Arakis Ltd announced that in a multicenter Phase IIa, placebo-controlled study, its candidate rheumatoid arthritis compound AD 452, a novel small-molecule cytokine modulator, demonstrated acceptable pharmacokinetics, safety, and tolerability in RA patients already receiving methotrexate.

The 28-day study in 99 RA patients also showed that the cytokine modulator was well tolerated at the three dose levels using once-daily oral administration.

A 3-month Phase IIb efficacy study of AD 452 in combination with methotrexate, designed to measure ACR20 and DAS28 scores, is set to begin in September 2005. The trial, anticipated to take 1 year to complete, will be conducted at centers in both the US and Europe.

According to Arakis, AD 452 is the enantiopure form of a drug that is currently marketed for a completely different indication. The racemic mixture, however, is not suitable for the required chronic dosing in patients with RA. Arakis has shown AD 452 to have a broad spectrum of activity inhibiting joint damage. In September 2004, Arakis announced the completion of a £29 million ($52 million) third round financing, jointly led by Novo A/S and Scottish Equity Partners Ltd.