Dr. Baselga on pan-PI3K Inhibitors in Breast Cancer

José Baselga, MD, PhD, Physician-in-Chief, Memorial Sloan-Kettering Cancer Center, discusses the investigation of pan-PI3K inhibitors for patients with metastatic breast cancer.

Following the success of mTOR inhibition in breast cancer, researchers are investigating the efficacy of blocking the PI3K/AKT/mTOR pathway further upstream. Baselga explains that initial pilot studies and early phase trials have shown promising activity for pan-PI3K inhibitors, which block the PI3K pathway directly at the PI3K molecule.

Larger registration studies are underway investigating pan-PI3K inhibitors for patients with breast cancer. The phase III BELLE-2 trial is currently enrolling postmenopausal patients with hormone receptor-positive, HER2-negative locally advanced or metastatic breast cancer that is refractory to aromatase inhibitors. This trial plans to randomize patients to receive either fulvestrant in combination with the PI3K inhibitor BKM120 or placebo.

Baselga notes that the patient population on this study is very similar to the BOLERO-2 trial that examined exemestane plus the mTOR inhibitor everolimus. The BELLE-2 trial plans to use fulvestrant instead of exemestane, since some believe fulvestrant is a superior hormonal therapy.