Horizon Pharma slumps as Friedreich's ataxia drug Phase III trial fails

Horizon Pharma (Nasdaq: HZNP) saw its shares slide 18.77% to $15.75 in pre-market trading, after the Ireland-incorporated drugmaker announced disappointing Phase III results with its rare genetic disease drug candidate.

The company today announced that the Phase III trial, STEADFAST (Safety, Tolerability and Efficacy of ACTIMMUNE Dose Escalation in Friedreich's Ataxia study), evaluating Actimmune (interferon gamma-1b) for the treatment of Friedreich's ataxia (FA) did not meet its primary endpoint of a statistically significant change from baseline in the modified Friedreich’s Ataxia Rating Scale (FARS‐mNeuro) at 26 weeks versus treatment with placebo. FARS‐mNeuro is an exam-based rating scale that measures disease progression based on functional parameters such as speech, ability to swallow, upper and lower limb coordination, gait and posture.

In addition, the secondary endpoints did not meet statistical significance. No new safety findings were identified on initial review of data other than those already noted in the Actimmune prescribing information for approved indications.