A trial assessing the alpha-specific PI3K inhibitor alpelisib with fulvestrant met its primary endpoint of PFS among patients with hormone receptor-positive, HER-2-negative advanced breast cancer with a PIK3CA mutation, according to the agent’s manufacturer.
Alpelisib (BYL719, Novartis) is an inhibitor of the PI3K pathway. About 40% of patients with hormone receptor-positive breast cancer harbor PIK3CA mutations.
The phase 3 global, double-blind SOLAR-1 study included 572 women and men with PIK3CA-mutated hormone receptor-positive, HER-2-negative advanced or metastatic breast cancer that progressed on or following prior aromatase inhibitor treatment with or without a CDK4/6 inhibitor.
Researchers randomly assigned patients 1:1 to receive 500 mg fulvestrant (Faslodex, AstraZeneca) with 300 mg alpelisib or placebo.
PFS served as the primary endpoint. Secondary endpoints included OS, overall response rate, clinical benefit rate, health-related quality of life, safety and tolerability.
Novartis announced that the SOLAR-1 trial met its primary endpoint of PFS.
“BYL719 is the only alpha-specific PI3K inhibitor and the first one to show potential increased benefit and acceptable tolerability for patients," Samit Hirawat, MD, head of Novartis Oncology Global Drug Development, said in a company-issue press release. “We are encouraged by the results observed in the SOLAR-1 study and look forward to submitting the data to an upcoming medical congress and starting discussions with health authorities worldwide.”
The adverse events observed with alpelisib plus fulvestrant appeared generally consistent with the known profiles of the individual agents.