CLINICAL TRIALS PROFILE FOR FUZEON

All Clinical Trials for FUZEON

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00050856 ↗	Fuzeon (Enfuvirtide) Early Access Program for Patients With HIV-1 Infection	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 3	2002-11-01	This study will determine the safety and tolerability of Fuzeon (enfuvirtide) used together with other treatments for HIV infection in patients with advanced HIV disease. Fuzeon is an antiretroviral drug. Unlike other antiretrovirals, however, which work against the virus once it is already in the cell, Fuzeon prevents the virus from getting into healthy cells. Patients 18 years of age and older with advanced HIV-1 infection, who do not respond to approved antiretroviral therapy, may be eligible for this study. Candidates must have a CD4 lymphocyte count less than 100 cells/mm3 and a viral load greater than 10,000 copies/mL. They will be screened with a medical history, physical examination, and blood tests, and may also have an electrocardiogram (ECG), chest x-ray and urine test. Patients enrolled in the study will be re-examined and have additional blood tests before beginning treatment with Fuzeon. They will then be taught how to self-inject the medicine under the skin and will take two doses daily (less than 1/4 teaspoon each), 12 hours apart. After the first treatment, participants will have follow-up visits at weeks 1, 2, 4, 8, 12, 24, 36, 48, and every 12 weeks after that, if necessary, until 12 weeks after the drug becomes commercially available. Visits may be scheduled more often if a problem arises. During the follow-up visits, patients will have blood drawn, and their blood pressure, pulse rate and temperature will be checked. They will also report any drug side effects they have experienced. Patients may continue to take Fuzeon as long as they benefit from therapy and do not experience severe side effects from the treatment. The drug will be provided to participants until 12 weeks after it is sold in the United States.
NCT00051831 ↗	Effect of an Enfuvirtide-based Anti-HIV Drug Regimen on Latent HIV Reservoirs in Treatment Naive Adults	Completed	AIDS Clinical Trials Group	N/A	2003-10-01	HIV replication in resting CD4 cells is so minimal that anti-HIV drugs often fail to destroy the virus in these cells. Enfuvirtide, also known as T-20, is a type of anti-HIV drug called a fusion inhibitor. The purpose of this study is to test the ability of a T-20-enhanced treatment regimen to decrease the number of resting CD4 cells that become infected with HIV.
NCT00051831 ↗	Effect of an Enfuvirtide-based Anti-HIV Drug Regimen on Latent HIV Reservoirs in Treatment Naive Adults	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	N/A	2003-10-01	HIV replication in resting CD4 cells is so minimal that anti-HIV drugs often fail to destroy the virus in these cells. Enfuvirtide, also known as T-20, is a type of anti-HIV drug called a fusion inhibitor. The purpose of this study is to test the ability of a T-20-enhanced treatment regimen to decrease the number of resting CD4 cells that become infected with HIV.
NCT00086710 ↗	Study of Enfuvirtide in HIV-Positive Subjects	Completed	Hoffmann-La Roche	Phase 1	1969-12-31	A total of 26 patients will be admitted to the clinic where they will be dosed with each injection device. There will be a 7-day washout between doses and a 7-10 day follow-up period.
NCT00086710 ↗	Study of Enfuvirtide in HIV-Positive Subjects	Completed	Trimeris	Phase 1	1969-12-31	A total of 26 patients will be admitted to the clinic where they will be dosed with each injection device. There will be a 7-day washout between doses and a 7-10 day follow-up period.
NCT00089492 ↗	A Study Comparing the Efficacy and Safety of Once-Daily Fuzeon (Enfuvirtide) Dosing Versus the Currently Recommended Twice-Daily Dosing in Human Immunodeficiency Virus-Type 1 (HIV-1) Infected Patients	Completed	Trimeris	Phase 2	2004-07-01	This study will assess the safety and efficacy of once-daily administration of Fuzeon compared with twice-daily administration in HIV-1 infected patients who have received prior treatment. Patients will also receive an optimized treatment consisting of antiretroviral (ARV) therapy as determined by the treating physician. The anticipated time on study treatment is 3-12 months, and the target sample size is 100-500 individuals.
NCT00089492 ↗	A Study Comparing the Efficacy and Safety of Once-Daily Fuzeon (Enfuvirtide) Dosing Versus the Currently Recommended Twice-Daily Dosing in Human Immunodeficiency Virus-Type 1 (HIV-1) Infected Patients	Completed	Hoffmann-La Roche	Phase 2	2004-07-01	This study will assess the safety and efficacy of once-daily administration of Fuzeon compared with twice-daily administration in HIV-1 infected patients who have received prior treatment. Patients will also receive an optimized treatment consisting of antiretroviral (ARV) therapy as determined by the treating physician. The anticipated time on study treatment is 3-12 months, and the target sample size is 100-500 individuals.

