Tyra Biosciences Stock Plunges 30% After Bladder Cancer Drug Trial Data

Shares of Tyra Biosciences (NASDAQ: TYRA) plummeted approximately 30% in Wednesday's trading after the biotechnology company released initial data from its Phase 2 SURF302 trial for the cancer therapy dabogratinib. The significant sell-off suggests the results for the treatment, aimed at a specific form of bladder cancer, fell short of investor expectations.

Trial Results Detailed

The company reported data from the study evaluating dabogratinib in patients with FGFR3-altered, low-grade, intermediate-risk non-muscle invasive bladder cancer. As of the August 31, 2026 data cutoff, the results for the 60 mg once-daily dose cohort showed notable response rates.

Key efficacy findings for the 60 mg dose included:

• An overall response rate (ORR) of 79%.
• A complete response rate (CR) of 64%.

In a smaller subgroup of patients with single marker lesions, the response was even stronger, with a 100% ORR and a 75% CR reported.

Safety Profile and Market Reaction

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Tyra Biosciences also presented a safety profile it described as manageable. For the 60 mg dose cohort, there were no Grade 4 or 5 treatment-emergent adverse events (TEAEs) and no discontinuations due to treatment-related side effects. Grade 3 TEAEs occurred in 14% of participants, though the company noted none were deemed treatment-related at that dose level. The most common adverse events were fatigue, diarrhea, and dry eye.

Despite the reported efficacy and safety data, the sharp decline in the company's stock price indicates a strongly negative reception from investors. Such a market reaction often signals that trial results, while potentially positive on the surface, did not meet the high bar of expectations for clinical significance or competitive positioning in the field.

Path Forward

The company announced it plans to complete enrollment in the 60 mg dose cohort and will initiate a new cohort to evaluate a higher 70 mg once-daily dose. Tyra also intends to engage with health authorities to discuss the design for a potential Phase 3 pivotal study.

Separately, Tyra noted that in another Phase 2 study, SURF303, the first patient treated with dabogratinib for low-grade upper tract urothelial cancer achieved a complete response at the three-month assessment.