Novo Nordisk struck a definitive asset purchase and license agreement with Omeros for zaltenibart, an experimental MASP‑3 inhibitor, in a deal worth up to $2.1 billion including $340 million in up‑front and near‑term milestones. Novo gains global rights to develop and commercialize the compound across rare blood and kidney disorders, and will start Phase 3 testing in paroxysmal nocturnal hemoglobinuria (PNH). Omeros reported positive Phase 2 PNH signals and framed MASP‑3 inhibition as a distinct complement‑system approach that may block both intravascular and extravascular hemolysis. Novo’s chief scientific officer Martin Holst Lange characterized zaltenibart as having “multiple potential advantages” and said the company will explore additional indications beyond PNH. The transaction sharpened valuations: Omeros shares surged on the announcement, reflecting investor appetite for differentiated complement‑targeting assets. The move also underscores big‑pharma interest in rare‑disease franchises—companies are willing to pay multibillion sums for mid‑stage assets that can be positioned as best‑in‑class therapies.