Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-27. ← Back to Evidence Library

Enfuvirtide (Fuzeon, T-20): what the evidence says

Name: Enfuvirtide (Fuzeon, T-20)
Published: 2026-10-27

At a glance

What it is: a 36-amino-acid synthetic peptide that blocks HIV-1 from fusing with cells, approved as Fuzeon; Drugs@FDA now lists it as discontinued. ^R1 UNVERIFIED the residue count against the label.

What the evidence says: in TORO 1 (501 patients, Americas) and TORO 2 (512, Europe/Australia), adding enfuvirtide to an optimized regimen lowered viral load more than the regimen alone at 24 weeks. ^{R2, R3}

Biggest risks: injection-site reactions in 98% of patients; more pneumonia than controls. ^R2

Rating


Human Human evidence	Strong: TORO 1 and TORO 2 RCTs ^{R2, R3}
Animal Animal / lab evidence	Not reviewed
Regulatory	FDA-approved, discontinued ^R1 · not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page ^{R4, R5, R6} · not named by WADA ^R7
Established human dose	Yes, label dose (see Study details)

Evidence verdict: Drug-resistant HIV-1 (with other drugs): Strong (two phase 3 RCTs)

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: both trials were open-label, but viral load is an objective measure. It was a salvage drug for multidrug-resistant HIV.

What is it?

Related pages: LL-37, Thymosin alpha-1.

Does it work?

Human TORO 1: viral load −1.70 vs −0.76 log10 copies/mL (P < 0.001). ^R2
Human TORO 2: −1.43 vs −0.65 log10 copies/mL (P < 0.001). ^R3

Is it safe?

Human Injection-site reactions in 98%; more pneumonia. ^R2

Gray-market vials: extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe.

Is it legal?

US: FDA-approved, listed discontinued. ^R1
Compounding: not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page. ^{R4, R5, R6}
Sport: not named on WADA's 2026 Prohibited List. ^R7

Study details

These are amounts researchers used, not recommendations.

Study	People / model	Route	Amount used	Follow-up	Reported	Citation
TORO 1 2003	501, drug-resistant HIV-1	SC	Per study	24 weeks	−1.70 vs −0.76 log10	PMID 12637625
TORO 2 2003	512, drug-resistant HIV-1	SC	90 mg twice daily	24 weeks	−1.43 vs −0.65 log10	PMID 12773645

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 26, 2026)

^R1 Drugs@FDA, Fuzeon (enfuvirtide), listed discontinued, application NDA021481 (openFDA drugsfda record checked Oct 26, 2026). https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=NDA021481
^R2 Lalezari JP, et al. N Engl J Med. 2003. PMID 12637625
^R3 Lazzarin A, et al. N Engl J Med. 2003. PMID 12773645
^R4 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R5 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R6 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
^R7 WADA. The 2026 Prohibited List, full list checked; compound not named. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use Enfuvirtide (Fuzeon, T-20). This is a prescription medicine. Use it only under the care of a licensed clinician; do not buy it from research-chemical or gray-market sellers. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).