filed with the SEC with respect to our 2025 Annual Meeting of Stockholders, which is expected to be filed no later than 120 days after the end of our last fiscal year ended December 31, 2024 and is incorporated herein by reference.

Item 14. Principal Accounting Fees and Services

The information required by this Item 14 will be included in our definitive proxy statement to be filed with the SEC with respect to our 2025 Annual Meeting of Stockholders, which is expected to be filed no later than 120 days after the end of our last fiscal year ended December 31, 2024 and is incorporated herein by reference.

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PART IV

Item 15. Exhibits, Financial Statement Schedules

The following documents are filed as part of this Report:

(a)

Financial Statements. The following documents are included on pages F4-F35 attached hereto and are filed as part of this Annual Report on Form 10-K:

(b)

Financial Statement Schedules. Schedules have been omitted since they are either not required or not applicable or the information is otherwise included herein.

(c)

Exhibits. The exhibits filed as part of this Annual Report on Form 10-K are set forth on the Exhibit Index below. The Exhibit Index is incorporated herein by reference.

Item 16. Form 10-K Summary

None.

Exhibit Index

Incorporation by Reference

ExhibitNumber Description Form Date of Filing ExhibitNumber FiledHerewith

3.5 Amended and Restated By-laws of the Registrant 8-K 1/10/2025 3.2

4.2 Description of Securities of the Registrant 10-K 4/15/2024 4.2

121

122

19.1* Aileron Insider Trading Policy X

23.1 Consent of Marcum LLP, independent registered public accounting firm X

123

97.1 Aileron Therapeutics, Inc. Compensation Recovery Policy 10-K 4/15/2024 97.1

101.SCH Inline XBRL Taxonomy Extension Schema With Embedded Linkbase Documents

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

* Indicates management contract or compensatory plan.

+ In accordance with Item 601(b)(10)(iv) of Regulation S-K, certain information (indicated by “[**]”) has been excluded from this exhibit because it is both not material and private or confidential. A copy of the omitted portion will be furnished to the SEC upon request.

++ Confidential treatment has been requested and/or granted as to certain portions, which portions have been omitted and filed separately with the SEC.

# Certain schedules and similar attachments have been omitted pursuant to Item 601(a)(5) of Regulation S-K. The registrant undertakes to furnish supplemental copies of any of the omitted schedules upon request by the SEC.

^ SEC File No. 333-218474

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Report to be signed on its behalf by the undersigned, thereunto duly authorized.

Rein Therapeutics, Inc.

Date: April 7, 2025 By: /s/ Brian Windsor, Ph.D.

Brian Windsor, Ph.D.

President and Chief Executive Officer(principal executive officer)

POWER OF ATTORNEY

Each person whose signature appears below constitutes and appoints Brian Windsor, Ph.D. and Timothy M. Cunningham, each or any of them, such person's true and lawful attorney-in-fact and agent with full power of substitution and resubstitution for such person and in such person's name, place and stead, in any and all capacities, to sign any and all amendments to this report on Form 10-K, and to file the same with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing necessary or desirable to be done in and about the premises, as fully to all intents and purposes as such person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them or his or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this Report has been signed below by the following persons on behalf of the Registrant in the capacities and on the dates indicated.

Name Title Date

Brian Windsor, Ph.D.

Timothy M. Cunningham

/s/ Josef H. Von Rickenbach Chairman of the Board of Directors April 7, 2025

Josef H. Von Rickenbach

/s/ Manuel C. Aivado Director April 7, 2025

Manuel C. Aivado, M.D. Ph. D.

/s/ Reinhard J. Ambros, Ph.D. Director April 7, 2025

Reinhard J. Ambros, Ph.D.

/s/ William C. Fairey Director April 7, 2025

William C. Fairey

/s/ Alan Musso Director April 7, 2025

Alan Musso

125

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Report of Independent Registered Public Accounting Firm (PCAOB ID 688) F-1

Consolidated Balance Sheets as of December 31, 2024 and 2023 F-4

Notes to Consolidated Financial Statements F-8

126

Report of Independent Registered Public Accounting Firm

To the Shareholders and Board of Directors of

Rein Therapeutics Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Rein Therapeutics Inc.(the “Company”) as of December 31, 2024 and 2023, the related consolidatedstatements of operations and comprehensive loss, changes in convertible preferred stock and stockholders’ equity and cash flows for each of the two years in the period ended December 31, 2024, and the related notes(collectively referred to as the “financial statements”). In our opinion, based on our audits, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2024, in conformity with accounting principles generally accepted in the United States of America.

Explanatory Paragraph – Going Concern

The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As more fully described in Note 1, the Company has incurred significant losses and expects to continue to incur operating losses and needs to raise additional funds to meet its obligations and sustain its operations. These conditions raise substantial doubt about the Company's ability to continue as a going concern. Management's plans in regard to these matters are also described in Note 1. The consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) ("PCAOB") and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our auditsprovide a reasonable basis for our opinion.

