Santhera Pharmaceuticals has unveiled results from a study showing that its Syros in combination with idebenone consistently reduced the rate of respiratory function loss in Duchenne muscular dystrophy (DMD) patients, for up to six years.

The study showed long-term efficacy, and showed that switching to and maintaining long-term treatment with idebenone reduced the annual rate of predicted decline predicted by 50%, the firm said. The treatment effect was also consistently maintained year-on-year for up to six years.

The Phase III study consisted of 64 patients, not taking concomitant steroids, who received either 900 mg a day of idebenone or matching placebo for on average 4.2 years.

The trial met its primary endpoint, the change from baseline in Peak Expiratory Flow (PEF), which demonstrated that idebenone can slow the loss of respiratory function. Additional respiratory function and clinical outcomes supported the results of the primary endpoint.

“We are very excited to see that the significant treatment effect with idebenone observed in our 52-week Phase III DELOS study is maintained over the long-term,” said Kristina Sjöblom Nygren, chief medical officer and head of development at Santhera.

“The new findings are highly relevant for DMD patients in respiratory decline who have an urgent need for a therapy to modify the declining course of respiratory function decline and ultimately delay the need for assisted ventilation.”

DMD is one of the most common and devastating types of progressive muscle weakness and degeneration starting at an early age and leading to early morbidity and mortality due to respiratory failure. It is a genetic, degenerative disease that occurs almost exclusively in males with an incidence of up to one in 3,500 live male births worldwide.