OXFORDSHIRE biotech company Summit has bucked the economic downturn by signing a £70m deal with a US company which could offer hope to sufferers of a fatal genetic disorder.

The deal covers Summit's development at Milton Park, near Abingdon, of a treatment for Duchenne muscular dystrophy (DMD).

Most sufferers die in their twenties. Steroids are the only therapy, but simply delay progression of the disease.

The US company will invest £3.5m in Summit's shares now, and pay £25.5m if it meets certain milestones, followed by royalties.

Jean-Jacques Bienaimé, chief executive of BioMarin, said Summit's work may have the potential for treating the entire spectrum of DMD patients, not just those with a particular gene.

If all goes well, clinical trials will start next year. Any treatment for DMD is considered an 'orphan' drug and could be approved by regulators more quickly than usual.

Summit chief executive Steven Lee said: "We are very pleased that BioMarin has become our partner for the DMD program.

"BioMarin has an unparalleled track record in developing orphan drugs to market and has developed and launched successfully three such drugs in record time.

"The expertise and commitment of the BioMarin team gives me great confidence that they are an excellent partner for this program.

"I believe they will help to deliver a medicine in the shortest timeframe possible for the benefit of all DMD patients.

"For Summit, this deal is important as it is the first of many that we anticipate signing."

After the share deal, BioMarin will hold about 9.16 per cent of Summit.

Duchenne muscular dystrophy is a fatal neuromuscular disorder that affects 1 in 3,500 boys, with an estimated patient population of over 40,000 in the developed world.

DMD is caused by a genetic defect meaning DMD patients lack an important protein called dystrophin, which is crucial to maintaining muscle function.

The absence of dystrophin results in extensive muscle wasting in all voluntary muscles as well as the heart and breathing muscles and causes severe restriction in the mobility by the early teens and is ultimately fatal.

Summit has identified a drug which replaces dystrophin with a similar protein called utrophin.