F-1

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the financial statements that were communicated or required to be communicated to the audit committee and that: (1) relate to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

Goodwill and Indefinite-Lived Intangible Assets Impairment Assessment

Critical Audit Matter Description

As described in Notes 1 and 6 to the consolidated financial statements, the Company’s consolidated balances of Goodwill and In-process Research and Development (“IPR&D”) indefinite-lived intangible assets were $6.3 million and $42.2 million, respectively, as of December 31, 2024. The Company reviews goodwill for impairment at least annually or more frequently if events or circumstances indicate the carrying value at the reporting unit level might exceed its fair value. The IPR&D indefinite-lived intangibles are tested annually for impairment, or more frequently if events or circumstances indicate it is more likely than not the fair value is less than their carrying value. The Company estimated the fair value of its reporting unit using an income approach. The Company estimated the fair value of certain IPR&D assets using a multi period excess earnings model. The Company performed impairment analyses for IPR&D and Goodwill, which resulted in an impairment charge of $37 million relating to the IPR&D and no impairment relating to Goodwill.

The principal consideration, for our determination that the evaluation of the fair values of the indefinite-lived intangible assets and the Company’s reporting unit, as a critical audit matter is the high degree of subjective auditor judgment associated with evaluating management’s determination of the fair values, which is primarily due to the complexity of the valuation models used and the sensitivity of the underlying significant assumptions.

The key assumptions used in the determination of the fair value of the reporting unit include estimates of future cash flows and the discount rate applicable to those future cash flow periods. The key assumptions used in the determination of the fair value of certain IPR&D assets include estimates of future cash flows, the probability of success in various phases of its development programs, the discount rate applicable to those future cash flow periods, the tax rate and the timing of regulatory approval. Changes to these key assumptions could have a significant impact on the measurement of the fair value of the reporting unit and certain IPR&D. Auditing management’s valuation methods and these assumptions involve especially challenging and subjective auditor judgment due to the nature and extent of auditor effort required to address these matters, including the specialized knowledge and skill needed.

How the Critical Audit Matter was Addressed in the Audit

Our audit procedures related to the valuation of the fair values of goodwill and indefinite-lived intangible assets included the following, among others:

•We evaluated the reasonableness of the valuation analysis from management and the third-party specialist engaged by management.

•We assessed the qualifications and competence of management and the third-party specialist.

F-2

•We evaluated the methodologies used to determine the fair values of the indefinite-lived intangible assets and goodwill.

•We tested the assumptions used to estimate the fair values, which included key assumptions such as the estimates of future cash flows, the probability of success in various phases of its development programs, the discount rate applicable to those future cash flow periods, the tax rate, and the timing of regulatory approval.

•We assessed the reasonableness of management’s forecast of estimated future cash flows by inquiring with management to understand how the forecast was developed and comparing the projections to external sources including industry trends and data and peer companies’ historical data.

•We involved our internal valuation specialist who assisted in (i) evaluating the reasonableness of valuation methods, (ii) testing the mathematical accuracy of the Company’s calculations, (iii) evaluating the reasonableness of the implied control premium; and (iv) evaluating the reasonableness of the significant assumptions to the models, including the discount rate applied to future cash flows.

/s/ Marcum llp

Marcum llp

We have served as the Company’s auditor since 2024.

New York, New York

April 7, 2025

F-3

REIN THERAPEUTICS, INC.

CONSOLIDATED BALANCE SHEETS

(In thousands, except share and per share data)

Assets

Current assets:

Prepaid expenses and other current assets 792 882

Restricted cash — 25

Operating lease, right-of-use asset, current portion — 46

Property and equipment, net 1 19

Other non-current assets 2 2,193

Liabilities, Convertible Preferred Stock and Stockholders’ Equity

Current liabilities:

Accrued expenses and other current liabilities 4,838 3,147

Operating lease liabilities, current portion — 48

Other long-term liability 277 —

Commitments and contingencies (Note 14)

Stockholders’ equity:

Accumulated other comprehensive loss (18 ) (63 )

The accompanying notes are an integral part of these consolidated financial statements.

F-4

REIN THERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(In thousands, except share and per share data)

Year Ended December 31,

Revenue $ — $ —

Operating expenses:

Impairment loss on intangible assets 37,000 —

Restructuring and other costs — 928

Income tax benefit 1,544 —

Net loss per share—basic and diluted $ (3.51 ) $ (3.42 )

Comprehensive loss:

Other comprehensive gain (loss):

Unrealized gain on investments, net of tax of $0 45 48

Foreign currency translation adjustments — (63 )

Total other comprehensive gain (loss) 45 (15 )

The accompanying notes are an integral part of these consolidated financial statements.

F-5

REIN THERAPEUTICS, INC.

