Bagsværd, Denmark & Seattle, USA – October 15, 2025 – In a move strengthening its foothold in immunology and complement-mediated diseases, Novo Nordisk A/S has entered into a definitive asset purchase and license agreement with Omeros Corporation (Nasdaq: OMER) for zaltenibart (formerly OMS906), a clinical-stage MASP-3 inhibitor targeting rare blood and kidney disorders. Under the terms, Novo Nordisk gains exclusive global rights to develop and commercialize zaltenibart across all indications, marking a major expansion of its Rare Disease portfolio.
Science Significance
Zaltenibart represents a next-generation therapeutic approach in complement biology, offering a novel mechanism that selectively inhibits mannan-binding lectin-associated serine protease-3 (MASP-3) — the key upstream activator of the complement system’s alternative pathway. MASP-3 converts pro-factor D to its active form, factor D, thereby initiating the cascade responsible for abnormal immune activation in multiple rare diseases. By blocking MASP-3, zaltenibart may provide a more selective, durable, and safer intervention than existing C3 or C5 inhibitors, which suppress broader immune functions. Unlike downstream inhibitors, MASP-3 blockade preserves the classical complement pathway, maintaining immune defense and vaccine responsiveness. With low systemic concentration and slow clearance, MASP-3 is considered an ideal drug target with potentially lower infection risk and longer dosing intervals. Omeros’ Phase 2 data in paroxysmal nocturnal hemoglobinuria (PNH) showed that zaltenibart achieved strong hematologic responses, hemoglobin stabilization, and an acceptable safety profile, indicating best-in-class potential among complement inhibitors.
Regulatory Significance
The acquisition positions Novo Nordisk to advance zaltenibart into global Phase 3 clinical trials in PNH while expanding into IgA nephropathy (IgAN), C3 glomerulopathy (C3G), and atypical hemolytic uremic syndrome (aHUS). The transaction is subject to customary closing conditions and regulatory approvals and is expected to complete in Q4 2025. Given the unique mechanism of MASP-3 inhibition, regulators may classify zaltenibart as a first-in-class therapy, potentially eligible for Orphan Drug, Fast Track, or Breakthrough Therapy designations in the US and EU. This deal reflects a broader policy and regulatory trend: authorities are increasingly prioritizing innovative complement-targeted therapies for ultra-rare diseases that address high unmet medical needs and offer differentiated safety advantages.
Business Significance
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Novo Nordisk will pay Omeros USD 340 million in upfront and near-term milestone payments, with potential total consideration reaching USD 2.1 billion, including development and commercial milestones and tiered royalties on global net sales. The transaction marks one of Novo Nordisk’s largest, rare disease investments, reinforcing its commitment to expanding beyond metabolic disorders into hematology and nephrology.
According to Martin Holst Lange, Executive Vice President of Research & Development at Novo Nordisk, “Zaltenibart’s novel mode of action could offer several advantages over other treatments for complement-mediated diseases. We aim to build on Omeros’ pioneering work to maximize the therapeutic and commercial value of this asset.” For Omeros, the agreement provides significant non-dilutive funding, supporting the company’s continued efforts to secure regulatory approval and commercialization of narsoplimab, its MASP-2 inhibitor, and to advance other programs in oncology and CNS disorders. Omeros retains rights to its preclinical MASP-3 small-molecule programs, offering flexibility to develop assets in other niche indications.
Patients’ Significance
For patients with PNH and rare renal diseases, zaltenibart could represent a transformational therapy that reduces the disease burden while maintaining immune protection. Current complement inhibitors, such as C5 blockers, can increase susceptibility to meningococcal and other bacterial infections — a major clinical challenge. MASP-3 inhibition, by contrast, preserves essential immune pathways, offering a safer, long-term alternative with potentially fewer adverse effects and less frequent dosing. “With zaltenibart, we have an opportunity to help a significant number of people living with rare blood and kidney disorders,” said Ludovic Helfgott, Executive Vice President of Product and Portfolio Strategy at Novo Nordisk. “This acquisition strengthens our leadership in rare diseases and enhances our capacity to deliver innovative therapies globally.” If successful in Phase 3, zaltenibart could benefit thousands of patients affected by complement-driven disorders, a group that remains underserved despite major scientific advances.
Policy Significance
This collaboration underscores a growing policy emphasis on global partnerships to accelerate innovation in rare and orphan diseases. By integrating Omeros’ scientific discovery platform with Novo Nordisk’s global regulatory, clinical, and commercial capabilities, the deal aligns with regulatory policies promoting knowledge transfer and public-private collaboration. The transaction also highlights how rare disease frameworks — including the FDA’s Orphan Drug Act and the EU’s Horizon Rare Program — are incentivizing cross-border licensing deals that bring first-in-class therapeutics to market faster. From a policy standpoint, Novo Nordisk’s acquisition exemplifies sustainable innovation, combining scientific novelty, global patient reach, and long-term economic value.
Transaction Highlights
Under the definitive agreement, Novo Nordisk acquires global rights to zaltenibart, including all related intellectual property, data, and clinical assets. Omeros will receive USD 340 million upfront and near-term milestone payments, with additional potential payments up to USD 2.1 billion linked to development, regulatory, and commercial achievements. The agreement includes tiered royalties on global net sales of zaltenibart. Following closing, Novo Nordisk will initiate a global Phase 3 program in PNH and evaluate further indications in rare blood and kidney diseases. Omeros retains its preclinical MASP-3 programs for small-molecule inhibitors under limited indications. The acquisition is expected to close by Q4 2025, pending customary regulatory approvals.
Source: Novo Nordisk A/S and Omeros Corporation Press Release
