What does Enfuvirtide do?

Enfuvirtide is a synthetic 36-amino-acid peptide antiretroviral known as Fuzeon or T-20. The source describes it as an FDA-approved HIV fusion inhibitor used in salvage-therapy contexts where other antiretroviral options have failed.

How does Enfuvirtide work?

The source describes enfuvirtide as mimicking the HR2 region of HIV gp41. By binding the HR1 region, it interferes with the gp41 shape change that normally brings viral and host-cell membranes together, so HIV entry is blocked before fusion occurs.

Is Enfuvirtide FDA approved?

Yes. The source lists enfuvirtide as FDA approved and also notes later commercial discontinuation and withdrawal from the US, UK, and Canadian markets as of the cited February 2025 status note.

What side effects are reported for Enfuvirtide?

The source reports injection-site reactions, diarrhea, nausea, fatigue, a higher incidence of pneumonia, and hypersensitivity reactions. Injection-site reactions are listed as very common in the source.

What dose information is listed for Enfuvirtide?

Community dose information in the source is limited. The research-labeling row reports 90 mg by subcutaneous injection twice daily, with duration described as ongoing as part of an HIV regimen.

Immune FDA Approved - approved for specific uses

Enfuvirtide

Also known as: Fuzeon, T-20

At a glance

PeptiGuide dataset · reviewed Aug 2026

What it is

FDA-approved peptide HIV fusion inhibitor also known as Fuzeon or T-20.

Status

FDA Approved

Evidence level: human clinical evidence

Typical dose

90mg

Subcutaneous injection twice daily

Researched for

HIV treatment, viral infection management

Trial progress

PrePreclinical
IPhase I
IIPhase II
IIIPhase III
IVPhase IV
FDAFDA approved

FDA approved - FDA-approved for specific uses with established human evidence

Use the tools

In plain language

Enfuvirtide is a 36-amino-acid synthetic also known as Fuzeon or T-20.
The source identifies it as an FDA-approved HIV fusion inhibitor with prescription antiretroviral status.
It is administered by injection, with research labeling listing twice-daily dosing.
The research context is HIV treatment and viral infection management, especially salvage-therapy use described by the source.

How it's thought to work

Enfuvirtide is described as a HIV fusion inhibitor that targets gp41. It resembles the HR2 segment of gp41 and binds the HR1 region, disrupting the conformational pairing needed to draw viral and host-cell membranes together. Because that fusion step is blocked, the virus is prevented from entering the cell through this pathway.

What the research shows

Where the research stands

The source characterizes enfuvirtide as a well-studied antiretroviral rather than a speculative research compound. It cites the TORO 1 and TORO 2 phase 3 trials in heavily treatment-experienced participants, where enfuvirtide added to an optimized background regimen produced larger viral-load reductions than optimized background therapy alone. The source also notes earlier dose-ranging studies in HIV-infected adults, frequent injection-site reactions, practical burden from twice-daily injections, resistance linked to gp41 HR1 mutations, and combination-regimen use.

What it shows

✓ Human clinical evidence

FDA-approved for specific uses with established human evidence

△ Limitations

Use only according to approved labeling and qualified medical guidance.

Bottom line: FDA approved; source also reports commercial discontinuation in February 2025 and withdrawal from US, UK, and Canadian markets. FDA Approved

Typical dosing

CommunityCommunity dataset

Limited community data available

See research protocols

Range: See research dosing

Community dose reporting is limited in the source and defers to research or labeling context; this is not individualized dosing guidance.

Research dosing

Indication-specificApproved for specific uses - study doses are indication-specific

Doses observed in studies

90 mg subcutaneous twice daily

FDA Approved Labeling - Prescribed dose

Use only according to approved labeling and qualified medical guidance.

Duration: Ongoing as part of HIV regimen
Administration: Subcutaneous injection twice daily
Frequency: Twice daily

Timing & administration

Best time to take

Morning or as directed

Follow recommended protocol

Food recommendation

With or without food

Why this timing?

The source does not establish a unique time-of-day requirement; it emphasizes protocol consistency over a specific clock time.

Possible side effects

Not everyone experiences these. Individual responses vary with dose, duration, and personal factors.

Injection site reactions
Diarrhea
Nausea
Fatigue
Pneumonia
Hypersensitivity reactions

Not everyone experiences side effects, and severity can vary by context, purity, route, and individual health factors.

Sources

PubMed ClinicalTrials.gov FDA.gov

Frequently asked questions

Sequence

Ac-YTSLIHSLIEESQNQQEKNEQELLELDKWASLWNWF-NH2

One open dataset

Every fact on this page - doses, side effects, references - comes from the same PeptiGuide dataset that powers the Tracker, Compare, and the Lab.

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Educational resource, not medical advice. Talk to your clinician before acting on anything here.

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Enfuvirtide

In plain languageIn plain language

How it's thought to workHow it's thought to work

What the research showsWhat the research shows

Typical dosing

Research dosing

Timing & administrationTiming & administration

Possible side effectsPossible side effects

SourcesSources

Frequently asked questionsFrequently asked questions