CONSOLIDATED STATEMENT OF CHANGES IN CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY

(In thousands, except share data)

Series X Non-Voting Convertible Preferred Stock Common Stock Total Convertible

Stock-based compensation expense — — — — 1,190 — — 1,190

Unrealized gain on short-term investments — — — — — 48 — 48

Foreign currency translation adjustments — — — — — (63 ) — (63 )

Issuance cost in connection with the Offering — — (488 ) — — (488 )

Stock-based compensation expense — — — — 1,117 — — 1,117

Unrealized gain on investments 45 45

The accompanying notes are an integral part of these consolidated financial statements.

F-6

REIN THERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

Year Ended December 31,

Cash flows from operating activities:

Adjustments to reconcile net loss to net cash used in operating activities:

Depreciation and amortization expense 63 119

Net amortization of premiums and discounts on investments — 32

Stock-based compensation expense 1,117 1,190

Gain on sale of property and equipment — (42 )

Impairment loss on intangible assets 37,000 —

Loss on disposition of property and equipment — 6

Changes in operating assets and liabilities:

Prepaid expenses and other current assets 134 51

Operating lease liabilities (48 ) (65 )

Accrued expenses and other current liabilities 1,691 (382 )

Other long-term liabilities 277 —

Deferred tax liabilities (1,554 ) —

Net cash used in operating activities (22,291 ) (19,808 )

Cash flows from investing activities:

Proceeds from sale of property and equipment — 42

Proceeds from sales or maturities of investments — 16,250

Acquisition, net of cash acquired — (96 )

Net cash provided by investing activities — 16,196

Cash flows from financing activities:

Proceeds from issuance of common stock, net of offering costs 10,645 —

Proceeds from issuance of warrants, net of offering costs 7,030 —

Proceeds from the PIPE Financing — 15,794

Net cash provided by financing activities 17,818 15,794

Effect of exchange rate changes on cash and cash equivalents — (63 )

Cash, cash equivalents and restricted cash at beginning of year 17,338 5,219

Cash, cash equivalents and restricted cash at end of year $ 12,865 $ 17,338

Cash and cash equivalents at end of year $ 12,865 $ 17,313

Restricted cash at end of year — 25

Cash, cash equivalents and restricted cash at end of year $ 12,865 $ 17,338

Supplemental disclosure of non-cash investing and financing activities:

Unrealized gain on short-term investments $ — $ 48

Fair value of common shares issued in the Lung Acquisition $ — $ 403

Fair value of options assumed in the Lung Acquisition $ — $ 1,050

Fair value of warrants assumed in the Lung Acquisition $ — $ 627

The accompanying notes are an integral part of these consolidated financial statements.

F-7

REIN THERAPEUTICS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

(Amounts in thousands, except share and per share data)

1. Nature of the Business

On January 10, 2025, Aileron Therapeutics, Inc., or Aileron, amended its Restated Certificate of Incorporation, as amended, to effect a change of the Company’s name from “Aileron Therapeutics, Inc.” to “Rein Therapeutics, Inc.” (“Rein” or the “Company”). The name change became effective at 4:00 p.m. Eastern Time on January 10, 2025.

The Board of Directors of the Company, or the Board, approved the name change pursuant to Section 242 of the General Corporation Law of the State of Delaware. The name change does not affect the rights of the Company’s stockholders, and there were no other changes to the Certificate of Incorporation. A copy of the certificate of amendment to the Restated Certificate of Incorporation filed with the Secretary of State of the State of Delaware to affect the name change was filed with the Securities and Exchange Commission, or the SEC.

In connection with the name change, the Board also approved an amendment and restatement of the Company’s Amended and Restated Bylaws solely to reflect the name change (as amended and restated, the “Amended and Restated Bylaws”) effective as of January 10, 2025. A copy of the Amended and Restated Bylaws was filed with the SEC.

Aileron Therapeutics, Inc. was a clinical stage chemoprotection oncology company. Aileron's product candidate, ALRN-6924, was a MDM2/MDMX dual inhibitor that leverages its proprietary peptide drug technology. In February 2023, Aileron decided to terminate further development of ALRN-6924. On October 31, 2024, Aileron entered into an exclusive option agreement with Advancium Health Network, or Advancium, for the sale of ALRN-6924.

The Company is a clinical stage biopharmaceutical company focused on developing novel therapies for the treatment of fibrosis indications with no approved or limited effective treatments. The Company currently has two product candidates in clinical development, LTI-03 and LTI-01, and multiple candidates in preclinical development focused on fibrosis indications.

On October 31, 2023, the Company acquired Lung Therapeutics, Inc., or Lung Therapeutics or Lung, pursuant to an Agreement and Plan of Merger, dated October 31, 2023, or the Lung Acquisition Agreement, by and among the Company, AT Merger Sub I, Inc., a Delaware corporation and its wholly owned subsidiary, or the First Merger Sub, AT Merger Sub II, LLC, a Delaware limited liability company and its wholly owned subsidiary, or the Second Merger Sub, and Lung. Pursuant to the Lung Acquisition Agreement, First Merger Sub merged with and into Lung, pursuant to which Lung was the surviving entity and became its wholly owned subsidiary, or the First Merger. Immediately following the First Merger, Lung merged with and into Second Merger Sub, pursuant to which Second Merger Sub was the surviving entity, such merger, together with the First Merger, the Lung Acquisition. Lung was incorporated on November 13, 2012 under the laws of the state of Texas. Its principal offices are in Austin, Texas. Following the Lung Acquisition, the Company shifted its operating disease focus to advancing a pipeline of first-in-class medicines to address significant unmet medical needs in orphan pulmonary and fibrosis indications with the potential to greatly improve patient outcomes over currently available treatments. Following expiration of the lease on March 31, 2024, Rein currently operates and expects to operate virtually for the foreseeable future.

