Ardea Biosciences has announced additional positive results from its completed phase IIa proof-of-concept monotherapy study of RDEA806, its novel investigational non-nucleoside reverse transcriptase inhibitor (NNRTI), in patients with human immunodeficiency virus (HIV).

These additional results demonstrated that once-daily dosing with the enteric-coated tablet formulation of RDEA806 resulted in significant reductions in plasma viral load that were consistent with results previously presented with twice-daily dosing of the capsule formulation in the same study. All dosing regimens tested in the study were well tolerated. Ardea's lead investigator plans to present the full data from this study at a medical conference later this year.

"RDEA806's robust antiviral potency, combined with its excellent tolerability profile in over 130 healthy volunteers and HIV-infected patients treated in clinical studies to-date, make RDEA806 a promising candidate for further investigation as a first-line agent for the treatment of HIV," said Dr Graeme Moyle, director of HIV research, Chelsea and Westminster Hospital, and a lead investigator in the completed phase IIa trial and planned phase IIb study.

The phase IIa randomized, double-blind, placebo-controlled trial evaluated the antiviral activity, pharmacokinetics, safety and tolerability of once- and twice-daily oral dosing regimens of RDEA806 versus placebo in 48 HIV-positive patients who were naive to antiretroviral treatment. Nine out of 12 patients in each of four cohorts received RDEA806. The primary efficacy end point was the change from baseline in plasma viral load.