Monotherapy with Lopinavir/Ritonavir as maintenance after HIV-1 viral suppression: results of a 96-week randomized, controlled, open-label, pilot trial (KalMo study).

Background: Long-term adverse events and expenses associated with HAART have led to an interest in simplified therapy. Lopinavir/ritonavir monotherapy is attractive due to its potency and high genetic barrier. Methods: This is a 96-week, open-label, randomized study to assess the feasibility of using LPV/r monotherapy in patients with undetectable viral load after being on successful HAART for at least 6 months. Subjects were randomized (1:1) to either switch from HAART to LPV/r monotherapy or to maintain their previous regimen. Results: 60 patients were enrolled. Baseline characteristics were similar in both groups. At Week 96, by intention-to-treat analysis, 24/30 (80.0%) subjects in monotherapy group and 26/30 (86.6%) in the control group had a plasma viral load of <80 copies/mL. There was one virologic failure (defined as VL > 500 copies/mL) in each arm. Genotyping testing identified no resistance-associated mutations. The patient on the monotherapy arm was successfully resuppressed to <80 copies/mL after intensification with tenofovir and lamivudine. No statistically significant differences were found with regard to changes in CD4 counts. One subject in the monotherapy group discontinued due to diarrhea. Five subjects in the control group underwent regimen changes due to drug-related toxicities. Viral load from semen samples collected at the end of follow-up was undetectable on 14/15 patients randomized to monotherapy. Conclusions: Switching from various HAART regimens to LPV/r monotherapy in patients who were virologically suppressed and without a history of previous virologic failure was effective, safe, and well tolerated through 96 weeks.