SPH4336 + endocrine therapy

SPH4336 + endocrine therapy refers to the combination of SPH4336, a novel, orally bioavailable, highly selective small molecule inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), with unspecified standard endocrine therapy for cancer. SPH4336 functions by inhibiting CDK4/6, consequently blocking phosphorylation of the retinoblastoma (Rb) protein, enforcing the G1 restriction point in the cell cycle, and arresting cell proliferation—an approach validated in hormone receptor-positive breast cancer and other solid tumors. The combination aims to exploit targeted cell cycle inhibition and hormonal pathway suppression, a strategy particularly relevant in hormone receptor-positive, HER2-negative breast cancer. SPH4336 is under active clinical development and has demonstrated favorable tolerability, dose-dependent pharmacokinetics, and preliminary efficacy signals in solid tumors, including breast cancer, in early-phase trials[1][2][3][5].