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AzTrials

HIV InfectionPhase 3NCT05766501

A Study of Doravirine/Islatravir (DOR/ISL, MK-8591A) for the Treatment of Human Immunodeficiency Virus 1 (HIV-1) Infection in Participants Who Previously Received DOR/ISL (MK-8591A-054)

A Phase 3 study testing DOR/ISL in people with HIV Infection, run by Merck Sharp & Dohme LLC at 95 sites in 15 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

The purpose of this study is to evaluate the safety and tolerability of DOR/ISL in adult participants with HIV-1 who had been previously treated with DOR/ISL in earlier clinical studies. There are no formal hypotheses to be tested in this study. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
HIV Infection
What is being tested?
DOR/ISL
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
641 participants
Where
95 sitesin 15 countries
Study dates
17 Mar 2023to 6 Sep 2028
Phase
Phase 3
Are there results?
Not yet: the study is under way

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 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Is currently receiving doravirine/islatravir (DOR/ISL) adult fixed dose combination (FDC) tablet in Merck Sharp \& Dohme (MSD)-sponsored clinical studies (MK-8591A-018, -020, and -033 [except for heavily treatment-experienced (HTE) participants]).

Who cannot join

  • Has confirmed HIV-1 RNA ≥200 copies/mL in MSD DOR/ISL (100 mg/0.75 mg) MK-8591A-018 /-020, or at screening for participants entering from DOR/ISL (100 mg/0.75 mg) MK-8591A-033.
  • Has confirmatory laboratory findings for cluster of differentiation 4+ (CD4+) T-cell counts or lymphocyte counts in the prior DOR/ISL study that meet criteria for discontinuation of DOR/ISL.
  • Is a HTE participant receiving treatment in MK-8591A-019 or -033.

Trial locations and contacts

95 sites in 15 countries.

95 sites in 15 countries

United States31 sites

  • Augusta University-Infectious Diseases ( Site 3135)

    Augusta, Georgia, 30912

  • St Hope Foundation ( Site 3121)

    Bellaire, Texas, 77401

  • Pacific Oaks Medical Group ( Site 3123)

    Beverly Hills, California, 90211

  • University of Alabama at Birmingham-UAB 1917 Research Clinic ( Site 3104)

    Birmingham, Alabama, 35222

  • North Texas Infectious Diseases Consultants, P.A ( Site 3100)

    Dallas, Texas, 75246

  • Infectious Disease Specialists of Atlanta ( Site 3128)

    Decatur, Georgia, 30033

  • Therafirst Medical Center ( Site 3110)

    Fort Lauderdale, Florida, 33308

  • Texas Centers for Infectious Disease Associates ( Site 3111)

    Fort Worth, Texas, 76104

  • Midway Immunology and Research Center ( Site 3117)

    Ft. Pierce, Florida, 34982

  • ID Care ( Site 3131)

    Hillsborough, New Jersey, 08844

  • The Crofoot Research Center ( Site 3101)

    Houston, Texas, 77098

  • KC CARE Health Center ( Site 3103)

    Kansas City, Missouri, 64111

  • DCOL Center for Clinical Research ( Site 3119)

    Longview, Texas, 75605

  • Kaiser Permanente ( Site 3124)

    Los Angeles, California, 90027

  • Ruane Clinical Research Group, Inc ( Site 3126)

    Los Angeles, California, 90036

  • Mills Clinical Research ( Site 3114)

    Los Angeles, California, 90069

  • Mercer university, Department of internal medicine-Clinical Research ( Site 3129)

    Macon, Georgia, 31201

  • AHF The Kinder Medical Group ( Site 3108)

    Miami, Florida, 33133

  • Floridian Clinical Research, LLC ( Site 3133)

    Miami Lakes, Florida, 33016

  • Icahn School of Medicine at Mount Sinai-Clinical and Translational Research Center ( Site 3134)

    New York, New York, 10029

  • Orlando Immunology Center ( Site 3106)

    Orlando, Florida, 32803

  • Bliss Healthcare Services ( Site 3115)

    Orlando, Florida, 32806

  • Penn Medicine: University of Pennsylvania Health System-Perelman Center for Advanced Medicine ( Site

    Philadelphia, Pennsylvania, 19104

  • Pueblo Family Physicians ( Site 3102)

    Phoenix, Arizona, 85015

  • University of California Davis Health-Internal Medicine: Infectious Diseases ( Site 3137)

