HIV-1 InfectionPhase 2NCT04003103
Safety and Pharmacokinetics of Oral Islatravir (MK-8591) Once Monthly in Participants at Low Risk of Human Immunodeficiency Virus 1 (HIV-1) Infection (MK-8591-016)
A Phase 2 study testing Islatravir in people with HIV-1 Infection, run by Merck Sharp & Dohme LLC at 9 sites in 3 countries.
Trial summary
This study will evaluate the safety, tolerability and pharmacokinetics (PK) of 6 once-monthly doses of oral islatravir (60 mg and 120 mg) compared with placebo in adults at low risk of HIV-1 infection Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- HIV-1 Infection
- What is being tested?
- Islatravir
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 242 participants
- Where
- 9 sitesin 3 countries
- Study dates
- 19 Sep 2019to 24 Nov 2022
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Is in general good health with acceptable laboratory values at screening
- Is confirmed HIV-uninfected based on negative HIV-1/HIV-2 test result before randomization
- Has low risk of HIV infection, within 12 months prior to screening visit or the rescreening visit (if applicable)
- Use contraceptives consistent with local regulations
- Female is not pregnant or breastfeeding, and is not a woman of childbearing potential (WOCBP)
- A WOCBP is using an acceptable contraceptive method, or is abstinent from heterosexual intercourse as their preferred and usual lifestyle; or has a negative pregnancy test.
Who cannot join
- Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator
- Has an active diagnosis of hepatitis due to any cause
- Has a history of malignancy ≤5 years prior to signing informed consent except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer.
- Is taking or is anticipated to require systemic immunosuppressive therapy, immune modulators, or any prohibited therapies from 30 days prior to Day
- 1 through the duration of the study.
- Is currently participating in or has participated in an interventional clinical study with an investigational compound or device within 30 days prior to Day1 through the duration of the study.
Show all 9Show fewer
- Has previously been randomized in a study and received islatravir (MK-8591).
- Female is expecting to conceive or donate eggs at any time during the study
- Has QTc interval (using Fridericia correction) >450 msec (for males) or >460 msec (for females) or deemed clinically abnormal by the investigator.
Trial locations and contacts
9 sites in 3 countries.
9 sites in 3 countries
United States4 sites
Johns Hopkins School of Medicine - Drug Development Unit ( Site 0002)
Baltimore, Maryland, 21287
Research Centers of America, LLC ( Site 0007)
Hollywood, Florida, 33024
Celerion, Inc. ( Site 0006)
Lincoln, Nebraska, 68502
Magee Womens Research Institute ( Site 0001)
Pittsburgh, Pennsylvania, 15213
South Africa3 sites
JOSHA Research ( Site 0015)
Bloemfontein, Free State, 9301
Emavundleni Vaccine Centre ( Site 0011)
Cape Town, Western Cape, 7750
Clinical HIV Research Unit CHRU ( Site 0014)
Johannesburg, Gauteng, 2092
Israel2 sites
Rambam Medical Center ( Site 0017)
Haifa, 3109601
Hadassah Ein Karem Jerusalem ( Site 0016)
Jerusalem, Jerusalem, 9112001
About this study
Official title: A Phase 2a, Double-Blind, Placebo-Controlled Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Oral MK-8591 Once-Monthly in Participants at Low- Risk for HIV-1 Infection
This study will evaluate the safety, tolerability and pharmacokinetics (PK) of 6 once-monthly doses of oral islatravir (60 mg and 120 mg) compared with placebo in adults at low risk of HIV-1 infection
Read the detailed description
This study is ongoing for collection of safety follow-up of infants born to mothers participating in the study. The present results are based on the Week 68 interim analysis.
- Conditions
- HIV-1 Infection
- Being tested
- Islatravir, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
IslatravirDrug
Also called MK-8591
Islatravir 30 mg capsules taken by mouth.
PlaceboDrug
Placebo capsules taken by mouth.
| Study group | Role | What they receive |
|---|---|---|
| Islatravir 60 mg | Experimental | 60 mg islatravir + placebo for islatravir administered once monthly, orally in capsule form for 24 weeks Receives: Drug: Islatravir; Drug: Placebo |
| Islatravir 120 mg | Experimental | 120 mg islatravir administered once monthly, orally in capsule form for 24 weeks Receives: Drug: Islatravir |
| Placebo | Placebo comparator | Placebo for islatravir administered once monthly, orally in capsule form for 24 weeks Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With ≥1 Adverse Event (AE) Through Week 36
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to 36 weeks
Number of Participants Discontinuing From Study Therapy Due to AE
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to 20 weeks
Number of Participants Discontinuing From Study Therapy Due to ≥1 Drug-related AE
A drug-related AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, that is considered related to the study therapy.
