Drug Database: Alimatravir

What is alimatravir?What is alimatravir?

What is alimatravir?

Alimatravir is an investigational drug that is being studied to prevent HIV.^3,4

Alimatravir belongs to a group of HIV drugs called nucleoside reverse transcriptase translocation inhibitors (NRTTIs). NRTTIs use several different methods to block an HIV enzyme called reverse transcriptase. By blocking reverse transcriptase, NNRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body.^5,6

To learn about how investigational drugs are tested during clinical trials, read the HIVinfo What is an Investigational HIV Drug? and HIV and AIDS Clinical Trials fact sheets.

Select clinical trials of alimatravirSelect clinical trials of alimatravir

Select clinical trials of alimatravir

Study Names: MK-8527-007; NCT06045507

Phase: 2a
Status: This study has been completed.
Locations: United States, Israel, and South Africa
Purpose: The purpose of this study was to evaluate alimatravir taken once monthly in participants who had a low likelihood of getting HIV. Researchers looked at how the body handles alimatravir and whether alimatravir is safe and easy to tolerate.⁷
Selected Study Results: Results presented at the International AIDS Society Conference on HIV Science (IAS 2025) and showed that alimatravir, at all doses studied, was generally safe and well tolerated. The amount of alimatravir in the body increased in a predictable manner as the dose was increased.⁸

Study Names: EXPrESSIVE-10; MK-8527-010; NCT07071623

Phase: 3
Status: This study is currently recruiting participants.
Locations: Kenya, South Africa, and Uganda
Purpose: The purpose of this study is to see whether alimatravir taken once monthly is safe and works to prevent HIV in sexually active women in sub-Saharan Africa.^4,9

Study Names: EXPrESSIVE-11; MK-8527-011; NCT07044297

Phase: 3
Status: This study is currently recruiting participants.
Locations: Multiple countries, including United States
Purpose: The purpose of this study is to see whether alimatravir taken once monthly is safe and works to prevent HIV in sexually active people who could benefit from pre-exposure prophylaxis (PrEP).^3,9

For more details on the studies listed above, see the Health Professional version of this drug summary.

Multiple Phase 1 studies looking at alimatravir have been completed or are ongoing or planned. Some of these studies are described below.

• MK-8527-009 (NCT06580587) was a study that looked at the amount of alimatravir that enters breast milk in healthy women who are lactating (producing milk). This study has been completed.¹⁰
• MK‐8527‐001 and MK‐8527‐003 (Eudra CT: 2016‐004647‐36 and 2018‐000846‐20) were studies that looked at how the body handles alimatravir and whether alimatravir is safe in adults without HIV. These studies have been completed, and results are available from Clin Transl Sci (2025).¹¹

What side effects might alimatravir cause?What side effects might alimatravir cause?

What side effects might alimatravir cause?

One goal of HIV research is to identify safe new drugs that have fewer side effects. In the MK-8527-007 (NCT06045507) study discussed under the previous section, the safety profile of alimatravir, at all doses studied, was similar to that of placebo. Most of the drug-related side effects that occurred were mild or moderate and went away during the study. One participant had a serious drug-related side effect of spontaneous abortion. Two participants discontinued alimatravir because of a drug-related side effect—one participant due to mild decreases in CD4 and/or lymphocyte counts and another participant due to moderate numbness or loss of sensation.^7,8

Because alimatravir is still being studied, information on possible side effects of the drug is not complete. As testing of alimatravir continues, additional information on possible side effects will be gathered.

Where can I get more information about clinical trials studying alimatravir?Where can I get more information about clinical trials studying alimatravir?

Where can I get more information about clinical trials studying alimatravir?

More information about alimatravir-related research studies is available from ClinicalTrials.gov. (The ClinicalTrials.gov search can be modified so that you can get results that better match your interests.)

Some clinical trials may be looking for volunteer participants. Your health care provider can help you decide whether participating in a clinical trial is right for you. For more information, visit NIH Clinical Research Trials and You.

ReferencesReferences

References

1. National Center for Biotechnology Information. PubChem Compound Summary for CID 118389446. Accessed August 26, 2026
2. Merck website. Our pipeline at a glance. Accessed August 26, 2026
3. Merck Sharp & Dohme LLC. A Phase 3, randomized, active-controlled, double-blind clinical study to evaluate the efficacy and safety of MK-8527 oral once-monthly as HIV-1 preexposure prophylaxis. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on June 26, 2025. NLM Identifier: NCT07044297. Accessed August 26, 2026
4. Merck Sharp & Dohme LLC. A Phase 3, randomized, active-controlled, double-blind clinical study to evaluate the efficacy and safety of MK-8527 oral once-monthly as HIV-1 preexposure prophylaxis in women. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on July 8, 2025. NLM Identifier: NCT07071623. Accessed August 26, 2026
5. Raheem IT, Girijavallabhan V, Fillgrove KL, et al. MK-8527 is a novel inhibitor of HIV-1 reverse transcriptase translocation with potential for extended-duration dosing. PLOS Biol. 2025;23(8):e3003308. doi:10.1371/journal.pbio.3003308. Accessed August 26, 2026
6. Raheem I, Fillgrove K S, O’Donnell G, et al. Discovery of MK-8527: a long-acting HIV-1 nucleoside reverse transcriptase translocation inhibitor. Poster presented at: Conference on Retroviruses and Opportunistic Infections (CROI); March 3-6, 2024; Denver, CO. Poster 638. Accessed August 26, 2026
7. Merck Sharp & Dohme LLC. A Phase 2a, double-blind, placebo-controlled study to evaluate the safety, tolerability, and pharmacokinetics of oral MK-8527 once monthly in participants at low-risk for HIV-1 infection. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on September 13, 2023. NLM Identifier: NCT06045507. Accessed August 26, 2026
8. Mayer K, Kotze P, Lombaard J, et al. Safety and pharmacokinetics of MK-8527 oral once-monthly: a Phase 2 study in adults at low risk of HIV-1 exposure. IAS Conference on HIV Science; July 13-17, 2025; Kigali, Rwanda. Conference reports for National AIDS Treatment Advocacy Project (NATAP); 2025. Accessed August 26, 2026
9. Merck: Press release, dated July 14, 2025. Merck to initiate Phase 3 trials for investigational once-monthly HIV prevention pill. Accessed August 26, 2026
10. Merck Sharp & Dohme LLC. A clinical study to evaluate the breast milk, plasma and whole blood pharmacokinetics of MK-8527 in healthy lactating female participants. In: ClinicalTrials.gov. Bethesda (MD): National Library of Medicine (US). Registered on August 28, 2024. NLM Identifier: NCT06580587. Accessed August 26, 2026
11. Gillespie G, Carstens RP, Zang X, et al. Safety and pharmacokinetics of MK‐8527 in adults without HIV. Clin Transl Sci. 2025;18(9):e70331. doi:10.1111/cts.70331. Accessed August 26, 2026