Clinical Trial Conditions for FUZEON

Condition Name

Condition Name for FUZEON
Intervention	Trials
HIV Infections	22
AIDS	2
Antiretroviral Treatment	1
HIV	1

Condition MeSH

Condition MeSH for FUZEON
Intervention	Trials
HIV Infections	22
Infections	8
Infection	8
Communicable Diseases	5

Clinical Trial Locations for FUZEON

Trials by Country

Trials by Country for FUZEON
Location	Trials
United States	118
Puerto Rico	5
France	5
Canada	4
Australia	2

Trials by US State

Trials by US State for FUZEON
Location	Trials
California	9
Florida	8
Texas	7
New York	7
Missouri	7

Clinical Trial Progress for FUZEON

Clinical Trial Phase

Clinical Trial Phase for FUZEON
Clinical Trial Phase	Trials
Phase 4	9
Phase 3	3
Phase 2/Phase 3	1

Clinical Trial Status

Clinical Trial Status for FUZEON
Clinical Trial Phase	Trials
Completed	18
Unknown status	3
Terminated	2

Clinical Trial Sponsors for FUZEON

Sponsor Name

Sponsor Name for FUZEON
Sponsor	Trials
Hoffmann-La Roche	17
Trimeris	6
National Institute of Allergy and Infectious Diseases (NIAID)	5

Sponsor Type

Sponsor Type for FUZEON
Sponsor	Trials
Industry	28
Other	9
NIH	7

Fuzeon (enfuvirtide) Clinical Trials Update, Market Analysis, and Exclusivity/Generic-Biosimilar Outlook

Last updated: July 28, 2026

Fuzeon (enfuvirtide), an injectable HIV-1 fusion inhibitor (target: gp41), is not commercially positioned for new trial enrollment in major ongoing global studies and is approaching mature market conditions typical of an older antiretroviral. Patent and regulatory exposure is largely about confirming historical exclusivity status, residual protected formulations or methods (if any), and assessing whether any generic or biosimilar-style entrants are plausible, given the product’s biologic-like manufacturing profile and long-established competition in HIV combination therapy.

What is Fuzeon (enfuvirtide) and what clinical trials are active in 2026?

Fuzeon is an enfuvirtide subcutaneous formulation used in combination with other antiretroviral agents for heavily treatment-experienced adults with multidrug-resistant HIV-1 infection.

What clinical-trials signals matter for an older HIV fusion inhibitor?

For an established product like Fuzeon, the key clinical-trials update is usually not “new efficacy trials,” but:

• Studies focused on real-world effectiveness and adherence in combination regimens
• Pharmacokinetic (PK) comparisons (formulation, administration technique)
• Safety monitoring in specific populations
• Potential lifecycle trials that may support label maintenance in certain regions

What does the current trial landscape imply?

Fuzeon’s trial activity has historically been limited relative to newer classes (integrase inhibitors, CCR5 antagonists, long-acting injectables). The practical market consequence is that Fuzeon’s “clinical pipeline” contribution is usually low versus newer line extensions and new-drug entrants that capture the HIV treatment share.

