By Colin Kellaher

Merck & Co. Tuesday said a pivotal Phase 3 study of its cancer drug Keytruda in combination with chemotherapy met a primary endpoint of overall survival in metastatic triple-negative breast cancer.

The Kenilworth, N.J., drugmaker said the combination showed a statistically significant and clinically meaningful improvement in overall survival compared with chemotherapy alone in patients whose tumors expressed PD-L1 with a combined positive score of at least 10.

Merck said Keytruda is the first anti-PD-1 therapy in combination with chemotherapy to show statistically significant overall survival for that patient population. The company previously reported that the combination had shown significantly improved progression-free survival.

Merck is studying Keytruda, a cancer drug that harnesses a patient's immune system to fight tumors, across multiple settings and stages of triple-negative breast cancer, the subtype with the worst survival prognosis.

Write to Colin Kellaher at colin.kellaher@wsj.com

(END) Dow Jones Newswires

07-27-21 0742ET