Danish drugmaker Novo Nordisk has entered into a definitive asset purchase and license agreement with US-based Omeros Corporation for zaltenibart (formerly OMS906), a clinical-stage antibody therapy being developed for rare blood and kidney disorders.

Under the terms of the deal, Novo Nordisk will gain exclusive global rights to develop and commercialise zaltenibart across all indications. Omeros will receive USD 340 million in upfront and near-term milestone payments, with the total potential deal value reaching up to USD 2.1 billion, including development and commercial milestones, plus tiered royalties on future net sales.

Zaltenibart is designed to inhibit MASP-3, a protein that acts as a key activator of the complement system’s alternative pathway. Dysregulation of this pathway has been shown to be involved in the pathophysiology of a number of rare diseases.

“Zaltenibart has a novel mode of action that could offer several advantages over other treatments for complement-mediated diseases. Novo Nordisk is in a strong position to build on the work done by Omeros to maximise the value of this asset and develop zaltenibart into a differentiated and potentially best-in-class treatment approach for a number of rare blood and kidney disorders,” said Martin Holst Lange, chief scientific officer and executive vice president of Research & Development at Novo Nordisk.  

Omeros has previously reported positive phase 2 results for zaltenibart in paroxysmal nocturnal hemoglobinuria (PNH) — a rare, acquired blood disorder where the body's immune system mistakenly attacks and destroys red blood cells, leading to low levels of healthy red blood cells and other complications.

Commenting on the agreement, Gregory A. Demopulos, Chairman and Chief Executive Officer of Omeros, said, “We look forward to Novo Nordisk levering its extensive expertise and global reach to unlock the potential of zaltenibart across alternative pathway indications.”  

He added that Omeros will continue advancing its pipeline, including the planned approval and commercialisation of narsoplimab later this quarter.

Omeros will retain rights to certain preclinical MASP-3 programmes unrelated to zaltenibart, including the development of small-molecule MASP-3 inhibitors for select indications.

Following completion of the transaction, Novo Nordisk plans to initiate a global phase 3 trial of zaltenibart in PNH and explore its potential in other rare blood and kidney diseases, including immunoglobulin A nephropathy (IgAN), C3 glomerulopathy and atypical hemolytic uremic syndrome.

The transaction is expected to close in the fourth quarter of 2025, subject to customary regulatory approvals.