WOODCLIFF LAKE, N.J. /PRNewswire/ -- Eisai announced today that new data from a real world observational study of the use of eribulin mesylate injection (marketed as HALAVEN^®) following cyclin-dependent kinase (CDK) 4/6 inhibitor in community oncology practices will be presented during the 36^th Miami Breast Cancer Conference (MBCC). The conference will be held from March 7-10 in Miami.

"As adding CDK 4/6 inhibitors to endocrine therapy has become the standard of care in early-line treatment of HR-positive, HER2-negative metastatic breast cancer, it's important to better understand the impact these agents may have on subsequent use of eribulin after appropriate prior chemotherapies," said Alton Kremer, MD, PhD, Chief Medical Officer and Chief Clinical Officer, Oncology Business Group at Eisai. "These data provide insight that may help oncologists as they navigate the shifting treatment landscape in metastatic breast cancer in their efforts to help patients."

EMPOWER (Utilization and outcomes of Eribulin Mesylate POst a cyclin-dependent kinase 4/6 inhibitor: An observational real-World study in UnitEd States community oncology pRactices) was a retrospective, observational cohort study evaluating the use of eribulin in female patients with HR-positive HER2-negative metastatic breast cancer who received CDK 4/6 inhibitor therapy between February 2015 and December 2017. Patients were grouped according to the line of therapy in which they received eribulin, though no comparisons between cohorts were made. Toxicities of interest, objective response rate (ORR) per RECIST 1.1 criteria, median progression free survival (PFS) and mean duration of treatment post eribulin initiation until the time of data cutoff were reported.

Results from EMPOWER will be presented Thursday, March 7, from 6:00-8:00 p.m. ET, and Friday, March 8, from 5:15-6:30 p.m. ET.

This study discusses unapproved uses of an FDA-approved product. It is not intended to convey conclusions about efficacy and safety.

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 2019, an estimated 268,600 women will be diagnosed with invasive breast cancer in the United States and an estimated 41,760 women will die from the disease. It is estimated that approximately 6 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 percent. 

About HALAVEN^® (eribulin mesylate) Injection 
HALAVEN^® (eribulin mesylate) Injection 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, HALAVEN 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.