Experiences with the use of rilpivirine at a Danish HIV clinic

Sanne Jespersen1, Carsten Schade Larsen1.
Affiliates: 1Department of Infectious Diseases, Aarhus University Hospital, Denmark.

Background
The non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (RPV), combined with other antiretroviral drugs, is approved for use in antiretroviral treatment (ART) naïve, HIV-1-infected adults with an HIV viral load below 100.000 copies/ml. A single tablet, once-daily regimen containing RPV, emtricitabine and tenofovir disoproxil fumarate has been available in Denmark since 2012, but experiences with this treatment is still scarce, especially when used in treatment-experienced patients. The aim of this study was to describe the use of RPV at a Danish HIV clinic.

Methods
Follow-up study among all patients in care at the outpatient HIV clinic, Aarhus University Hospital, Denmark. We searched the combined clinical decision support tool and database InfCare HIV for all patients on past or present RPV treatment by August 1, 2014. We describe baseline characteristics, reason for prescribing RPV, reason for discontinuing RPV, HIV viral load during treatment, and development of resistance.

Results
By August 1, 2014, 584 HIV-1 infected patients were on ART at the clinic. Among those, 43 patients (7.4%) received a RPV based treatment regimen at present or in the past with a median time on RPV of 532 days, interquartile range (IQR) 493-709 days. Thirty-eight men (88%) and five women (12%) with a median age of 49 years (IQR 41-53) were included in the study. Thirty-nine of 43 patients (91%) receiving RPV were of Caucasian ethnicity. Only three patients (7.0%) were ART naïve when starting RPV and all had HIV viral load below 100.000 copies/ml. For the 40 treatment-experienced patients, the main reason for switching to RPV was neuropsychiatric adverse events of efavirenz, which was reported by 22 patients (56.4%). Four patients (9.3%) were not virally suppressed at time of switching to RPV but all had HIV viral load below 500 copies/ml. Eight of the 43 RPV treated patients (18.6%) were later discontinued RPV. Only two patients were switched due to suspected adverse events of RPV, and one patient was switched due to treatment failure. No resistance test was available for the patient with suspected treatment failure. Other reasons for switching were patient’s wish or poor adherence. Among patients presently on RPV, the most recent HIV viral was below lower limit of detection (20 copies/ml) for 32 of 35 patients (91.4%), and all had HIV viral loads below 50 copies/ml. No mutations conferring high-level resistance to RPV were detected before or after RPV therapy, but one patient harbored mutations conferring possible low-level RPV resistance (V179E and A98S) before RPV treatment.

Conclusions
Despite RPV only being licensed as a drug for treatment of ART naïve patients, most of the patients receiving RPV at a Danish HIV clinic were ART experienced. RPV was often chosen due to adverse events of efavirenz. ART experienced patients with undetectable HIV viral load and no preexisting NNRTI-mutations can safely be shifted to RPV concerning efficacy and tolerability.