On May 21, Merck & Co. announced the results of the Phase III KEYNOTE-119 study evaluating Keytruda monotherapy as second- or third-line treatment for metastatic triple-negative breast cancer (mTNBC). The results showed that patients receiving Keytruda monotherapy did not achieve a survival benefit compared to those receiving chemotherapy (capecitabine, eribulin, gemcitabine, or vinorelbine).
In terms of safety, consistent with previously reported data, no new safety concerns were identified. Detailed results will be presented at an upcoming medical conference.
Triple-Negative Breast Cancer (TNBC) refers to a subtype of breast cancer that is negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2). It accounts for 10%–20% of all breast cancer pathological subtypes and predominantly affects premenopausal women. TNBC is the most aggressive form of breast cancer, characterized by high invasiveness, a propensity for metastasis, and a very poor prognosis. The median survival time after diagnosis is typically no more than 20 months, and the 5-year survival rate is less than 15%.
Keytruda’s clinical development program in breast cancer includes several internal and external collaborative studies, including three ongoing registrational studies in triple-negative breast cancer (TNBC) (KEYNOTE-355, KEYNOTE-242, and KEYNOTE-522).
Dr. Roy Baynes, Senior Vice President and Head of Global Clinical Development and Chief Medical Officer at Merck Research Laboratories, stated, “Metastatic triple-negative breast cancer is an aggressive disease that is difficult to treat, particularly after initial standard therapy. Although we are disappointed with the results of this monotherapy trial, we continue to investigate Keytruda in combination with chemotherapy to address the unmet medical needs of patients with triple-negative breast cancer.”