Measured: Up to 20 weeks
Number of Participants With ≥1 Drug-related AE Through Week 36
A drug-related AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, that is considered related to the study intervention.
Measured: Up to 36 weeks
Number of Participants With ≥1 Serious Adverse Event (SAE) Through Week 36
An SAE is defined as any untoward medical occurrence that, at any dose, results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; or is an other important medical event.
Measured: Up to 36 weeks
Number of Participants With a ≥1 Grade 3 to Grade 5 AE up to Week 36
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study therapy, whether or not considered related to the study intervention. Toxicity grading was according to the National Institutes of Health Division of AIDS (NIH DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events version 2.1 (Grade 3 is 'severe'; Grade 4 is 'potentially life-threatening'; and Grade 5 'results in death').
Measured: Up to 36 weeks
Number of Participants With ≥1 Drug-related SAE Through Week 36
An drug-related SAE is defined as any untoward medical occurrence that, at any dose, results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; or is an other important medical event, that is considered related to study therapy.
Measured: Up to 36 weeks
Number of Participants With ≥1 Drug-related Grade 3 to 5 AE Through Week 36
A drug-related Grade 3 to Grade 5 AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention; has a toxicity Grade 3 (severe), 4 (potentially life-threatening), or 5 (results in death); and is considered related to study therapy. Toxicity grading was according to the NIH DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (v. 2.1).
Measured: Up to 36 weeks
Number of Participants With an AE Resulting in Death Through Week 36
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to 36 weeks
Secondary outcomes (11)
Area Under the Plasma Concentration-time Curve From Dosing to 672 Hours Postdose (AUC0-672) of Plasma ISL
The AUC0-672 of ISL after dosing on Day 1 and Day 140 is reported. Only ISL-treated participants are included in the PK analysis.
Measured: Day 1 and Day 140: predose and 30-min postdose. On Day 2 collect ~24 hours after Day 1 dose. On Weeks 4, 8, 12 and 16, collect predose. Weeks 1, 2, 3, 21, 22, 23 and 24: collect at any time during the study visit.
Maximum Plasma Concentration (Cmax) of ISL
The Cmax of ISL after dosing on Day 1 and Day 140 is reported. Only ISL-treated participants are included in the PK analysis.
Measured: Day 1 and Week 20, collect predose and 30-min postdose. On Day 2 collect ~24 hours after Day 1 dose. On Weeks 4, 8, 12 and 16, collect predose. Weeks 1, 2, 3, 21, 22, 23 and 24: collect at any time during the study visit.
Trough Plasma Concentration (Ctrough) of ISL
The plasma Ctrough of ISL after dosing on Day 1 and Day 140 is reported. Only ISL-treated participants are included in the PK analysis.
Measured: Day 1 and Week 20: predose and 30-min postdose. Day 2: 24 hours post Day 1 dose. Weeks 1, 2, 3, 21, 22, 23 and 24: any time during the study visit. Weeks 4, 8, 12 and 16: predose.
Apparent Plasma Terminal Half-life (t1/2) of ISL
The plasma t1/2 of ISL after dosing on Day 140 is reported. Only ISL-treated participants are included in the PK analysis.
Measured: Day 1 and Week 20, collect predose and 30-min postdose. On Day 2 collect ~24 hours after Day 1 dose. On Weeks 4, 8, 12 and 16, collect predose. Weeks 1, 2, 3, 21, 22, 23 and 24: collect at any time during the study visit.
Number of Participants With ≥1 AE Through Week 24
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to 24 weeks
Number of Participants With ≥1 Drug-related AE Through Week 24
A drug-related AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, that is considered related to the study intervention.
Measured: Up to 24 weeks
Number of Participants With ≥1 SAE Through Week 24
An SAE is defined as any untoward medical occurrence that, at any dose, results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; or is an other important medical event.
