Great Ormond Street Hospital has announced that a team led by scientists at its research partner, UCL Institute of Child Health (ICH), funded by the Medical Research Council (MRC) and AVI BioPharma, have made an important breakthrough in the development of a treatment for Duchenne Muscular Dystrophy (DMD).
Together with the MDEX Consortium, chaired by the ICH’s Professor Francesco Muntoni, the group showed that a gene based drug treatment was effective in restoring the dystrophin protein, missing in sufferers of DMD in seven out of 19 trial participants.
The results of the clinical trial will be published in The Lancet, a world leading general medical journal.
DMD is a devastating and life limiting condition, affecting one in 3,500 male births in the general population, with around 100 cases diagnosed in the UK each year.
Three of the participants in the higher dose cohort showed dystrophin levels exceeding 18 per cent of those found in normal muscle.
Thirteen per cent of boys with DMD could be treated with this specific ‘antisense’ gene therapy, the largest group by a single antisense. Overall, scientists say this approach could work for at least 70 per cent of DMD sufferers.
DMD causes progressive muscle weakness due to the breakdown and loss of muscle cells. Patients lack a single important protein in their muscle fibres called dystrophin. By ages eight to 12 years boys become unable to walk, and by their late teens or early twenties the condition can become severe enough to limit life expectancy.
In this clinical trial of 19 patients, study participants aged five to 15 at Great Ormond Street Hospital and the Royal Victoria Infirmary, Newcastle, were given weekly doses of the drug, AVI-4658. The drug had already been tested for safety and efficacy by the MDEX Consortium and AVI Biopharma in an earlier phase of the study.
Francesco Muntoni, professor of paediatric neurology at the ICH, said: “These are very exciting results that prove the case for an even more detailed look at this genetic therapy. I’ve worked with patients with DMD for many years and this is the first time we can say with confidence that we’ve made a significant breakthrough towards finding a targeted treatment.
“Importantly, the study drug was extremely well tolerated, with no appreciable side effects detected during the study period in any of the boys. If our strategy shows continued success, this therapy could substantially reduce muscle damage in affected boys with DMD, improve the quality of life for DMD patients, their mobility and the way their condition is managed as they get older.”
Professor Max Parmar, director of the MRC Clinical Trials Unit, said: “A large proportion of new drugs do not make it past the phase II stage of testing reached here, so there is real excitement that this treatment could work.
Brothers Jack, 11, and Tom, 8 were enrolled on the trial. Both have DMD with a deletion from 45-50. Their mum, Claire, said: “Jack and Tom were placed on a DMD genetic registry, co-ordinated by Action Duchenne, which is how we were approached about the clinical trial at Great Ormond Street Hospital.
“The boys were on the trial for 12 weeks between 2009 and 2010. Our whole family noticed a marked difference in both of their quality of life and mobility over that period. We feel that it helped prolong Jack’s mobility and that Tom has been considerably less fatigued.”