Tyra Biosciences Inc. (NASDAQ:TYRA) stock is trading lower on Wednesday after the company shared initial results from its Phase 2 SURF302 trial evaluating oral dabogratinib, delivering clinical proof of concept and identifying a 60 mg once-daily dose to support planned registrational studies.
The study evaluated dabogratinib in patients with FGFR3-altered low-grade intermediate-risk non-muscle invasive bladder cancer.
Exposure Analysis Demonstrates High Response Rates
Preliminary efficacy results across 26 evaluable patients revealed an overall response rate of 86% among participants achieving target exposure levels above the specified threshold, compared to 58% for those below it.
This exposure-response relationship was clearest in patients with multiple marker lesions, supporting the 60 mg daily dosage for adjuvant settings with minimal disease burden.
At 60 mg, complete response was 57%, and 50% for the 50mg and 60mg pooled cohort.
Analyst View
William Blair noted that the stock plunged as the 57% was well below prior expectations of a 70%-80% CR rate that would represent a successful outcome.
Analyst Sami Corwin noted that while the readout was more nuanced than anticipated and will likely require investors to recalibrate expectations.
Corwin expects that the dataset supports advancement into adjuvant Phase 3 development and preserves a viable path to generating clinically meaningful disease-free survival benefits.
Expansion Plans and Initial Upper Tract Results
The biotechnology company intends to finish enrolling the 60 mg group and initiate a 70 mg daily cohort to evaluate tumor ablation. Management also plans to consult health authorities regarding Phase 3 designs and dosing.
Additionally, initial observations from the SURF303 study in upper tract urothelial cancer showed the first patient receiving 60 mg daily achieved a complete response at three months with zero adverse events.
TYRA Stock Price Activity: Tyra Biosciences shares were down 21.60% to $20.95 at the time of publication on Wednesday, according to Benzinga Pro data.
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