PHARMACOKINETICS AND SAFETY OF RALTEGRAVIR IN 2 to 12 YEAR OLD CHILDREN WITH HIV RECEIVING RIFAMPICIN FOR TUBERCULOSIS

Drug-drug interactions limit current antiretroviral treatment options for HIV-infected children with tuberculosis (TB). Rifampicin (RIF) induces UDP-glucuronosyltransferase activity, accelerating the clearance of raltegravir (RAL). We sought to establish an optimal and well tolerated dose of RAL when administered with RIF to HIV and TB co-infected children.P1101 is a phase I/II open-label dose-finding study of RAL with RIF for children 2 to less than 12 years of age beginning treatment for HIV and active TB.Four sites in South Africa.Chewable RAL was given at 12 mg/kg per dose twice daily (twice the usual pediatric dose) with two nucleoside reverse transcriptase inhibitors. Intensive RAL pharmacokinetic sampling was conducted 5 to 8 days after antiretroviral therapy was initiated; a fourth antiretroviral agent was then added.Children were recruited into two age-defined groups: cohort 1 (2 to6 years old) and cohort 2 (6 to12 years old). Pharmacological targets [geometric mean (GM) AUC12 h of 14-45 μmol/l h and GM C12 h ≥75 nmol/l) were reached in both cohort 1 (28.8 μmol/l h and 229 nmol/l) and cohort 2 (38.8 μmol/l h and 228 nmol/l). The RAL-based ART was well tolerated by most participants: one participant discontinued treatment because of grade 4 hepatitis that was possibly treatment-related. At week 8, 22 of 24 participants (92%) had HIV RNA concentrations below 400 copies/ml; 19 of 24 (79%) were below 50 copies/ml.Giving 12 mg/kg twice daily of the chewable RAL formulation achieved pharmacokinetic targets safely in HIV-infected children receiving RIF for TB.