Merck's Keytruda Fails as Monotherapy in Breast Cancer Study

By Reuters Staff

May 22, 2019

(Reuters) - The Phase 3 KEYNOTE-119 trial evaluating Merck's Keytruda (pembrolizumab) as monotherapy for the second- or third-line treatment of patients with metastatic triple-negative breast cancer did not meet its pre-specified primary endpoint of superior overall survival compared to chemotherapy (capecitabine, eribulin, gemcitabine or vinorelbine), the company announced Monday.

"Metastatic triple-negative breast cancer is an aggressive and challenging disease to treat, especially after progression on initial standard-of-care treatment," Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories, said in a statement.

"While we are disappointed by the outcome of this monotherapy trial, we are continuing to study Keytruda in earlier stages of the disease and in combination with chemotherapy to address the unmet medical need of patients with triple negative breast cancer. We are grateful to the patients and investigators for their participation in this important study."

Triple negative breast cancer occurs in about 10% to 20% of breast cancer patients and is more difficult to treat, the company said.

Keytruda, which brought in sales of $2.27 billion for the company in the first quarter, has U.S. approval for other forms of cancer including skin and lung cancer.