Tyra's stock falls after revealing competitor to J&J’s Balversa

Tyra Biosciences revealed promising early clinical trial results for its FGFR3-specific inhibitor, TYRA-300, in patients with advanced bladder cancer. This marks the public company's first presentation of human data since its establishment in 2018. The biotech's data was highly anticipated, as indicated by a significant rise in its shares before the update. However, following the announcement, Tyra's shares experienced an 18% decline.

The Phase 1 part of the SURF301 study tested various doses of TYRA-300 in patients with metastatic urothelial carcinoma. The efficacy results highlighted those who received at least 90 mg of the drug, which the company identified as achieving "adequate target coverage." Among the 10 patients administered a 90 mg daily dose of TYRA-300, five showed a partial response. Additionally, one patient who received a 120 mg dose also exhibited a partial response. Notably, three of these six responses are still ongoing, showcasing the drug's potential effectiveness.

As of August 15, Tyra reported that 41 patients with FGFR3-positive cancer had enrolled in the study, including individuals previously treated with Johnson & Johnson's Balversa. Tyra aims to develop a treatment that is safer than Balversa, which gained FDA accelerated approval in 2019 and full approval earlier this year for advanced FGFR3-positive urothelial carcinoma. In its confirmatory trial, Balversa achieved a response rate of 35% in advanced bladder cancer with FGFR3 mutations.

TYRA-300 is designed to specifically target FGFR3 while avoiding other isoforms like FGFR1, FGFR2, and FGFR4, in an effort to reduce certain side effects such as eye problems, mouth sores, inflammation, and increased phosphate levels. According to Tyra CEO Todd Harris, the drug has shown a favorable safety profile, with infrequent FGFR2- and FGFR1-associated toxicities. This selective targeting could lead to better tolerability compared to pan-FGFR inhibitors like Balversa.

In the trial, 15 patients received a 90 mg dose of TYRA-300. The most common side effects observed were increased liver enzyme levels and dry mouth, each affecting six participants. One grade 3 case of elevated liver enzyme levels led to the discontinuation of treatment, and one grade 3 case of diarrhea was reported as a dose-limiting toxicity at the 90 mg dose.

Todd Harris expressed confidence in advancing TYRA-300 through Part B of the SURF301 study and exploring more extensive opportunities with Phase 2 studies. These future studies will focus on metastatic urothelial cancer, non-muscle invasive bladder cancer, and achondroplasia, a form of dwarfism. The plan includes testing lower doses of TYRA-300 for non-muscle invasive bladder cancer and achondroplasia compared to the 90 mg dose used in urothelial carcinoma.

In summary, Tyra Biosciences' initial human data for TYRA-300 shows potential in treating advanced bladder cancer, with a focus on achieving better safety and efficacy compared to existing treatments. The company's ongoing efforts and future studies aim to expand the drug's applicability to other conditions, potentially offering new hope for patients with FGFR3-positive cancers and related disorders.