FDA Approves First Generic Eribulin Mesylate (Lupin/Natco), Expanding Access to Halichondrin-Class Therapy for Metastatic Breast Cancer and Liposarcoma

On June 3, 2026, the FDA approved generic eribulin mesylate injection (Lupin Pharmaceuticals/Natco Pharma) as the first generic formulation of Halaven (eribulin mesylate; Eisai) for the treatment of patients with metastatic breast cancer who have previously received at least two chemotherapy regimens containing an anthracycline and a taxane, and for patients with unresectable or metastatic liposarcoma who have received a prior anthracycline-containing therapy. Eribulin is a non-taxane microtubule dynamics inhibitor derived from the marine natural product halichondrin B. The approval of a generic formulation is expected to substantially reduce the cost of eribulin — listed at approximately $4,000 per infusion cycle for Halaven — thereby improving access for patients with metastatic breast cancer and liposarcoma, particularly in community oncology settings and for underinsured patients. Liposarcoma is particularly relevant given the same-week ASCO 2026 presentation of the SARC041 trial showing abemaciclib activity in dedifferentiated liposarcoma. The FDA also cleared an automated PD-L1 22C3 testing platform (Dako Omnis) for four additional tumor types on June 3, expanding the companion diagnostic infrastructure for pembrolizumab (Keytruda) treatment selection. Accurate PD-L1 testing is critical for determining which patients benefit from pembrolizumab monotherapy versus combination regimens across multiple cancer types.