Study of the CHK1 Inhibitor BBI-355, an ecDNA-directed Therapy (ecDTx), and the RNR Inhibitor BBI-825, in Subjects With Tumors With Oncogene Amplifications
BBI-355 is an oral, potent, selective checkpoint kinase 1 (or CHK1) small molecule inhibitor in development as an ecDNA (extrachromosomal DNA) directed therapy (ecDTx). BBI-825 is an oral, potent, selective ribonucleotide reductase (or RNR) small molecule inhibitor. This is a first-in-human, open-label, 2-part, Phase 1/2 study to determine the safety profile and identify the maximum tolerated dose and recommended Phase 2 dose of BBI-355 administered as a single agent or in combination with BBI-825 or other select therapies.
Ask AI to explain this studyKey things to know
This describes the study’s primary purpose.
Plus 2 other study approaches.
These are broad labels—not an eligibility decision.
Checked against the public recordLast updated Aug 19, 2026 · Source: ClinicalTrials.gov
Ask the study team to confirm whether enrollment is open.
Interventional
Locations may change over time.
Study sponsor
What this study is about
- Purpose
- Treatment
- Study type
- Interventional
- Phase
- Phase 1
- Sponsor
- Boundless Bio, Inc.
- Interventions being studied
- Drug: BBI-355; Drug: Erlotinib; Drug: Futibatinib; Drug: BBI-825
How this study is categorized
These labels come from structured fields and exact terms in the public record.
Who may be able to participate
The sponsor separates these requirements into two groups. You do not need to interpret them alone—use them to guide a conversation with the study team.
- Key
- Locally advanced or metastatic non-resectable solid tumors, whose disease has progressed despite all standard therapies or for whom no further standard or clinically acceptable therapy exists,
- Evidence of oncogene amplification,
- Availability of FFPE tumor tissue, archival or newly obtained,
- Measurable disease as defined by RECIST Version 1.1,
- Adequate hematologic function,
- Adequate hepatic and renal function,
- Eastern Cooperative Oncology Group performance status (ECOG PS) 0 or 1,
- Other inclusion criteria per study protocol. Key
- Single agent arm: Prior exposure to CHK1 or WEE1 inhibitors,
- BBI-355 combination with BBI-825 arm: Prior exposure to combination therapy of any RNR inhibitor plus CHK1/2 inhibitor,
- Hematologic malignancies,
- Primary CNS malignancy, leptomeningeal disease, or symptomatic active CNS metastases, with exceptions per study protocol,
- Prior or concurrent malignancies, with exceptions per study protocol,
- History of HBV, HCV, or HIV infection,
- Clinically significant cardiac condition,
- Active or history of interstitial lung disease (ILD) or pneumonitis, or history of ILD or pneumonitis requiring steroids or other immunosuppressive medications,
- QTcF \> 470 msec,
- Prior organ allograft transplantations or allogeneic peripheral blood stem cell/bone marrow transplantation,
- Other
Important: This is the sponsor’s public criteria, not a determination of eligibility. The study team must review your individual situation.
U.S. locations
- UCLA Medical CenterLos Angeles, California
- Sarcoma OncologySanta Monica, California
- HealthONEDenver, Colorado
- Florida Cancer SpecialistsLake Mary, Florida
- The University of KansasFairway, Kansas
- Beth Israel Deaconess Medical CenterBoston, Massachusetts
- Dana Farber Cancer InstituteBoston, Massachusetts
- START MidwestGrand Rapids, Michigan
- Memorial Sloan Kettering Cancer CenterNew York, New York
- SCRI Oncology PartnersNashville, Tennessee
- MD Anderson Cancer CenterHouston, Texas
- NEXT Oncology - DallasIrving, Texas
Source and freshness
Processed from ClinicalTrials.gov. Last public update: Aug 19, 2026. Always confirm current availability with the study team.