Study of the Kinesin Oral Molecular Degrader BBI-940 in Subjects With Advanced or Metastatic Breast Cancer
← catalyst calendarSponsored by Boundless Bio, Inc. (industry) · BOLD — their whole pipeline →.
Phase
Phase 1
Status
Terminated
Study type
Interventional
Design
Non randomized · None · Treatment
Enrollment
8actual
Sites
8
Country
United States
Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →
Source: ClinicalTrials.gov, retrieved 2026-08-19
Why the sponsor stopped it
The study was terminated primarily due to a business decision related to a corporate transaction and was not driven by any safety signal.
As filed on the registry record, in the sponsor's own words.
Dates
each axis at the precision it was filed, with the registry's own basis| Date | Filed | Basis | What it is |
|---|---|---|---|
| Start | 2026-02-25 | actual | When the study began enrolling |
| Primary completion | 2026-07-28 | actual | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2026-07-28 | actual | The whole study's end, after follow-up |
| First posted | 2026-02-12 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2026-08-19 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Conditions
- Breast Cancer
- Metastatic Breast Cancer
- Advanced Breast Cancer
Interventions
- Drug: BBI-940
- Drug: Fulvestrant
Primary outcomes
what the primary-completion date above is the date OFRate of dose limiting toxicities (DLTs) in each BBI-940 monotherapy dose escalation cohort.
measured First 28 days of study treatment (through end of Cycle 1).
Incidence of treatment emergent adverse events (TEAEs) in each dose group and overall as assessed by CTCAE version 5.0.
measured First dose of study treatment through 30 days after the last dose of study treatment.
Incidence of study treatment discontinuation and/or interruption by dose group and overall.
measured First dose of study treatment through 30 days after the last dose of study treatment.
Permalink · BOLD's whole pipeline · Catalyst calendar · Every registered study · What changed