Adding the fusion inhibitor T-20 to a salvage regimen results in a significantly better viral load response after 24 weeks, and is well tolerated despite twice daily injections, according to preliminary results of a study conducted in North America and Brazil.
Preliminary results of the phase III study of T-20 were released last week to comply with US regulations that require US-listed companies to release available data into the public domain, in order to combat insider trading. T-20 has been developed by Trimeris Inc, and is being developed in partnership with the Swiss compnay Roche. Further data is expected to be available by the time of the World AIDS Conference in July.
Individuals who received T-20 experienced a reduction in HIV levels of 1.697 log10 copies/mL compared to 0.763 log10 copies/mL for those in the control arm, .a difference of 0.934 log10 copies/mL. This difference was statistically significant (p
491 patients with experience of all three classes of antiretrovirals and viral load above 5,000 copies/ml were randomised in a 2:1 ratio to add T-20 to a regimen selected by genotypic and phenotypic resistance testing or receive only the background regimen (also selected by resistance testing). Participants may have received up to five drugs in addition to T-20 depending on the degree of resistance detected to available agents.
Ten per cent of patients in the study discontinued treatment in each arm of the study, with 3% of the discontinuations in the T-20 arm attributed to injection site reactions (although the majority of T-20 recipients experienced them). Insomnia, headache, dizziness and peripheral neuropathy were also more common in the T-20 arm, but investigators say it was not possible to establish a causal relationship between these adverse events and T-20.
A second study, TORO-2, is currently ongoing in Europe. The study has similar entry criteria and design. Otherwise, T-20 is currently available only through an open label safety study in the UK, Europe and North America. Manufacturer Roche says that production problems mean that it only has enough drug to treat 450 new patients over and above those already recruited to clinical trials, and does not expect this situation to change until near to the end of 2002. Licensing of the drug is predicted for the first quarter of 2003.