Novartis AG is evaluating a bid for Avidity Biosciences Inc. as the Swiss drugmaker looks to strengthen its pipeline of rare-disease medicines, the Financial Times reported, citing people familiar with the matter. Shares of California-based Avidity jumped roughly 17%–18% after the report, while Novartis stock was little changed. Talks are described as preliminary, and neither company has commented publicly. Avidity is developing antibody-oligonucleotide conjugates aimed at muscle disorders and other rare conditions. A purchase would help Novartis offset revenue it expects to lose later in the decade when patents on several top-selling therapies expire. The company has previously signaled its willingness to pursue mid-sized deals to sustain growth. In a separate development, Prothena Corp. said partner Novo Nordisk A/S plans to move coramitug, an investigational treatment for transthyretin amyloidosis with cardiomyopathy, into Phase 3 trials in 2025. Prothena has already received a $100 million milestone payment and could earn as much as $1.2 billion if future targets are met.