PI3K Inhibitor Doubles Breast Cancer PFS

Genentech’s PI3K inhibitor inavolisib (Itovebi) dramatically increased progression-free survival (PFS) in patients with PIK3CA-mutated, hormone receptor–positive, HER2-negative advanced or metastatic breast cancer, according to new research (N Engl J Med 2024 Oct 30 [Epub ahead of print]). In the phase III, double-blind INAVO120 trial, 161 patients received inavolisib plus the CDK inhibitor palbociclib (Ibrance; Pfizer) and the estrogen receptor antagonist fulvestrant and 164 received a placebo with palbociclib and fulvestrant. The median PFS was 15 months in the inavolisib group and 7.3 months in the placebo group. Discontinuation due to adverse events occurred in 6.8% of the patients in the inavolisib group and 0.6% of those in the placebo group.