Tibremciclib

To investigate the absorption, metabolism and excretion of [14C]BPI-16350 in healthy Chinese male subjects after a single oral dose, and to provide a reference for the rational use of the drug in clinical practice

Primary objective: To evaluate the efficacy of BPI-16350 capsules combined with fulvestrant compared with placebo combined with fulvestrant in subjects with HR+/HER2- advanced breast cancer who have progressed after previous endocrine therapy. Secondary objectives: 1) To evaluate the safety of BPI-16350 capsules combined with fulvestrant versus placebo combined with fulvestrant in subjects with HR+/HER2- advanced breast cancer who have progressed after endocrine therapy; 2) To evaluate the population pharmacokinetic properties of the drug and explore the relationship between drug exposure and efficacy and safety; 3) To evaluate the effect of BPI-16350 capsules combined with fulvestrant versus placebo combined with fulvestrant on the health-related quality of life of subjects.