A growth hormone that an earlier study had suggested might be effective, showed no benefit compared to placebo in treating patients with amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease, according to a new study performed by researchers in the United States.
The research was conducted by lead author Dr Eric J Sorenson, of the Mayo Clinic in Rochester, Maine, USA, and colleagues, and was published in the 25 November issue of the journal Neurology. Sorenson is also a member of the American Academy of Neurology. The study was sponsored by the National Institutes of Health and the ALS Association.
The phase III, randomized, double blind, placebo-controlled, two-year study found that IGF-1 (growth hormone insulin-like growth factor-1) did not slow the progression of weakness in patients with ALS, a progressive and fatal neurological disease that causes muscles to weaken and waste away.
Two previous shorter studies had shown conflicting results: one done in North America found the drug helped, while a European study showed it did not.
Sorenson said the team was disappointed at not being able to confirm the results of the North American study, especially in view of the inadequacy of current treatments for ALS.
“More effective treatments are vitally needed,” said Sorenson.
For the study, the researchers recruited 330 ALS patients from 20 medical centers throughout the US and assigned them to either a treatment group or a placebo group where they received twice daily subcutaneous injections of 0.05 mg/kg body weight of human recombinant IGF-1 and placebo respectively. The growth hormone and placebo were provided by Cephalon Inc.
The main outcome measure was the change in patients’ manual muscle testing, which was done once at the start of the study and then at five different times thereafter.
Secondary outcome measures included how long patients were able to manage without having a tube inserted in their neck to help them breathe (tracheostomy-free survival), and the rate of change in a daily score of how well they carried out their daily activities (using a revised ALS functional rating scale).
The results showed no differences between the growth hormone and placebo groups in all three measurement areas: change in muscle strength, tracheostomy-free survival, and change in daily activities test.
The researchers concluded that:
“Insulin-like growth factor type I does not provide benefit for patients with amyotrophic lateral sclerosis.”
“Subcutaneous IGF-1 is not beneficial in 2-year ALS trial.”
E. J. Sorenson, A. J. Windbank, J. N. Mandrekar, W. R. Bamlet, S. H. Appel, C. Armon, P. E. Barkhaus, P. Bosch, K. Boylan, W. S. David, E. Feldman, J. Glass, L. Gutmann, J. Katz, W. King, C. A. Luciano, L. F. McCluskey, S. Nash, D. S. Newman, R. M. Pascuzzi, E. Pioro, L. J. Sams, S. Scelsa, E. P. Simpson, S. H. Subramony, E. Tiryaki, and C. A. Thornton.
Neurology, Volume 71, Issue 22, pages 1770-1775, published online November 25, 2008.
Sources: Journal abstract, American Academy of Neurology.
Written by: Catharine Paddock, PhD