DRUG INTERACTIONS BETWEEN DOLUTEGRAVIR AND ARTEMETHER-LUMEFANTRINE OR ARTESUNATE-AMODIAQUINE.
Walimbwa SI., Lamorde M., Waitt C., Kaboggoza J., Else L., Byakika-Kibwika P., Amara A., Gini J., Winterberg M., Chiong J., Tarning J., Khoo SH.
Across sub-Saharan Africa, patients with HIV on antiretrovirals often get malaria and need co-treatment with artemisinin-containing therapies. We undertook two pharmacokinetic studies in healthy volunteers, using standard adult doses of artmether-lumefantrine or artesunate-amodiaquine given with 50mg once daily dolutegravir (DTG) to investigate the drug-drug interaction between artmether-lumefantrine or artesunate-amodiaquine and dolutegravir. The dolutegravir/artmether-lumefantrine interaction was evaluated in a two-way cross-over study and measured artemether, dihydroartemisinin, lumefantrine, desbutyl-lumefantrine over 264 hours. The dolutegravir/artesunate-amodiaquine interaction was investigated using a parallel study design due to long half-life of the amodiaquine metabolite, desethylamodiaquine and measured artesunate, amodiaquine, desethylamodiaquine over 624 hours. Non-compartmental analysis was performed, and geometric mean ratios and 90% confidence intervals generated for evaluation of both interactions. Dolutegravir did not significantly change the maximum concentration in plasma, time to maximum concentration and area under the concentration-time curve (AUC) for artemether, dihydroartemisinin, lumefantrine and desbutyl-lumefantrine nor significantly alter AUC for artesunate, dihydroartemisinin, amodiaquine and desethylamodiaquine. Co-administration of dolutegravir with artmether-lumefantrine resulted in a 37% decrease in DTG trough concentrations. Co-administration of dolutegravir with artesunate-amodiaquine resulted in a decrease of approximately 42% and 24% in DTG trough concentrations and AUC respectively. The significant decreases in DTG trough concentrations with artemether-lumefantrine and artesunate-amodiaquine and dolutegravir exposure with artesunate-amodiaquine are unlikely to be of clinical significance as DTG trough concentrations were above dolutegravir target concentrations of 300ng/mL. Study drugs were well-tolerated with no serious adverse events. Standard doses of artemether-lumefantrine and artesunate-amodiaquine should be used in patients receiving dolutegravir.