Omeros, a Seattle-based biopharma focused on immune disorders, announced this week that it would be halting its phase 3 trial, ARTEMIS-IGAN, which evaluated narsoplimab for the treatment of immunoglobulin A (IgA) nephropathy.
IgA nephropathy is a kidney disorder characterized by the deposition of excessive IgA protein in the kidneys, leading to inflammation and potential kidney damage. Symptoms can include blood in the urine, high blood pressure, and proteinuria, and treatment involves symptom management, blood pressure control, and, in some cases, immunosuppressive therapy.
Narsoplimab, developed by Omeros, is a monoclonal antibody that inhibits MASP-2, a component of the complement system, which plays a role in inflammation and immune response. By blocking MASP-2, narsoplimab hoped to reduce complement-mediated damage and inflammation, offering a potential treatment for conditions driven by excessive complement activation, including immunologic disorders and complement-mediated diseases.
The primary objective of ARTEMIS-IGAN was to assess the reduction in proteinuria, as measured by 24-hour urine protein excretion (UPE) at the 36-week mark in comparison to a placebo. This evaluation involved 180 IgA nephropathy patients with high baseline proteinuria. But according to Omeros, the topline results indicated that narsoplimab did not demonstrate a statistically significant improvement over the placebo.
In fact, the placebo group displayed a significantly greater reduction in UPE than seen in previous IgA nephropathy trials involving other agents. Now, in line with prior agreements with the FDA, Omeros has decided not to submit an application for narsoplimab's approval in this indication and will terminate the ARTEMIS-IGAN clinical trial.
In its statement this week, Omeros CEO Gregory Demopulos expressed gratitude, and further noted that in-depth data analysis would be conducted to understand the substantial placebo effect and overall trial results better, as well as to identify potential biomarkers.
The funds allocated for the commercialization of IgAN and the continuation of the ARTEMIS-IGAN trial will now be redirected to other later-stage programs, such as the ongoing phase 2 and forthcoming phase 3 initiatives for OMS906, an alternative pathway inhibitor. Additionally, the company's immediate focus remains on the planned resubmission of the biologics license application for narsoplimab in the context of hematopoietic stem-cell transplant-associated thrombotic microangiopathy.