Favipiravir pharmacokinetics in Ebola-Infected patients of the JIKI trial reveals concentrations lower than targeted.

• Published in: PLOS Neglected Tropical Diseases
• Main Authors: Thi Huyen Tram Nguyen, Jérémie Guedj, Xavier Anglaret, Cédric Laouénan, Vincent Madelain, Anne-Marie Taburet, Sylvain Baize, Daouda Sissoko, Boris Pastorino, Anne Rodallec, Géraldine Piorkowski, Sara Carazo, Mamoudou N Conde, Jean-Luc Gala, Joseph Akoi Bore, Caroline Carbonnelle, Frédéric Jacquot, Hervé Raoul, Denis Malvy, Xavier de Lamballerie, France Mentré, JIKI study group
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science (PLoS) 2017
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Public aspects of medicine; RA1-1270; Arctic
• Online Access: https://doi.org/10.1371/journal.pntd.0005389; https://doaj.org/article/7f6efdf3b05345baa7f586719e1ce176

BACKGROUND:In 2014-2015, we assessed favipiravir tolerance and efficacy in patients with Ebola virus (EBOV) disease (EVD) in Guinea (JIKI trial). Because the drug had never been used before for this indication and that high concentrations of the drugs were needed to achieve antiviral efficacy against EBOV, a pharmacokinetic model had been used to propose relevant dosing regimen. Here we report the favipiravir plasma concentrations that were achieved in participants in the JIKI trial and put them in perspective with the model-based targeted concentrations. METHODS AND FINDINGS:Pre-dose drug concentrations were collected at Day-2 and Day-4 of treatment in 66 patients of the JIKI trial and compared to those predicted by the model taking into account patient's individual characteristics. At Day-2, the observed concentrations were slightly lower than the model predictions adjusted for patient's characteristics (median value of 46.1 versus 54.3 μg/mL for observed and predicted concentrations, respectively, p = 0.012). However, the concentrations dropped at Day-4, which was not anticipated by the model (median values of 25.9 and 64.4 μg/mL for observed and predicted concentrations, respectively, p<10-6). There was no significant relationship between favipiravir concentrations and EBOV viral kinetics or mortality. CONCLUSIONS:Favipiravir plasma concentrations in the JIKI trial failed to achieve the target exposure defined before the trial. Furthermore, the drug concentration experienced an unanticipated drop between Day-2 and Day-4. The origin of this drop could be due to severe sepsis conditions and/or to intrinsic properties of favipiravir metabolism. Dose-ranging studies should be performed in healthy volunteers to assess the concentrations and the tolerance that could be achieved with high doses. TRIAL REGISTRATION:ClinicalTrials.gov NCT02329054.