VIKTORIA-1 and Gedatolisib in HR+/HER2− mBC

The panel examines the VIKTORIA-1 study and its implications for treatment selection in hormone receptor-positive, HER2-negative metastatic breast cancer (HR+/HER2− mBC) after CDK4/6 inhibitor therapy. Dr. Erica Mayer describes the two study populations, including patients with PI3K pathway wild-type disease and those with PI3K pathway alterations, all of whom had received prior CDK4/6 inhibition. In the wild-type population, gedatolisib-based doublet and triplet regimens demonstrated meaningful improvements in progression-free survival compared with fulvestrant alone, with response rates of approximately 30%. Mucositis was the most prominent toxicity, while rates of diarrhea, rash, and hyperglycemia were comparatively lower than those associated with some other PI3K pathway inhibitors. The discussion then turns to the PI3K pathway-altered population, where gedatolisib-based therapy produced encouraging progression-free survival and response rates compared with alpelisib plus fulvestrant. Dr. Mayer also highlights the practical consideration of gedatolisib's intravenous administration and the potential implications of continuing CDK4/6 inhibition with palbociclib.