ITOVEBI

Inavolisib is an inhibitor of phosphatidylinositol 3-kinase (PI3K) with inhibitory activity predominantly against PI3Kα. In vitro, inavolisib induced the degradation of mutated PI3K catalytic alpha subunit p110α (encoded by the PIK3CA gene), inhibited phosphorylation of the downstream target AKT, reduced cellular proliferation, and induced apoptosis in PIK3CA-mutated breast cancer cell lines. In vivo, inavolisib reduced tumor growth in PIK3CA-mutated, estrogen receptor-positive, breast cancer xenograft models. The combination of inavolisib with palbociclib and fulvestrant increased tumor growth inhibition compared to each treatment alone or the doublet combinations.