Eisai, Halozyme partner to evaluate eribulin and PEGPH20 in HER2-negative metastatic breast cancer

Eisai Inc. announced today that its parent company Eisai Co., Ltd. (Headquarters: Tokyo, President and CEO: Haruo Naito, "Eisai") and Halozyme Therapeutics, Inc. (Headquarters: San Diego, California, President and CEO: Dr. Helen Torley, "NASDAQ: HALO") have signed a clinical collaboration agreement to evaluate Eisai's agent eribulin mesylate (brand name: Halaven^®, "eribulin") in combination with Halozyme's investigational drug PEGPH20 (PEGylated recombinant human hyaluronidase) in first line HER2-negative metastatic breast cancer. The companies will jointly share the costs of a phase 1b/2 clinical trial to assess whether or not eribulin, in combination with PEGPH20, can improve overall response rate (ORR) -- the proportion of women that have a predefined reduction in tumor burden -- as compared with eribulin alone as a therapy in women with advanced breast cancer.

PEGPH20 (PEGylated recombinant human hyaluronidase) is an investigational drug administered intravenously that targets the degradation of hyaluronan, a glycosaminoglycan – or chain of natural sugars throughout the body – that can accumulate around cancer cells to inhibit other therapies. The collaborative study will seek to determine whether or not the combination therapy of eribulin and PEGPH20 can improve the overall response rate in patients with high levels of hyaluronan. In hyaluronan-rich triple-negative breast preclinical animal models, the addition of PEGPH20 to eribulin showed a significantly higher tumor growth inhibition and overall tumor regression when compared to eribulin alone.

Eribulin is not indicated for first-line therapy for patients with HER2-negative metastatic breast cancer.

Eribulin is the first in the halichondrin class of microtubule dynamics inhibitors with a novel mechanism of action. Structurally, eribulin is a modified and synthetically produced analog of halichondrin B, a natural product isolated from the marine sponge Halichondria okadai. Eribulin is believed to work by inhibition of the growth phase of microtubule dynamics which prevents cell division.

"This is a very important collaboration, one that speaks to our continued commitment to address the unmet medical needs of patients with advanced breast cancer," said RuiRong Yuan, MD, Vice President and Chief Medical Officer, Eisai Global Oncology. "We look forward to enrolling patients in the clinical trial and assessing the results."

"This agreement marks the first clinical collaboration agreement for Halozyme and extends the study of PEGPH20 to a substantially wider population of patients with a partner that is a clear leader in the treatment of metastatic breast cancer," said Dr. Helen Torley, President and CEO, Halozyme Therapeutics.