biostudies-literatureUnknown8(1)Rugo HSEli Lilly and CompanyMerckThis nonrandomized, open-label, multi-cohort Phase 1b study (NCT02779751) investigated the safety and efficacy of abemaciclib plus pembrolizumab with/without anastrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC) without prior CDK4 and 6 inhibitor exposure. Patients were divided into two cohorts: treatment naïve (cohort 1) and pretreated (cohort 2). Patients received abemaciclib plus pembrolizumab with (cohort 1) or without (cohort 2) anastrozole over 21-day cycles. The primary objective was safety, and secondary objectives included efficacy and pharmacokinetics (PK). Cohort 1/2 enrolled 26/28 patients, respectively. Neutropenia (30.8/28.6%), AST increase (34.6/17.9%), ALT increase (42.3/10.7%),NPJ breast cancer118https://www.ebi.ac.uk/biostudies/studies/S-EPMC9637121biostudies-literatureAbemaciclib in combination with pembrolizumab for HR+, HER2- metastatic breast cancer: Phase 1b study.PMC9637121Chapman SCKabos PJerusalem GRugo HSTolaney SMPaz-Ares LBeck JTWildiers HChisamore MJHossain AMChen YSevillano EfalseAbemaciclib in combination with pembrolizumab for HR+, HER2- metastatic breast cancer: Phase 1b study.This nonrandomized, open-label, multi-cohort Phase 1b study (NCT02779751) investigated the safety and efficacy of abemaciclib plus pembrolizumab with/without anastrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC) without prior CDK4 and 6 inhibitor exposure. Patients were divided into two cohorts: treatment naïve (cohort 1) and pretreated (cohort 2). Patients received abemaciclib plus pembrolizumab with (cohort 1) or without (cohort 2) anastrozole over 21-day cycles. The primary objective was safety, and secondary objectives included efficacy and pharmacokinetics (PK). Cohort 1/2 enrolled 26/28 patients, respectively. Neutropenia (30.8/28.6%), AST increase (34.6/17.9%), ALT increase (42.3/10.7%),2022-01-01T00:00:00Z2022 Nov2026-07-14T15:57:08.386Z2025-02-19T00:32:07.467ZS-EPMC96371213633512010.1038/s41523-022-00482-2