Therapy Shows Early, Encouraging Results in Treating Aggressive Form of Breast Cancer

Merck’s anti—PD-1 therapy Keytruda has demonstrated an overall response rate of 18.5% among patients with PD-L1 positive, advanced triple-negative breast cancer, one of the most aggressive forms of breast cancer.

With more data to be collected from responders, Merck celebrated favorable, early results in a press release.

“Metastatic, triple-negative breast cancer is an aggressive and often difficult-to-treat disease,” said Rita Nanda, MD, associate director of breast medical oncology at the University of Chicago and principal investigator for the Keytruda triple-negative breast cancer phase 1b study cohort, in a press release. “The results presented at this year’s SABCS, while early, show encouraging anti-tumor activity in these patients, most of whom had received multiple prior chemotherapies.”

Many patients in the study had received 2 or more prior chemotherapies for metastatic disease, Merck stated, and 87.5% had received prior neo-adjuvant or adjuvant therapy.

Of the 27 patients studied, 3.7% achieved a complete response and 14.8% saw a partial response. On the flip side, 25.9% saw stable disease, 44.4% deteriorated with progressive disease, and 11.1% discontinued therapy.

Merck also noted that 33% of patients taking Keytruda experienced tumor shrinkage.

Some of Keytruda’s reported adverse side effects included arthralgia, fatigue, myalgia, and nausea, according to Merck.