How does Fuzeon fit into current HIV treatment guidelines and standard-of-care?

Fuzeon is used as a salvage-line option due to its mechanism and resistance profile. In modern HIV care, first-line and most regimen construction is dominated by:

• Integrase strand transfer inhibitors (INSTIs)
• High-barrier combination regimens with improved tolerability
• Long-acting delivery strategies for select patients

Why does this impact market dynamics?

• Salvage-line drugs typically face shrinking addressable populations over time as patients start effective therapy earlier
• Oral regimens and long-acting injectables displace injectable multi-drug regimens when alternatives exist
• Uptake depends on availability in specific markets, clinician familiarity, and reimbursement

Fuzeon market analysis: how has demand moved and where is revenue likely to land?

Fuzeon is characterized by a niche, salvage-market profile. Demand tends to track:

• Proportion of patients with multidrug-resistant HIV
• Access to Fuzeon through procurement, tendering, and reimbursement
• Inventory cycles around supply continuity
• Competitive substitution by other salvage agents and combinations

Market drivers that push demand down

• Earlier initiation of ART reduces the pool of heavily treatment-experienced patients requiring fusion inhibition
• Superior tolerability and simpler administration of newer drugs
• Declining regimen share as salvage options diversify

Market drivers that can stabilize demand

• Regional procurement programs that maintain supply for resistant cohorts
• Limited sequencing options in certain resistance patterns
• Real-world use where clinicians retain fusion inhibitor options

Revenue projection directionality (non-numeric)

• Base-case: continued erosion in treated-patient count and regimen share
• Downside: stronger displacement from newer salvage combinations and tightened formularies
• Upside: localized stabilization in regions with procurement continuity and cost advantage relative to alternatives

When does Fuzeon lose exclusivity, and what patent timelines govern generics?

Fuzeon’s exclusivity is governed by a mix of:

• Core composition and manufacturing patents (often longer legacy terms)
• Potential formulation and method-of-use patents (if still in force in specific jurisdictions)
• Any data exclusivity frameworks tied to original regulatory approvals (jurisdiction-specific)

Patent-expiration and regulatory-exclusivity relevance

For market modeling, the question is not “does exclusivity exist” but:

• Are any enforceable, product-specific patents still in force in key jurisdictions?
• Are any competitors positioned to enter via FDA pathways (if applicable) or national equivalents (EU/UK/other markets)?
• Do any residual protections relate to the specific route (subcutaneous injection), device/injection method, or formulation?

What is the Orange Book status of Fuzeon, and are there Paragraph IV challenges?

Fuzeon is an older anti-HIV product with complex biologic-like manufacturing characteristics, so the Orange Book exercise typically focuses on whether an application is linked to FDA-listed patents through an abbreviated pathway and whether there are generic labels or P-IV listings.

The practical question for entry risk

For a business projection, the presence of:

• Listed patents tied to an approved NDA route
• ANDA filings or court dockets referencing Paragraph IV
• Settlement agreements restricting launch timing

…is what turns “theoretical generic possibility” into “modeled launch risk.”

If those signals were active, you would typically see them in Orange Book listings and associated court filings. In the absence of visible, active FDA patent challenge indicators, market modeling should weight continued incumbency or substitution by other active drugs rather than generic manufacturing entry.

Which patents protect Fuzeon enfuvirtide in major markets?

For an IP-driven market outlook, you model:

• Composition-of-matter protection (enfuvirtide itself)
• Process/manufacturing know-how and specific steps
• Formulation patents for the subcutaneous presentation
• Method-of-use patents tied to salvage treatment regimens

How patent estate structure changes entry probability

• If the estate is dominated by formulation/process patents, competitors need more than “one-to-one” molecule copying
• If it is dominated by composition-of-matter, entry can be blocked via patent injunction risk
• If enforcement is jurisdiction-limited, entrants may still launch selectively

How strong is the patent estate for Fuzeon, and what is the litigation landscape?

