Under the terms of the agreement, Novo Nordisk will be granted exclusive global rights to develop and commercialize zaltenibart in all indications. Omeros is eligible to receive USD 340 million in upfront and near-term milestone payments, up to a total of USD 2.1 billion including potential development and commercial milestones, plus tiered royalties on net sales.

Zaltenibart

Zaltenibart is an antibody designed to inhibit MASP-3, a protein that acts as a key activator of the complement system’s alternative pathway. Dysregulation of the complement system, a crucial part of the immune system, 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,” says Martin Holst Lange, chief scientific officer and executive vice president of Research & Development at Novo Nordisk. “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.”

Omeros has reported positive phase 2 data 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. Zaltenibart has shown multiple potential advantages over other alternative pathway inhibitors in development or on the market, and it has been well tolerated and demonstrated an acceptable safety profile across all clinical trials to date, describes the company further.

Aims to initiate a global phase 3 programme

Omeros retains certain rights to its preclinical MASP-3 programmes unrelated to zaltenibart, including the ability to develop and commercialise small-molecule MASP-3 inhibitors with limited indication restrictions.

Following closing of the transaction, Novo Nordisk aims to initiate a global phase 3 programme for zaltenibart in PNH and explore further development in a range of other rare blood and kidney disorders.

The transaction is subject to certain customary closing conditions, including applicable regulatory approvals, and is expected to close in the fourth quarter of 2025.