Eisai to Present New Research on HALAVEN® (eribulin mesylate) Injection at 41st Annual San Antonio Breast Cancer Symposium

WOODCLIFF LAKE, N.J. /PRNewswire/ --Eisai announced today that new study results on its in-house discovered and developed anticancer agent eribulin mesylate (marketed as HALAVEN^®) will be presented during the 41^st San Antonio Breast Cancer Symposium (SABCS). The symposium will be held from December 4-8, 2018, in San Antonio, Texas.

Eisai is presenting a total of four abstracts at this year's SABCS. Presentations will include the results of biomarker research on PTEN alterations and tumor mutational burden (TMB) as potential predictors of resistance or response to immune checkpoint inhibitors (ICI) in metastatic triple-negative breast cancer (mTNBC). This study included patients from the ENHANCE I phase 2 trial evaluating eribulin in combination with Merck's (known as MSD outside the United States and Canada) anti-PD-1 therapy pembrolizumab (marketed as KEYTRUDA^®).

"With these new data, we hope to further understand the role that eribulin may play in treating metastatic breast cancer, specifically triple-negative disease," said Alton Kremer, Chief Clinical Officer and Chief Medical Officer at Eisai Inc. "As a human health care company, we aim to examine ways to address the needs of patients living with metastatic breast cancer."

This release discusses investigational uses for FDA-approved products. It is not intended to convey conclusions about efficacy and safety. There is no guarantee that any investigational uses of FDA-approved products will successfully complete clinical development or gain FDA approval.

Eisai presentations at this year's SABCS:

About Metastatic Breast Cancer
Metastatic breast cancer is an advanced stage of the disease that occurs when cancer spreads beyond the breast to other parts of the body. In 2018, an estimated 266,120 women will be diagnosed with invasive breast cancer in the United States and an estimated 40,920 women will die from the disease. It is estimated that approximately 6 to 10 percent of women with breast cancer will have metastatic disease at the time of breast cancer diagnosis. Women diagnosed with metastatic disease have an estimated 5-year relative survival rate of about 27%.

About HALAVEN^® (eribulin mesylate) Injection
HALAVEN^® (eribulin mesylate) is a microtubule dynamics inhibitor indicated for the treatment of patients with:

• Metastatic breast cancer who have previously received at least two chemotherapeutic regimens for the treatment of metastatic disease. Prior therapy should have included an anthracycline and a taxane in either the adjuvant or metastatic setting. 
• Unresectable or metastatic liposarcoma who have received a prior anthracycline-containing regimen.

Discovered and developed by Eisai, eribulin is a synthetic analog of halichondrin B, a natural product that was isolated from the marine sponge Halichondria okadai. First in the halichondrin class, eribulin is a microtubule dynamics inhibitor. Eribulin is believed to work primarily via a tubulin-based mechanism that causes prolonged and irreversible mitotic blockage, ultimately leading to apoptotic cell death. Additionally, in preclinical studies of human breast cancer, eribulin demonstrated complex effects on the tumor biology of surviving cancer cells, including increases in vascular perfusion resulting in reduced tumor hypoxia, and changes in the expression of genes in tumor specimens associated with a change in phenotype, promoting the epithelial phenotype, opposing the mesenchymal phenotype. Eribulin has also been shown to decrease the migration and invasiveness of human breast cancer cells.

Important Safety Information

Warnings and Precautions
Neutropenia: Severe neutropenia (ANC <500/mm³) lasting >1 week occurred in 12% of patients with mBC and liposarcoma or leiomyosarcoma. Febrile neutropenia occurred in 5% of patients with mBC and 2 patients (0.4%) died from complications. Febrile neutropenia occurred in 0.9% of patients with liposarcoma or leiomyosarcoma, and fatal neutropenic sepsis occurred in 0.9% of patients. Patients with mBC with elevated liver enzymes >3 × ULN and bilirubin >1.5 × ULN experienced a higher incidence of Grade 4 neutropenia and febrile neutropenia than patients with normal levels. Monitor complete blood cell counts prior to each dose, and increase the frequency of monitoring in patients who develop Grade 3 or 4 cytopenias. Delay administration and reduce subsequent doses in patients who experience febrile neutropenia or Grade 4 neutropenia lasting >7 days.

