Inavolisib Added to Standard Tx Shows Sustained Benefit in Advanced BC

Rationale for Using PFS2 as Endpoint

The PFS2 endpoint has emerged with studies of targeted cancer therapies, Kevin Kalinsky, MD, director of the Glenn Family Breast Center at Winship Cancer Institute of Emory University, in Atlanta, said in an interview.

“Presenting PFS2 is not a new thing — we’ve been doing this in other breast cancer studies (of CDK4/6 inhibitors),” said Dr. Kalinsky, a coauthor of the study. “The concern is that you give a drug, and then, after that, things grow so rapidly that then you’re actually not benefiting the patient.

“If you’re giving a targeted agent in the first-line, then the biology changes after that first-line, are you really even making a difference? Or is the drug so toxic that they’re not able to tolerate a next line of treatment?” Dr. Kalinsky continued. “So that’s really the intent of PFS2. The PFS2 included the next line of treatment, so it’s really a first, and second-line representation of treatment. The study presented at ASCO was really about toxicity.”

The study was funded by F. Hoffmann-La Roche Ltd. Dr. Juric disclosed having stock and other ownership interests in PIC Therapeutics, Relay Therapeutics, and Vibliome Therapeutics; consulting or advisory roles with AstraZeneca, Eisai, Genentech, Lilly, MapKure, Novartis, Pfizer, PIC Therapeutics, Relay Therapeutics, and Vibliome Therapeutics; and research funding from Amgen, Arvinas, AstraZeneca, Blueprint Medicines, Eisai, Genentech, Infinity Pharmaceuticals, InventisBio, Novartis, Pfizer, Ribon Therapeutics, Scorpion Therapeutics, Syros Pharmaceuticals, and Takeda.