Fig. 7

Optimization of neratinib dosing for enhanced CDK4/6 inhibitor combined with endocrine therapy efficacy. (A) Tumor photographs in animals treated with normal saline (control group), CDK4/6 inhibitor (palbociclib, 150 mg/kg, i.g.) + endocrine therapy (fulvestrant, 100 mg/kg, i.m.), medium-dose neratinib (20 mg/kg) alone, a triple therapy consisting of medium-dose neratinib group (20 mg/kg, i.g.), CDK4/6 inhibitor, and endocrine therapy, and a triple therapy consisting of low-dose neratinib (10 mg/kg, i.g.), CDK4/6 inhibitor, and endocrine therapy. (C) Weight changes in various groups of HR⁺/HER2-low tumor-bearing mice. (B) Tumor inhibition rates and (D) tumor growth curves of HR⁺/HER2-low tumor-bearing mice in various groups. For HER2-low tumor volume on day 21: normal saline vs. medium-dose ET + CDK4/6i + Ner, P = 0.0001; normal saline vs. low-dose ET + CDK4/6i + Ner, P = 0.0017; normal saline vs. ET + CDK4/6i, P = 0.003; ET + CDK4/6i vs. medium-dose ET + CDK4/6i + Ner, P = 0.0021. For HER2-low tumor inhibition rate on day 21: normal saline vs. medium-dose ET + CDK4/6i + Ner, P = 0.0217; normal saline vs. low-dose ET + CDK4/6i + Ner, P = 0.1271. ^**P < 0.01; ^***P < 0.001; n = 5. ET endocrine therapy, CDK4/6i CDK4/6 inhibitor, Ner neratinib.