Coformulated darunavir/cobicistat: an alternative to separate ritonavir boosting
Simon Collins, HIV i-Base
Results from a phase I cross-over study in HIV negative volunteers reported bioequivilence for a new fixed-dose formulation of darunavir/cobicistat compared to the two compounds dosed separately.
Earlier studies have reported that 800 mg darunavir achieved similar PK whether boosted by 150 mg cobicistat or 100 mg.
Least square mean (LSM) ratio values were close to 100% for both darunavir and cobicistat under both fed (high fat breakfast) and fasted conditions, with tight 90% CI values that were well within the 80%-125% range allowed for bioequivlence.
Food increased darunavir and cobicistat Tmax similarly (approximately 4 hr fed vs 3 hr fasted) with combined and single formulations. Food significantly increased (LSM ratio) darunavir Cmax by 227% and AUC by 70% compared to fasted state, with little impact of food on cobicistat levels.
The collaboration between Janssen and Gilead (who manufacture cobicistat) to enable a coformulated boosted-PI will also be used in single-tablet fixed-dose combinations that include Gilead’s NRTIs.
Kakuda TN et al. Bioequivalence of darunavir/cobicistat fixed-dose combination (FDC) versus single agents in healthy volunteers. 14th International Workshop on Clinical Pharmacology. 22-24 April 2013. Amsterdam. Poster abstract P_10.