Researchers tested enfuvirtide, a synthetic peptide modeled on part of the virus's own outer protein, in patients who had run out of options after their HIV had become resistant to standard combination therapy.
In the TORO 1 trial of 501 patients in the US, Canada, Mexico and Brazil, adding twice-daily enfuvirtide injections to an optimized background regimen cut blood levels of HIV about 50-fold by 24 weeks, against about 6-fold on the background regimen alone.
Enfuvirtide works by physically blocking the step where HIV's outer protein folds and fuses with a cell's membrane, stopping infection before it starts rather than slowing the virus once it is inside. It requires twice-daily injections and caused injection-site reactions in 98 percent of patients, which limited its use once oral drugs with similar resistance coverage reached the market.
Read the original study
Lalezari et al., New England Journal of Medicine, 2003 · doi.org/10.1056/NEJMoa035026
The first drug to stop HIV at the door.
Source
- Lalezari, J. P., Henry, K., O'Hearn, M., Montaner, J. S. G., Piliero, P. J., Trottier, B., Walmsley, S., Cohen, C., Kuritzkes, D. R., Eron, J. J., Chung, J., DeMasi, R., Donatacci, L., Drobnes, C., Delehanty, J., Salgo, M., & TORO 1 Study Group (2003). Enfuvirtide, an HIV-1 fusion inhibitor, for drug-resistant HIV infection in North and South America. New England Journal of Medicine, 348(22), 2175–85. https://doi.org/10.1056/NEJMoa035026