Summary
Shares of Celcuity Inc. (NASDAQ: CELC) fell 15% on Tuesday after the company published detailed results from the PIK3CA mutant cohort of the Phase 3 VIKTORIA-1 clinical trial evaluating gedatolisib in adults with hormone receptor positive, human epidermal growth factor receptor 2 negative, PIK3CA mutated, locally advanced or metastatic breast cancer.
Key points
- Gedatolisib in a three-drug regimen with fulvestrant and palbociclib cut the risk of progression or death by 50% versus alpelisib plus fulvestrant; median progression-free survival (PFS) was 11.1 months versus 5.6 months.
- Gedatolisib with fulvestrant alone reduced the risk of progression or death by 49% versus alpelisib plus fulvestrant; median PFS was 11.3 months versus 5.6 months.
- Tolerability was generally favorable, with low-grade treatment-related adverse events predominating and lower discontinuation rates in the gedatolisib groups compared with the alpelisib plus fulvestrant arm.
Detailed trial outcomes
The VIKTORIA-1 PIK3CA mutant cohort compared gedatolisib in two regimens against alpelisib plus fulvestrant. In the gedatolisib-triplet arm (gedatolisib plus fulvestrant and palbociclib), the risk of disease progression or death was reduced by 50% relative to alpelisib plus fulvestrant. Median progression-free survival in that triplet arm was 11.1 months versus 5.6 months for alpelisib plus fulvestrant.
When given as a doublet with fulvestrant, gedatolisib reduced the risk of disease progression or death by 49% compared with alpelisib plus fulvestrant. Median PFS for the gedatolisib-doublet was 11.3 months compared with 5.6 months for the alpelisib plus fulvestrant cohort.
Response rates and duration
The gedatolisib-triplet produced an objective response rate of 48.9% with a median duration of response of 15.7 months. The gedatolisib-doublet achieved a 35.7% objective response rate with a median duration of response of 24.2 months.
Safety and discontinuations
Both gedatolisib regimens were described as generally well tolerated, with most treatment-related adverse events classified as low-grade. Treatment-related adverse events resulted in discontinuation for 2.6% of patients in the gedatolisib-triplet arm, 3.8% in the gedatolisib-doublet arm and 7.1% in the alpelisib plus fulvestrant arm.
Regulatory steps and corporate actions
Celcuity said it intends to submit the PIK3CA cohort data to the U.S. Food and Drug Administration as a supplemental New Drug Application and to other regulatory authorities. Separately, the FDA has granted Priority Review of Celcuity's New Drug Application for gedatolisib in patients with HR+/HER2-/PIK3CA wild-type advanced breast cancer, with a PDUFA goal date set for July 17, 2026.
Market reaction
Despite positive efficacy and safety findings reported for the PIK3CA mutant cohort, Celcuity's stock declined 15% on the trading day when the detailed results were released.
Impacted sectors
- Biotechnology and pharmaceutical sectors due to drug-clinical trial and regulatory developments.
- Healthcare sector more broadly given the implications for treatment options in HR+/HER2- breast cancer with PIK3CA mutations.
Notes: If additional details or regulatory outcomes are reported later by the company or regulators, those items will determine future market and clinical interpretations. This article reflects only the information released by the company about the VIKTORIA-1 PIK3CA cohort.