A 24-week pilot study of dual maintenance therapy with raltegravir plus lamivudine.

Background: There is an increasing interest in two-drug regimens. We hypothesized that maintenance therapy with raltegravir and lamivudine would keep HIV-1 suppressed and be well tolerated. Methods: Virally suppressed HIV-1-infected adults without previous viral failures or known resistance mutations to integrase inhibitors or 3TC/FTC or chronic hepatitis B were randomized 2 : 1 to switch to fixed-dose combination 150 mg lamivudine/300 mg raltegravir twice daily or to continue therapy. Primary outcome was the proportion of patients free of therapeutic failure (defined as viral failure, change in treatment for any reason, consent withdrawal, loss to follow-up or death) at week 24. Secondary outcomes were changes in laboratory, body composition, sleep quality, adherence, and adverse effects. Results: There were 75 patients included: men 78%; median age 50 years; median CD4(+) 622/mu l. At week 24, 7 (9%) patients had therapeutic failure: raltegravir and lamivudine 2 (4%) vs. control 5 (20%). The difference in proportions of therapeutic failures raltegravir and lamivudine minus control was -0.159 (95% confidence interval: -0.353 to -0.012). There was a trend to more weight gain with raltegravir and lamivudine, but no significant changes in other secondary outcomes. Sixty-four percent of patients in each arm had at least one adverse effect. Two (6%) patients in control arm and 4 (7%) patients in raltegravir and lamivudine arm had severe adverse effects. Conclusion: This pilot study suggests that switching to raltegravir along with lamivudine in patients with viral suppression maintains efficacy and is well tolerated. A larger study of longer duration is required to confirm these findings.