Compact Quadruple Therapy with the Lamivudine/Zidovudine Combination Tablet Plus Abacavir and Efavirenz, Followed by the Lamivudine/Zidovudine/Abacavir Triple Nucleoside Tablet Plus Efavirenz in Treatment-Naïve HIV-Infected Adults

Abstract

Purpose: To assess efficacy, safety, and adherence with compact quadruple therapy comprising one lamivudine 150-mg/zidovudine 300-mg tablet (COM) twice daily + one abacavir (ABC) 300-mg tablet twice daily + three efavirenz (EFV) 200-mg capsules at bedtime for 24 weeks, followed by one lamivudine 150-mg/zidovudine 300-mg/ABC 300-mg triple nucleoside tablet (TZV) twice daily + three EFV 200-mg capsules at bedtime for 24 weeks. Method: A pilot 48-week, prospective, open-label trial in which 38 antiretroviral-naïve HIV-infected adults (baseline median HIV-1 RNA 5.1 log₁₀ copies/mL, CD4+ cell count 285/μL) received the above treatment and were monitored regularly with respect to plasma HIV-1 RNA levels, CD4+ cell counts, T-cell receptor excision circles (TRECs), adherence, and adverse events. Results: At Week 48, intent-to-treat, switch-included analysis showed plasma HIV-1 RNA levels <400 copies/mL in 100% (29/29) of patients and <50 copies/mL in 93% (27/29); 59% of patients who achieved <50 copies/mL had <3 copies/mL (16/27). Similar virologic suppression was observed in patients with baseline HIV-1 RNA above or below 100,000 copies/mL. HIV-1 RNA and CD4+ cell counts changed from baseline by a median of –3.4 log₁₀ copies/mL and +172 cells/μL, respectively. One virologic failure occurred at Week 16. Median TRECs/100,000 peripheral blood lymphocytes increased 6-fold between baseline and Week 48. Median adherence rates were consistently 100% by self-report and 94% by pill count. Grade 2-4 treatment-related adverse events included dreams (16%), nausea (13%), decreased white cells (8%), dizziness (8%), sleep disorders (8%), and malaise and fatigue (8%). A suspected ABC hypersensitivity reaction occurred in 8% (3/38) of patients. Conclusion: COM/ABC/EFV or TZV/EFV produced potent, durable virologic suppression and immunologic benefits, was associated with high adherence rates, and was generally well tolerated.

Keywords:

• abacavir
• adherence
• Combivir
• efavirenz
• HIV infection
• immune reconstitution
• quadruple combination antiretroviral therapy
• Trizivir