Japanese biopharmaceutical company Sosei has started Phase II testing of AD 337, a novel enantiomer of an approved centrally-acting non-opioid analgesic, in the treatment of fibromyalgia syndrome (FMS).

The proof-of-principle trial for will investigate the efficacy, safety and tolerability of AD 337 in the treatment of fibromyalgia in female subjects. It will involve the recruitment of some 100 patients in up to 20 centers in the UK and Australia.

According to Sosei, earlier single and multiple-dose Phase I studies in a total of 49 subjects showed that AD 337 is well-tolerated with an attractive pharmacokinetic profile.

AD 337 exhibits comparable pharmacology to drugs that are showing promising results in fibromyalgia and has demonstrated antidepressant and anxiolytic activity. In addition, the compound is expected to have a low-incidence of drug-drug interaction

Currently there are no drugs specifically approved for fibromyalgia although some treatments are available to deal with various symptoms of the disease.

Sosei said that it expects the global market forFMS treatments to grow to over $1 billion in the next 10 years.