Pembrolizumab Approval Expansion: MSI-High Colorectal and Triple-Negative Breast Cancer
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FDA Approval Announcement
- August 31, 2021
On August 25, 2021, MSD announced FDA approval of pembrolizumab for two additional cancer indications: MSI-high unresectable colorectal cancer and PD-L1+ triple-negative breast cancer.
MSI-High Colorectal Cancer Approval
Evidence Base: KEYNOTE-177 Phase III trial (n=307 untreated, unresectable, MSI-high colorectal cancer)
Efficacy Results:
- Significant progression-free survival improvement with pembrolizumab vs chemotherapy
- 40% disease progression/mortality risk reduction
Triple-Negative Breast Cancer Approval
Evidence Base: KEYNOTE-355 Phase III trial (n=847; n=323 PD-L1+)
Trial Design: Treatment-naive recurrent/locally advanced triple-negative breast cancer
Efficacy Results:
- Significant progression-free survival improvement with pembrolizumab + chemotherapy vs placebo + chemotherapy
- 35% disease progression/mortality risk reduction in PD-L1+ subgroup
Clinical Significance
These approvals expand pembrolizumab indication scope to early-stage disease settings and biomarker-defined populations, supporting earlier intervention in immune-responsive cancers.
Data Source
MSD Product Announcement: https://www.msd.co.jp/newsroom/msd-archive/2021/product_news_0825.xhtml
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