Horizon Pharma plc, a biopharmaceutical company, has initiated the phase 3 Safety, Tolerability and Efficacy of Actimmune Dose Escalation in Friedreich's Ataxia study (STEADFAST) of Actimmune (interferon gamma-1b) for the treatment of people with Friedreich's Ataxia (FA), a degenerative neuro-muscular disorder.

"As a rare disease with no currently approved treatments, Friedreich's Ataxia represents an area of significant unmet medical need," said Timothy P. Walbert, chairman, president and chief executive officer, Horizon Pharma plc.

"The phase 3 study represents a significant next step in evaluating Actimmune in this population, which is approximately four thousand people in the United States. We look forward to continuing to work with the FDA with the goal of providing a potential treatment option to the FA community."

This phase 3 trial (NCT02415127) is a randomised, multi-centre, double-blind, placebo-controlled study with patients randomised 1:1 to receive subcutaneous doses of either Actimmune or placebo three times a week for a total of 26 weeks. Approximately 90 patients will be enrolled at four sites in the United States. The primary endpoint will measure the change in neurological outcome and evaluate the effect of Actimmune versus placebo as measured by the modified Friedreich's Ataxia Rating Scale (mFARS), focused on objective neurologic measures such as upper and lower extremity coordination improvement from baseline. FARS is used to measure neurological signs associated with FA, with higher scores reflecting a greater level of disability.
In addition to safety and efficacy, the STEADFAST trial will evaluate the pharmacokinetic characteristics of Actimmune in people with FA.

"This clinical trial is an example of the progress the scientific community has made in understanding FA," said Ronald J. Bartek, president, director and co-founder, Friedreich's Ataxia Research Alliance (FARA).

"Less than 20 years ago, we had not identified the cause of FA, and today we have a late-stage clinical study that brings us one step closer to potentially having the first treatment for people with FA."

In April 2015, Actimmune was granted Fast Track status for FA by the US Food and Drug Administration (FDA). This designation provides greater access to and more frequent communication with the FDA throughout the entire drug development and review process, with the goal of possibly expediting approval. Fast Track designation also gives Horizon Pharma the opportunity to potentially submit sections of the Actimmune registration dossier for FA on a rolling basis, and allows Actimmune to be considered for priority review at the time of submission based on forthcoming clinical data.

FA is a debilitating, life-shortening and degenerative neuro-muscular disorder that affects approximately 4,000 people in the United States. Onset of symptoms can vary from five years old to adulthood, with the childhood onset tending to be associated with a more rapid progression. A progressive loss of coordination and muscle strength leads to motor incapacitation and often the full-time use of a wheelchair. Most young people diagnosed with FA require mobility aids such as a cane, walker or wheelchair by their teens or early 20's. There are currently no approved treatments for FA.

The Friedreich's Ataxia Research Alliance (FARA) is a national, public, 501(c)(3), non-profit, tax exempt organisation dedicated to curing Friedreich's ataxia (FA), a rare neuromuscular disorder, through research.

Actimmune (interferon gamma-1b) is a biologically manufactured protein similar to one the body makes naturally to help prevent infection. Actimmune is currently approved by the US Food and Drug Administration (FDA) for use in two rare diseases. It is indicated to reduce the frequency and severity of serious infections associated with Chronic Granulomatous Disease (CGD), a genetic disorder that affects the functioning of some cells of the immune system. In addition, Actimmune is indicated to slow the worsening of severe, malignant osteopetrosis (SMO), a genetic disorder that affects normal bone formation.