Why Is Cancer-Focused Tyra Biosciences Stock Falling On Friday?

On Thursday, Tyra Biosciences, Inc. TYRA released clinical proof-of-concept data for TYRA-300 in patients with metastatic urothelial (mUC) cancer from its ongoing SURF301 Phase 1/2 study.

These data will be presented at the EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics.

TYRA-300 is a potential first-in-class, investigational, oral, FGFR3-selective inhibitor designed to avoid the toxicities associated with the inhibition of FGFR1, FGFR2, and FGFR4 while being agnostic for the FGFR3 gatekeeper mutations.

Also Read: BofA Upgrades Tyra Biosciences As Investors Focus On Preclinical Data Amid High Benchmarks Set By Johnson & Johnson’s Drug

As of Aug. 15, the data cutoff date, 41 patients were enrolled in the Phase 1 portion of the SURF301 Phase 1/2 study.

The enrolled patient population was heavily pre-treated. Treatment with TYRA-300 was evaluated across six dose levels, ranging from 10 mg to 120 mg once daily (QD). 

Preliminary PK/PD analysis in 41 patients as of the data cutoff date: TYRA-300 plasma concentrations indicate adequate target coverage at ≥ 90 mg QD, with ongoing pharmacokinetic characterization.

In patients with FGFR3+ mUC who received doses ≥ 90 mg QD, anti-tumor activity was observed in all patients:

• 6 out of 11 (54.5%) patients at ≥ 90 mg QD achieved a partial response, 3 of which are still ongoing.
• 5 out of 10 (50%) patients at 90 mg QD achieved a partial response.
• 1 out of 1 (100%) patient at 120 mg QD achieved a partial response.
• For all patients at ≥ 90 mg QD (PR + stable disease), a 100% disease control rate (DCR) was achieved.

TYRA-300 has demonstrated favorable interim safety results:

• Preliminary data from SURF301 suggest TYRA-300 to be generally well-tolerated, with infrequent FGFR2- and FGFR1-associated toxicities.
• In doses from 10 mg up to 120 mg QD, there were 4 (10%) serious adverse events related to TYRA-300, one dose-limiting toxicity (DLT) of grade 3 diarrhea at 90 mg QD, and one grade 3 treatment-related adverse event leading to discontinuation of treatment (90 mg QD).

The 120 mg QD dose was the highest dose evaluated, and no DLTs were reported.

Price Action: TYRA stock is down 18.4% at $23.34 at last check Friday.

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Image created using artificial intelligence via Midjourney.