Measured: Up to 24 weeks
Number of Participants With a ≥1 Grade 3 to Grade 5 AE up to Week 24
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study therapy, whether or not considered related to the study intervention. Toxicity grading was according to the National Institutes of Health Division of AIDS (NIH DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events version 2.1 (Grade 3 is 'severe'; Grade 4 is 'potentially life-threatening'; and Grade 5 'results in death').
Measured: Up to 24 weeks
Number of Participants With ≥1 Drug-related SAE Through Week 24
An drug-related SAE is defined as any untoward medical occurrence that, at any dose, results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; or is an other important medical event, that is considered related to study therapy.
Measured: Up to 24 weeks
Number of Participants With ≥1 Drug-related Grade 3 to 5 AE Through Week 24
A drug-related Grade 3 to Grade 5 AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention; has a toxicity Grade 3 (severe), 4 (potentially life-threatening), or 5 (results in death); and is considered related to study therapy. Toxicity grading was according to the NIH DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (v. 2.1).
Measured: Up to 24 weeks
Number of Participants With an AE Resulting in Death Through Week 24
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Jul 2019
- Study start19 Sep 2019
- Primary completion18 Mar 2022
- Study completion24 Nov 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for HIV-1 InfectionStudies of the same condition, open and under way.
- More trials run by Merck Sharp & Dohme LLCThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 242 participants (actual)
Sponsor and investigators
- Lead sponsor
- Merck Sharp & Dohme LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Merck Sharp & Dohme LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04003103
- Sponsor's protocol ID
- 8591-016
- Other IDs
- Merck Protocol Number, 2019-001704-38, 2019
- Status last verified
- Jul 2025
- First submitted
- 27 Jun 2019
- Last updated
- 18 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Publications
Hillier SL, Bekker LG, Riddler SA, Hendrix CW, Badal-Faesen S, Macdonald P, Nair G, Lombaard J, Caraco Y, Peer A, Patel M, Vargo R, Homony B, Nedrow K, Evans B, Wickremasingha P, Zhou YP, Teal V, Hwang P, McMullan C, Kaufman KD, Robertson MN, Plank RM. Safety, Tolerability, and Pharmacokinetics of Once-Monthly Oral Islatravir: A Phase 2a Study in Participants at Low Risk for Acquiring Human Immunodeficiency Virus Type 1. J Infect Dis. 2025 Nov 14;232(5):1050-1060. doi: 10.1093/infdis/jiaf222.
PubMed 40327547Hendrix CW, Hillier SL, Bekker LG, Badal-Faesen S, Riddler SA, Marzinke MA, Fuchs EJ, Macdonald P, Edick S, Weld ED, Chavez-Eng CM, Evans B, Zang X, Vargo R, Homony B, Nedrow K, Plank RM, Robertson MN, Wickremasingha P, Patel M. Islatravir distribution in plasma, peripheral blood mononuclear cells, and mucosal tissues after monthly oral dosing. AIDS. 2026 Aug 1;40(8):1087-1096. doi: 10.1097/QAD.0000000000004477. Epub 2026 Mar 25.
PubMed 41789892Pham M, Wickremasingha P, Vargo R, Patel M, Nedrow K, Homony B, Robertson MN, Plank RM. Brief Report: Exploratory Substudy of a Phase 2 Trial to Evaluate the Pharmacokinetic Effect of Once-Monthly Islatravir on Long-Acting Reversible Contraceptives. J Acquir Immune Defic Syndr. 2025 Aug 1;99(4):374-378. doi: 10.1097/QAI.0000000000003678.
PubMed 40260892Devanathan AS, Cottrell ML. Pharmacology of HIV Cure: Site of Action. Clin Pharmacol Ther. 2021 Apr;109(4):841-855. doi: 10.1002/cpt.2187. Epub 2021 Mar 5.
