FDA Approves First PI3K Inhibitor for Breast Cancer

The US Food and Drug Administration (FDA) has approved the first treatment of its kind for people with advanced breast cancer whose tumors have a certain genetic mutation. Piqray (alpelisib) is a targeted therapy called a PI3K inhibitor. It’s specifically for advanced breast cancer patients – postmenopausal women and men – whose tumors have the PIK3CA mutation and are hormone receptor (HR) positive and HER2 negative. PIK3CA mutations are found in about 30-40% of breast cancers.

The drug is meant to be used along with Faslodex (fulvestrant), a hormone therapy already approved by the FDA.

Piqray is the first drug approved under the FDA's Real-Time Oncology Review pilot program, which allows drug manufacturers to start the review process before an application is officially submitted. The FDA also granted the application Priority Review designation, which is designed to speed up the time it takes to review and approve a drug.

The FDA based its decision on the SOLAR-1 trial, a study of 572 women and men with HR-positive, HER2-negative, advanced breast cancer that grew or spread during or after they were being treated with an aromatase inhibitor (such as anastrozole, letrozole, or exemestane). The study showed improvement in progression-free survival for participants whose tumors had a PIK3CA mutation and who received Piqray and Faslodex. Progression-free survival is the amount of time a person lives with the disease without it getting worse. Those with the mutation who received Piqray had a progression-free survival of an average 11 months compared with an average 5.7 months for those with the mutation who didn’t receive Piqray.

The FDA also approved a companion test called therascreen PIK3CA RGQ PCR Kit, which is used to find the PIK3CA mutation in blood or tumor tissue.

Piqray is a tablet taken by mouth. Common side effects were high blood sugar levels, signs of kidney, liver, or pancreatic problems, diarrhea, rash, low blood counts, nausea and vomiting, fatigue, decreased appetite, mouth sores, weight loss, low calcium levels, blood clotting problems, and hair loss. Very severe skin reactions, such as rashes with peeling and blistering, are possible and should be reported to a doctor. Patients with a history of severe skin reactions should tell their doctor before taking Piqray.

Piqray is marketed by Novartis. Therascreen PIK3CA RGQ PCR Kit is marketed by QIAGEN Manchester, Ltd.