The FDA has approved Dovato (ViiV), a fixed-dose combination of the integrase strand transfer inhibitor (INSTI) dolutegravir (Tivicay) and the nucleoside reverse transcriptase inhibitor (NRTI) lamivudine (Epivir, and generics), as a once-daily complete regimen for treatment of adults with HIV-1 infection who are antiretroviral-treatment naive and have no known substitutions associated with resistance to either drug. Dolutegravir/lamivudine is the first complete regimen to be approved by the FDA for initial treatment of HIV-1 infection that contains 2 rather than 3 antiretroviral drugs. Juluca, a fixed-dose combination of dolutegravir and the non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (Edurant), was approved in 2018 for treatment of adults with HIV-1 infection already taking a stable, suppressive antiretroviral regimen.

The FDA has approved three new once-daily fixed-dose antiretroviral drug combinations for treatment of HIV-1 infection. Symfi and Symfi Lo (Mylan) contain the non-nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz and the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine and tenofovir disoproxil fumarate (TDF) and were approved as complete antiretroviral regimens. Symfi Lo contains a lower dose of efavirenz than both Symfi and Atripla, a fixed-dose combination of efavirenz, TDF, and the NRTI emtricitabine that was approved in 2006. Cimduo (Mylan), which contains lamivudine and TDF, was approved for use in combination with other antiretroviral drugs. All three new products are marketed as less expensive alternatives to other available fixed-dose antiretroviral combinations (see Table 1).

The FDA has approved Juluca (ViiV Healthcare/Janssen), a fixed-dose combination of the integrase strand transfer inhibitor (INSTI) dolutegravir (Tivicay) and the non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (Edurant), as a once-daily complete regimen for treatment of adults with HIV-1 infection who do not have a history of treatment failure or known substitutions associated with resistance to either drug and have been taking a stable suppressive antiretroviral regimen for ≥6 months. Dolutegravir/rilpivirine is the first complete regimen to be approved for treatment of HIV-1 infection that contains 2 rather than 3 antiretroviral drugs and the first that does not include a nucleoside reverse transcriptase inhibitor (NRTI).

The FDA has approved Biktarvy (Gilead), a once-daily, fixed-dose combination of bictegravir, a new integrase strand transfer inhibitor (INSTI), and the nucleoside reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir alafenamide (TAF), for treatment of HIV-1 infection in adults. The new combination is indicated for use in patients who are antiretroviral-naive or who have been virologically suppressed on a stable antiretroviral regimen for ≥3 months with no history of treatment failure and no known substitutions associated with resistance to any component of the combination.

The FDA has approved Genvoya (Gilead), a fixed-dose combination of the integrase strand transfer inhibitor (INSTI) elvitegravir, the pharmacokinetic enhancer cobicistat, and the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir alafenamide, for treatment of HIV-1 infection in patients ≥12 years old. This is the first approval for tenofovir alafenamide (TAF), a tenofovir prodrug. Stribild, a fixed-dose combination of elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate (TDF), was approved in 2012.

The FDA has approved elvitegravir (Vitekta – Gilead), an integrase strand transfer inhibitor (INSTI), for use with a protease inhibitor (PI) plus ritonavir and other antiretroviral drugs for treatment of HIV-1 infection in treatment-experienced adults. Elvitegravir is also available in a fixed-dose combination (Stribild) with the pharmacokinetic enhancer cobicistat and the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir disoproxil fumarate (DF). A similar combination (Genvoya) that includes tenofovir alafenamide instead of tenofovir DF was recently approved by the FDA and will be reviewed in a future issue.

The FDA has approved Triumeq (Viiv Healthcare), a fixed-dose combination of the integrase strand transfer inhibitor (INSTI) dolutegravir and the nucleoside reverse transcriptase inhibitors (NRTIs) abacavir and lamivudine, for once-daily treatment of HIV-1 infection. Dolutegravir (Tivicay) was approved as a single agent in 2013.

Guidelines for use of antiretroviral agents continue to shift toward earlier and more continuous treatment, both to treat the patient and to prevent transmission of the disease to others. Resistance testing is now recommended when antiretroviral drugs are started. Increases in HIV RNA levels ("viral load") while on therapy may indicate development of drug resistance, requiring further testing and a change in the treatment regimen. Antiretroviral drugs interact with each other and with many other drugs; complete information on these interactions is available at www.aidsinfo.nih.gov.

New guidelines for use of antiretroviral agents have been published, with a shift towards earlier and more continuous treatment. HIV infection is treated with combinations of antiretroviral drugs depending on the patientÆs HIV RNA levels ("viral load") and CD4 cell count. Increases in viral load while on therapy may indicate development of drug resistance, requiring further testing and a change in treatment regimen. Resistance testing is now recommended when a patient is first seen, regardless of when therapy will be started.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment could also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

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The approval of new drugs and continuing concerns about drug toxicity and resistance have prompted new antiretroviral treatment guidelines. Resistance testing is not recommended before starting antiretroviral therapy. HIV infection is treated with combinations of antiretroviral drugs while monitoring the patient's HIV RNA levels ("viral load") and CD4 cell count. Increases in viral load while on therapy may indicate development of drug resistance requiring further testing and a change in treatment regimen.

The FDA has approved emtricitabine/tenofovir (Truvada - Gilead) and abacavir/lamivudine (Epzicom - GSK), two new fixed-dose combinations of nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), for once-daily use in treatment of HIV infection. Two other fixed-dose NRTI combinations were previously approved for twice-daily dosing. Dual NRTI therapy is generally used in either an NNRTI (non-nucleoside reverse transcriptase inhibitor)-based or a PI (protease inhibitor)-based regimen.

New drug approvals as well as continuing concerns about drug toxicity and the development of resistance have prompted new antiretroviral treatment guidelines (Panel on Clinical Practices for Treatment of HIV Infection, November 10, 2003, www.aidsinfo.nih.gov).

Atazanavir (Reyataz - Bristol-Myers Squibb), a new protease inhibitor (PI), and emtricitabine (Emtriva - Gilead), a nucleoside analogue reverse transcriptase inhibitor (NRTI) chemically similar to lamivudine, have been approved by the FDA for treatment of HIV-1 infection. Both are taken once daily, unlike most anti-HIV drugs.

Since the last Medical Letter article on this subject, continuing concerns about drug toxicity and development of resistance have prompted new antiretroviral treatment guidelines. The dosage and cost of drugs for HIV infection are listed in the table in this article.

Highly active anti-retroviral therapy (HAART) combining three or four drugs has become the standard of care for treatment of human immunodeficiency virus (HIV) infection

Amprenavir is the fifth protease inhibitor to become available for treatment of HIV infection. It was approved by the FDA for use with other drugs in the treatment of HIV-infected adults and children at least four years old.

Combination antiretroviral therapy including protease inhibitors has dramatically changed the treatment of HIV infection and the prognosis of those affected (Medical Letter Handbook of Antimicrobial Therapy, 1998, page 122). Due to limitations and failures with these drugs in many patients, however, three new drugs, none of them protease inhibitors, have rapidly come into wide use in clinical trials or 'expanded access' programs. They are abacavir (Ziagen - Glaxo Wellcome), adefovir (Preveon - Gilead) and efavirenz (Sustiva - DuPont). Efavirenz was recently approved for treatment of adults and children by the FDA. Abacavir has been recommended for approval by an FDA advisory committee.