BridgeBio Oncology Therapeutics (BBOT) Study Update summary

Portfolio overview and strategy

• Advancing a differentiated portfolio of small molecules targeting RAS and PI3K alpha pathways for precision oncology, focusing on KRAS-driven cancers and internal combination potential.

• Portfolio designed for synergistic KRAS combination strategies with standard of care and internal assets, including dual inhibition of KRAS ON/OFF states and panRAS inhibition of PI3K alpha activation.

• Multiple clinical assets (BBO-8520, BBO-11818, BBO-10203) with anticipated value inflection points in 2026 and financial strength to fund operations into 2028.

• Precision oncology portfolio leverages differentiated chemistry for innovative RAS PI3K alpha inhibition.

• Estimated annual incidence of over 250,000 patients in the U.S. across multiple indications.

BBO-8520 clinical data/results

• BBO-8520 monotherapy in KRASG12C NSCLC showed a 65% overall response rate, 100% disease control rate, and 83% of eligible patients remained on treatment for at least 6 months.

• Demonstrated favorable and differentiated safety profile, with no grade 3 or higher liver toxicity, no dose-limiting toxicities, and most common adverse events being mild gastrointestinal symptoms.

• Combination with pembrolizumab showed promising efficacy and tolerable safety, including in heavily pretreated patients and those with prior ICI and G12Ci exposure, with no increased liver toxicity.

• Early efficacy signals observed in STK11/KEAP1 co-mutant tumors, a highly resistant population, with all five initial patients achieving partial response.

• Additional data updates and combination studies with BBO-10203 are planned for the second half of 2026.

BBO-11818 clinical data/results

• BBO-11818 is an orally bioavailable, reversible pan-KRAS inhibitor showing anti-tumor activity and favorable safety in KRAS mutant tumors, with strong monotherapy activity and promising combination potential.

• Initial phase 1a cohorts demonstrated anti-tumor activity at predicted efficacious dose levels across tumor types, including a confirmed partial response in pancreatic ductal adenocarcinoma with a 56% tumor reduction.

• Monotherapy appears tolerable, with no dose-limiting toxicities and mainly gastrointestinal-related adverse events.

• Dose escalation ongoing, with 600 mg BID covering G12D and G12V mutant alleles; expansions and combinations planned in pancreatic, lung, and colorectal cancers.

• Additional monotherapy and combination data updates are expected in the second half of 2026.