Mersana Therapeutics Announces Additional FDA Fast Track Designation Granted to Emiltatug Ledadotin (XMT-1660)

On January 10, 2025 Mersana Therapeutics, Inc. (NASDAQ: MRSN), a clinical-stage biopharmaceutical company focused on discovering and developing a pipeline of antibody-drug conjugates (ADCs) targeting cancers in areas of high unmet medical need, reported the U.S. Food and Drug Administration (FDA) recently granted an additional Fast Track designation to XMT-1660 (Press release, Mersana Therapeutics, JAN 10, 2025, View Source [SID1234649595]). The company also announced that the World Health Organization has approved emiltatug ledadotin (abbreviated as Emi-Le) as XMT-1660’s international nonproprietary name (INN).

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The new Fast Track designation is for the treatment of advanced or metastatic breast cancer in patients with human epidermal growth factor receptor 2 (HER2) low (IHC 1+ or IHC 2+/ISH–) or HER2-negative (IHC 0) disease, including triple-negative breast cancer (TNBC), who have received a prior topoisomerase-1 inhibitor ADC. Additionally, hormone-receptor positive patients should also have received or be ineligible for endocrine therapy. The FDA previously granted Fast Track designation to Emi-Le for the treatment of adult patients with advanced or metastatic recurrent TNBC.

"Topoisomerase-1 inhibitor ADCs are rapidly becoming the standard of care for metastatic TNBC and hormone-receptor positive breast cancer, and an increasing amount of research shows that these patients are exceedingly difficult to treat thereafter," said Martin Huber, M.D., President and Chief Executive Officer of Mersana Therapeutics. "This growing population is a primary focus for us as we advance the development of Emi-Le. We are excited to announce this additional Fast Track designation and the initial clinical data from our ongoing Phase 1 clinical trial that were press released separately this morning."

The FDA’s Fast Track program is designed to facilitate the development and expedite the review of drug candidates to treat serious conditions and fill an unmet medical need. A product candidate granted Fast Track designation may be eligible for several benefits, including more frequent meetings and communications with the FDA and, if certain criteria are met, the potential for Accelerated Approval, Priority Review or Rolling Review of a Biologics License Application (BLA) by the FDA.

Conference Call Information
Mersana will host a conference call today at 8:30 a.m. ET to discuss the initial clinical data from its Phase 1 clinical trial of Emi-Le. To access the call, please dial 833-255-2826 (domestic) or 412-317-0689 (international). A live webcast that includes the data presentation will be available on the Investors & Media section of the Mersana website at www.mersana.com, and a replay of the webcast will be available in the same location following the conference call for approximately 90 days.