Sarepta Therapeutics (SRPT) said Monday that the second part of a phase 3 clinical study of the gene therapy Elevidys for the potential treatment of Duchenne muscular dystrophy has yielded "positive" topline results.

Patients treated with a placebo in the first part of the study but began receiving the drug, also known as delandistrogene moxeparvovec-rokl, after 52 weeks showed an improvement of 2.34 from the baseline.

Patients who received the drug for the full two years showed an improvement of 2.88 from the baseline, the company said.

Both the crossover patients and those who received it for the full two years also showed "clinically meaningful" and "statistically significant" improvements compared with an external control group, the company said.