The abstract is read at the publisher; the summary is JClub's.
Pembrolizumab plus chemotherapy improved progression-free survival versus placebo plus chemotherapy in PD-L1–positive (CPS ≥1) HR+/HER2− advanced breast cancer, with PFS HR 0.74.
- Why it matters: After progression on prior endocrine-based therapy, effective first-line chemotherapy options are limited, and the benefit of adding immune checkpoint blockade in PD-L1–positive disease needed confirmation.
- What they did: In KEYNOTE-B49, participants with locally recurrent inoperable or metastatic HR+/HER2− breast cancer and PD-L1 CPS ≥1 were randomized to pembrolizumab 200 mg or placebo every 3 weeks with chemotherapy, and PFS was assessed by blinded independent central review.
- The result: At final analysis (median follow-up 34.9 months), overall survival was not significantly improved (HR 1.04; P=0.6185), while PFS remained statistically better at interim analysis (median 6.7 vs 6.0 months), with grade ≥3 treatment-related AEs of 38% vs 33%.
The findingWhy it mattersWhat they didThe result
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