A Pilot Study of the Pharmacokinetics and Safety of Lopinavir/Ritonavir 400/100mg Bid Versus Lopinavir/Ritonavir 600/150 mg BID Combined With Nucleoside Analogue Reverse Transcriptase Inhibitors in HIV/TB Co-infected Patients Receiving Rifampicin Containing Anti-tuberculosis Therapy

Fixed dose combination of d4T+3TC+NVP (GPOvir) is widely used in Thai HIV infected since June 2002. The prevalence of NNRTI resistance has increased since 2005. Tuberculosis can develop following NNRTI-based regimen failure or after introduction of a new salvage regimen with a boosted PI (immune recovery syndrome). Although, Efavirenz based HAART is preferred in TB/HIV with rifampicin containing antituberculosis. However, Efavirenz could not be used in case of NNRTI failure, intolerance or toxicity. It remains unknown how to optimally treat HIV /TB in populations in which rifampicin has to be used. Moreover, Rifabutin which is recommended when use concomitant with boosted PI4, 5, is not feasible in Thailand and other developing countries due to cost, toxicity and dosing considerations. If ritonavir-boosted LPV demonstrates suitable pharmacokinetics, and is well tolerated, this regimen might prove extremely useful and could be widely implemented. LPV/r is potent and widely available boosted PI in National Health System in Thailand. We therefore believe that there is a strong rationale and impetus for the study of LPV/r 400/100 mg bid versus LPV/r 600/150 mg bid as a boosted-PI combination that in the presence of RMP, is able to produce a satisfactory PK profile associated with adequate antiretroviral potency, tolerability and efficacy .