A new phase 1b study is assessing the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy of OMS906 in 12 adult patients with paroxysmal nocturnal hemoglobinuria who have had an insufficient response to ravulizumab.

The study drug will be administered in up to 6 intravenous (IV) doses of 3 or 5 mg/kg, first along with the C5 inhibitor ravulizumab and later as monotherapy, at 8-week intervals. Those with a clinical response at week 24 will receive 3 additional doses, and those with an incomplete response will have the option of receiving an additional 3 doses of OMS906. Nonresponders will not have the additional dose option.

The study is a phase 1b proof of concept, nonrandomized, open-label study. The primary outcome measures will be the number and percentage of participants with treatment-emergent adverse events, including abnormal laboratory results, echocardiograms, and physical examinations.

Secondary outcome measures include the incidence of participants with an increase in hemoglobin of 2.0 or more grams per decaliter from baseline, reticulocyte count, lactate dehydrogenase levels, transfusion requirements, pharmacokinetics and pharmacodynamics, and OMS906 antidrug antibodies.

Read more about PNH therapies

PNH is a genetic hematopoietic stem cell disorder caused by mutations in the PIGA gene, leading to the immune system attacking its own red blood cells. It is characterized by hemolytic anemia and hemoglobinuria, which can result in chest pain, dysphagia, fatigue, and difficulty breathing.

OMS906 is a human monoclonal antibody that targets mannan-binding lectin-associated serine protease-3 (MASP-3), thereby inhibiting a key activator of the alternative pathway of the complement system. By inhibiting MASP-3, the immune system overreaction is reduced while still allowing an immune response.

The study was launched on March 27, 2023, and the expected primary completion date is May 31, 2025. The final study completion date is set for July 31, 2025.


Safety and efficacy of OMS906 in paroxysmal nocturnal hemoglobinuria patients with a sub-optimal response to ravulizumab. Clinicaltrials.gov. August 2, 2023. Accessed August 4, 2023.