Median PFS was 5.9 months with 95% CI (3, 10.1). CBR at 6 months was 50% (9/18) (95% CI (0.26, 0.74)). The ORR was 6% (0 CR, 1 PR cohort B2), but best response was SD in 11 pts….Bos + palbo + fulv was well tolerated at the RP2D. A robust CBR of 50% was seen despite all patients having prior PD on palbo and 83% on fulv. This is an effective combination for HR+/HER2- MBC...