The FDA has now approved alpelisib (Piqray®, Novartis) as the first PIK3CA inhibitor for postmenopausal women and men with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated advanced or metastatic breast cancer. Alpelisib is to be used in combination with fulvestrant following progression on or after an endocrine-based regimen.
PIK3CA mutations are usually a predictor of poor prognosis, and these mutations occur in about 40% of patients with hormone receptor-positive, HER2-negative breast cancer.
Approval was based on the phase 3 trial SOLAR-1 (NCT02437318), results of which were published in the New England Journal of Medicine. For this study, 572 patients with HR-positive, HER2-negative advanced breast cancer previously treated with endocrine therapy were grouped based on tumor-tissue PIK3CA mutation status. Patients in each group were then randomized to receive alpelisib (300 mg once daily) plus fulvestrant (500 mg every 28 days and once on day 15) or placebo plus fulvestrant.
After a median follow-up of 20 months, alpelisib/fulvestrant improved progression-free survival compared with placebo/fulvestrant (11.0 vs 5.7 months). The overall response rate was also higher for those who were administered alpelisib/fulvestrant (26.6% vs 12.8%). The most common grade 3/4 side effects in the alpelisib/fulvestrant group included hyperglycemia (36.6%) and rash (9.9%).
"[Alpelisib] is the first PI3K inhibitor to demonstrate a clinically meaningful benefit in treating patients with this type of breast cancer," commented Richard Pazdur, MD, Director of the FDA's Oncology Center of Excellence and Acting Director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research. "The ability to target treatment to a patient's specific genetic mutation or biomarker is becoming increasingly common in cancer treatment, and companion diagnostic tests assist oncologists in selecting patients who may benefit from these targeted treatments."
For More Information
Andre F, Ciruelos E, Rubovszky G, et al (2019). Alpelisib for PIK3CA-mutated, hormone receptor-positive advanced breast cancer. N Engl J Med, 380(20):1929-1940. DOI:10.1056/NEJMoa1813904
Clinicaltrials.gov (2019). Study assessing the efficacy and safety of alpelisib plus fulvestrant in men and postmenopausal women with advanced breast cancer which progressed on or after aromatase inhibitor treatment. (SOLAR-1). NLM Identifier: NCT02437318.
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