aTyr Pharma, Inc., a biotherapeutics company engaged in the discovery and development of Physiocrine-based therapeutics to address severe rare diseases, announced the continued expansion of its Resolaris clinical programme in rare myopathies with an immune component (RMICs) by initiating a phase 1b/2 clinical trial in patients with early onset facioscapulohumeral muscular dystrophy (FSHD), a rare and severe genetic myopathy for which there are currently no approved treatments.

"The initiation of our early onset FSHD Resolaris programme is an important step in addressing the needs of some of the most severely effected FSHD patients," said John Mendlein, Ph.D., CEO and executive chairman of aTyr Pharma.

"With this trial, we continue to advance our new class of Physiocrine-based therapeutics to harness the body's natural immune processes in rare muscle disease."

The phase 1b/2 clinical trial in early onset FSHD is an international multi-center, open-label, intra-patient dose escalation study designed to assess the safety, tolerability, immunogenicity, and biological activity of Resolaris. Clinical trial sites are preparing to screen patients for inclusion in the study and are expected to enroll up to 16 early onset FSHD patients who displayed signs or symptoms of the disease prior to 10 years of age. In the first stage of the trial, up to eight patients between the ages of 16 and 25 years will be enrolled. The second stage of enrollment is expected to include up to eight patients between the ages of 12 and 15 years.

The early onset FSHD clinical research program, which will involve both young adults and children, is in addition to the company's recently initiated phase 1b/2 clinical trial in limb girdle muscular dystrophy (LGMD2B) and the ongoing phase 1b/2 clinical trial evaluating Resolaris in adult patients with FSHD.

All three trials, adult FSHD, early onset FSHD and LGMD2B, will assess Resolaris' impact on the immune component of the disease using blood borne markers and magnetic resonance imaging (MRI) of skeletal muscle.

Facioscapulohumeral muscular dystrophy (FSHD) refers to a rare genetic myopathy affecting approximately 19,000 people in the US and for which there are no approved treatments. Most FSHD patients harbor molecularly definable truncations of the fourth chromosome that lead to the undesired expression of the repressed DUX4 gene in skeletal muscle. FSHD patients experience debilitating muscle weakness and immune cell involvement in the muscle. Early onset FSHD occurs in individuals who experience symptoms of progressive muscle involvement as a juvenile, some of whom suffer from a particularly severe form of the disease. Both early onset and adult FSHD patients are assessed for clinical symptoms, and skeletal muscle health may be also be assessed by MRI.

Limb girdle muscular dystrophy (LGMD) refers to a group of rare genetic myopathies, of which there are more than 20 different subtypes, none with approved therapies. LGMD affects an estimated 16,000 patients in the US, approximately 3,000 of whom have LGMD2B. LGMD2B is a recessive genetic disease caused by mutations in the dysferlin gene. Patients experience debilitating muscle weakness and atrophy as well as immune cell invasion in the skeletal muscle. Patients are assessed for clinical symptoms and MRI may also be used to assess skeletal muscle health.