Peripheral Neuropathy: Grade 3 peripheral neuropathy occurred in 8% of patients with mBC (Grade 4=0.4%) and 22% developed a new or worsening neuropathy that had not recovered within a median follow-up duration of 269 days (range 25-662 days). Neuropathy lasting >1 year occurred in 5% of patients with mBC. Grade 3 peripheral neuropathy occurred in 3.1% of patients with liposarcoma and leiomyosarcoma receiving HALAVEN and neuropathy lasting more than 60 days occurred in 58% (38/65) of patients who had neuropathy at the last treatment visit. Patients should be monitored for signs of peripheral motor and sensory neuropathy. Withhold HALAVEN in patients who experience Grade 3 or 4 peripheral neuropathy until resolution to Grade 2 or less.

Embryo-Fetal Toxicity: HALAVEN can cause fetal harm when administered to a pregnant woman. Advise females of reproductive potential to use effective contraception during treatment with HALAVEN and for at least 2 weeks following the final dose. Advise males with female partners of reproductive potential to use effective contraception during treatment with HALAVEN and for 3.5 months following the final dose.

QT Prolongation: Monitor for prolonged QT intervals in patients with congestive heart failure, bradyarrhythmias, drugs known to prolong the QT interval, and electrolyte abnormalities. Correct hypokalemia or hypomagnesemia prior to initiating HALAVEN and monitor these electrolytes periodically during therapy. Avoid in patients with congenital long QT syndrome.

Adverse Reactions
In patients with mBC receiving HALAVEN, the most common adverse reactions (≥25%) were neutropenia (82%), anemia (58%), asthenia/fatigue (54%), alopecia (45%), peripheral neuropathy (35%), nausea (35%), and constipation (25%). Febrile neutropenia (4%) and neutropenia (2%) were the most common serious adverse reactions. The most common adverse reaction resulting in discontinuation was peripheral neuropathy (5%).

In patients with liposarcoma and leiomyosarcoma receiving HALAVEN, the most common adverse reactions (≥25%) reported in patients receiving HALAVEN were fatigue (62%), nausea (41%), alopecia (35%), constipation (32%), peripheral neuropathy (29%), abdominal pain (29%), and pyrexia (28%). The most common (≥5%) Grade 3-4 laboratory abnormalities reported in patients receiving HALAVEN were neutropenia (32%), hypokalemia (5.4%), and hypocalcemia (5%). Neutropenia (4.9%) and pyrexia (4.5%) were the most common serious adverse reactions. The most common adverse reactions resulting in discontinuation were fatigue and thrombocytopenia (0.9% each).

Use in Specific Populations
Lactation: Because of the potential for serious adverse reactions in breastfed infants from eribulin mesylate, advise women not to breastfeed during treatment with HALAVEN and for 2 weeks after the final dose.

Hepatic and Renal Impairment: A reduction in starting dose is recommended for patients with mild or moderate hepatic impairment and/or moderate or severe renal impairment.

For more information about HALAVEN, click here for the full Prescribing Information.

About Eisai Inc.
At Eisai Inc., human health care (hhc) is our goal. We give our first thoughts to patients and their families, and helping to increase the benefits health care provides. As the U.S. pharmaceutical subsidiary of Tokyo-based Eisai Co., Ltd., we have a passionate commitment to patient care that is the driving force behind our efforts to discover and develop innovative therapies to help address unmet medical needs.

Eisai is a fully integrated pharmaceutical business that operates in two global business groups: oncology and neurology (dementia-related diseases and neurodegenerative diseases). Each group functions as an end-to-end global business with discovery, development, manufacturing and marketing capabilities. Our U.S. headquarters, commercial and clinical development organizations are located in New Jersey; our discovery labs are in Massachusetts and Pennsylvania; and our global demand chain organization resides in Maryland and North Carolina. To learn more about Eisai Inc., please visit us at eisai.com/us.

KEYTRUDA^® is a registered trademark of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, N.J., U.S.A.

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SOURCE Eisai Inc.