Novo Nordisk Acquires Rare Disease Drug Zaltenibart from Omeros in Multi-Billion Dollar Deal

Novo Nordisk Expands Rare Disease Portfolio with Zaltenibart Acquisition

Novo Nordisk, a leading Danish pharmaceutical company, announced on October 15, 2025, its definitive agreement to acquire the clinical-stage rare disease drug zaltenibart (formerly OMS906) from U.S.-based biopharmaceutical firm Omeros Corporation. The deal involves an initial payment of $340 million USD in upfront and near-term milestone payments. The total value of the acquisition could reach up to $2.1 billion USD, including potential development and commercial milestones, along with tiered royalties on net sales, which translates to approximately 13.5 billion DKK.

This strategic move is set to significantly enhance Novo Nordisk's rare disease pipeline, particularly in the area of rare blood and kidney disorders. The transaction is subject to customary closing conditions and regulatory approvals, with completion anticipated in the fourth quarter of 2025.

Zaltenibart: A Novel Approach to Complement-Mediated Diseases

Zaltenibart is an investigational humanized monoclonal antibody designed to inhibit MASP-3, a protein identified as a key activator of the complement system's alternative pathway. Dysregulation of this pathway is implicated in the pathophysiology of several rare diseases.

The drug has shown promising positive Phase 2 data in paroxysmal nocturnal hemoglobinuria (PNH), a rare, life-threatening blood disorder characterized by the immune system mistakenly attacking red blood cells. Novo Nordisk plans to initiate a global Phase 3 program for zaltenibart in PNH and explore its development for a range of other rare blood and kidney disorders, including C3 glomerulopathy (C3G).

According to Martin Holst Lange, Chief Scientific Officer and Executive Vice President of Research & Development at Novo Nordisk, 'Zaltenibart has a novel mode of action that could offer several advantages over other treatments for complement-mediated diseases.' The drug's potential for a convenient once-every-eight-weeks intravenous dosing schedule is also highlighted as a significant differentiator from existing therapies.

Financial Details and Strategic Implications

The financial structure of the deal provides Omeros Corporation with substantial capital, addressing previous concerns regarding funding for Phase 3 trials. Omeros is eligible to receive $340 million USD in upfront and near-term milestone payments, with the potential for the total consideration to reach $2.1 billion USD based on development and commercial achievements.

For Novo Nordisk, this acquisition aligns with its broader strategy to strengthen its presence in rare disease therapeutics and diversify its portfolio beyond its strong position in obesity and diabetes treatments. The company has previously expressed interest in the 'hemato-renal area,' which encompasses rare blood and kidney disorders.

Following the announcement, Omeros Corporation's stock experienced a significant surge, climbing over 150%, reflecting investor optimism regarding the financial backing and validation of its pipeline.

Future Outlook

With Novo Nordisk taking the lead, zaltenibart is poised for accelerated development. The Danish pharmaceutical giant aims to maximize the drug's value and establish it as a potentially best-in-class treatment option for various rare blood and kidney disorders. This acquisition underscores Novo Nordisk's commitment to innovation and its ambition to become a leader in the rare disease space.