WASHINGTON — The FDA approved the first PI3K inhibitor for breast cancer.
Alpelisib (Piqray) received approval for use in combination with the hormonal agent fulvestrant (Faslodex) to treat advanced, PIK3CA-mutated, hormone receptor (HR)-positive, HER2-negative breast cancer in postmenopausal women and in men following disease progression during or after initial hormonal therapy. At the same time, the agency approved a companion diagnostic test to detect PIK3CA mutations in tissue or liquid biopsy.
“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,” Richard Pazdur, MD, acting director of the FDA Office of Hematology and Oncology Products, said in a statement.
Alpelisib is the first novel therapy approved through the FDA’s Real-Time Oncology Review pilot program and with use of the updated multidisciplinary review template known as the Assessment Aid, part of an ongoing effort to “streamline reviews without compromising the quality of our assessment,” Pazdur added.
Principal supporting data for the approval application came from the randomized SOLAR-1 trial involving 572 postmenopausal women and men with advanced or metastatic HR-positive/HER2-negative breast cancer that had progressed during or after treatment with an aromatase inhibitor. Patients received fulvestrant alone or in combination with alpelisib, and the primary endpoint was progression-free survival (PFS).
Among the 341 patients with PIK3CA mutations in the trial, the addition of alpelisib significantly improved median PFS from 5.7 months with fulvestrant alone to 11.0 months (P=0.00065). The combination was no better than single-agent fulvestrant in patients without the mutation.
Potential side effects of alpelisib include hyperglycemia, elevated creatinine, diarrhea, rash, decreased lymphocyte count, elevated liver enzymes, nausea, fatigue, low red blood cell count, increased lipase, decreased appetite, stomatitis, vomiting, weight loss, low calcium levels, prolonged clotting time, and hair loss. Grade 3/4 adverse events in SOLAR-1 were topped by hyperglycemia (36.6%), rash (9.9%), and diarrhea (6.7%).
Novartis received the alpelisib approval and Qiagen received approval for the screening test.