Trizivir (Abacavir/Lamivudine/Zidovudine) plus Lopinavir/Ritonavir Induction Therapy Followed by Trizivir-Alone Maintenance for HIV-1-Infected Patients: A 96-Week Pilot Treatment Simplification Study

Objective: The purpose of this study was to investigate whether switching HIV-infected patients stabilized on Trizivir (abacavir 300 mg/lamivudine 150 mg/zidovudine 300 mg) plus lopinavir/ritonavir 400 mg/100mg twice daily to Trizivir alone affects clinical efficacy and tolerability. Methods: This phase 4, open-label, pilot study was conducted over 96 weeks in 23 antiretroviral-naïve, HIV-infected patients. Initially, these patients received induction therapy with Trizivir plus lopinavir/ritonavir 400 mg/100mg twice daily. Patients who achieved a viral load < 50 copies/mL at week 36 or 44 started maintenance therapy with Trizivir alone at week 48 and continued this regimen through week 96. Results: The study population was a median of 37 years of age, predominantly male (78%) and African American (61%, with 39% Caucasians), and had a baseline mean viral load of 5.45 log10 copies/mL and CD4+ count of 232 cells/mm3. Nineteen patients completed induction; of the four who did not, three were lost to follow-up and one withdrew due to gastrointestinal adverse events. In 14 induction completers who had viral load measurements taken at week 48, intent-to-treat: observed analysis showed a week 48 viral load < 400 copies/mL attained in 100% (14/14) and <50 copies/mL attained in 71% (10/14). Median week 48 CD4+ cell count was 192 cells/mm3 higher than the baseline count. Twelve patients completed the subsequent 48-week Trizivir-alone maintenance phase, of whom 11 (92%) achieved viral loads of both <400 and <50 copies/mL at week 96. Median week 96 CD4+ cell count was 208 cells/mm3 above baseline. Trizivir-only maintenance was associated with fewer adverse events than the Trizivir-lopinavir/ritonavir induction phase and with improvement in total cholesterol, LDL-cholesterol, and triglycerides. Conclusions: Trizivir-alone maintenance after Trizivir-lopinavir/ritonavir induction maintained virologic and CD4+ cell response, and was associated with an improved adverse event and lipid profile.