AVI BioPharma announces exon skipping trial results
30mg dose raises dystrophin 22.5 percent in 24 weeks
* No improvement seen in clinical outcomes
By Deena Beasley
April 2 (Reuters) A small trial of U.S.-based AVI BioPharma Inc's experimental muscular dystrophy drug met its goal of increasing levels of a key protein, but did not demonstrate that the drug had an impact on walking ability or other clinical endpoints.
The mid-stage trial, or Phase IIb, which involved 12 boys with Duchenne muscular dystrophy, found that the four patients treated for 24 weeks with a 30 mg dose of the drug, eteplirsen, had a 22.5 percent average increase in levels of dystrophin, a protein essential to building muscle, compared to no increase for four patients treated with a placebo.
Duchenne muscular dystrophy — a muscle degeneration disease affecting young children, almost exclusively boys — leads to paralysis and death in young adulthood. At least 250,000 people worldwide are believed to be afflicted with the disease.
Eteplirsen is designed to silence a specific strand of RNA so that the body can produce the dystrophin that people with Duchenne muscular dystrophy are unable to produce.
The trial found that the four patients treated for 12 weeks with a 50 mg dose of the drug did not show a significant increase in dystrophin, suggesting that a longer duration of dosing is needed. It also found no significant improvements in clinical outcomes, including a six-minute walk test, in the treated groups compared to placebo.
"We anticipate that these levels of dystrophin could lead to significant clinical benefit if maintained over a longer course of treatment," Dr. Jerry Mendell, director of the Centers for Gene Therapy and Muscular Dystrophy at Nationwide Children's Hospital in Columbus, Ohio and the study's lead investigator, said in a statement.
There were no treatment-related adverse events, no serious side effects, and no evidence of kidney toxicity.
AVI BioPharma Chief Executive Officer Chris Garabedian said the company plans to discuss with U.S. regulators how best to conduct a longer pivotal trial of the drug.
"The hope is that if we can delay or halt the progression of the disease we would be able to avoid these kids ending up in a wheelchair," he said. "It would avoid the need for ventilators, maybe even prevent death."
Eteplirsen is designed to skip a specific "exon," or protein-coding sequence of the dystrophin gene that is mutated in about 15 percent of people with Duchenne muscular dystrophy.
AVI BioPharma is also developing drugs targeting other exon mutations responsible for muscular dystrophy.
Garabedian said he would prefer raising funding for a pivotal trial from capital markets, rather than a partnership.
"In the rare disease area, it doesn't take a large commercial infrastructure to do this," he said.
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