In some patients, injected molecule appears to restart production of missing protein
TUESDAY, Aug. 25 (HealthDay News) -- Injecting a therapeutic molecule into muscle appears to jump-start the production of a crucial protein that's missing in patients with Duchenne muscular dystrophy, British researchers report.
The treatment so far is only applicable to about 13 percent of people with the debilitating and ultimately fatal disease, but scientists are hopeful that similar molecules might expand the treatment to a wider range of patients.
Duchenne muscular dystrophy affects about one in 3,500 males, and involves a progressive wasting of muscle due to a genetic inability to produce the protein dystrophin, a key component of muscle structure. No treatments are available for the illness, and most of those affected die by age 30.
Recently, molecules called antisense oligonucleotides have shown some promise. These molecules work by "skipping over" portions of the defective gene that would otherwise block dystrophin production.
In their study, published online Aug. 25 in The Lancet Neurology, researchers at the University College London Institute of Child Health selected seven patients for whom a particular oligonucleotide molecule, called AVI-4658, appeared suitable. In these patients, the molecule "skipped" exon 51 -- the portion of the dystrophin-blocking gene that appeared to get in the way of effective dystrophin production.
Injecting the molecule into the muscles of these seven patients resulted in increased dystrophin production in all treated muscles, according to a journal news release. "Intramuscular AVI-4658 was safe and induced the expression of dystrophin locally within treated muscles," the team wrote. "On the basis of these observations, we have initiated a dose-ranging study to assess the safety and efficacy of repeated doses of systemic intravenous AVI-4658."
In a commentary, Annemieke Aartsma-Rus and Gert-Jan van Ommen, from Leiden, the Netherlands, noted that while only about 13 percent of Duchenne muscular dystrophy patients can be expected to be helped by AVI-4658, molecules that skip other exons on the gene could be used, potentially spreading the benefit to more than 70 percent of patients.
Find out more about Duchenne muscular dystrophy at the Muscular Dystrophy Association.
-- E.J. Mundell
SOURCE: The Lancet Neurology, news release, Aug. 25, 2009
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