A new study has demonstrated meaningful increases in hemoglobin (Hgb) and reductions in lactate dehydrogenase, transfusion independence, and reticulocyte reduction after treatment with OMS906, a humanized monoclonal antibody (mAb) for the treatment of paroxysmal nocturnal hemoglobinuria (PHN).

The study results were presented at the European Hematology Association 2023 Hybrid Congress on June 1, 2023, in Frankfurt, Germany.

“MASP-3 is a key activator of the alternative pathway, upstream of Factor D,” Jens Panse, the author wrote. “OMS906 is a humanized monoclonal antibody that binds to and inhibits MASP-3. In a phase 1 study in healthy subjects, OMS906 was well tolerated with a long duration of MASP-3 inhibition.”

The research team is conducting a single-arm, open-label, clinical trial to assess the safety, preliminary efficacy, pharmacokinetics, and pharmacodynamics of OMS906 in adults with PNH. The primary endpoints are safety and tolerability, and secondary endpoints include change from baseline in Hgb and lactate dehydrogenase as well as transfusion independence from week 4 through weeks 24 and 48.

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As of May 2, 2023, 9 treatment-naive patients have been treated with OMS906. The total planned enrollment is approximately 10 patients, all of whom will receive 5 mg/kg of subcutaneous OMS906 once every 4 weeks.

Four weeks after the first dose, there was a significant increase in Hgb and a decrease in lactate dehydrogenase in all patients. At the latest timepoint of 16 weeks, all patients had an increase in Hgb of more than 2 g/dL, and no patients required transfusions following treatment. Mean reticulocyte counts declined by 70,000/µL to 136,000/µL at all timepoints.

The treatment was well tolerated, and no safety concerns were noted. The most common adverse events included iron deficiency and transient neutropenia.

The research team concluded that this preliminary proof-of-concept study demonstrates the encouraging potential of once-monthly OMS906 for treatment-naive patients with PNH.


Panse J. OMS906, a mannan-binding lectin-associated serine protease-3 (masp-3) inhibitor, normalizes hemoglobin levels in treatment-naïve PNH patients: interim data from a proof-of-concept clinical trial. Presented at: European Hematology Association (EHA) 2023 Hybrid Congress, Frankfurt, Germany; June 1, 2023.