    Sacramento, California, 95817

  • CAN Community Health - Sarasota ( Site 3118)

    Sarasota, Florida, 34237

  • Chatham County Health Department - Chatham CARE Center-Infectious Disease ( Site 3105)

    Savannah, Georgia, 31401

  • Private Practice - Dr. Peter Shalit ( Site 3120)

    Seattle, Washington, 98104

  • Multicare Institute for Research and Innovation ( Site 3127)

    Spokane, Washington, 99202

  • Georgetown University Medical Center ( Site 3130)

    Washington D.C., District of Columbia, 20007

  • Triple O Research Institute, P.A ( Site 3116)

    West Palm Beach, Florida, 33407

Other trials in United States

South Africa9 sites

  • Josha Research ( Site 2603)

    Bloemfontein, Free State, 9301

  • Family Clinical Research Unit (Fam-Cru)-Adult Infectious Diseases ( Site 2608)

    Cape Town, Western Cape, 7505

  • Desmond Tutu Health Foundation ( Site 2602)

    Cape Town, Western Cape, 7925

  • Wentworth Hospital ( Site 2604)

    Durban, KwaZulu-Natal, 4052

  • Perinatal HIV Research Unit (PHRU)-Adult Treatment and Research ( Site 2605)

    Johannesburg, Gauteng, 2013

  • Helen Joseph Hospital-Clinical HIV Research Unit ( Site 2609)

    Johannesburg, Gauteng, 2092

  • Ezintsha-Clinical Research Site ( Site 2607)

    Johannesburg, Gauteng, 2193

  • Be Part Yoluntu Centre ( Site 2601)

    Paarl, Western Cape, 7646

  • Private Practice Dr. Marleen de Jager ( Site 2600)

    Pretoria, Gauteng, 0083

Other trials in South Africa

Russia7 sites

  • Republican Clinical Hospital for Infectious Diseases A.F. Agafonova ( Site 2503)

    Kazan', Tatarstan, Respublika, 420140

  • Kemerovo Regional Center for the Prevention and Control of AIDS and Infectious Diseases ( Site 2505)

    Kemerovo, Kemerovo Oblast, 650056

  • Krasnoyarsk Regional Center for the Prevention and Control of AIDS ( Site 2504)

    Krasnoyarsk, Krasnoyarsk Krai, 660049

  • Moscow Infectious Diseases Clinical Hospital Number 2 ( Site 2506)

    Moscow, Moscow, 105275

  • Scientific Advisory Clinical Diagnostic Center Central Resea-Federal AIDS Center ( Site 2502)

    Moscow, Moscow, 115035

  • Republican Clinical Infectious Hospital ( Site 2500)

    Saint Petersburg, Leningradskaya Oblast', 196645

  • Saint-Petersburg Center for Prophylactic of AIDS and Infecti-Saint-Petersburg Center for Prophylact

    Saint Petersburg, Sankt-Peterburg, 190020

Other trials in Russia

Canada6 sites

  • Hamilton Health Sciences- Urgent Care Centre ( Site 1304)

    Hamilton, Ontario, L8S 1A4

  • Clinique de médecine Urbaine du Quartier Latin ( Site 1305)

    Montreal, Quebec, H2L 4E9

  • Clinique Medicale lActuel ( Site 1303)

    Montreal, Quebec, H2L 4P9

  • McGill University Health Centre ( Site 1306)

    Montreal, Quebec, H4A 3J1

  • Maple Leaf Research ( Site 1301)

    Toronto, Ontario, M5G 1K2

  • Toronto General Hospital ( Site 1300)

    Toronto, Ontario, M5G 2C4

Other trials in Canada

Chile6 sites

  • Biomedica Research Group-Infectology ( Site 1401)

    Santiago, Region M. de Santiago, 7500710

  • Pontificia Universidad Catolica de Chile ( Site 1407)

    Santiago, Region M. de Santiago, 8330034

  • Universidad de Chile - Hospital Clínico Universidad de Chile-Inmunologia Alergia y VIH ( Site 1400)

    Santiago, Region M. de Santiago, 8380420

  • Cardio Sur ( Site 1409)

    Santiago, Region M. de Santiago, 8910259

  • Clinica Universidad Catolica del Maule ( Site 1405)

    Talca, Maule Region, 3460000

  • Hospital hernan henriquez aravena de temuco-Unidad de Investigación Clínica ( Site 1403)

