Atazanavir and Lamivudine for Treatment Simplification

Pilot Study for the Evaluation of the Safety and the Feasibility of Treatment Simplification to Atazanavir/Ritonavir + Lamivudine in Patients Stably Treated With Two NRTIs + Atazanavir/Ritonavir With Optimal Virologic Response.

Objectives of the study:

1. To verify the safety of the study treatment, defined as the persistent control of the virus' replication at 48 weeks after the simplification to lamivudine + atazanavir with ritonavir.
2. To collect relevant information about the safety and the metabolic impact of this strategy in order to eventually design a non-inferiority randomized controlled trial for the evaluation of the safety and the efficacy of this strategy in the future.

Combined antiretroviral therapy has greatly improved the natural history of HIV infection/AIDS. Yet, it is associated with important short- and long- term side effects. In particular, nucleoside and nucleotide analogs may cause anemia, pancreatitis, mitochondrial dysfunction, lactic acidosis, lipoatrophy and reduction of renal function or of bone density.

Our study aims to verify the safety and efficacy of a simplification of a dual therapy (Lamivudine plus Atazanavir with Ritonavir), confiding on the potency and high genetic barrier of ritonavir-boosted agents.

Inclusion Criteria:

• Patients treated with the same regimen including 2NRTIs + ATV/r from at least 6 months
• Aged 18 years or older
• Who gave informed consent to the participation to the study
• With at least two viral load < 50 copies/mL in two consecutive determinations at least 3 months apart
• With CD4 cell count > 200 cells/μL and absence of any opportunistic infection or AIDS-related disease by one year at least

Exclusion Criteria:

• Pregnancy or breast feeding, desire of pregnancy in the short term
• Previous virological failure to antiretroviral therapy and/or previous exposure to mono- or dual therapies with reverse transcriptase nucleosidic analogues
• Patients with insufficient atazanavir plasma through concentration (lower than 0.23 μg/mL at 12th hour or 0.15 μg/mL at 24th hour) at screening and/or at baseline
• Patients with grade 3 or 4 laboratory abnormalities at screening (except for glucose or lipid serum levels and direct or indirect bilirubin)
• Concomitant treatment with antacids or proton-pump blockers or any other drug with known interactions or contraindications with the study medications