Novartis (NYSE: NVS) announced that its global Phase III HARBOR study evaluating del-desiran in patients with myotonic dystrophy type 1 (DM1) did not meet its primary endpoint of statistically significant improvement versus placebo on video hand opening time, a measure of hand myotonia.

The company said secondary endpoints and exploratory analyses showed evidence of clinical activity. Safety findings were described as consistent with previously reported data. Novartis said it is evaluating the full HARBOR dataset and plans to engage with health authorities to determine a development path for del-desiran.

"Despite decades of research, there are still no approved treatment options for DM1, and patients and caregivers continue to face a significant daily burden," said Shreeram Aradhye, President of Development and Chief Medical Officer at Novartis.

Del-desiran is one of three antibody oligonucleotide conjugate therapies that Novartis added to its neuromuscular pipeline through its acquisition of Avidity Biosciences. The two other therapies from that pipeline remain in active development. Novartis filed delpacibart zotadirsen for accelerated approval with the U.S. Food and Drug Administration for Duchenne muscular dystrophy and received priority review designation. The company also said it plans to meet with the FDA regarding next steps for delpacibart braxlosiran in facioscapulohumeral muscular dystrophy, following positive Phase I/II biomarker data.