Effectiveness of ritonavir-boosted protease inhibitor monotherapy in routine practice

Reference World Health Organization. Use of efavirenz during pregnancy: a public health perspective [Internet]; 2012 [cited 2012 Jul]. Available from: http://www.who.int/hiv/pub/treatment2/efavirenz/en/index.html#. DOI: [...]
Background: Recent trials have shown the potential benefits of ritonavir?boosted protease inhibitor (PI/r) monotherapy. As this alternative strategy has recently been included in European HIV treatment guidelines, its effectiveness needs to be assessed in routine practice. Methods: From 1st January to 31 December 2011, we identified all patients receiving a current PI/r monotherapy at a university?based hospital setting using the Diamm database system. Antiretroviral?naïve patients who directly initiated PI/r monotherapy were excluded. Patients who continued PI/r monotherapy after ending participation in a clinical trial were also included. We performed a retrospective, descriptive analysis of demographic, clinical and therapeutic characteristics of these patients. For biological variables, the last available value in 2011 was retained. Results: In 2011, among 3140 antiretroviral?treated patients in our department, 107 (3.4%) received PI/r monotherapy (lopinavir/r n = 58, darunavir/r n= 49). Of them, 30 (28%) started during 2011 and 31 (29%) continued after a prior trial. Two patients switched to DRV/r due to intolerance. Eighty?eight percent were male and median age at initiation was 45 years. The median time from starting multitherapy and switching to monotherapy was 30 months (range 2?117). At PI/r monotherapy initiation, median CD4 count was 567 cells/mm[sup.3] and HIV RNA was below 50 copies/mL in 90% of patients. The median duration under PI/r monotherapy was 25.4 months (range 0.5?93). At the end of follow?up, median CD4 count was 643 cells/mm[sup.3] and HIV RNA was below 50 copies/mL in 89% of cases. During 2011, 11 patients discontinued PI/r monotherapy, of whom 8 presented viral rebound. Only one patient exhibited major protease mutations. All these 8 patients achieved an undetectable viral load 3 months after therapeutic intensification. Conclusion: This descriptive analysis shows that PI/r monotherapy in routine practice could be considered as an alternative and successful maintenance strategy, especially among patients who achieved an undetectable viral load while undergoing prior multitherapy.