This is a Multicenter, Randomized, Double-blind, Placebo-controlled Phase III Clinical Study Evaluating the Efficacy and Safety of FCN-437c Versus Placebo in Combination With Letrozole or Anastrozole ± Goserelin in Women With HR+ and HER2- Advanced Breast Cancer.

FCN-437c：available in 25mg and 100mg capsules for oral administration on an empty stomach. 200mg once daily on Day 1 to Day 21 of every 28-day cycle followed by 7 days off treatment until progressive disease。Letrozole or anastrozole：Letrozole 2.5 mg or anastrozole 1 mg once daily；Goserelin acetate：premenopausal /perimenopausal patients should be coadministered with 3.6mg, Subcutaneously at every 28 days until progressive disease。

"Placebo：available in 25mg and 100mg capsules, and is administered in the same way as FCN-437c。~Letrozole or anastrozole：Letrozole 2.5 mg or anastrozole 1 mg once daily；~Goserelin acetate：premenopausal /perimenopausal patients should be coadministered with 3.6mg, Subcutaneously at every 28 days until progressive disease。"