The Company is subject to risks and uncertainties common to clinical-stage companies in the biotechnology industry, including, but not limited to the risk that the Company never achieves profitability, the need for substantial additional financing, the risk of relying on third parties, risks of clinical trial failures, dependence on key personnel, protection of proprietary technology, and compliance with government regulations. The Company’s lead product candidate, LTI-03, is being developed for the treatment of Idiopathic Pulmonary Fibrosis, or IPF, and has completed a healthy volunteer Phase 1a clinical trial and has conducted a Phase 1b clinical trial in IPF patients. The Company’s second product candidate, LTI-01, is in development for loculated pleural effusion, or LPE. The Company has completed Phase 1b and Phase 2a clinical trials in LPE patients.

F-8

Liquidity and Going Concern

In accordance with Accounting Standards Update, or ASU, No. 2014-15, Disclosures of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), the Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the accompanying consolidated financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the consolidated financial statements are issued. When substantial doubt exists, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the consolidated financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Generally, to be considered probable of being effectively implemented, the plans must have been approved before the date that the consolidated financial statements are issued.

The Company’s consolidated financial statements have been prepared assuming that the Company will continue to operate as a going concern, which contemplates the continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business. Through December 31, 2024, the Company has financed its operations primarily through $145,467 in net proceeds from sales of common stock and warrants, $131,211 from sales of preferred stock prior to its initial public offering, or IPO, $34,910 from a collaboration agreement in 2010, $17,536 in net proceeds in connection with a private placement following the Lung Acquisition in 2023, and $17,675 in net proceeds in connection with an underwritten offering of the Company's common stock and accompanying warrants to purchase common stock in May 2024. As of December 31, 2024, the Company had $12,865 in cash and cash equivalents.

In May 2024, the Company completed an underwritten follow-on public offering, or the Offering, pursuant to which the Company issued and sold 4,273,505 shares of the Company’s common stock, par value $0.001 per share, or the Offering Shares, and accompanying warrants, or the Offering Warrants, to purchase 4,273,505 shares of common stock, or the Offering Warrant Shares. All of the Offering Shares and Offering Warrants were sold by the Company. Each Offering Share was offered and sold together with an accompanying Offering Warrant at a combined offering price of $4.68, and the underwriter purchased each Offering Share with an accompanying Offering Warrant from the Company at a combined price of $4.35. Net proceeds from the Offering were $17,675, after deducting underwriting discounts and commissions and offering expenses, and excluding any proceeds that may be received from exercise of the Offering Warrants. As of December 31, 2024, none of the Offering Warrants had been exercised.

On July 26, 2024, the Company entered into an Equity Distribution Agreement with Citizens JMP Securities, LLC, or Citizens JMP, as agent and/or principal, under which the Company may offer and sell up to $50,000 of shares of its common stock from time to time through or to Citizens JMP. Sales of common stock through or to Citizens JMP may be made by any method that is deemed an “at the market” offering as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended, including sales made directly on or through the Nasdaq Capital Market. There have been no sales on the “at the market” offering through December 31, 2024. Refer to Note 17 for sales on the “at the market” offering subsequent to the consolidated balance sheet date.

Management believes that, based on the Company’s current operating plan, the Company’s cash and cash equivalents of $12,865 as of December 31, 2024 will not be sufficient to enable the Company to fund its operating expenses and capital expenditure requirements for at least twelve months from the date of issuance of these consolidated financial statements, which raises substantial doubt about our ability to continue as a going concern.

Since its inception, the Company has not generated any revenue from product sales and has never generated an operating profit. The Company has incurred significant losses on an aggregate basis. The Company’s net losses were $62,883 and $15,732 for the years ended December 31, 2024 and 2023, respectively. As of December 31, 2024, the Company had an accumulated deficit of $351,400. These losses have resulted primarily from costs incurred in connection with research and development activities, licensing and patent investment and general and administrative costs associated with the Company’s operations. Management expects to continue to incur operating losses for the foreseeable future. The Company expects to finance its operations primarily through utilization of its current financial resources and through the sale of additional equity or debt financings, collaborations, licensing arrangements or other sources.

