The first of the fusion inhibitors, enfuvirtide [T-20, 'Fuzeon'] has been shown to enhance the efficacy of an optimised base regimen in heavily pretreated patients with HIV infections. Eagerly anticipated 24-week results from the TORO*1 and TORO 2 studies were presented at the XIV International AIDS Conference [Barcelona, Spain; July 2002]. Patients treated with enfuvirtide were significantly more likely than those receiving the background regimen alone to achieve viral RNA levels of ≤ 400 copies/ml, and had a longer time to virological failure. Enfuvirtide was generally well tolerated, and did not appear to increase the incidences of adverse events, compared with the optimised regimen alone; although injection site reactions were common in enfuvirtide recipients, only a small proportion discontinued treatment as a result.'These pivotal studies of T-20 were conducted among heavily treatment-experienced HIV patients, a population for whom treatment options are limited',commented Dr Jay Lalezari from Quest Clinical Research in San Francisco, US.'It is exciting and encouraging to see that when T-20 is added to the best available combination of conventional antiretrovirals, patients are twice as likely to achieve undetectable levels of the virus than those who took combination therapy without T-20, bringing new hope to these patients'.