Prevalence of the potential drug-drug interactions between pangenotypic direct-acting antivirals and the concomitant medications associated with patients with chronic hepatitis C virus infection in Spain

Objective: To determine the comorbidity and potential for drug-drug interactions (DDIs) among pangenotypic direct-acting-antivirals (pDAAs) and the concomitant medications associated with chronic hepatitis C (CHC) patients in routine clinical practice in Spain.

Methods: Retrospective observational study. Included patients were ≥18 years, diagnosed with CHC, on antiviral treatment and required medical attention during 2017. Two groups were differentiated according to age ranges (<50 and ≥50 years). The variables collected were: age, gender, general/specific comorbidity, concomitant medication and potential DDIs (www.hep-druginteractions.org). The pDAAs analysed were: a) Sofosbuvir/Velpatasvir (SOF/VEL), b) Glecaprevir/Pibrentasvir (GLE/PIB) and c) Sofosbuvir/Velpatasvir/Voxilaprevir (SOF/VEL/VOX). Bivariate statistical analysis, P<.05.

Results: 3,430 patients with a mean age of 56.9 years and 60.3% males were enrolled. The average Charlson index was 0.8. Age range distribution: 18-49 years (28.9%) and ≥50 years (71.1%). The average number of medications per patient/year was 3.1 (SD 2.6). The total percentage of potential DDIs was: 8.6% minor DDIs, 40.5% clinically significant DDIs and 10.0% contraindicated medication. These DDIs were greater in patients ≥50 years (8.6%, 43.8% and 12.4%, respectively, P<.001). For all ages, SOF/VEL showed a lower percentage of: minor interactions (1.3% vs. 6.6% and 5.9%, P<.001); clinically significant interactions (53.4%, vs. 77.4% and 66.3%, P<.001) and contraindicated medication (1.7% vs. 8.3% and 10.7%, P<.001) compared to GLE/PIB and SOF/VEL/VOX, respectively.

Conclusions: Patients with CHC present high comorbidity and concomitant medication use, particularly elderly patients, thus implying a greater exposure to potential DDIs. Although the DDI rate was considerable with the three combinations analysed, SOF/VEL showed a lower number of clinically significant interactions.