F-9

The Company plans to address these conditions by, among other things, raising additional funds through equity or debt financings, strategic collaborations, licensing arrangements or other sources. However, there is no assurance that such funding will be available to the Company, will be obtained on terms favorable to the Company or will provide the Company with sufficient funds to meet its objectives. The Company’s funding estimates are based on assumptions that may prove to be wrong, and the Company could use its available capital resources sooner than it currently expects. If additional funds are not available, the Company could be forced to delay, reduce or eliminate its research and development programs or future commercialization efforts and its business could be materially harmed. The Company’s future viability is dependent on its ability to raise additional capital, enter into a financing, consummate a successful acquisition, merger, business combination, or a sale of assets or other transaction. If the Company becomes unable to continue as a going concern, it may have to liquidate its assets and the values it receives for its assets in liquidation or dissolution could be significantly lower than the values reflected in its consolidated financial statements. The consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, or U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification, or ASC, and as amended by ASUs of the Financial Accounting Standards Board, or FASB.

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Lung Therapeutics, LLC, Lung Therapeutics Australia Pty Ltd, and Lung Therapeutics Limited. Lung Therapeutics Limited is currently inactive. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual for research and development expenses, the prepaid research and development expenses, valuation of intangibles and goodwill, the valuation of warrants, and the value of stock-based compensation. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.

Foreign Currency Transactions

The functional currency for the Company’s wholly owned foreign subsidiary, Lung Therapeutics Australia Pty Ltd., is the United States dollar. All foreign currency transaction gains and losses are recognized in the consolidated statements of operations and comprehensive loss.

Concentration of Credit Risk and of Significant Suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Periodically, the Company maintains balances in operating accounts above federally insured limits. The Company deposits its cash in financial institutions that it believes have high credit quality. The Company has not experienced any losses on such accounts and does not believe it is exposed to any significant credit risk on cash and cash equivalents.

F-10

The Company is dependent on third-party manufacturers to supply products for research and development activities of its programs, including preclinical and clinical testing. In particular, the Company relied on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could have been adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs.

Cash and Cash Equivalents

The Company maintains cash balances in various accounts, including those insured by the Federal Deposit Insurance Corporation (FDIC). The FDIC provides insurance coverage up to applicable limits for deposits held in participating financial institutions.

The Company considers all short-term, highly liquid investments with original maturities of 90 days or less at the acquisition date to be cash equivalents. The Company’s cash equivalents are comprised of fundsheld in money market accounts and treasury bills account and are measured at fair value on a recurring basis.

Fair Value Measurements

Certain assets and liabilities are carried at fair value under GAAP. ASC 820, Fair Value Measurement, or ASC 820, establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable.

•

Level 1—Quoted prices in active markets for identical assets or liabilities.

•

Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

•

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

The Company’s cash equivalents are carried at fair value, determined according to the fair value hierarchy described above (see Note 4). The carrying values of the Company’s accounts payable and accrued expenses approximate their fair value due to the short-term nature of these liabilities.

Leases

The Company accounts for leases under ASC Topic 842, Leases, or ASC 842. Under ASC 842, at inception of a contract, the Company determines whether an arrangement is or contains a lease. For all leases, the Company determines the classification as either operating leases or financing leases. Operating leases are included in operating lease right-of-use assets and operating lease liabilities in the Company’s consolidated balance sheets.

Lease recognition occurs at the commencement date and lease liability amounts are based on the present value of lease payments over the lease term. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. If a lease does not provide information to determine an

F-11

implicit interest rate, the Company uses its incremental borrowing rate in determining the present value of lease payments. Right-of-use, or ROU, assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments under the lease. ROU assets also include any lease payments made prior to the commencement date and exclude lease incentives received. Operating lease payments are expensed using the straight-line method as a general and administrative expense over the lease term. The depreciable life of assets and leasehold improvements are limited by the expected lease term unless there is a transfer of title or purchase option reasonably certain of exercise. The Company has elected to apply the practical short-term expedient to leases with a lease term of 12 months or less, which does not subject the leases to capitalization.

The Company had an operating lease of office space. The lease expired March 31, 2024, and the Company did not renew the lease. Following expiration of the lease, the Company is operating virtually, and expects to do so for the foreseeable future.

Goodwill and Indefinite-Lived Intangible Assets

Goodwill represents the excess of the purchase price of an acquired business over the amount assigned to the assets acquired and liabilities assumed. The Company's indefinite-lived intangible assets, which consist of in-process research and development, or IPR&D, acquired in the Lung Acquisition were recorded at fair value on their acquisition date. Goodwill and indefinite-lived intangible assets are not amortized but are subject to impairment testing on an annual basis as of December 31 or more frequently if events or circumstances indicate a potential impairment. The Company accounts for goodwill and indefinite-lived intangible assets in accordance with ASC 350, Intangibles Goodwill and Other, and ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. The Company’s goodwill and intangible assets are deductible for tax purposes.

Impairment of Long-Lived Assets

Long-lived assets consist of property and equipment, goodwill and intangible assets. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows.

