AVEXA ANNOUNCES RESULTS OF NRTI STUDY

Avexa has announced highly successful results from its Phase IIb trial for apricitabine (ATC), the company's novel nucleoside reverse transcriptase inhibitor (NRTI) being developed for the treatment of HIV infection in patients with drug-resistant HIV.

The Phase IIb trial compared the effectiveness of ATC in reducing the viral load of patients with drug-resistant HIV with the effectiveness of lamivudine, a leading NRTI in widespread use. A total of 47 patients completed 21-day dosing. Of these, 17 patients received 600-mg doses of ATC, 16 received 800-mg doses of ATC and the control group of 14 patients was treated with lamivudine.

The results for patients in both ATC cohorts exceeded the Phase IIb trial primary endpoint by a substantial margin. Patients who received ATC achieved on average a reduction of greater than 0.8 log10 in the level of HIV in the blood after 21 days, compared with a reduction of less than 0.03 log10 in patients treated with lamivudine. Nine patients achieved a greater than 1.5 log10 reduction after 21 days, with three patients achieving a reduction of more than 2.0 log10. Furthermore, one patient achieved a decrease in the amount of virus of more than 2.5 log10 after 21 days on ATC.

Patients with the highest degree of drug resistance still achieved a significant benefit from treatment with ATC, the company said. The demonstration of superior activity in this study indicates that ATC will be an effective antiviral drug for the treatment of many drug-resistant patients, including even those who are most highly resistant.

ATC was very well tolerated, with some patients having received more than 12 months of treatment to date. Currently there are 14 patients in the open-label section of the Phase IIb trial, and six patients have elected to enter into an extension study (where they continue to be treated with ATC), having completed the full 48 weeks of the study.

No evidence of mutation in the virus resulting in resistance to ATC was detected over the course of the treatment, according to Avexa. This indicates that antiviral resistance to ATC does not occur quickly, giving ATC a significant competitive advantage over several other drugs.