Novartis said its del-desiran Phase 3 Harbor trial missed a crucial primary endpoint, dealing another blow to the asset acquired in Avidity Biosciences’ $12 billion takeover. The failure adds to a pattern of setbacks for the acquired portfolio, coming after Novartis’ earlier heart-disease disappointment tied to other late-stage readouts. The news matters for pipeline strategy because del-desiran had been positioned as a potential next-generation therapeutic in a competitive cardiology landscape where outcomes data are decisive. With multiple failures in a short window, the company’s confidence in the cardiovascular risk reduction pathway tied to this program is likely to face scrutiny. For investors and partners, the update signals the difficulty of translating biomarker movement into endpoint benefits in large Phase 3 programs.