Novartis' DM1 drug del-desiran misses primary endpoint in Phase 3 HARBOR trial

Novartis announced that its experimental therapy del-desiran did not improve muscle function in a pivotal Phase 3 study for myotonic dystrophy type 1 (DM1). The trial, called HARBOR, evaluated the drug’s effect on video hand opening time, a measure of hand relaxation after squeezing, and the results showed no advantage over placebo.

The failure marks the company's second major trial setback within days, following a recent miss in a cardiovascular study. The negative outcome adds pressure on Novartis as it faces a looming patent cliff and evaluates its acquisition strategy.

Shares of Novartis fell as much as 10% in early Swiss trading after the news. While the setback dampens optimism, the company noted a recent positive result for a multiple sclerosis drug announced the week before.