Administering a therapy using DNA-based compounds could extend survival and reverse signs of neuromuscular damage in animals of inherited amyotrophic lateral sclerosis (ALS), finds a study.

ALS is a progressive fatal disease that kills the nerve cells that controls walking, eating and breathing, about one fifth of which are caused due to mutations in a gene called SOD1. These mutations cause the SOD1 protein to be overly active, which suggests that reducing protein levels might help ALS patients, the researchers said. The findings showed that the drug could increase the lifespan by 22 per cent as the subjects who received the therapy lived 37 days longer than those given the placebo. "This drug had an impressive effect in mice and rats with just one or two doses," said Timothy Miller, professor of neurology at the Washington University.

"We don't know yet if this works in people, but we're very hopeful. We've completed the first phase of safety testing, and now we're working on finding the right dose," Miller added. For the study, published in the Journal of Clinical Investigation, the team tested two DNA-based compounds -- known as antisense oligonucleotides or oligos -- in mice and rats. The animals were genetically modified to carry a mutated form of the human SOD1 gene. By a few months old, such animals start having trouble walking and feeding themselves.

The mice were given an anti-SOD1 oligo or a placebo at day 50, and a second dose about six weeks later. Those who received the drug maintained their weight 26 days longer and experienced 22 per cent increased life span. The rats that received an active oligo fared much better than the ones that received the placebo and survived eight to nine weeks longer. Further, the oligos also reversed signs of neuromuscular damage in the animals. These results have led to a phase one/two clinical trial to investigate whether the drug could benefit humans with ALS.