PubMed 33540481
Study at a glance
From the registry record, last updated by the sponsor on 18 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2a, Double-Blind, Placebo-Controlled Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Oral MK-8591 Once-Monthly in Participants at Low- Risk for HIV-1 Infection
- ClinicalTrials.gov ID
- NCT04003103
- Acronym / sponsor ID
- 8591-016
- Conditions
- HIV-1 Infection
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 242 participants (actual)
- Lead sponsor
- Merck Sharp & Dohme LLCIndustry (pharma, biotech, devices)
- Study start
- 19 Sep 2019 (actual)
- Primary completion
- 18 Mar 2022 (actual)
- Study completion
- 24 Nov 2022 (actual)
- First posted
- 1 Jul 2019 (actual)
- Results
- Posted 21 Mar 2023
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the safety, tolerability and pharmacokinetics (PK) of 6 once-monthly doses of oral islatravir (60 mg and 120 mg) compared with placebo in adults at low risk of HIV-1 infection
Detailed description
This study is ongoing for collection of safety follow-up of infants born to mothers participating in the study. The present results are based on the Week 68 interim analysis.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Islatravir 60 mg | Experimental | Drug: Islatravir, Drug: Placebo60 mg islatravir + placebo for islatravir administered once monthly, orally in capsule form for 24 weeks |
| Islatravir 120 mg | Experimental | Drug: Islatravir120 mg islatravir administered once monthly, orally in capsule form for 24 weeks |
| Placebo | Placebo comparator | Drug: PlaceboPlacebo for islatravir administered once monthly, orally in capsule form for 24 weeks |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Is in general good health with acceptable laboratory values at screening
- Is confirmed HIV-uninfected based on negative HIV-1/HIV-2 test result before randomization
- Has low risk of HIV infection, within 12 months prior to screening visit or the rescreening visit (if applicable)
- Use contraceptives consistent with local regulations
- Female is not pregnant or breastfeeding, and is not a woman of childbearing potential (WOCBP)
Key exclusion criteria (9 listed)
- Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator
- Has an active diagnosis of hepatitis due to any cause
- Has a history of malignancy ≤5 years prior to signing informed consent except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer.
- Is taking or is anticipated to require systemic immunosuppressive therapy, immune modulators, or any prohibited therapies from 30 days prior to Day
- 1 through the duration of the study.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| IslatravirAlso: MK-8591Islatravir 30 mg capsules taken by mouth. | Drug | Islatravir 120 mg, Islatravir 60 mg |
| PlaceboPlacebo capsules taken by mouth. | Drug | Islatravir 60 mg, Placebo |
Primary outcome
Number of Participants With ≥1 Adverse Event (AE) Through Week 36
Time frame: Up to 36 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Number of Participants Discontinuing From Study Therapy Due to AE
Time frame: Up to 20 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Number of Participants Discontinuing From Study Therapy Due to ≥1 Drug-related AE
Time frame: Up to 20 weeks
A drug-related AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, that is considered related to the study therapy.
Number of Participants With ≥1 Drug-related AE Through Week 36
Time frame: Up to 36 weeks
A drug-related AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, that is considered related to the study intervention.
Number of Participants With ≥1 Serious Adverse Event (SAE) Through Week 36
Time frame: Up to 36 weeks
An SAE is defined as any untoward medical occurrence that, at any dose, results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; or is an other important medical event.
Number of Participants With a ≥1 Grade 3 to Grade 5 AE up to Week 36
Time frame: Up to 36 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study therapy, whether or not considered related to the study intervention. Toxicity grading was according to the National Institutes of Health Division of AIDS (NIH DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events version 2.1 (Grade 3 is 'severe'; Grade 4 is 'potentially life-threatening'; and Grade 5 'results in death').
Number of Participants With ≥1 Drug-related SAE Through Week 36
Time frame: Up to 36 weeks
An drug-related SAE is defined as any untoward medical occurrence that, at any dose, results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; or is an other important medical event, that is considered related to study therapy.
Number of Participants With ≥1 Drug-related Grade 3 to 5 AE Through Week 36
Time frame: Up to 36 weeks
A drug-related Grade 3 to Grade 5 AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention; has a toxicity Grade 3 (severe), 4 (potentially life-threatening), or 5 (results in death); and is considered related to study therapy. Toxicity grading was according to the NIH DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (v. 2.1).
Number of Participants With an AE Resulting in Death Through Week 36
Time frame: Up to 36 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
11 secondary outcomes
Area Under the Plasma Concentration-time Curve From Dosing to 672 Hours Postdose (AUC0-672) of Plasma ISL
Time frame: Day 1 and Day 140: predose and 30-min postdose. On Day 2 collect ~24 hours after Day 1 dose. On Weeks 4, 8, 12 and 16, collect predose. Weeks 1, 2, 3, 21, 22, 23 and 24: collect at any time during the study visit.
