medwireNews: The combination of alpelisib and fulvestrant could be a promising option for patients with PIK3CA-mutated, hormone receptor-positive, HER2-negative advanced breast cancer who have progressed on prior CDK4/6 inhibitor and aromatase inhibitor treatment, indicate trial data.
Presenting the data at the virtual 2020 ASCO Annual Meeting, Hope Rugo (University of California San Francisco, USA) commented that the combination showed “clinically meaningful efficacy” and added that BYLieve supports use of the PI3Kα inhibitor and fulvestrant in this patient population.
She explained that the phase 2 noncomparative trial comprises three cohorts, with the current report focusing on cohort A, which included 121 participants who had received a CDK4/6 inhibitor plus an aromatase inhibitor as the immediately prior regimen.
Following treatment with alpelisib 300 mg/day and fulvestrant 500 mg every 4 weeks, the primary endpoint of progression-free survival (PFS) at 6 months was achieved by 50.4% of patients.
The lower bound of the 95% confidence interval exceeded the prespecified threshold and therefore the primary endpoint of cohort A was met, said Rugo. The median PFS duration was 7.3 months.
Over a median follow-up of 11.7 months, the overall response rate was 17.4% for the total cohort and 21.0% for the 100 patients with measurable disease at baseline. The clinical benefit rates were 45.5% and 42.0%, respectively.
Grade 3 or worse treatment-related adverse events (AEs) occurred in 62.2% of patients, with hyperglycemia the most common AE of this severity, at 28.3%, followed by rash (9.4%) and diarrhea (5.5%).
A total of 20.5% of participants discontinued treatment due to AEs of any grade, while 64.6% required a dose adjustment or interruption.
Rugo pointed out that strategies for managing AEs, such as the prophylactic use of antihistamines for rash, were effective.
“Implementation of management strategies and education are critical for improving therapeutic efficacy,” she stressed in conclusion.
medwireNews is an independent medical news service provided by Springer Healthcare. © 2020 Springer Healthcare part of the Springer Nature Group