20 October 2021 - - US-based biopharmaceutical company Omeros Corp. (NASDAQ: OMER) has received a Complete Response Letter from the US Food and Drug Administration regarding its Biologics License Application for narsoplimab in the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (HSCT-TMA), the company said.

Following HSCT, patients generally have complex clinical courses and are often severely ill. HSCT-TMA increases that complexity and worsens outcomes.

In the CRL, FDA expressed difficulty in estimating the treatment effect of narsoplimab in HSCT-TMA and asserted that additional information will be needed to support regulatory approval.

There were no chemistry, manufacturing and controls, safety, or non-clinical issues precluding approval raised in the CRL.

Omeros remains confident in the efficacy and safety data for narsoplimab in HSCT-TMA. The company worked closely with FDA on the clinical development plan, including with respect to both the single-arm trial to support approval and the definition of response as the primary endpoint.

Omeros plans to request a Type A meeting as soon as possible with FDA to discuss the CRL and determine the most expeditious path forward for the approval of narsoplimab in the treatment of HSCT-TMA.

Narsoplimab is the first drug candidate submitted to FDA for approval in HSCT-TMA. It has Breakthrough Therapy and Orphan designations in both HSCT-TMA and IgA nephropathy.

Omeros is a commercial-stage biopharmaceutical company focused on discovering, developing and commercializing small-molecule and protein therapeutics for large-market and orphan indications targeting inflammation, immunologic diseases (e.g., complement-mediated diseases and cancers) and central nervous system disorders.