Maximum Plasma Concentration (Cmax) of ISL
Time frame: Day 1 and Week 20, collect predose and 30-min postdose. On Day 2 collect ~24 hours after Day 1 dose. On Weeks 4, 8, 12 and 16, collect predose. Weeks 1, 2, 3, 21, 22, 23 and 24: collect at any time during the study visit.
Trough Plasma Concentration (Ctrough) of ISL
Time frame: Day 1 and Week 20: predose and 30-min postdose. Day 2: 24 hours post Day 1 dose. Weeks 1, 2, 3, 21, 22, 23 and 24: any time during the study visit. Weeks 4, 8, 12 and 16: predose.
Apparent Plasma Terminal Half-life (t1/2) of ISL
Time frame: Day 1 and Week 20, collect predose and 30-min postdose. On Day 2 collect ~24 hours after Day 1 dose. On Weeks 4, 8, 12 and 16, collect predose. Weeks 1, 2, 3, 21, 22, 23 and 24: collect at any time during the study visit.
Number of Participants With ≥1 AE Through Week 24
Time frame: Up to 24 weeks
Number of Participants With ≥1 Drug-related AE Through Week 24
Time frame: Up to 24 weeks
Number of Participants With ≥1 SAE Through Week 24
Time frame: Up to 24 weeks
Number of Participants With a ≥1 Grade 3 to Grade 5 AE up to Week 24
Time frame: Up to 24 weeks
Number of Participants With ≥1 Drug-related SAE Through Week 24
Time frame: Up to 24 weeks
Number of Participants With ≥1 Drug-related Grade 3 to 5 AE Through Week 24
Time frame: Up to 24 weeks
Number of Participants With an AE Resulting in Death Through Week 24
Time frame: Up to 24 weeks
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Results publication: PubMed 40327547Hillier SL, Bekker LG, Riddler SA, Hendrix CW, Badal-Faesen S, Macdonald P, Nair G, Lombaard J, Caraco Y, Peer A, Patel M, Vargo R, Homony B, Nedrow K, Evans B, Wickremasingha P, Zhou YP, Teal V, Hwang P, McMullan C, Kaufman KD, Robertson MN, Plank RM. Safety, Tolerability, and Pharmacokinetics of Once-Monthly Oral Islatravir: A Phase 2a Study in Participants at Low Risk for Acquiring Human Immunodeficiency Virus Type 1. J Infect Dis. 2025 Nov 14;232(5):1050-1060. doi: 10.1093/infdis/jiaf222.
- Derived from this study: PubMed 41789892Hendrix CW, Hillier SL, Bekker LG, Badal-Faesen S, Riddler SA, Marzinke MA, Fuchs EJ, Macdonald P, Edick S, Weld ED, Chavez-Eng CM, Evans B, Zang X, Vargo R, Homony B, Nedrow K, Plank RM, Robertson MN, Wickremasingha P, Patel M. Islatravir distribution in plasma, peripheral blood mononuclear cells, and mucosal tissues after monthly oral dosing. AIDS. 2026 Aug 1;40(8):1087-1096. doi: 10.1097/QAD.0000000000004477. Epub 2026 Mar 25.
- Derived from this study: PubMed 40260892Pham M, Wickremasingha P, Vargo R, Patel M, Nedrow K, Homony B, Robertson MN, Plank RM. Brief Report: Exploratory Substudy of a Phase 2 Trial to Evaluate the Pharmacokinetic Effect of Once-Monthly Islatravir on Long-Acting Reversible Contraceptives. J Acquir Immune Defic Syndr. 2025 Aug 1;99(4):374-378. doi: 10.1097/QAI.0000000000003678.
- Derived from this study: PubMed 33540481Devanathan AS, Cottrell ML. Pharmacology of HIV Cure: Site of Action. Clin Pharmacol Ther. 2021 Apr;109(4):841-855. doi: 10.1002/cpt.2187. Epub 2021 Mar 5.
- Merck Clinical Trials InformationLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Medical Director study director
Merck Sharp & Dohme LLC
9 sites in 3 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Islatravir in people with HIV-1 Infection, run by Merck Sharp & Dohme LLC at 9 sites in 3 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 9 sites in United States, South Africa, Israel. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 21 Mar 2023). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With ≥1 Adverse Event (AE) Through Week 36 (time frame: Up to 36 weeks). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04003103, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Jul 2025.