Novartis updated its Phase 3 HARBOR program for del-desiran (del-desiran; an antibody oligonucleotide conjugate) in myotonic dystrophy type 1 (DM1), reporting it did not meet the trial’s primary endpoint of video hand opening time (vHOT) versus placebo. The company said the study nevertheless showed clinical activity in secondary endpoints and exploratory analyses and that the full dataset is under evaluation. HARBOR used vHOT, a novel measure of hand myotonia, as a differentiating efficacy endpoint in the DM1 setting where no approved disease-modifying therapies exist. Safety findings were described as generally consistent with earlier disclosed results. Novartis said it will engage with regulators to determine the most appropriate development path for del-desiran, while separately maintaining advancement of its neuromuscular pipeline—supported by FDA priority review granted for delpacibart zotadirsen in DMD44.