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Peptide

Enfuvirtide (Fuzeon)

Enfuvirtide is a 36-amino acid synthetic peptide and the first FDA-approved HIV fusion inhibitor (2003). Derived from gp41, it blocks HIV entry into CD4 cells. Phase III trials showed superior viral suppression vs background regimen alone in treatment-experienced patients. Administered as 90mg subcutaneous injection twice daily.

Research notice. This page is for education and research. Peptides may not be FDA-approved for human use and may only be legally available for research. Talk to a qualified clinician before considering any peptide.

Best evidence
Grade A
Conditions studied
1
Outcomes
9
Graded outcomes
5220

Evidence by condition

  • Strong
  • Moderate
  • Limited
  • Very limited

1 condition, plus general outcomes

HIV Infection

HIV Infection: outcomes studied for Enfuvirtide (Fuzeon)
GradeOutcomeEffectSizeStudiesPeopleStudies list
Viral Load Reduction

Phase III: Superior virological activity vs optimized background regimen alone at 24 weeks in treatment-experienced patients.

Improves (the measure goes down)Large effect14 studies

Studies that measured viral load reduction

and 4 more in the citations list

CD4 Count Improvement

Significant immunological improvement demonstrated in pivotal Phase III trials (TORO-1 and TORO-2).

Improves (the measure goes up)Moderate effect14 studies

Studies that measured cd4 count improvement

and 4 more in the citations list

Treatment-Experienced Efficacy

Effective in patients with documented resistance to NRTIs, NNRTIs, and PIs. Valuable rescue therapy option.

Improves (the measure goes up)Large effect14 studies

Studies that measured treatment-experienced efficacy

and 4 more in the citations list

Viral Suppression Rate

Higher proportion achieving viral suppression when added to optimized background therapy in clinical trials.

Improves (the measure goes up)Moderate effect14 studies

Studies that measured viral suppression rate

and 4 more in the citations list

Time to Treatment Failure

Prolonged time to virologic failure compared to control arm in Phase III studies.

Improves (the measure goes up)Moderate effect14 studies

Studies that measured time to treatment failure

and 4 more in the citations list

General

General: outcomes studied for Enfuvirtide (Fuzeon)
GradeOutcomeEffectSizeStudiesPeopleStudies list
Immune Function

7 human trials support this finding. Human clinical trial data available.

Improves (the measure goes up)Small effect11 studies

Studies that measured immune function

and 1 more in the citations list

Safety/Tolerability

5 human trials support this finding. Human clinical trial data available.

Improves (the measure goes up)Small effect9 studies

Studies that measured safety/tolerability

Liver Protection

4 human trials support this finding. Human clinical trial data available.

Improves (the measure goes up)Small effect8 studies

Studies that measured liver protection

Antimicrobial Activity

3 systematic reviews and preclinical studies support this finding. Evidence includes systematic reviews/meta-analyses. Primarily preclinical evidence.

Improves (the measure goes up)Small effect7 studies

Studies that measured antimicrobial activity

Key findings

  • Viral Load ReductionHIV InfectionImproves (the measure goes down)
  • CD4 Count ImprovementHIV InfectionImproves (the measure goes up)
  • Treatment-Experienced EfficacyHIV InfectionImproves (the measure goes up)

