Although many patients achieve viral suppression to levels below detection after initiating highly active anti-retroviral therapy (HAART) in clinical trials, about 50% of infected patients fail to respond to treatment in the ‘real world’. One of the main reasons for treatment failure is lack of compliance with HAART regimens as a result of failure to adhere to complex drug administration schedules, large pill burdens, and the incidence of adverse effects. One way to address these limitations is to develop new and more potent drugs that can be administered more conveniently, delegates were told at the 12th World AIDS Conference [Geneva, Switzerland; June 1998]. Abacavir [‘Ziagen’; Glaxo Wellcome] is a potent second-generation nucleoside reverse transcriptase inhibitor (NRTI) that is in late phase III clinical development. Abacavir may help simplify HAART regimens since it can be administered as 1 tablet twice daily, has no food or fluid restrictions, and preliminary data suggest no drug interactions. Results from several studies of abacavir were presented at the meeting.