Atazanavir/Ritonavir Maintenance Therapy

• Grade 3 and 4 laboratory abnormalities and signs and symptoms
• time to treatment discontinuation because of toxicity or intolerance
• virologic failure at or before Week 54
• viral load determined by modified ultrasensitive RT-PCR assay
• minor PI variants at virologic failure
• total cholesterol, high-density lipoprotein (HDL) cholesterol, calculated low-density lipoprotein (LDL) cholesterol, and triglycerides
• CD4 cell count and percentages at Weeks 30 and 54
• self-reported adherence scores
• plasma drug levels characterized by Cmin and AUC
• detectable viral load in the genital compartment at Week 30

Long-term side effects, the expense of medications, and the difficulty of taking medications continuously for long periods of time are all problems with complicated anti-HIV drug regimens. The purpose of this study is to determine whether two drugs, atazanavir (ATV) and ritonavir (RTV), will control HIV infection when taken together without any other anti-HIV drugs after 48 weeks of viral suppression.

Hypothesis: Simplified maintenance therapy with ATV and RTV alone after virologic suppression does not markedly increase the risk of virologic failure.

The expense, difficulty, and long-term adverse events associated with sustained adherence to combination antiretroviral therapy emphasize the need for simpler, alternative treatment strategies for HIV infection. Studies have shown that single protease inhibitor (PI) maintenance therapy may provide sufficient virologic suppression while reducing the risk of nucleoside reverse transcriptase inhibitor (NRTI)-associated metabolic complications. However, it is not known whether ritonavir-boosted atazanavir (ATV/RTV) maintenance therapy would be effective in controlling HIV replication in the genital compartments and whether viral load testing by blood collection would be effective in detecting elevated levels of HIV in the genital compartments. This study will determine whether simplified maintenance therapy with ATV/RTV after 48-week virologic suppression will increase the likelihood of virologic failure.

This study will last 54 weeks. Participants will undergo an electrocardiogram (EKG) at screening. At study start, participants will switch from their current PIs to ATV/RTV and stay on their current NRTIs until Week 6, when they will discontinue their NRTIs and remain on a maintenance regimen of ATV/RTV alone for the duration of the study. Study visits will take place at Weeks 3 and 6, then every 4 weeks until Week 30, then every 8 weeks until the end of the study at Week 54. Medication assessment, physical exam, and blood work will occur at each study visit. At Week 30, viral load will be measured in the genital secretions of both male and female study participants.

• Drug: Atazanavir
• Drug: Ritonavir

• Swindells S, DiRienzo AG, Wilkin T, Fletcher CV, Margolis DM, Thal GD, Godfrey C, Bastow B, Ray MG, Wang H, Coombs RW, McKinnon J, Mellors JW; AIDS Clinical Trials Group 5201 Study Team. Regimen simplification to atazanavir-ritonavir alone as maintenance antiretroviral therapy after sustained virologic suppression. JAMA. 2006 Aug 16;296(7):806-14.
• Havlir DV, Marschner IC, Hirsch MS, Collier AC, Tebas P, Bassett RL, Ioannidis JP, Holohan MK, Leavitt R, Boone G, Richman DD. Maintenance antiretroviral therapies in HIV infected patients with undetectable plasma HIV RNA after triple-drug therapy. AIDS Clinical Trials Group Study 343 Team. N Engl J Med. 1998 Oct 29;339(18):1261-8.
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• Kahlert C, Hupfer M, Wagels T, Bueche D, Fierz W, Walker UA, Vernazza PL. Ritonavir boosted indinavir treatment as a simplified maintenance "mono"-therapy for HIV infection. AIDS. 2004 Apr 9;18(6):955-7. No abstract available.
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• Wilkin TJ, McKinnon JE, DiRienzo AG, Mollan K, Fletcher CV, Margolis DM, Bastow B, Thal G, Woodward W, Godfrey C, Wiegand A, Maldarelli F, Palmer S, Coffin JM, Mellors JW, Swindells S. Regimen simplification to atazanavir-ritonavir alone as maintenance antiretroviral therapy: final 48-week clinical and virologic outcomes. J Infect Dis. 2009 Mar 15;199(6):866-71.

Inclusion Criteria:

• HIV infected
• On first antiretroviral regimen, including at least 2 NRTIs and 1 PI, for at least 48 weeks immediately prior to study entry
• CD4 count of 250 cells/mm3 or greater
• Viral load less than 50 copies/ml within 30 days prior to entry
• Willing to use acceptable methods of contraception

Exclusion Criteria:

• Current or prior use of an NNRTI
• Certain PI mutations
• Hepatitis B infection within 90 days prior to study entry
• Certain therapies or medications within 30 days prior to study entry
• Heartbeat abnormalities or symptoms potentially related to heart block, such as unexplained fainting, dizziness, or palpitations, occurring within 180 days prior to study entry
• Drug or alcohol use or dependence that would interfere with adherence to the study requirements
• Serious illness requiring systemic treatment or hospitalization until the participant either completes therapy or has been clinically stable on therapy for at least 14 days prior to study entry
• Allergy or sensitivity to study medications or their formulations
• Current involuntarily incarceration for treatment of either a mental or physical illness
• Treatment for an active AIDS-defining opportunistic infection within 30 days prior to screening
• Pregnant or breastfeeding