337   Final Analysis of Ritonavir (RTV) Intensification in Indinavir (IDV) Recipients with Detectable HIV RNA Levels.

A. Hsu*¹, A. Zolopa², N. Shulman², D. Havlir³, J. Gallant⁴, E. Race⁵, P. Jiang¹, S. Boller¹, J. Swerdlow¹, O. Jasinsky¹, C. Renz¹, A. J. Japour¹, D. Kempf¹, and E. Sun¹.
¹Abbott Labs., Abbott Park, IL;²Stanford Univ., Palo Alto, CA;³Univ. of California San Diego, La Jolla;⁴Johns Hopkins Univ., Baltimore, MD; and⁵Univ. of Texas, Dallas.

Background:Elevating the trough plasma levels of protease inhibitors intensifies their antiviral activity. This study evaluates the virological response and safety of RTV/IDV (400/400 mg BID) in patients previously receiving IDV 800 mg TID with detectable viremia.

Methods:Patients (n = 37) with 50-50,000 copies/mL HIV RNA on stable IDV (+2 NRTIs) regimen were switched to open label RTV/IDV by dose titration of RTV. IDV plasma drug concentrations (mg/mL) were determined over a dosing interval at baseline (IDV TID) and at wk 3 (RTV/IDV BID) in a subset of patients (n = 16). NRTI changes were permitted after wk 3. Dose reduction of RTV to 300 mg was allowed in patients intolerant of 400 mg.

Results:The median IDV trough concentration (n = 34 at baseline and n = 32 at wk 3) was 650% higher than IDV 800 mg TID. IDV AUC was unchanged and C_maxwas 51% lower. The data presented will be updated with wk 48 results.

12 of 17 discontinuations at wk 36 were due to drug-related AEs. The most commonly reported AE of at least moderate severity and probable or possible relationship to drug was diarrhea (16 of 37 patients). 22 of 37 patients had Grade 3/4 cholesterol or triglyceride elevations.

Conclusions:In this study, RTV intensification of IDV trough levels was associated with improved virological response in long-term IDV recipients.