Pharmacokinetics and Safety of Darunavir/Ritonavir in HIV-Infected Pregnant Women.

The dosage of darunavir/ritonavir is 800/100 mg once daily for treatment-naive patients or treatment-experienced patients with no prior darunavir resistance associated mutations, and 600/100 mg twice daily for treatment-experienced patients with one or more darunavir resistance associated mutations. Results from the five available pharmacokinetic studies show reductions in total darunavir plasma concentrations of between 20-50% during the third trimester of pregnancy. The unbound darunavir concentrations have been measured only in subsets of patients in two of the five pharmacokinetic studies. The unbound concentrations were 11% higher during pregnancy in one study of the 600/100 mg twice-daily dosage, and 13-38% lower during pregnancy for the 800/100 mg once-daily dosage. Ratios of darunavir concentration in cord blood compared to maternal plasma are in the range of 0.11-0.18, suggesting that darunavir does not have high trans-placental penetration. Despite the decrease in exposure, the darunavir/ritonavir 800/100 mg once-daily regimen in HIV-positive pregnant women in combination with background antiretroviral therapy has been effective in preventing mother-to-child transmission in the studies included in this review. Among the 137 infants born across the five studies, there was one case of mother-to-child transmission, which was in a mother taking the 600/100 mg twice-daily dose but who had documented poor adherence to treatment.

Analysis of neurocognitive function and CNS endpoints in the PROTEA trial: darunavir/ritonavir with or without nucleoside analogues.

INTRODUCTION: During treatment with protease inhibitor monotherapy, the number of antiretrovirals with therapeutic concentrations in the cerebrospinal fluid (CSF) is lower, compared to standard triple therapy. However, the clinical consequences are unclear. METHODS: A total of 273 patients with HIV RNA <50 copies/mL for over 24 weeks on current antiretrovirals randomized to darunavir/ritonavir (DRV/r) 800/100 mg once-daily, either as monotherapy (n=137) or with 2NRTIs (n=136). Neurocognitive function was evaluated in all patients by the Hopkins Verbal Learning Tests, the Colour Trail Tests and the Grooved Pegboard Test at screening, baseline and at Week 48. A global neurocognitive score (NPZ-5) was derived by averaging the standardized results of the five domains. In a central nervous system (CNS) sub-study (n=70), HIV RNA levels in the CNS were evaluated at baseline and Week 48. Clinical adverse events related to the CNS were collected at each visit. RESULTS: Patients were 83% male and 88% White, with median age 43 years. There were more patients with nadir CD4 count below 200 cells/µL in the DRV/r monotherapy arm (41/137, 30%) than the triple therapy arm (30/136, 22%). At Week 48, there was no difference between the treatment arms for the five combined domains of the neurocognitive score. At Week 48, the percentage of patients with an abnormal neurocognitive score among the five domains was 12.2% for DRV/r monotherapy and 14.9% for triple therapy. However, one patient on DRV/r monotherapy with a CD4 nadir of 17 cells/µL was hospitalized with HIV encephalomyelitis at Week 24, with HIV RNA 2500 copies/mL in the CSF and 125 copies/mL in the plasma. Symptoms resolved after intensification with high dose zidovudine. A second patient on DRV/r monotherapy with CD4 nadir of 166 cells/µL had a rise in HIV RNA in CSF from <40 copies/mL at baseline to 654 copies/mL at Week 48, with concurrent plasma HIV RNA of 77 copies/mL. CONCLUSIONS: In this study for patients with HIV RNA <50 copies/mL at baseline, there was no difference in neurocognitive function between the treatment arms. However two patients on PI monotherapy with CD4 nadir <200 cells/µL developed viraemia in both CSF and plasma, with one symptomatic case. DRV/r monotherapy should be used with caution in patients with nadir CD4 counts below 200 cells/µL.

Efficacy of PI monotherapy versus triple therapy for 1964 patients in 10 randomised trials.

INTRODUCTION: The efficacy of protease inhibitor monotherapy has been analyzed with different endpoints: initial HIV-1 RNA rebound, long-term HIV-1 RNA suppression after re-intensification, treatment-emergent drug resistance, neurocognitive testing and HIV-1 RNA in the cerebrospinal fluid (CSF). METHODS: A PUBMED search identified nine randomised trials of PI monotherapy versus triple therapy in patients with HIV RNA<50 copies/mL at baseline. RESULTS from the recently completed PROTEA trial were also included. The percentage of patients with HIV RNA suppression <50 copies/mL was analyzed using switch equals failure and intensification included endpoints (ITT). The number of patients with new drug resistance mutations, HIV RNA in the CSF or change in neurocognitive function was analyzed by treatment arm. RESULTS: Four trials evaluated darunavir/r monotherapy (n=785: MONET, MONOI, MONARCH, PROTEA), five evaluated lopinavir/r monotherapy (n=592: OK-04, KalMo, KALESOLO, KRETA, MOST) and one evaluated both (MRC PIVOT, n=587). HIV-1 RNA suppression rates tended to be lower on PI monotherapy than triple therapy in "switch equals failure" analysis (76% vs 82%), but not when the outcome of intensification was included (87% vs 85%). There were small numbers of patients taking PI monotherapy with detectable HIV-1 RNA in the CSF, in three trials: PROTEA (n=2), MONOI (n=2) and MOST (n=5), but only two cases of CSF viral escape (MONOI). In two trials, there was no difference in neurocognitive test results between PI monotherapy and triple therapy, based on z-scores from five domains (in PROTEA, mean change in NPZ-5 score=0.0 for DRV/r monotherapy vs -0.10 for triple therapy); similar results were observed in the MRC PIVOT trial. The risk of treatment emergent NRTI or PI resistance (Table 1) was 11/973 (1.1%) for patients on PI monotherapy, versus 7/991 (0.7%) for patients on triple therapy. CONCLUSIONS: In 10 randomised trials of 1964 patients with HIV-1 RNA suppression at baseline, PI monotherapy showed a higher risk of HIV RNA elevations, and small numbers with HIV RNA detectable in CSF and concomitantly in the plasma. However there was no increased risk of treatment-emergent drug resistance, neurocognitive endpoints were not different between the arms and HIV-1 RNA suppression rates after intensification were similar between PI monotherapy and triple therapy.