Sino Biopharmaceutical reports positive phase III breast cancer trial for culmerciclib

Sino Biopharmaceutical Limited announced positive interim analysis results from its Phase III clinical study (CULMINATE-2) of culmerciclib in combination with fulvestrant for the first-line treatment of HR+/HER2-advanced breast cancer. Results, presented at ESMO 2025, showed a median progression-free survival (PFS) of NR (not yet reached) in the study group versus 20.2 months in the control group, representing a 44% reduction in the risk of disease progression/death. The Independent Review Committee (IRC) also assessed a median PFS of NR (not yet reached) versus 22.0 months, with a 60% reduction in risk.

The study group also demonstrated a higher objective response rate (ORR) of 59.3% versus 42.3% and a median duration of response (DoR) of NR (not yet reached) versus 16.7 months. Culmerciclib, a CDK2/4/6 inhibitor, exhibited manageable safety, with grade ≥ 3 neutropenia occurring in only 20.3% of patients and treatment termination due to adverse events in only 3.5%.

CULMINATE-2 is the first Phase III clinical study globally to achieve positive results for an oral CDK2/4/6 inhibitor combined with endocrine treatment for this indication. The Centre for Drug Evaluation of the National Medical Products Administration of the PRC accepted marketing applications for culmerciclib in combination with fulvestrant in July 2024 and for its second indication as initial endocrine therapy in July 2025.