Enfuvirtide
Also known as: Fuzeon, T-20
A 36-amino-acid HIV fusion inhibitor for treatment-experienced HIV-1. FDA-approved as Fuzeon (2003); US distribution ended Feb 2025.
Last updated
Mechanism of Action
Enfuvirtide is a synthetic peptide matching a segment of the HIV-1 gp41 envelope protein. It binds the first heptad-repeat region of gp41 and stops the protein from folding into the six-helix bundle needed to fuse the viral and cell membranes. This blocks HIV from entering CD4 cells. It was the first approved HIV fusion inhibitor.
- Half-life
- ~4 hours (subcutaneous)
- Administration Routes
- Subcutaneous
- Research Status
- Clinical
Reported Benefits
- Reduces viral load in treatment-experienced adults with ongoing HIV-1 replication, as part of combination therapy
- Active against virus resistant to other drug classes
- Raised CD4 counts in the TORO trials when added to an optimized regimen
Potential Side Effects
- Injection-site reactions in nearly all users (pain, nodules, redness)
- Increased rate of bacterial pneumonia
- Hypersensitivity reactions (rare)
- Nerve pain and bruising reported with the needle-free injection device
Common Dosing
Labeled dosing in adults is 90 mg by subcutaneous injection twice daily, always combined with other antiretrovirals; children were dosed by weight. The prescribing clinician sets and supervises dosing.
The dosing information above is aggregated from research literature and anecdotal community reports for educational purposes only. It is not a recommendation, prescription, or medical advice. Peptides are sold as research chemicals only and are not intended for human use.
Contraindications
- Known hypersensitivity to enfuvirtide
- Not for use as a single agent
- Caution in people at high risk of pneumonia
No documented stacking partners for Enfuvirtide yet.