Kyntra Bio Reports 21% Response Rate, 10.1-Month Median rPFS in Phase 1b/2 Trial
Kyntra Bio reported Phase 1b/2 data for FG-3246 plus enzalutamide showing a median rPFS of 10.1 months in 44 metastatic castration-resistant prostate cancer patients and a 21% composite response rate overall (40% in one-ARPI subgroup). Safety data matched prior monotherapy trials, with neutropenia rates mitigated by G-CSF prophylaxis.
1. Phase 1b/2 Trial Data
The Phase 1b/2 study evaluated FG-3246 in combination with enzalutamide in 44 metastatic castration-resistant prostate cancer patients. The overall cohort achieved a median radiographic progression-free survival (rPFS) of 10.1 months, with a composite response rate of 21%, rising to 40% in patients with progression on a single prior ARPI. A subgroup analysis indicated higher tumor uptake correlated with increased PSA50 responses.
2. Safety Profile and Prophylaxis
Safety findings were consistent with the prior FG-3246 monotherapy trial, with neutropenia as the primary dose-limiting toxicity. Prophylactic administration of granulocyte colony-stimulating factor (G-CSF) mitigated neutropenia risk, allowing maintenance of dosing intensity. No new safety signals emerged, supporting further development.
3. Analyst Perspectives and Next Steps
Analysts consider the combination results provocative but emphasize the need for caution ahead of the Phase 2 monotherapy interim analysis expected in H2 2026. William Blair reiterated a Market Perform rating, noting validation of the FG-3246 program and potential for data-driven valuation shifts. Further data from the ongoing Phase 2 trial could drive future stock movement.