Horizon Pharma drug fails key study in rare neuromuscular disease

Horizon Pharma Plc said its drug, Actimmune, failed the main goal in a late-stage study involving patients with Friedreich’s ataxia (FA), a rare, degenerative neuromuscular disorder that has no approved treatment.

Horizon’s stock tumbled 22 percent to $15.06 in heavy premarket trading on Thursday, after the company also said it would discontinue the trial.

The drug failed to demonstrate a statistically significant benefit over a placebo after 26 weeks on a rating scale that measures parameters of disease progression, the Ireland-based company said.

Actimmune is already approved by the U.S. Food and Drug Administration for use in two rare, genetic conditions – chronic granulomatous disease and severe, malignant osteopetrosis.

The drug also fell short on secondary goals in the trial.

The announcement does not impact Horizon’s full-year 2016 adjusted net sales, the Dublin, Ireland-based company said.

In the first nine months of 2016, Actimmune accounted for about 12 percent, or $80.5 million, of Horizon’s net sales.

Friedreich’s ataxia is named after Nicholaus Friedreich, a German doctor who first described the condition in the 1860s.

The inherited incurable disorder typically emerges in childhood causing nervous system damage and problems with motor function, and afflicts between 4,000 and 6,000 Americans.

(Reporting by Natalie Grover in Bengaluru; Editing by Saumyadeb Chakrabarty)