Other Names: ACH-126443, L-F-D4C
Drug Class: Nucleoside Reverse Transcriptase Inhibitors

What is elvucitabine?

Elvucitabine is an investigational drug for the treatment of HIV infection.

• Elvucitabine is an investigational anti-HIV drug included in the nucleoside reverse transcriptase inhibitor (NRTI) drug class.
• NRTIs prevent HIV from replicating by blocking reverse transcriptase, an HIV enzyme. By preventing HIV from replicating, NRTIs reduce the amount of HIV in the blood.
• Elvucitabine is similar in chemical structure to the FDA-approved NRTIs lamivudine (brand name: Epivir) and emtricitabine (brand name: Emtriva).
• In vitro studies have shown that elvucitabine may be active against certain NRTI-resistant HIV.
• In vitro studies have shown that elvucitabine is active against hepatitis B virus (HBV).

What is an investigational drug?

An investigational drug is one that is under study and is not approved by the U.S. Food and Drug Administration (FDA) for sale in the United States. Medical research studies are conducted to evaluate the safety and effectiveness of an investigational drug. These research studies are also called clinical trials. Once an investigational drug has been proven safe and effective in clinical trials, FDA may approve the drug for sale in the United States.

How are clinical trials of investigational drugs conducted?

Clinical trials are conducted in "phases." Each phase has a different purpose and helps researchers answer different questions.

• Phase I trials: Researchers test an investigational drug in a small group of people (20-80) for the first time. The purpose is to evaluate its safety and identify side effects.
• Phase II trials: The investigational drug is administered to a larger group of people (100-300) to determine its effectiveness and to further evaluate its safety.
• Phase III trials: The investigational drug is administered to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it with standard or equivalent treatments, and collect information that will allow the investigational drug to be used safely.

An investigational drug must be proven safe and effective in a Phase III clinical trial to be considered for traditional approval by the FDA for sale in the United States. Some drugs go through the FDA's accelerated approval process and are approved before a Phase III clinical trial is complete. After a drug is approved by the FDA and made available to the public, researchers track its safety in Phase IV trials to seek more information about the drug's risks, benefits, and optimal use.

In what phase of testing is elvucitabine?

Elvucitabine has been studied in Phase II clinical trials.

What have recent studies shown about elvucitabine?

In a Phase II study, elvucitabine taken once daily was compared with lamivudine in HIV-infected, treatment-naive participants. All study participants also received tenofovir disoproxil fumarate (brand name: Viread) and efavirenz (brand name: Sustiva) as part of their background regimens. (A background regimen is a combination of drugs that are not being studied as the investigational drug[s] in the clinical trial, but are being given to help control a participant's HIV infection.)

In this study, using an as-treated analysis (looking at data from the participants who completed the full length of the trial), elvucitabine proved as effective as lamivudine, with similar numbers of patients in both treatment arms experiencing reductions in viral load after 96 weeks. However, using an intention-to-treat anaylsis (looking at data from all study participants, including those who discontinued the study), fewer participants in the elvucitabine treatment arm had a virologic response than in the lamivudine arm. This difference is because of the higher proportion of study drop-outs in the elvucitabine arm than in the lamivudine arm. In terms of safety, elvucitabine was comparable to lamivudine. One participant discontinued elvucitabine due to a drug-related side effect.

An additional Phase II study of elvucitabine in HIV-infected, treatment-experienced adults with the M184V HIV resistance mutation was completed.

More information on testing of elvucitabine is available from these sources:

• Elvucitabine study results presented at the 17^th Conference on Retroviruses and Opportunistic Infections, February 16-19, 2010:
  • DeJesus E, Saple D, Morales-Ramirez J, et al. Elvucitabine vs Lamivudine with Tenofovir and Efavirenz in Antiretroviral-Treatment-Naive HIV-1 Infected Patients: 96 Week Final Results
• PubMed abstract:
  • Dutschman GE, Bridges EG, Liu SH, et al. Metabolism of 2',3'-dideoxy-2',3'-didehydro-beta-L(-)-5-fluorocytidine and its activity in combination with clinically approved anti-human immunodeficiency virus beta-D(+) nucleoside analogs in vitro. Antimicrob Agents Chemother. 1998 Jul;42(7):1799-804.
• Elvucitabine study of treatment-experienced adults with M184V viral mutation from ClinicalTrials.gov:
  • Study of Once Daily Elvucitabine Versus Lamivudine in Subjects With a Documented M184V Mutation (Resistance)

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

More information about elvucitabine-related research studies is available from the AIDSinfo database of ClinicalTrials.gov study summaries. Click on the title of any trial in the list to see the ClinicalTrials.gov trial summary and more information about the study.

I am interested in participating in a clinical trial of elvucitabine. How can I find more information about participating in a clinical trial of an investigational drug?

Clinical trials involve benefits and risks. Before deciding to participate in a clinical trial, talk to your health care provider. For more information on participating in clinical trials, visit NIH Clinical Research Trials and You.