Narsoplimab

Narsoplimab, also known as OMS721, is a human monoclonal antibody that targets MASP-2 (mannose-binding lectin-associated serine protease-2), a protease in the lectin pathway of the complement system. By inhibiting MASP-2, narsoplimab blocks activation of the lectin pathway and reduces downstream complement activation and inflammatory injury to endothelial cells. This mechanism is being explored in diseases in which complement-mediated endothelial injury and thrombotic microangiopathy contribute to pathology.

Narsoplimab was developed by Omeros Corporation and has been evaluated in several clinical trials. The most extensive program has focused on transplant-associated thrombotic microangiopathy (HSCT-TMA) after hematopoietic stem cell transplantation, where investigators have assessed whether MASP-2 inhibition can mitigate microangiopathic injury. Additional studies have explored its potential in IgA nephropathy and other complement-mediated disorders; early-phase trials have examined safety and signals of efficacy in diverse settings, including inflammatory and infectious diseases.

As of 2024, narsoplimab remains an investigational therapy and has not been approved by major regulatory authorities for any indication. The clinical development program has reported varying results across trials, with ongoing assessment of efficacy, safety, dosing, and patient selection. Adverse events observed in trials have been reported consistent with immune modulation, but specific safety profiles depend on the trial and population.