The key for projections is whether there is evidence of:

• Ongoing patent litigation
• Challenged patents
• Active settlement agreements controlling generic entry
• Court outcomes affecting remaining patent term

Business impact of litigation

• If there is no active litigation, generic launch risk usually comes from clean entry windows and freedom-to-operate assessments
• If litigation exists, launch timing becomes a function of stay orders, settlement terms, and injunction leverage

What generic or “biosimilar-like” entry risks exist for Fuzeon?

Fuzeon is a peptide therapeutic with biologic manufacturing considerations. Even when a molecule is chemically defined, market entrants still face:

• Manufacturing process replication complexity
• Impurity profile similarity expectations
• Stability, peptide integrity, and lot-to-lot reproducibility requirements
• Regulatory demonstration costs

What entry paths are realistically relevant

• If the product is treated as a biologic-like product under the applicable regulatory framework in a jurisdiction, a biosimilar pathway may be required
• If treated under NDA-compatible product rules, generic substitution hinges on FDA/Orange Book patent coverage and ANDA availability

How does Fuzeon compare with newer HIV drugs in commercial adoption and pricing power?

In commercial terms, Fuzeon competes as a salvage option. Comparative dynamics:

• INSTI-centered regimens have displaced many older agents in routine care
• Other salvage agents may have fewer administration burdens
• Real-world switching depends on resistance profile, tolerability, and clinician practice patterns

Competitive displacement mechanism

Fuzeon’s market contraction typically occurs when:

• Patients move to alternative salvage combinations
• Clinicians reduce use of injectable multi-injection regimens
• Formularies restrict fusion inhibitors to narrow circumstances

What market projection scenarios fit Fuzeon over the next 3 to 7 years?

A structured forecast for an older salvage HIV product typically uses three scenarios.

Base case

• Continued decline in patients treated and share of salvage regimens
• Stable pricing relative to procurement cycles but shrinking volume
• Limited new clinical expansion

Downside case

• Faster displacement by newer salvage agents
• Increased formulary restrictions
• Supply substitution to other products with better support economics

Upside case

• Local procurement continuity in high-need regions
• Resistance-driven continued role in specific patient cohorts
• Improved administrative handling or cost support maintains physician preference

Key takeaways

• Fuzeon remains a niche salvage therapy defined by mechanism and resistance utility, not by trend growth in HIV pharmacology.
• Clinical-trials momentum is not the primary market driver for Fuzeon; penetration depends on salvage population size, access, and guideline-driven regimen sequencing.
• Market outlook is dominated by gradual volume erosion and competitive displacement by newer ART classes and combination strategies.
• The principal exclusivity and entry-risk question is whether enforceable patents and any active FDA or litigation signals exist in key jurisdictions; absent clear generic entry indicators, projection should assume continued incumbent supply with shrinking demand rather than disruptive generic launches.

FAQs

1. Is Fuzeon still used for multidrug-resistant HIV, and in which line of therapy?
2. Do any new formulation or delivery improvements exist for subcutaneous enfuvirtide?
3. What patient populations are most likely to remain eligible for fusion inhibitors like enfuvirtide?
4. What are the main safety and tolerability issues that affect real-world continuation of Fuzeon?
5. How do resistance patterns to gp41 fusion inhibitors determine ongoing use of enfuvirtide?

References

1. FDA. Drug product and labeling information for Fuzeon (enfuvirtide). U.S. Food and Drug Administration.
2. ClinicalTrials.gov. Enfuvirtide (Fuzeon) search results and trial records. U.S. National Library of Medicine.
3. EMA. Fuzeon (enfuvirtide) product information and assessment history. European Medicines Agency.
4. Department of Health and Human Services (DHHS). Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents with HIV. U.S. DHHS.