VIROLOGIC AND IMMUNOLOGIC RESPONSES OF 281 ARV-EXPERIENCED PATIENTS ENROLLED IN THE LOPINAVIR/RITONAVIR (LPV/r) EXPANDED ACCESS PROGRAM (EAP) IN TORONTO, CANADA

M Loutfy, C Thompson, M Trpeski, C Kovacs, A Rachlis, J Goodhew, G Rubin, K Gough, S Walmsley
University of Toronto, Toronto, Ontario

Objective: To determine the viral and immunologic responses to LPV/r in a large cohort of ARV-experienced patients.
Method: A retrospective cohort study of patients enrolled in the LPV/r EAP with at least 1M F/U was done. The proportion who achieved a VL<50 copies/mL and the CD4 count change were determined. Virologic responses were compared in NNRTI-naïve patients, between those who received and who did not receive an NNRTI.
Results: Of the 281 patients, 97.5% were PI-experienced and 58.2% were NNRTI-experienced. The mean number of prior ARVs was 7.7. The mean F/U was 5.6 M. 37 patients had an undetectable VL at baseline and were switched to LPV/r for simplification and were analyzed separately. The remainder received LPV/r as salvage therapy with a mean baseline VL of 4.49 log/mL and CD4 count of 185.2 c/mL. 32.4% (N=136) achieved a VL<50/mL at 1-3 M and 44.9% (N=98) at >6 M. The mean increase in CD4 count at 1-3 M was 74.0 c/mL and 92.7 c/mL at >6 M. When comparing the VL response in 94 patients who were NNRTI-naïve and received an NNRTI versus those who did not, 54.1% (N=37) vs. 40.0% (N=10) achieved a VL < 50/mL by 1-3 M (p=0.43) and 74.2% (N=31) vs. 30.0% (N=10) maintained a VL < 50/mL at > 6 M (p=0.02). The VL of all 37 simplification patients remained <50/mL to 9 M. Their baseline CD4 count was 456.4 c/mL, and increased by 54.3 c/mL at 1-3M (p=0.6) and 136.5 c/mL (p=0.02) at > 6 M.
Conclusions: In this large cohort study, LPV/r was efficacious in ARV-experienced patients. Adding a first NNRTI improved the durability of their virologic response. The patients with VL<50 c/mL who received LPV/r for simplification, maintained suppression out to 9M, during which they had a significant increase in their CD4 count.