Novartis Announces Positive Results From Global Phase III SOLAR-1 Trial

(RTTNews) - Novartis (NVS) announced positive results from the global Phase III SOLAR-1 trial evaluating the investigational alpha-specific PI3K inhibitor BYL719 (alpelisib) in combination with fulvestrant. The trial evaluated the efficacy and safety of alpelisib in postmenopausal women with PIK3CA mutated hormone-receptor positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) advanced or metastatic breast cancer that progressed on or after an aromatase inhibitor with or without a CDK4/6 inhibitor.

In patients with PIK3CA mutated HR+/HER2- advanced breast cancer, BYL719 plus fulvestrant demonstrated a median progression-free survival (PFS) of 11 months (95% CI: 7.5-14.5 months) compared to 5.7 months (95% CI: 3.7-7.4 months) for fulvestrant alone.

BYL719 plus fulvestrant reduced the risk of death or progression in those patients by an estimated 35% compared to fulvestrant alone (HR=0.65; 95% CI: 0.50-0.85; p<0.001). Overall response rate (ORR), indicating a reduction in tumor size of at least 30%, was more than doubled in patients with measurable disease who received BYL719 plus fulvestrant (36%) compared to those receiving fulvestrant alone (16%).

PFS treatment effect was consistent across all subgroups, and regardless of whether aromatase inhibitor treatment was given, with or without a CDK4/6 inhibitor. The significant PFS improvement demonstrated with BYL719 plus fulvestrant in patients with a PIK3CA mutation was not observed for patients without the mutation.

Most adverse events were mild to moderate in severity and generally manageable through dose modifications and medical management. The discontinuation rate of BYL719 plus fulvestrant due to adverse events was 5% compared to 1% for fulvestrant alone. The most common all-grade adverse events (>=30%) were hyperglycemia (64% vs 10%), diarrhea (58% vs. 16%), nausea (45% vs. 22%), decreased appetite (36% vs. 11%) and rash (36% vs. 6%). Of these, the most common grade 3/4 events (>=5%) were hyperglycemia (37% vs. <1%), rash (10% vs. <1%), and diarrhea (7% vs. <1%).

The SOLAR-1 trial is ongoing to evaluate secondary endpoints, including overall survival.