Mersana Restructures, Prioritises Breast Cancer ADC Development To Extend Cash Runway Through 2026

Mersana Therapeutics has announced a major strategic restructuring and reprioritisation initiative designed to extend its cash runway and focus its development pipeline. As part of this plan, the company will reduce its workforce by approximately 55%, a move expected to be largely completed by the end of Q3 2025. The restructuring comes as Mersana narrows its focus to the advancement of its lead antibody-drug conjugate candidate, emiltatug ledadotin (Emi-Le; XMT-1660), which targets B7-H4 in cancer.

“We continue to believe that Emi-Le’s differentiated profile offers an opportunity to meaningfully benefit patients. Given today’s increasingly challenging macro-economic conditions and our objective to achieve additional important clinical milestones with Emi-Le, we have made the difficult decision to significantly reduce our workforce and deprioritize other investments. I want to extend my personal thanks to our talented colleagues who were impacted by this decision for their hard work and many contributions to Mersana’s programs and culture focused on patients waiting for new therapies,” said Martin Huber, M.D., President and Chief Executive Officer of Mersana Therapeutics.

The company will reduce research activities and halt all internal development programs to support its new market direction. The company dedicates all research activities towards obtaining more clinical and safety data from the treatments of breast cancer patients with Emi-Le. XMT-2056 Phase 1 dose escalation trials will proceed while the company maintains connections with outside research partners. Mersana's cost-saving initiatives and pipeline restructuring will keep their financial stability until mid-2026.