Avexa starts phase IIb trial of HIV drug

Melbourne-based biotech Avexa (ASX:AVX) has started the phase IIb trial of AVX754, the HIV compound it in-licensed from UK company Shire Pharmaceuticals in January.

AVX754, a nucleoside reverse transcriptase inhibitor (NRTi), blocks synthesis of the HIV reverse transcriptase enzyme, which replicates the virus' genetic blueprint.

The trial will investigate the effect of AVX754 on the level of virus in HIV patients that have been treated with existing HIV therapies but are failing these therapies.

The enrolment target for the study is 60 patients, with results expected in the first quarter of 2006.

The trial will be conducted primarily in Australia, although other locations will be considered if it means that the trial can be expedited, said Avexa's CEO Julian Chick.

"There were a number of centres involved in the phase IIa and there's always the possibility of going back to them and getting them involved because they primarily know the drug and so on," said Chick.

The clinical trial design has been successfully reviewed by both the US Food and Drug Administration (FDA) and Australian Ethics Committees. The trial is being conducted under the AVX754 investigational new drug status (IND) held by Avexa as well as local regulatory requirements.

Patients will be dosed initially for 21 days, with the possibility of an extension which would enable them to remain on the drug for a further period of dosing to 24 weeks.

"There's reasons why people may drop out that are outside the fact that the drug is working," said Chick.

The primary end point of the trial is a four fold decrease in viral load, said Chick.

The initiation of phase IIb trials in July is in accordance with Avexa's timeline and the company expects to enter phase III trials by the third quarter of 2006.

AVX491

When asked about progress on Avexa's hepatitis B candidate AVX491 - which showed inadequate absorption by the body in a preclinical efficacy study forcing the company to rethink it's development plans for the drug - Chick said that the company is still gathering information, with a review date in the next month or so.

"It's really an ongoing activity," he said.