Two phase 1b clinical trials are underway to evaluate OMS906—Omeros Corporation’s inhibitor of mannose-binding lectin-associated serine protease 3 (MASP-3), the key activator of the alternative complement pathway—in patients with paroxysmal nocturnal hemoglobinuria (PNH).

One of the trials is designed to evaluate OMS906 in patients with PNH who are treatment-naïve, while the other trial includes patients with PAH who have demonstrated an unsatisfactory response to the complement 5 inhibitor ravulizumab (Ultomiris®).

Participants in the second trial will receive OMS906 in combination with ravulizumab for 24 weeks. Then, OMS906 monotherapy will be provided for those who demonstrate a hemoglobin response with combination therapy.

Enrollment has begun for both trials. OMS906 dosing is ongoing for the trial enrolling treatment-naïve patients and is scheduled to begin this month for the trial enrolling patients who have had an unsatisfactory response to ravulizumab, once the ravulizumab monotherapy period has ended.

Read more about PNH therapies

Gregory A. Demopulos, MD, chairman and chief executive officer of Omeros, highlighted recent advances of OMS906 and other Omeros’ drugs in a press release.

“OMS906, targeting the key activator of the alternative pathway MASP-3, we expect can also be dosed once quarterly [as the MASP-2 inhibitor OMS1029] and, given its significant biological advantages over potential competitors, pending efficacy data in PNH followed by [complement 3 glomerulopathy] will go a long way in answering whether MASP-3 and OMS906 are the premier alternative-pathway target and therapeutic.”

Recently, Omeros announced positive results from the single-ascending-dose phase 1 study evaluating both intravenous and subcutaneous administration of OMS906 in healthy participants. The drug was well-tolerated and no treatment-emergent serious adverse events were reported.

The results of the phase 1 study were presented at the 64th ASH Annual Meeting and Exposition.


Omeros Corporation reports fourth quarter and year-end 2022 financial results. News release. Omeros Corporation; March 13, 2023.