In performing the Company’s annual goodwill impairment test, the Company is permitted to first assess qualitative factors to determine whether it is more likely than not that the fair value of the Company’s reporting unit exceeds its carrying amount, including goodwill. In performing the qualitative assessment, the Company considers certain events and circumstances specific to the reporting unit and to the entity as a whole, such as macroeconomic conditions, industry and market considerations, overall financial performance and cost factors when evaluating whether it is more likely than not that the fair value of the reporting unit exceeds its carrying amount. The Company is also permitted to bypass the qualitative assessment and proceed directly to the quantitative assessment. If the Company chooses to undertake the qualitative assessment and concludes that it is more likely than not that the fair value of the reporting unit is less than its carrying amount, the Company would then proceed to the quantitative impairment assessment. In the quantitative assessment, the Company compares the fair value of the reporting unit to its carrying amount, which includes goodwill. If the fair value exceeds the carrying value, no impairment loss exists. If the fair value is less than the carrying amount, a goodwill impairment loss is measured and recorded.

In the fourth quarter of 2024, the Company recorded an impairment loss on intangible assets of $37,000. For additional details regarding goodwill and intangible assets, refer to Note 6.

F-12

Series X Convertible Preferred Stock

The Company has classified its Series X convertible preferred stock, referred to as Series X Preferred Stock, as temporary equity in the accompanyingconsolidated balance sheets due to terms that allow for redemption of the shares in cash upon certain change in control events that are outside of the Company’s control, including sale or transfer of control of the Company as holders of the Series X Preferred Stock could cause redemption of the shares in these situations. The Company did not accrete the carrying values of the preferred stock to the redemption values since a liquidation event was not considered probable as of December 31, 2024. Subsequentadjustments of the carrying values to the ultimate redemption values will be made only when it becomes probable that such a liquidation event will occur.

Research and Development Costs

Research and development costs are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including stock-based compensation and benefits, facilities costs, costs of clinical trials, sponsored research, manufacturing, and external costs of outside vendors engaged to conduct preclinical development activities and trials.

Costs incurred in obtaining technology licenses are immediately recognized as research and development expense if the technology licensed has not reached technological feasibility and has no alternative future uses.

The Company has entered into various research and development and other agreements with commercial firms, researchers, universities, and others for provisions of goods and services. These agreements are generally cancelable, and the related costs are recorded as research and development expenses as incurred. Research and development expenses include costs for salaries, employee benefits, subcontractors, facility-related expenses, depreciation and amortization, stock-based compensation, laboratory supplies, and external costs of outside vendors engaged to conduct discovery, preclinical and clinical development activities, and clinical trials as well as to manufacture clinical trial materials, and other costs. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ materially from the Company’s estimates. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. Such prepaid expenses are recognized as an expense when the goods have been delivered or the related services have been performed, or when it is no longer expected that the goods will be delivered, or the services rendered.

Upfront payments, milestone payments and annual maintenance fees under license agreements are expensed in the period in which they are incurred in the consolidated statements of operations and comprehensive loss.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.

Accounting for Stock-Based Compensation

The Company measures all stock options and other stock-based awards granted to employees, directors and non-employee consultants based on the fair value on the date of the grant and recognizes compensation expense of those awards, net of forfeitures, over the requisite service period, which is generally the vesting period of the respective award. The Company applies the straight-line method of expense recognition to all awards with only service-based vesting conditions and applies the graded vesting method to all awards with performance-based vesting conditions or both service-based and performance-based vesting conditions.

F-13

The Company recognizes compensation expense for only the portion of awards that are expected to vest. The Company accounts for forfeitures as they occur. For performance-based awards, the Company does not recognize expense until the underlying vesting conditions are deemed to be probable of occurrence.

The Company classifies share-based compensation expenses in its consolidated statement of operations and comprehensive loss in the same manner in which the award recipient's payroll costs are classified or in which the award recipient's service payments are classified, either to general and administrative expenses or research and development expenses.

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company estimates its expected stock volatility using a combination of its own historical stock price volatility and the historical volatilities of a group of peer companies in its industry with similar market characteristics. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The quoted market price of the Company’s common stock is used to estimate the fair value of the stock-based awards at grant date.

Restructuring and Other Costs

The Company incurred restructuring-related charges of $928 for the year ended December 31, 2023 relating to the Company's decision to terminate its Phase 1b breast cancer trial of ALRN-6924 and further development of ALRN-6924. One-time termination costs were in connection with the reduction-in-workforce, including severance, benefits, and related costs. The Company paid all restructuring-related charges during the year ended December 31, 2023.

Income Taxes

The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse.

The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Changes in valuation allowances from period to period are included in the Company’s tax provision in the period of change. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.

Inflation Reduction Act of 2022

F-14

On August 16, 2022, the Inflation Reduction Act of 2022, or IR Act, was signed into federal law. The IR Act provides for, among other things, a new U.S. federal 1% excise tax on certain repurchases of stock by publicly traded U.S. domestic corporations and certain U.S. domestic subsidiaries of publicly traded foreign corporations occurring on or after January 1, 2023. The excise tax is imposed on the repurchasing corporation itself, not its shareholders from which shares are repurchased. The amount of the excise tax is generally 1% of the fair market value of the shares repurchased at the time of the repurchase. However, for purposes of calculating the excise tax, repurchasing corporations are permitted to net the fair market value of certain new stock issuances against the fair market value of stock repurchases during the same taxable year. In addition, certain exceptions apply to the excise tax. The U.S. Department of the Treasury, or Treasury, has been given authority to provide regulations and other guidance to carry out and prevent the abuse or avoidance of the excise tax.

