Novartis has reported positive results from the SOLAR-1 trial after the study met its primary endpoint.
The global trial is a Phase III, randomised, double-blind, placebo-controlled study evaluating BYL719 (alpelisib) in combination with fulvestrant against fulvestrant alone for the treatment of post-menopausal women.
It also evaluated the study drug combination for men with hormone-receptor positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) PIK3CA-mutant advanced or metastatic breast cancer that progressed on or following aromatase inhibitor treatment with or without a CDK4/6 inhibitor.
During the trial, a total of 572 patients were randomised in a 1:1 ratio to receive continuous oral treatment of BYL719 at 300mg or placebo once daily in combination with 500mg of fulvestrant intramuscular injections on days one and 15 on the first cycle and day one of each subsequent 28-day cycle.
The patients were distributed on the basis of tumour tissue evaluation to either a PIK3CA-mutant cohort or a PIK3CA non-mutant cohort.
Stratification in the trial was conducted on the basis of visceral metastases and prior CDK4/6 inhibitor treatment.
The trial’s primary endpoint includes progression-free survival (PFS) for patients with PIK3CA mutation.
Its secondary endpoints comprise overall survival, overall response rate, clinical benefit rate, health-related quality of life, efficacy in PIK3CA non-mutant cohort, safety and tolerability, among others.
Results from the trial have showed that the adverse events observed with BYL719 in combination with fulvestrant were generally similar to those observed in previous BYL719 and fulvestrant trials.
Novartis Oncology Global Drug Development head Samit Hirawat said: “BYL719 is the only alpha-specific PI3K inhibitor and the first one to show potential increased benefit and acceptable tolerability for patients.
“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.”
Novartis also plans to continue evaluating data from the SOLAR-1 trial for secondary endpoints.