Celcuity (CELC) said Tuesday that detailed results from the Phase 3 Viktoria-1 trial showed its investigational breast cancer treatment gedatolisib outperformed Novartis' (NVS) alpelisib plus fulvestrant in patients with hormone receptor-positive, HER2-negative, PIK3CA-mutated advanced breast cancer.

Celcuity said the gedatolisib plus fulvestrant and palbociclib, or gedatolisib-triplet reduced the risk of disease progression or death by 50% compared with alpelisib plus fulvestrant, and nearly doubled median progression-free survival to 11.1 months from 5.6 months, while gedatolisib plus fulvestrant, or gedatolisib-doublet extended progression-free survival to 11.3 months, with objective response rates of 48.9% and 35.7%, respectively.

The gedatolisib triplet and doublet regimens were generally well tolerated, with mostly low-grade treatment-related adverse events, while overall survival data, a key secondary endpoint, showed promising trends but remain immature. Celcuity plans to submit the data to the US Food and Drug Administration as a supplemental new drug application.

Shares of Celcuity were down more than 25% in Tuesday trading.

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