Any redemption or other repurchase that occurs after December 31, 2022, in connection with a business combination, extension vote or otherwise, may be subject to the excise tax. Whether and to what extent the Company would be subject to the excise tax in connection with a business combination, extension vote or otherwise would depend on a number of factors, including (i) the fair market value of the redemptions and repurchases in connection with the business combination, extension or otherwise, (ii) the structure of a business combination, (iii) the nature and amount of any private investment in public equity, or the PIPE, or other equity issuances in connection with a business combination (or otherwise issued not in connection with a business combination but issued within the same taxable year of a business combination) and (iv) the content of regulations and other guidance from the Treasury. In addition, because the excise tax would be payable by the Company and not by the redeeming holder, the mechanics of any required payment of the excise tax have not been determined. The foregoing could cause a reduction in the cash available on hand to complete a business combination and in the Company’s ability to complete a business combination.

Segment reporting

Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker, or CODM, in deciding how to allocate resources and in assessing performance. The Company’s CODM is its Chief Executive Officer, or CEO. The Company operates and manages its business as a single operating and reportable segment on a consolidated basis, which is consistent with how its CODM reviews financial performance and allocates resources.

Comprehensive Loss

Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders. The Company’s other comprehensive loss in all periods presented includes unrealized gains (losses) on available-for-sale investments and foreign currency translation adjustments.

Net Loss per Share

Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net loss attributable to common stockholders is computed by adjusting loss per share attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares. For purpose of this calculation, Series X non-voting convertible preferred stock, outstanding options and warrants to purchase common stock are considered potentially dilutive securities.

Acquisition Accounting

The fair value of the consideration exchanged in a business combination is allocated to tangible assets and identifiable intangible assets acquired and liabilities assumed at acquisition date fair value. Goodwill is measured as the excess of the consideration transferred over the net fair value of identifiable assets acquired and liabilities assumed.

F-15

The accounting for an acquisition involves a considerable amount of judgment and estimation. Cost, income, market or a combination of approaches may be used to establish the fair value of consideration exchanged, assets acquired, and liabilities assumed, depending on the nature of those items. The valuation approach is determined in accordance with generally accepted valuation methods. Key areas of estimation and judgment may include the selection of valuation approaches, cost of capital, market characteristics, cost structure, impacts of synergies, and estimates of terminal value, among other factors.

While the Company uses estimates and assumptions as part of the purchase price allocation process to estimate the fair value of assets acquired and liabilities assumed, estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed, with a corresponding offset to goodwill, to the extent that adjustments are identified to the preliminary purchase price allocation. Upon conclusion of the measurement period, or final determination of the value of the assets acquired and liabilities assumed, whichever comes first, any subsequent adjustments are recorded to results of operations.

Recently Adopted Accounting Pronouncements

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Segment Disclosures, to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. This ASU is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. On January 1, 2023, the Company adopted this ASU. The Company has evaluated the impact of the new requirements and prepared the required disclosures. Refer to Note 2 for the Company's segment reporting accounting policy and Note 15 for a summary of the segment loss, including significant segment expenses.

Accounting Pronouncements Not Yet Adopted

In January 2025, the FASB issued ASU 2025-01, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date, to clarify the effective date of ASU 2024-03, Income Statement—Reporting Comprehensive Income: Disaggregation of Income Statement Expenses. FASB clarified that all public business entities should initially adopt the disclosure requirements in the ASU 2024-03 in the first annual reporting period beginning after December 15, 2026, and interim reporting periods within annual reporting periods beginning after December 15, 2027. The Company is currently assessing the effect of this ASU on its consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU 2024-04, Debt—Debt with Conversion and Other Options (Subtopic 470-20): Induced Conversions of Convertible Debt Instruments, to improve the relevance and consistency in application of the induced conversion guidance in Subtopic 470-20. The ASU 2024-04 is effective for all entities for annual reporting periods beginning after December 15, 2025, and interim reporting periods within those annual reporting periods. Early adoption is permitted as of the beginning of the annual reporting period for all entities that have adopted the amendments in ASU 2020-06, Debt—Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity’s Own Equity: Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity. The Company is currently assessing the effect of this ASU on its consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income (Topic 220): Disaggregation of Income Statement Expenses, to enhance the transparency and decision usefulness of financial information presented in the income statement by requiring disaggregated information about certain income statement expense line items. The amendments apply to all public business entities. This ASU is effective for annual periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. The Company is currently assessing the effect of this ASU on its consolidated financial statements and related disclosures.