Studies cited

29 studies from PubMed

  1. Quality by Design-Guided Development of Hydrogel-Forming Microneedles for Transdermal Delivery of Enfuvirtide.ACS applied materials & interfaces, 2025 · PMID 40063825
  2. Transdermal delivery of enfuvirtide using dissolving microneedles integrated with novel insertion and removal indicator.Journal of controlled release : official journal of the Controlled Release Society, 2025 · PMID 40532764
  3. Isopeptide Bond Bundling Superhelix for Designing Antivirals against Enveloped Viruses with Class I Fusion Proteins: A Review.Current pharmaceutical biotechnology, 2023 · PMID 37005549
  4. Metabolic, mitochondrial, renal and hepatic safety of enfuvirtide and raltegravir antiretroviral administration: Randomized crossover clinical trial in healthy volunteers.PloS one, 2019 · PMID 31120908
  5. Transdermal Delivery of Enfuvirtide in a Porcine Model Using a Low-Frequency, Low-Power Ultrasound Transducer Patch.Ultrasound in medicine & biology, 2019 · PMID 30583819
  6. Long-lasting enfuvirtide carrier pentasaccharide conjugates with potent anti-human immunodeficiency virus type 1 activity.Antimicrobial agents and chemotherapy, 2010 · PMID 19805567
  7. Fuzeon-induced collagenophagic granuloma: a peculiar granulomatous injection site reaction to Fuzeon--a case report and review of literature.International journal of surgical pathology, 2010 · PMID 19223380
  8. Efficacy and safety of switching from enfuvirtide to raltegravir in patients with virological suppression.HIV clinical trials, 2009 · PMID 20133273
  9. Enfuvirtide antiviral activity despite rebound viremia and resistance mutations: fitness tampering or a case of persistent braking on entering?The Journal of infectious diseases, 2007 · PMID 17205468
  10. A cohort study of enfuvirtide immunological and virological efficacy in clinical practice.Journal of medical virology, 2006 · PMID 16927284
  11. Enfuvirtide, the first fusion inhibitor to treat HIV infectionAIDS Rev, 2005 · PMID 16302461
  12. Safety of enfuvirtide in combination with an optimized background of antiretrovirals in treatment-experienced HIV-1-infected adults over 48 weeks.Journal of acquired immune deficiency syndromes (1999), 2005 · PMID 16280695
  13. Enfuvirtide for nurses: answering patient questions on activity, safety, and lifestyle impact.The Journal of the Association of Nurses in AIDS Care : JANAC, 2005 · PMID 16433107
  14. Enfuvirtide resistance mutations: impact on human immunodeficiency virus envelope function, entry inhibitor sensitivity, and virus neutralization.Journal of virology, 2005 · PMID 15795284
  15. Enfuvirtide: a review of its use in the management of HIV infection.Drugs, 2005 · PMID 15907147
  16. Enfuvirtide, a new fusion inhibitor for therapy of human immunodeficiency virus infectionAntimicrob Agents Chemother, 2004 · PMID 14998221
  17. Resistance to enfuvirtide, the first HIV fusion inhibitorJ Antimicrob Chemother, 2004 · PMID 15231762
  18. Enfuvirtide: the first therapy to inhibit the entry of HIV-1 into host CD4 lymphocytes.Nature reviews. Drug discovery, 2004 · PMID 15031735
  19. [Enfuvirtide, first fusion inhibitor in the treatment of human immunodeficiency virus infection: mechanism of action and pharmacokinetics].Medecine et maladies infectieuses, 2004 · PMID 15742549
  20. [Clinical efficacy and tolerance of enfuvirtide (Fuzeon), new antiretroviral inhibitors of intracellular penetration of human immunodeficiency virus (HIV) type 1].Medecine et maladies infectieuses, 2004 · PMID 15742550
  21. Peptide inhibitors of virus-cell fusion: enfuvirtide as a case study in clinical discovery and developmentAntiviral Res, 2003 · PMID 15219553
  22. Enfuvirtide: a fusion inhibitor for the treatment of HIV infectionDrugs Today (Barc), 2003 · PMID 15110129
  23. Enfuvirtide: first fusion inhibitor for treatment of HIV infectionAm J Health Syst Pharm, 2003 · PMID 15259753
  24. Enfuvirtide: the first HIV fusion inhibitorExpert Opin Pharmacother, 2003 · PMID 15794736
  25. Enfuvirtide (T-20): a novel human immunodeficiency virus type 1 fusion inhibitor.Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2003 · PMID 14523775
  26. Fuzeon data review.GMHC treatment issues : the Gay Men's Health Crisis newsletter of experimental AIDS therapies, 2003 · PMID 12728857
  27. Clinical trials for enfuvirtide (Fuzeon, T-20).AIDS (London, England), 2003 · PMID 15065580
  28. Antiviral drugs with extra-cellular sites of action.Reviews in medical virology, 2001 · PMID 11590665
  29. Pentafuside effective.AIDS patient care and STDs, 1996 · PMID 11361691