#ESMO26 | VIKTORIA-1 – Study 2
In PIK3CA-mutant HR+/HER2− advanced breast cancer after CDK4/6i, gedatolisib + palbociclib + fulvestrant showed a PFS benefit over alpelisib + fulvestrant in patients with visceral metastases (9.8 vs 5.6 months; HR 0.52) and liver metastases (9.1 vs 4.6 months; HR 0.47).

Superiority over an active control and lower rates of hyperglycemia are important strengths. However, my main question remains the added contribution of palbociclib. Gedatolisib + fulvestrant also showed substantial activity; although the small doublet arm does not establish equivalence, it raises questions about the additional toxicity and cost of the triplet.

Weekly IV administration and stomatitis remain practical limitations. Excluding patients previously treated with PI3K/AKT/mTOR inhibitors also limits applicability to contemporary treatment sequencing.