    Temuco, Araucania, 4781151

Other trials in Chile

Switzerland6 sites

  • University Hospital Basel-Infectiology ( Site 2802)

    Basel, Canton of Basel-City, 4056

  • Inselspital Bern-Inselspital Infektiologie ( Site 2803)

    Bern, 3010

  • Hôpitaux Universitaires de Genève (HUG)-Infectious Disease Department ( Site 2804)

    Geneva, Canton of Geneva, 1211

  • Ospedale Regionale di Lugano, Sede Civico-Servizio Malattie Infettive ( Site 2805)

    Lugano, Canton Ticino, 6903

  • Cantonal Hospital St.Gallen ( Site 2801)

    Sankt Gallen, Canton of St. Gallen, 9007

  • UniversitätsSpital Zürich ( Site 2800)

    Zurich, Canton of Zurich, 8091

Other trials in Switzerland

Argentina5 sites

  • Helios Salud ( Site 1002)

    Buenos Aires, C1141ACG

  • Fundación Huésped ( Site 1001)

    Buenos Aires, C1202ABB

  • Fundación IDEAA ( Site 1005)

    Buenos Aires, C1405CKC

  • Instituto Oulton ( Site 1004)

    Córdoba, Córdoba Province, X5000JJS

  • Instituto CAICI SRL ( Site 1003)

    Rosario, Santa Fe Province, S2000PBJ

Other trials in Argentina

Japan5 sites

  • Tokyo Metropolitan Komagome Hospital ( Site 2105)

    Bunkyo, Tokyo, 113-8677

  • National Hospital Organization Nagoya Medical Center ( Site 2103)

    Nagoya, Aichi-ken, 460-0001

  • National Hospital Organization - Osaka National Hospital - Institute For Clinical Research ( Site 21

    Osaka, 540-0006

  • Tokyo Medical University Hospital ( Site 2104)

    Shinjuku-ku, Tokyo, 160-0023

  • Center Hospital of the National Center for Global Health and Medicine ( Site 2101)

    Shinjyuku-ku, Tokyo, 162-8655

Other trials in Japan

United Kingdom5 sites

  • Southmead Hospital ( Site 3003)

    Bristol, Bristol, City of, BS10 5NB

  • North Manchester General Hospital ( Site 3005)

    Crumpsall, Manchester, M8 5RB

  • University Hospitals Sussex NHS Foundation Trust ( Site 3004)

    East Sussex, Brighton And Hove, BN2 1ES

  • Royal Free Hospital ( Site 3002)

    London, England, NW32QG

  • King's College Hospital ( Site 3001)

    London, London, City of, SE5 9RL

Other trials in United Kingdom

Australia4 sites

  • Holdsworth House Medical Practice - Brisbane ( Site 1101)

    Brisbane, Queensland, 4006

  • Holdsworth House Medical Practice ( Site 1100)

    Darlinghurst, New South Wales, 2010

  • Prahran Market Clinic ( Site 1102)

    Melbourne, Victoria, 3181

  • St Vincent's Hospital-IBAC ( Site 1103)

    Sydney, New South Wales, 2010

Other trials in Australia

Israel4 sites

  • Rambam Health Care Campus-Institute of Allergy, Clinical Immunology, ( Site 1901)

    Haifa, 3109601

  • Hadassah Medical Center-Infecious Disease ( Site 1902)

    Jerusalem, 9112001

  • Sheba Medical Center-HIV unit ( Site 1903)

    Ramat Gan, 5262100

  • Sourasky Medical Center ( Site 1904)

    Tel Aviv, 64239

Other trials in Israel

Colombia3 sites

  • Hospital Universitario San Ignacio-Infectious ( Site 1501)

    Bogotá, Bogota D.C., 110231

  • Clinica Colsanitas S.A, Sede Clínica Universitaria Colombia ( Site 1502)

    Bogotá, Bogota D.C., 111321

  • Fundación Valle del Lili ( Site 1500)

    Cali, Valle del Cauca Department, 760032

Other trials in Colombia

Puerto Rico2 sites

  • Clinical Research Puerto Rico ( Site 2400)

    San Juan, 00909

  • HOPE Clinical Research ( Site 2401)

    San Juan, 00909

Other trials in Puerto Rico

New Zealand1 site

  • Christchurch Hospital-Infectious Diseases ( Site 2200)

    Christchurch, Canterbury, 8011

Other trials in New Zealand

Taiwan1 site

  • Kaohsiung Veterans General Hospital ( Site 2901)

    Kaohsiung City, 81362

Other trials in Taiwan

About this study

Official title: A Phase 3 Open-label Clinical Study of Doravirine/Islatravir (DOR/ISL [100 mg/0.25 mg]) Once Daily for the Treatment of HIV-1 Infection in Participants Who Previously Received DOR/ISL (100 mg/0.75 mg) QD in a Phase 3 Clinical Study

The purpose of this study is to evaluate the safety and tolerability of DOR/ISL in adult participants with HIV-1 who had been previously treated with DOR/ISL in earlier clinical studies. There are no formal hypotheses to be tested in this study.

