Santhera has been hit with more bad news regarding its flagship mitochondrial disease therapy idebenone, after it failed to hit targets in a trial assessing its potential in multiple sclerosis.

The drug, which is marketed under the brand name Raxone for the treatment of patients with the rare disorder Leber’s Hereditary Optic Neuropathy (LHON), failed to show any difference to placebo on disease progression in patients with primary progressive multiple sclerosis.

The Phase I/II trial, which was sponsored by the National Institute of Neurological Disorders and Stroke, part of the US NIH, involved 77 patients, 66 of which completed the trial which combined a one-year observational pre- treatment phase, followed by a two-year placebo-controlled intervention period.

Top-line analysis of data showed that there was no difference between treatment groups for measures on disease progression. On the plus side, it also showed no difference in the occurrence and severity of adverse events between the treatment groups, indicating that the higher dose of the drug than currently marketed for LHON was well tolerated.

“Clearly, the small sample size is a limitation when studying a therapeutic intervention in such a complex, relentlessly progressing neurological disease,” said Thomas Meier, PhD, chief executive of Santhera, commenting on the results.

The news comes just weeks after the drug was rejected by European Medicines Agency advisors as a treatment for Duchenne Muscular Dystrophy (DMD).

The Committee for Medicinal products for Human Use (CHMP) concluded that an approval for Raxone in DMD could not be granted on current evidence.

It acknowledged the positive outcome of the Phase III DELOS trial - which the firm said shows that the drug slows the decline of respiratory function in DMD patients - but said it needed more data to further link the observed treatment effects on respiratory function outcomes to patient benefit.