molecules of the month

What is it? Inavolisib is a PI3Kα isoform-selective kinase inhibitor and monovalent degrader of the mutant p110α catalytic subunit of mutant PI3Kα. The molecule selectively depletes mutant p110α in cancer cells with active receptor tyrosine kinase (RTK) signaling, and is in several ongoing or planned Ph. III trials for breast cancer. Why do we care? PI3K is an extensively studied oncology target, and over 2 million cancer patients are diagnosed annually with mutations in PIK3CA, the gene encoding p110α. Despite the unmet medical need, it has been challenging to identify drugs for mutant PI3Kα with significant benefit due to the toxicities associated with wild-type PI3K-family inhibition and a negative feedback loop triggered by PI3K inhibition that activates RTK signaling, counteracting…