Although significant toxicity was reported in the FAKTION clinical study with combined capivasertib and fulvestrant, particularly diarrhea, rash, and hyperglycemia, these side effects are also observed with other drugs targeting regulators of the PI3K/AKT-mTOR pathway and do not overlap with the palbociclib hematological toxicity profile, indicating that the side effects associated with the addition of CDK4/6i to this double combination might be clinically manageable19. This evidence concerns the gene PIK3CA and Hyperglycemia.