Keytruda®/Halaven® Combo May Be Effective in Advanced Triple-Negative Breast Cancer


The investigative treatment combination including Keytruda (pembrolizumab) plus Halaven (eribulin) could provide a potential therapeutic option for patients with advanced triple-negative breast cancer whose disease has advanced following prior therapies. These results were recently presented at the 2016b annual San Antonio Breast Cancer Symposium (SABCS).

Approximately 12% of breast cancers are triple-negative breast cancers (TNBC), meaning that they are estrogen-receptor negative (ER-), progesterone-receptor negative (PR-), and human epidermal growth factor receptor 2-negative (HER2-). This means that TNBC is not stimulated to grow from exposure to the female hormones estrogen or progesterone, nor through an overactive HER2 pathway.

Unfortunately, many available and effective treatment options for the majority of breast cancers block the growth stimulating effects of ER, PR and/or HER2; therefore, TNBC has limited therapeutic options.

In addition, TNBC tends to be an aggressive type of cancer, tends to be diagnosed at a more advanced stage, and proportionately affects younger women more often than other breast cancers. Novel treatment options for TNBC have lagged behind that of other types of breast cancers.

Researchers recently conducted an early-phase clinical trial to evaluate the safety and effectiveness of a treatment combination consisting of pembrolizumab plus eribulin. Pembrolizumab is referred to as an anti-PD1 agent, and works to stimulate the immune system to identify cancer cells and mount an attack against them. It is currently approved for several different types of cancers; however, it is not approved for the treatment of breast cancer. Eribulin is an agent that blocks the formation of certain components in cells that provide structural integrity to a cell, as well as other biologic systems that provide life-sustaining effects to cells. It is approved for the treatment of advanced breast cancer that has progressed following prior therapies.

The data presented at this year’s SABCS included interim data from 39 patients in the recent trial. All patients had advanced TNBC that had spread to distant sites in the body, and had progressed following at least two prior therapies – representing a very difficult stage of disease to treat. All patients received the combination of pembrolizumab and eribulin.
• Approximately one-third of the patients achieved an anti-cancer response
• No patient died from side effects of therapy
• 10 patients discontinued treatment due to side effects

The researchers concluded that it appears that the combination of pembrolizumab and eribulin provides anti-cancer activity among this difficult-to-treat patient population. As these were only interim data, researchers await more mature data that include larger numbers of patients that are involved in the trial to truly determine the potential safety and effectiveness of the pembrolizumab/eribulin treatment combination.

Reference: Merck. News Release. Interim Results from Phase 1b/2 Study Evaluating the Combination of Merck’s Keytruda® (pembrolizumab) and Eisai’s Halaven® (eribulin mesylate) injection in Metastatic Triple-Negative Breast Cancer Presented at the 2016 annual San Antonio Breast Cancer Symposium. Available at: Accessed December 20, 2016.