FDA Approves Generic Eribulin Mesylate for Metastatic Breast Cancer

The FDA has approved an abbreviated new drug application (ANDA) for generic eribulin mesylate injection, offering a new therapeutic option for patients with pretreated metastatic breast cancer and unresectable or metastatic liposarcoma.¹

The approval was granted to Natco Pharma Limited and its global alliance partner, Lupin Limited, for eribulin mesylate injection, 1 mg/2 mL (0.5 mg/mL) single-dose vials. The newly approved therapeutic is designated as a bioequivalent to the reference listed drug (RLD). According to IQVIA MAT April 2026 data, the RLD maintained an estimated annual sales figure of approximately USD 43.7 million in the United States.

The therapeutic indications for eribulin mesylate mirror those of the reference agent. Clinically, it is indicated for the treatment of adult patients with metastatic breast cancer who have previously received at least 2 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. Additionally, eribulin mesylate is indicated for patients with unresectable or metastatic liposarcoma who have progressed on a prior anthracycline-containing regimen.

About Eribulin Mesylate

Eribulin mesylate is a synthetic analogue of halichondrin B, a macrocyclic ketone naturally derived from the marine sponge Halichondria okadai. Mechanistically, the agent acts as a nontaxane microtubule dynamics inhibitor. Unlike traditional tubulin-targeting agents such as taxanes or vinca alkaloids that impact both microtubule growth and shortening phases, eribulin mesylate selectively binds to the positive ends of microtubules. This action inhibits the microtubule growth phase without altering the shortening phase, sequestering tubulin into non-functional aggregates. The result is a prolonged, irreversible mitotic blockade during the G2/M phase of the cell cycle, leading to apoptotic cell death.

Clinical Support

The clinical efficacy underpinning the initial approval of the reference listed drug in metastatic breast cancer was established in the pivotal EMBRACE trial (NCT00388726). This phase 3, open-label, randomized, global multicenter study evaluated overall survival (OS) in patients with locally recurrent or metastatic breast cancer who had previously received between 2 and 5 prior chemotherapeutic regimens. Patients randomized to receive eribulin mesylate demonstrated a statistically significant improvement in median OS compared to those receiving the treatment of physician's choice.²

For the liposarcoma indication, clinical efficacy was verified through a separate randomized, open-label, multicenter phase 3 trial (NCT01327885). This trial compared eribulin mesylate against dacarbazine in patients with advanced soft tissue sarcomas (specifically leiomyosarcoma or adipocytic/liposarcoma) whose disease had progressed within six months of standard regimens, including an anthracycline. In the prespecified subgroup analysis of patients with advanced liposarcoma, eribulin mesylate demonstrated an absolute median OS benefit of approximately 7 months over dacarbazine, driving regulatory approval for this difficult-to-treat malignancy.³

The introduction of a generic alternative is expected to provide substantial cost-mitigation pathways for oncology practices and healthcare systems managing late-stage malignancies. Eribulin mesylate is administered intravenously over 2 to 5 minutes on days 1 and 8 of a 21-day cycle. Common adverse reactions associated with the therapy include neutropenia, anemia, asthenia, alopecia, peripheral neuropathy, nausea, and constipation. Clinicians are advised to monitor complete blood counts prior to each dose and to delay treatment or adjust dosages in cases of severe cytopenias or peripheral neuropathy.

REFERENCES

1. Lupin and Natco Receive Approval from U.S. FDA for Eribulin Mesylate Injection. News release. Lupin Pharmaceuticals Inc. June 3, 2026. Accessed June 3, 2026. https://tinyurl.com/3pvdzabs

2. Cortes J, O'Shaughnessy J, Loesch D, et al. Eribulin monotherapy versus treatment of physician's choice in patients with metastatic breast cancer (EMBRACE): a phase 3 open-label randomised study. Lancet. 2011 Mar 12;377(9769):914-23. doi: 10.1016/S0140-6736(11)60070-6. Epub 2011 Mar 2. PMID: 21376385.

3. Schöffski P, Chawla S, Maki RG, et al. Eribulin versus dacarbazine in previously treated patients with advanced liposarcoma or leiomyosarcoma: a randomised, open-label, multicentre, phase 3 trial. Lancet. 2016 Apr 16;387(10028):1629-37. doi: 10.1016/S0140-6736(15)01283-0. Epub 2016 Feb 10. PMID: 26874885.