The Journal of antimicrobial chemotherapy 2017 12 05() doi 10.1093/jac/dkx417
Darunavir/ritonavir is a potent PI with a high genetic barrier and pharmacological robustness favourably investigated as monotherapy. Whether darunavir could be dose reduced in the context of monotherapy deserves investigation.
Patients with HIV suppressed viraemia (plasma viral load <50 copies/mL for 12 months) under ART who had switched to darunavir/ritonavir monotherapy at 600/100 mg/day between 2013 and 2015 were included in this observational 48 week single-centre study. The primary outcome was the proportion of patients with virological success (defined as plasma viral load <50 copies/mL) at week 24. Secondary outcomes included treatment strategy success and resistance. Results
Thirty-one patients were included with the following baseline characteristics [median (IQR)]: age 52 years (47-57), CD4+ 649 cells/mm3 (463-813), ART duration 16.3 years (9.2-22.3), nadir CD4+ 195 cells/mm3 (144-261) and duration of HIV suppression 7.8 years (4.8-9.7). Prior to switch, ART consisted of PI monotherapy for 28 of 31 patients [darunavir/ritonavir 800/100 mg/day (n = 26), lopinavir/ritonavir (n = 1) and atazanavir/ritonavir (n = 1)] and a triple drug regimen for 3 of 31 patients. Within the 48 weeks of follow-up, no virological failure occurred and two patients discontinued 600/100 mg of darunavir/ritonavir due to side effects at week 16 and 40, leading to a virological suppression rate of 100% (95% CI = 89-100) at weeks 24 and 48. Strategy success rates were 96.8% (95% CI = 83.3-99.9) at week 24 and 93.5% (95% CI = 78.6-99.2) at week 48. Median (IQR) Ctrough values of 800/100 mg of darunavir/ritonavir and 600/100 mg of darunavir/ritonavir were 1537 ng/mL (1286-1724) and 1255 ng/mL (873-2161), respectively.
A lower dose of darunavir/ritonavir used as monotherapy (600/100 mg/day) was highly effective in virologically suppressed HIV-infected patients. Further studies are needed to confirm these data.