A Phase 1 interventional study of BBO-10203 and Trastuzumab in Solid Tumor, Adult, Metastatic Breast Cancer and Advanced Breast Cancer, sponsored by TheRas, Inc., d/b/a BBOT (BridgeBio Oncology Therapeutics). Recruiting at 44 sites in 6 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-01.
Sponsored by TheRas, Inc., d/b/a BBOT (BridgeBio Oncology Therapeutics) · Phase 1, Interventional, and Treatment
First in human study to evaluate the safety, tolerability, and pharmacokinetics (PK) of BBO-10203, a PI3Kα:RAS breaker, alone and in combination with other anti-cancer agents in patients with advanced solid tumors.
This is an open-label, multi-center Phase 1a/1b study designed to evaluate the safety, tolerability, preliminary antitumor activity, and PK of BBO-10203 as a single agent and in combination with Trastuzumab, Fulvestrant +/- Ribociclib, or FOLFOX + Bevacizumab in patients with locally advanced unresectable or metastatic (ie, advanced) solid tumors. The study includes a dose escalation phase and an expansion phase.
12,544 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.
This study's planned enrollment of 392 is above the median of 72 across 9,303 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →TheRas, Inc., d/b/a BBOT (BridgeBio Oncology Therapeutics) is the lead sponsor of 3 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Other inclusion/exclusion criteria are specified in the protocol
Participants enrolled in this cohort will receive BBO-10203 tablets orally (different dose levels will be evaluated) once daily as monotherapy. This cohort will enroll patients with HER2-positive advanced breast cancer, HR-positive HER2-negative advanced breast cancer, advanced colorectal cancer, and advanced lung cancer.
Drug: BBO-10203
Participants enrolled in this cohort will receive BBO-10203 tablets orally in combination with trastuzumab. This cohort will enroll patients with HER2-positive advanced breast cancer.
Drug: BBO-10203 · Drug: Trastuzumab
Participants enrolled in this cohort will receive BBO-10203 tablets orally in combination with fulvestrant. This cohort will enroll patients with HR-positive, HER2-negative advanced breast cancer.
Drug: BBO-10203 · Drug: Fulvestrant · Drug: Ribociclib
Participants enrolled in this cohort will receive BBO-10203 tablets orally in combination with fulvestrant and ribociclib as determined in the dose escalation. This cohort will enroll patients with HR-positive, HER2-negative advanced breast cancer.
Drug: BBO-10203 · Drug: Fulvestrant · Drug: Ribociclib
Participants enrolled in this cohort will receive BBO-10203 tablets orally in combination with FOLFOX and bevacizumab. This cohort will enroll patients with KRAS-mutant advanced colorectal cancer.
Drug: BBO-10203 · Drug: FOLFOX · Drug: Bevacizumab
Participants will receive assigned dose of BBO-10203 orally once daily
Participants will receive trastuzumab as infusion or subcutaneous injection every 21 days
Patients will receive Fulvestrant as an intramuscular injection every 28 days (additional dose on C1D15)
Patients will receive Ribociclib orally once a day (21 days on treatment, 7 days off)
Patients will receive FOLFOX as infusion every 14 days
Patients will receive bevacizumab as infusion every 28 days
Determination of maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of BBO-10203 as a single agent
Time frame: Up to approximately 5 years
Percentage of patients with treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), and dose-limiting toxicities (DLTs)
Time frame: Up to approximately 5 years
Recommended BBO-10203 dose in combination with trastuzumab, fulvestrant +/- ribociclib, and FOLFOX + bevacizumab
Time frame: Up to approximately 5 years
Clinical benefit rate (CBR) as assessed by RECIST v1.1.
Time frame: Up to approximately 5 years
Duration of response (DOR) as assessed by RECIST v1.1.
Time frame: Up to approximately 5 years
Progression-free survival (PFS) as assessed by RECIST v1.1
Time frame: Up to approximately 5 years
Overall survival (OS)
Time frame: Up to approximately 5 years
Area under the concentration-time curve (AUC
Time frame: Predose (within 30 minutes) of C1D1 until up to approximately 5 years
Maximum plasma drug concentration (Cmax)
Time frame: Predose (within 30 minutes) of C1D1 until up to approximately 5 years
Time for maximum plasma drug concentration (Tmax)
Time frame: Predose (within 30 minutes) of C1D1 until up to approximately 5 years
Objective response rate (ORR) as assessed by RECIST v1.1 for patients with measurable disease
Time frame: Up to approximately 5 years
Plan to share: Yes
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
TheRas, Inc., d/b/a BBOT (BridgeBio Oncology Therapeutics)