Inavolisib in PIK3CA-Mutated Advanced Breast Cancer

For patients with ER+/HER2− metastatic breast cancer, standard first line therapy is usually an endocrine agent plus an aromatase inhibitor. The subset of patients with tumors harboring a PIK3CA mutation, particularly patients with rapid progression following adjuvant therapy, have a shorter progression-free interval than those with PIK3CA wild-type tumors.

In the industry-funded, phase 3 INAVO120 trial, researchers enrolled 325 adults with locally advanced or metastatic PIK3CA-mutated, hormone receptor–positive, HER2-negative, endocrine-resistant breast cancer who had disease recurrence or progression after completing adjuvant endocrine therapy. Patients were randomized to receive either the selective PI3Kα inhibitor inavolisib (9 mg orally…