IGF-1 No Help in Amyotrophic Lateral Sclerosis
Phase III trial yields disappointing results
TUESDAY, Nov. 25 (HealthDay News) -- Insulin-like growth factor type I (IGF-1) does not benefit patients with amyotrophic lateral sclerosis, according to the results of a phase III, randomized, double-blind, placebo-controlled trial published in the Nov. 25 issue of Neurology.
Eric J. Sorenson, M.D., of the Mayo Clinic in Rochester, Minn., and colleagues conducted a study of 330 patients recruited from 20 medical centers who were randomized to receive either 0.05 mg/kg body weight of human recombinant IGF-1 twice daily or placebo for two years. The outcome measures of the trial were manual muscle testing score, as well as tracheostomy-free survival rate and rate of change in the revised amyotrophic lateral sclerosis functional rating scale.
After two years, outcomes in both groups were the same, the researchers found. The study used a number of novel methods, the authors note, such as performing strength examinations in patients' homes, which minimized missing data, and enlisting trained physical therapists with annual recertifications in performing the strength examinations. The trial was also the longest amyotrophic lateral sclerosis trial to date, they state.
"Despite these advantages, we did encounter limitations," the authors write. "The long duration of the study did create subject 'fatigue.' Many subjects became dissatisfied with the ongoing rigors of the clinical trial as their disease progressed with many stopping their drug. As a result any apparent impact IGF-1 may have on amyotrophic lateral sclerosis may be diminished as a result."