Tyra’s bladder-cancer data offer a bright spot—but miss investor expectations

Tyra Biosciences’ shares fell roughly 20–30% after initial Phase 2 SURF302 results for dabogratinib in FGFR3-altered, low-grade intermediate-risk non-muscle-invasive bladder cancer failed to meet investor expectations.

At the 60 mg once-daily dose, 14 efficacy-evaluable patients had a 79% overall response rate and a 64% best overall complete-response rate—below the approximately 70% complete-response benchmark investors had anticipated.

The key positive finding was in patients with a single marker lesion:
all eight patients responded at 60 mg, while six achieved complete responses at the three-month assessment. This subgroup showed a 75% best overall complete-response rate.

Safety was comparatively encouraging. Most side effects were Grade 1–2; there were no Grade 4 or 5 adverse events, no dose reductions or treatment-related discontinuations at 60 mg, and no Grade 3 treatment-related adverse events in that cohort.

Tyra said the results provide proof of concept and support advancing the 60 mg dose into a planned registrational study, although the small sample size and weaker results in patients with multiple lesions remain important uncertainties.