Completed

A Phase II Double-Blind, Randomized, Placebo-Controlled Study to Evaluate the Antiretroviral Effect of Immunization With the MRK Ad5 HIV-1 Gag Vaccine in HIV-1 Infected Individuals Who Interrupt Antiretroviral Therapy

0 criteria met from your profileSee at a glance how your profile meets each eligibility criteria.
What is being tested

MRK Ad5 HIV-1 gag vaccine

+ Vaccine placebo

BiologicalOther
Who is being recruted

Blood-Borne Infections+11

+ Urogenital Diseases

+ Genital Diseases

From 18 to 55 Years
See all eligibility criteria
How is the trial designed

Treatment Study

Placebo-ControlledPhase 2
Interventional
Study Start: June 2004
See protocol details

Summary

Principal SponsorNational Institute of Allergy and Infectious Diseases (NIAID)
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: June 1, 2004

Actual date on which the first participant was enrolled.

Antiretroviral therapy (ART) has a significant impact on HIV disease; however, HIV cannot be cured with current drug regimens. While the majority of patients initially benefit from ART, drug regimens subsequently fail for many patients due to drug resistance, poor adherence, or toxicity. If given while HIV replication is kept in check by ART, an HIV vaccine may be able to generate an effective long-term immune response capable of controlling the virus, even if ART is discontinued. The MRK Ad5 HIV-1 gag vaccine uses a replication-defective adenovirus vector and has been found safe in clinical trials of both HIV infected and HIV uninfected adults. This study will evaluate the ability of immunization with the MRK Ad5 HIV-1 gag vaccine to control HIV replication in individuals undergoing treatment interruption. The study will enroll individuals whose HIV replication has been successfully suppressed with ART for at least 2 years. Participants in this study will be randomly assigned to receive either vaccine or placebo. Both vaccine and placebo will be injected into the upper arm muscle. Participants will take their antiretroviral medications during the first 3 months of the study. Injections will be given on Day 1, Week 4, and Week 26. A study nurse will call participants 1 or 2 days after each injection and participants will be asked to fill out a card with any reactions they have to the injections. About 3 months after the third injection, participants will stop taking their antiretroviral medications for 4 months. Participants will have study visits every 2 to 3 weeks while off medication. After 4 months, participants will have the option of restarting antiretroviral medications or continuing without medication. Participants will then have study visits every 2 months for 8 months. Study visits will include physical exams and blood collection. All participants will continue to see their primary care provider for HIV treatment and will be restarted on antiretroviral medications if clinically indicated. Participants or their primary care provider will be contacted by phone for updates every 6 months for an additional 3.5 years.

Official TitleA Phase II Double-Blind, Randomized, Placebo-Controlled Study to Evaluate the Antiretroviral Effect of Immunization With the MRK Ad5 HIV-1 Gag Vaccine in HIV-1 Infected Individuals Who Interrupt Antiretroviral Therapy 
NCT00080106
Principal SponsorNational Institute of Allergy and Infectious Diseases (NIAID)
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

114 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Treatment Study

These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.



Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

From 18 to 55 Years

Range of ages for which participants are eligible to join.

Healthy volunteers not allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

Blood-Borne InfectionsUrogenital DiseasesGenital DiseasesCommunicable DiseasesImmunologic Deficiency SyndromesImmune System DiseasesInfectionsRetroviridae InfectionsRNA Virus InfectionsSexually Transmitted DiseasesVirus DiseasesSexually Transmitted Diseases, ViralHIV InfectionsLentivirus Infections

Criteria

Inclusion Criteria * HIV infected * On a stable antiretroviral medication regimen (no changes to treatment within 4 weeks of study entry) * Viral load less than 50 copies/ml * Viral suppression for 2 years prior to study entry (documented viral loads less than 500 copies/ml) * CD4 count of 500 cells/mm3 or greater * Ad5 neutralizing antibody less than 200 units at screening * Willing to stop antiretroviral medications for at least 16 weeks post-vaccination * Hepatitis B surface antigen negative * Weight more than 110 lbs * Willing to use acceptable methods of contraception Exclusion Criteria * Two consecutive viral loads of 500 copies/ml or greater at least 14 days apart during the 24 months prior to study entry * Two consecutive CD4 counts less than 200 cells/mm3 before starting antiretroviral medications * History of anaphylaxis * Allergy to vaccine components * History of cardiac, pulmonary, gastrointestinal, hepatic, renal, pancreatic, or neurologic disease which, in the opinion of the study official, will compromise study participation * Pregnancy or breastfeeding * Contraindication to intramuscular injection, such as anticoagulant therapy or thrombocytopenia * Immune globulin or blood products within 3 months prior to study entry * Live vaccine within 30 days prior to study entry * Inactivated vaccine within 14 days prior to study entry * Previous HIV vaccine * History of an AIDS-defining illness. Patients with a history of Kaposi's sarcoma limited to the skin may participate. * Currently taking drugs or other substances not approved by the FDA. Patients may be on antiretroviral agents not yet approved by the FDA as part of a clinical trial or through an expanded access program. * Immunomodulatory agents (interferon, IL-2, GM-CSF, systemic corticosteroids, etc.) within 30 days prior to study entry * Active alcohol or substance abuse which may interfere with the study

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

50% chance of being blinded to the placebo group

Treatment Groups

Group I

Experimental
Participants in the experimental arm will receive the MRK Ad5 HIV-1 gag vaccine on Day 1, Week 4 and Week 26. Participants will take their antiretroviral medications during the first 3 months of the study.

Group II

Placebo
Participants in Arm 2 will receive a placebo vaccine on Day 1, Week 4 and Week 26. Participants will take their antiretroviral medications during the first 3 months of the study.

Study Objectives

Primary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 28 locations

Suspended

UCLA CARE Center CRS

Los Angeles, United StatesSee the location
Suspended

Stanford CRS

Palo Alto, United States
Suspended

Univ. of California Davis Med. Ctr., ACTU

Sacramento, United States
Suspended

Ucsd, Avrc Crs

San Diego, United States
Completed28 Study Centers