Cytokinetics Inc. said a certain dose of its investigational drug reldesemtiv helped reduce the symptoms of patients with spinal muscular atrophy.

Spinal muscular atrophy is a genetic disorder that affects the control of muscle movements due to the loss of specialized nerve cells called motor neurons in the spinal cord and part of the brain connected to the spinal cord.

The phase 2 study, conducted in 70 patients, evaluated two doses of reldesemtiv, 150 milligrams and 450 milligrams, administered twice a day.

Results showed that patients who were treated with 450 milligrams of the drug were able to walk 35.63 meters further in six minutes after four weeks of treatment and 24.89 meters further after eight weeks, compared to placebo. At four weeks, patients in the 150-milligram group increased the distance of their walk by 10.86 meters and by 7.72 meters after eight weeks of treatment.

Additionally, patients treated with the drug experienced an increase in the strength of their respiratory muscles after four weeks and eight weeks of treatment.

The company is developing reldesemtiv in collaboration with Japan's Astellas Pharma Inc. for people with spinal muscular atrophy and certain other debilitating diseases and conditions associated with skeletal muscle weakness or fatigue.