Celcuity's Breast Cancer Combination Therapy Shows Promising Phase 3 Results

Celcuity, a biotechnology company focused on precision medicine for cancer treatment, has announced groundbreaking results from its phase 3 VIKTORIA-1 trial, potentially reshaping the landscape of breast cancer therapy. The study, which evaluated gedatolisib-based combination treatments for PIK3CA wild-type breast cancer, has met its primary endpoints with impressive efficacy data.

Remarkable Efficacy in Combination Therapies

The VIKTORIA-1 trial tested two combination regimens: a doublet of gedatolisib with fulvestrant, and a triplet adding palbociclib to the mix. Both combinations demonstrated significant improvements in progression-free survival (PFS) compared to fulvestrant monotherapy:

• The triplet combination reduced the risk of disease progression or death by 76%, with a median PFS of 9.3 months.
• The doublet combination showed a 67% reduction in risk, achieving a median PFS of 7.4 months.
• In contrast, the control arm receiving fulvestrant alone had a median PFS of just 2.0 months.

These results translate to hazard ratios of 0.24 and 0.33 for the triplet and doublet, respectively, far exceeding the company's benchmark for success. Celcuity CEO Brian Sullivan had previously indicated that a hazard ratio of 0.5 or below would be considered "very compelling."

Expert Commentary and Clinical Significance

Dr. Sara Hurvitz from the Fred Hutchinson Cancer Center emphasized the potential impact of these findings, stating, "The topline data for both gedatolisib regimens from VIKTORIA-1 are potentially practice-changing." She noted that the quadrupling of survival without disease progression relative to the control group is unprecedented in HR-positive, HER2-negative advanced breast cancer studies.

Safety Profile and Next Steps

Celcuity reported that the rate of treatment discontinuation due to adverse events was lower in both the doublet and triplet arms compared to currently approved combinations and previous phase 1b studies. This favorable safety profile adds to the promising efficacy data, potentially positioning gedatolisib-based regimens as attractive treatment options.

The company plans to present more detailed data at an upcoming medical conference and is preparing for an FDA filing in the fourth quarter of 2025. Additionally, Celcuity anticipates releasing topline data from a cohort of patients with PIK3CA mutations later this year, further expanding the potential applications of their combination therapy approach.