EN101 antisense reduces the severity of muscle weakness in myasthenia gravis

A new type of treatment significantly reduces the severity of muscle weakness in myasthenia gravis, giving hope for a new class of drugs to treat neurological disorders, according to a study published in the Neurology.

The drug, oral EN101 antisense, inhibits the production of acetylcholine esterase, which is an important enzyme in the function of the neuromuscular junction, where nerves connect with muscles. Antisense is a synthetic, short segment of DNA that locks onto a strand of mRNA and blocks production of specific proteins.

“ This is the first time we’ve been able to show that antisense is effective and safe when taken orally for a neurological disease,” said study author Zohar Argov, at Hadassah Hebrew University Medical Center in Jerusalem. “ Oral delivery of antisense has long been sought after since it is expected to improve patient compliance because daily injections won’t be needed.”

People with myasthenia gravis have increased fatigue and reduced strength in their voluntary muscles. Symptoms may also include a drooping eyelid, double vision, difficulty in swallowing, or slurred speech. Myasthenia gravis is believed to affect 20 out of every 100,000 people.

For the study, 16 people with myasthenia gravis were given daily doses of oral EN101 antisense for four days and monitored for one month. Four of the people later took the drug for a month. The study found that oral antisense reduced disease severity by an average of 46 percent, with patients experiencing improved muscle function, improved swallowing time and the disappearance of a drooping eyelid. Side effects reported during the study were dryness of eyes and mouth.

Experts say this discovery may have implications beyond myasthenia gravis. “ Oral antisense may become another mode of therapy in neuromuscular disease and further study is needed, ” said Argov. “ However, these preliminary results should be evaluated with caution since this was an open label study.”

Source: American Academy of Neurology, 2007


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