Novartis DM1 Drug Misses Primary Endpoint in Phase III Trial

Novartis (NYSE:NVS) said on Tuesday that its experimental treatment for myotonic dystrophy type 1, delpacibart etedesiran, did not meet the primary endpoint of a Phase III clinical trial.

The global HARBOR study evaluated delpacibart etedesiran, also known as del-desiran, in approximately 150 people with myotonic dystrophy type 1, or DM1.

The 54-week randomised, double-blind and placebo-controlled study did not demonstrate a statistically significant improvement compared with placebo in video hand opening time, the trial’s primary endpoint and a measure of hand muscle stiffness.

Novartis said the study showed evidence of clinical activity on other measures and in additional analyses. Safety findings were generally consistent with previously reported data.

Novartis to Review HARBOR Trial Data

The company said it will evaluate the complete dataset and engage with health authorities to determine the appropriate 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, Novartis’s president of development and chief medical officer.

“Developing therapies for a complex disease like DM1 remains challenging, and setbacks are part of scientific progress.”

DM1 is a progressive neuromuscular disease caused by an expansion of CTG repeats, which are repeated sections of DNA, in the DM1 protein kinase gene.

Del-desiran is an antibody oligonucleotide conjugate designed to target and break down disease-causing DMPK messenger RNA.

Del-desiran Holds FDA and EU Designations

Del-desiran has received Orphan Drug, Fast Track and Breakthrough Therapy designations from the U.S. Food and Drug Administration. It also has Orphan Medicinal Product designation in the European Union.

The treatment is one of three antibody oligonucleotide conjugate therapies added to Novartis’s neuromuscular pipeline through its acquisition of Avidity Biosciences.

Another candidate, delpacibart zotadirsen, has been submitted for accelerated FDA approval for Duchenne muscular dystrophy involving mutations amenable to exon 44 skipping and has received priority review designation.

Novartis also plans to meet with the FDA to discuss the next steps for delpacibart braxlosiran in facioscapulohumeral muscular dystrophy, based on positive Phase I/II biomarker data.

Novartis Maintains Five-Year Sales Guidance

Despite the HARBOR trial result, Novartis maintained its existing five-year sales outlook.

The company continues to forecast a sales compound annual growth rate of between 5% and 6% for the period from 2025 through 2030.

Novartis has not yet specified what changes, if any, will be made to the development programme for del-desiran. The company said its next steps will be determined after reviewing the full HARBOR dataset and discussions with health authorities.

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