In March 2024, the FASB issued ASU 2024-02, Codification Improvements—Amendments to Remove References to the Concepts Statements, that contains amendments to the Codification that remove references to various FASB Concepts Statements. This effort facilitates Codification updates for technical corrections such as conforming amendments, clarifications to guidance, simplifications to wording or the structure of guidance, and other minor

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improvements. The amendments are effective for public business entities for fiscal years beginning after December 15, 2024, with early adoption permitted. Early application of the amendments in this ASU is permitted for all entities, for any fiscal year or interim period for which financial statements have not yet been issued (or made available for issuance). If an entity adopts the amendments in an interim period, it must adopt them as of the beginning of the fiscal year that includes that interim period. The Company is currently assessing the effect of this ASU on its consolidated financial statements and related disclosures.

In March 2024, the FASB issued ASU 2024-01, Compensation—Stock Compensation (Topic 718): Scope Application of Profits Interest and Similar Awards, to improve GAAP by adding an illustrative example that includes four fact patterns to demonstrate how an entity should apply the scope guidance in paragraph 718-10-15-3 to determine whether a profits interest award should be accounted for in accordance with Topic 718, Compensation—Stock Compensation. For public business entities, the amendments in this ASU are effective for annual periods beginning after December 15, 2024, and interim periods within those annual periods. Early adoption is permitted for both interim and annual financial statements that have not yet been issued or made available for issuance. If an entity adopts the amendments in an interim period, it should adopt them as of the beginning of the annual period that includes that interim period. The Company is currently assessing the effect of this ASU on its consolidated financial statements and related disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, to enhance the transparency and decision usefulness of income tax disclosures by requiring disaggregated information about an entity’s effective tax rate reconciliation, as well as information on taxes paid. This ASU is effective for annual periods beginning after December 15, 2024. The Company is currently assessing the effect of this ASU on its consolidated financial statements and related disclosures.

3. Business Acquisition

On October 31, 2023, the Company acquired 100% of Lung, pursuant to the Lung Acquisition Agreement. At the closing of the Lung Acquisition, the Company issued to the stockholders of Lung 344,345 shares of its common stock (excluding 221 fractional shares from the total 344,566 shares pursuant to the Lung Acquisition Agreement) and 19,903 shares of its newly designated Series X non-voting convertible preferred stock, or the Series X Preferred Stock, (excluding 238 fractional shares from the total 20,141 shares pursuant to the Lung Acquisition Agreement). Each share of Series X Preferred Stock is convertible into 1,000 shares of common stock. The Company paid $290 cash in lieu of fractional shares of both common stock and Series X Preferred Stock. In addition, the Company assumed all of Lung’s stock options (1,780,459) and all warrants (726,437) exercisable for Lung common stock immediately outstanding prior to the closing of the Lung Acquisition, each subject to adjustment pursuant to the terms of the Lung Acquisition Agreement.

Immediately following the closing of the Lung Acquisition, on October 31, 2023, the Company entered into a Stock and Warrant Purchase Agreement, or the Purchase Agreement, with a group of accredited investors, pursuant to which the Company issued and sold (i) an aggregate of 4,707 shares of Series X Preferred Stock, and (ii) warrants, or the PIPE Warrants, to purchase up to an aggregate of 2,353,500 shares of the Company’s common stock, or the PIPE Warrant Shares, for an aggregate purchase price of approximately $18,429, which included the conversion of certain convertible promissory notes in the aggregate principal amount of $1,553 issued by Lung to Bios Partners, the majority stockholder of Lung prior to the closing of the Lung Acquisition, at a 10% discount to the per share price of the Series X Preferred Stock (collectively, the “PIPE Financing”). The PIPE Financing closed on November 2, 2023. Each share of Series X Preferred Stock is convertible into 1,000 shares of common stock.

The net proceeds from the Financing of approximately $17,536 are expected to be used to advance Rein’s clinical development pipeline, business development activities, working capital and other general corporate purposes.

The Lung Acquisition was accounted for under the acquisition method of accounting under ASC 805, Business Combinations. Under the acquisition method, the total purchase price of the acquisition is allocated to the net tangible and identifiable intangible assets acquired and liabilities assumed based on the fair values as of the date of the acquisition. Consideration transferred is the sum of the acquisition-date fair values of the assets transferred, the liabilities incurred by the acquirer to the former owners of the acquiree, and the equity interests issued by the acquirer

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to the former owners of the acquiree (except for the measurement of share-based payment awards). The total purchase price consideration consisted of the following:

Fair value of common stock issued to Lung stockholders $ 403

Fair value of Series X Preferred Stock issued to Lung stockholders 74,615

Cash in lieu of fractional shares 290

Fair value of the options assumed 1,050

Fair value of the warrants assumed 627

Total purchase price consideration $ 76,985

The Company recorded the assets acquired and liabilities assumed as of the date of the Lung Acquisition based on the information available at that date. The following table presents the allocation of the purchase price to the estimated fair values of the assets acquired and liabilities assumed as of the Lung Acquisition date: