FDA has approved Eisai’s Halaven™ (eribulin mesylate) injection for the treatment of metastatic breast cancer in patients who have previously received at least two chemotherapeutic regimens. Applications to the regulatory authorities in the EU, Japan, Switzerland, and Singapore have been submitted.
FDA clearance for Halaven was based on data from the pivotal Embrace study, which demonstrated that patients treated using the new drug survived a median of 2.5 months longer than those treated using single-agent therapy chosen by their physician. Median survival was 13.12 months among Halaven-treated patients, and 10.65 months among those receiving physician-selected therapy. Embrace included 762 patients who had previously been treated with an average of four chemotherapies.
The drug is not without side-effects, however. Over 25% of patients receiving the drug developed either neutropenia, anemia, asthenia/fatigue, alopecia, peripheral neuropathy, nausea, or constipation. Neutropenia with or without fever was the most common serious single side-effect, experienced by 6% of patients. About 10% of patients reported severe weakness or tiredness. Some 5% of patients had to stop treatment due to the development of peripheral neuropathy.
Halaven acts a nontaxane microtubule dynamics inhibitor. The drug is a synthetic analog of halichondrin B, originally isolated from the marine sponge Halichondria okadai. Eisai has a number of trials ongoing to evaluate eribulin mesylate in a variety of tumor types including non-small-cell lung cancer, soft-tissue sarcoma, and prostate cancer.