Experimental HIV vaccine trimer 4571 tested in small safety trial
NCT ID NCT04985760
First seen Jun 24, 2026 · Last updated Jun 27, 2026 · Updated 2 times
Summary
This early-stage trial tested an experimental HIV vaccine called Trimer 4571 in 32 adults with HIV who were already on effective antiretroviral therapy (ART). The main goal was to check if the vaccine is safe and tolerable, and to see if it helps the immune system produce broadly neutralizing antibodies against HIV. Participants received either a low dose, high dose, or placebo vaccine, and were monitored for side effects and immune responses.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Trimer 4571 HIV vaccine with alum adjuvant
- What this could lead to
- If successful, this could help develop a vaccine that trains the immune system to produce broadly neutralizing antibodies against HIV, potentially leading to better HIV control or prevention strategies.
- What could go wrong
- This is a very early Phase 1 trial with only 32 participants, so results may not apply broadly. The vaccine is still experimental and may not produce the desired immune response or could cause side effects.
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Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 1
The first testing in people. Mainly checks safety and dose, usually in a small group.
- Participants
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32 people
The number who actually took part.
- Started
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Sep 2021
- Finished
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Jan 2026
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. HIV-1 infection, documented by any FDA-approved assay. NOTE: The term 'licensed' refers to a US FDA approved kit, which is required for all investigational new drug (IND) studies. 2. Receiving continuous antiretroviral therapy (ART) for at least 24 months (defined as no interruptions longer than 30 consecutive days) and with no changes in the components of the ART for at least 8 weeks prior to study entry. A change in formulation (for example tenofovir disaproxil fumarate to tenofovir alafenamide) will not be considered a change in ART. 3. Screening CD4+ cell count ≥200cells/mm3 obtained within 60 days prior to study entry by any US laboratory that has a CLIA certification or its equivalent. 4. Plasma HIV-1 RNA levels \< 50 copies/ml for at least 24 months on ART prior to study entry using a FDA-approved assay performed by any laboratory that has a CLIA certification or its equivalent. Participants must have at least one documented HIV-1 RNA \< 50 copies/ml within 12 months prior to study entry. All available HIV-1 RNA measurements must be \< 50 copies/ml during the 24 months prior to study entry except as allowed by the following note. NOTE: Unconfirmed plasma HIV-1 RNA \> 50 copies/ml but \<200 copies/mL is allowed if followed by a subsequent value \< 50 copies/ml. 5. Screening HIV-1 RNA levels \<50 copies/mL using a FDA-approved assay performed by any laboratory that has a CLIA certification or its equivalent within 60 days prior to entry. 6. Men and women ages \> 18 years. 7. The following laboratory values obtained within 60 days prior to entry: * Hemoglobin ≥10 g/dL * Absolute neutrophil count (ANC) ≥1000/mm3 * Platelet count ≥100,000/mm3 * Creatinine ≤ 1.5x upper limit of normal (ULN) * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (SGPT) ≤2.5x ULN 8. Ability and willingness of participant to provide informed consent. 9. In the opinion of the investigator, no medical, mental health or other condition that precludes participation. 10. For persons who can become pregnant, negative serum or urine pregnancy test within 48 hours prior to entry by any US clinic or laboratory that has a CLIA certification or its equivalent, or is using a point-of-care (POC)/ CLIA-waived test. Persons who can become pregnant include women who have not been post-menopausal for at least 12 consecutive months, (i.e., who have had menses within the preceding 12 months) or women who have not undergone surgical sterilization (e.g. hysterectomy, bilateral oophorectomy, bilateral tubal ligation or salpingectomy). Self- report is acceptable documentation of menopause and sterilization. 11. All participants must agree not to participate in the conception process (eg, active attempt to become pregnant or to impregnate, sperm donation, in vitro fertilization), and if participating in sexual activity that could lead to pregnancy, the participant/partner must use at least one reliable form of contraception (condoms, with or without a spermicidal agent; a diaphragm or cervical cap with spermicide; an IUD; or hormone-based contraceptive), while receiving study treatment and for 12 weeks following the final study vaccine. Exclusion Criteria: 1. Known to have been started on antiretroviral therapy within 3 months of the presumed or known date of first acquiring HIV-1 infection; i.e., treated during acute HIV-1 infection 2. Currently breastfeeding or pregnant 3. Known allergy/sensitivity or any hypersensitivity to components of study vaccine or their formulation. 4. Known chronic inflammatory conditions such as, but not limited to, rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, inflammatory bowel disease (i.e., Crohn's disease or ulcerative colitis), chronic pancreatitis, or autoimmune hepatitis, myositis, or myopathy. 5. Active drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements. 6. Serious medical illness that requires systemic treatment and/or hospitalization within 30 days prior to entry. 7. Use of systemic immunomodulators (e.g., interleukins, interferons, Cyclosporine), systemic cytotoxic chemotherapy, or investigational therapy within 60 days prior to study entry. NOTE: Participants receiving stable physiologic doses of glucocorticoids, defined as the equivalent of prednisone ≤10 mg/day, will not be excluded. Stable physiologic glucocorticoid doses should not be discontinued for the duration of the study. In addition, participants receiving inhaled or topical corticosteroids, or topical imiquimod will not be excluded. 8. Receipt of any investigational HIV immunotherapy or HIV therapeutic vaccination within 12 months prior to study entry. 9. History of positive HCV antibody with detectable HCV RNA in plasma within 48 Weeks prior to study entry. NOTE: Persons with positive HCV Ab but negative plasma HCV RNA are allowed to participate. Sites must document negative HCV RNA within 24 weeks of study entry. 10. Treatment for hepatitis C within 6 months prior to study entry. 11. History of positive HBsAg within 48 weeks prior to study entry. 12. History of severe reaction or anaphylaxis to prior vaccinations. 13. Body Mass Index \>40kg/m2. 14. Receipt of Blood products or immune globulins within 16 weeks prior to Enrollment as per protocol section 5.3.2. 15. Receipt of Live attenuated vaccines within 4 weeks prior to enrollment. 16. Current allergen immunotherapy with antigen injections, unless on maintenance schedule.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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AIDS Clinical Trials Unit/The Ohio State University
Columbus, Ohio, 43210, United States
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University of Pittsburgh
Pittsburgh, Pennsylvania, 15213, United States
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