Tyra Biosciences Announces Initial Phase 2 SURF302 Results; 60 mg QD Selected

What Happened
Tyra Biosciences (TYRA) announced on September 9, 2026 (data cutoff August 31, 2026) initial results from SURF302, its Phase 2 study of oral dabogratinib in FGFR3‑altered low‑grade intermediate‑risk non‑muscle invasive bladder cancer (LG IR NMIBC). The company reported clinical proof‑of‑concept for selective oral FGFR3 inhibition and identified 60 mg once‑daily (QD) as the potential dose to support a planned registrational adjuvant strategy. TYRA also reported a complete response in the first patient in SURF303 (LG upper tract urothelial cancer) at 3 months and clearance of the fifth dose level in the BEACH301 pediatric sentinel cohort (ages 5–10) with no safety signals.

Key Details

• Safety (as of Aug 31, 2026): 60 mg QD cohort n=22 and 50 mg QD cohort n=22; most TEAEs Grade 1–2; Grade 3 TEAEs in 3 participants (14%) at 60 mg and 2 (9%) at 50 mg; Grade 3 treatment‑related AEs in 2/44 (4.5%), both at 50 mg; no Grade 4/5 events. No dose reductions or treatment‑related discontinuations at 60 mg.
• Efficacy (evaluable n=26): Combined ORR at 3 months/BOR — 60 mg: 79% (11/14) with CR 57% (8/14); 50 mg: 67% (8/12) with CR 33% (4/12). Single‑marker lesion cohort: 60 mg ORR 100% (8/8); pooled ORR 94% (15/16). All 3‑month CRs with 6‑month data remained in response.
• Exposure‑response: Participants with steady‑state AUC >2500 ng·hr/mL had ORR 86% vs 58% below that threshold, supporting 60 mg QD for adjuvant use and higher doses for ablative settings. TYRA will complete 60 mg enrollment and open a 70 mg QD cohort.
• Development & market: TYRA plans engagement with regulators on Phase 3/dose selection and aims to start a registrational adjuvant study in 2027; company estimates a potential IR NMIBC market >$5 billion assuming full branded penetration.

Why It Matters
For investors, these results provide early clinical proof‑of‑concept and a tolerable safety profile for chronic once‑daily oral dosing—key attributes for an adjuvant therapy in a disease where many patients receive no adjuvant treatment. The 60 mg QD selection and exposure‑response data are material because they drive next steps (completing enrollment, testing 70 mg, regulatory discussions) and the timing of a potential registrational Phase 3 expected in 2027. However, TYRA notes these are initial/interim data and forward‑looking plans (including efficacy durability, regulatory outcomes, and market opportunity) are subject to significant risks and may change.