Conditions
HIV Infection
Being tested
DOR/ISL
Medical subject headings
HIV Infections

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • DOR/ISLDrug

    Also called MK-8591A, Doravirine/islatravir

    FDC tablet of 100 mg doravirine (DOR)/0.25 mg islatravir (ISL) taken once daily

Study groups in NCT05766501
Study groupRoleWhat they receive
DOR/ISLExperimentalParticipants will receive fixed dose combination (FDC) tablet of DOR/ISL (100 mg/0.25 mg) taken once daily (QD) orally from Day 1 to Week 96. After Week 96, eligible participants may continue on DOR/ISL until week 240 or until DOR/ISL becomes commercially accessible, whichever comes first.
Receives: Drug: DOR/ISL

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Percentage of Participants with One or More Adverse Event (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. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The percentage of participants who experience an AE through Week 96 will be presented.

    Measured: Up to 96 Weeks

  2. Percentage of participants who Discontinue Study Intervention Due to an 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. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The percentage of participants who discontinue study intervention due to an AE through Week 96 will be presented.

    Measured: Up to 96 Weeks

Secondary outcomes (4)

  1. Percentage of Participants with HIV-1 Ribonucleic Acid (RNA) ≥50 copies/mL at Week 96

    The percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 96 will be reported.

    Measured: Week 96

  2. Percentage of Participants with HIV-1 RNA <50 copies/mL at Week 96

    The percentage of participants with HIV-1 RNA <50 copies/mL at Week 96 will be reported.

    Measured: Week 96

  3. Percentage of Participants with HIV-1 RNA <200 copies/mL at Week 96

    The percentage of participants with HIV-1 RNA <200 copies/mL at Week 96 will be reported

    Measured: Week 96

  4. Percentage of Participants with Evidence of Viral Drug Resistance-Associated Substitutions

    Viral drug resistance is defined as participants with HIV-1 RNA ≥400 copies/mL and/or genotypic or phenotypic data showing evidence of resistance to the study intervention. The percentage of participants who demonstrate drug resistance through Week 96 will be presented.

    Measured: Up to Week 96

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted13 Mar 2023
  2. Study start17 Mar 2023
  3. Primary completion16 Oct 2025
  4. Study completion6 Sep 2028 (estimated)

Resources

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 3
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
641 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05766501
Sponsor's protocol ID
8591A-054
Other IDs
MK-8591A-054, 2022-502126-40-00, jRCT2051230002, U1111-1283-3863
Status last verified
Dec 2025
First submitted
1 Mar 2023
Last updated
17 Dec 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Publications

  • Diamond TL, Grandhi A, Fuszard M, Xu Y, Nwoke U, Zhang Y, Klopfer SO, Eves K, Benner J, Li M, Greaves W, Lahoulou R, Kim J, Fox MC, Asante-Appiah E. Switching to Daily Doravirine/Islatravir (100/0.25 mg) Maintains Viral Suppression Through Week 48 Despite Baseline Non-Nucleoside Reverse Transcriptase Inhibitor Resistance-Associated Mutations or M184I/V in Proviral DNA. J Infect Dis. 2026 May 29:jiag257. doi: 10.1093/infdis/jiag257. Online ahead of print.

    PubMed 42213454

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing DOR/ISL in people with HIV Infection, run by Merck Sharp & Dohme LLC at 95 sites in 15 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 1 inclusion and 3 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: under way, not looking for participants, as of the sponsor's last update on 17 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 95 sites in United States, South Africa, Russia, Canada, Chile and 10 more countries. 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. 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

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?

Percentage of Participants with One or More Adverse Event (AE) (time frame: Up to 96 Weeks). The study lists 2 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 NCT05766501, which also lists 1 linked publication.

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 17 Dec 2025.

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