Eisai Co. Ltd. updated its analysis of Halaven combined with Merck & Co. Inc.'s Keytruda as a treatment for triple-negative breast cancer.

Triple-negative breast cancer is a type of breast cancer where the cancer cells tested negative for expression of estrogen receptors, progesterone receptors and HER-2 receptors. This renders common treatments, such as hormone therapy and drugs that target HER-2, ineffective.

The phase 1b/2 trial evaluated anti-cancer agent Halaven, also known as eribulin, and PD-1 protein inhibitor Keytruda, also known as pembrolizumab. The analysis covered 106 patients who received the combination therapy over 21-day cycles.

Eisai said the phase 1b component focused on the treatment's safety and tolerability. The most common adverse events were fatigue, peripheral neuropathy, nausea, alopecia and constipation.

Meanwhile, the phase 2 component had the main goal of objective response rate, or the percentage of patients who saw their tumor shrink, which was 26.4%.

The study recorded three complete responses and 25 partial responses, which occurred regardless of the patients' prior treatment or PD-1 status.

Additionally, patients in the trial survived for a median of 4.2 months without the disease worsening, while median overall survival was 17.7 months. The median duration of response to the therapy was 8.3 months for the 28 patients who achieved a complete or partial response.