title: In vitro antiviral interaction of lopinavir with other protease inhibitors.
abstract: The in vitro inhibition of wild-type human immunodeficiency virus (HIV) by combinations of lopinavir and six other protease inhibitors over a range of two-drug combination ratios was evaluated. Combinations of lopinavir with indinavir, nelfinavir, amprenavir, tipranavir, and BMS-232632 generally displayed an additive relationship. In contrast, a consistent, statistically significant synergistic inhibition of HIV type 1 replication with combinations of lopinavir and saquinavir was observed. Analysis of the combination indices indicated that lopinavir with saquinavir was synergistic over the entire range of drug combination ratios tested and at all levels of inhibition in excess of 40%. Cellular toxicity was not observed at the highest drug concentrations tested. These results suggest that administration of combinations of the appropriate dose of lopinavir with other protease inhibitors in vivo may result in enhanced antiviral activity with no associated increase in cellular cytotoxicity. More importantly, the observed in vitro synergy between lopinavir and saquinavir provides a theoretical basis for the clinical exploration of a novel regimen of lopinavir-ritonavir and saquinavir.
authors.affiliation: Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois 60064, USA. akhter.m.molla@abbott.com
authors.forename: Akhteruzzaman
authors.initials: A
authors.lastname: Molla
authors.forename: Hongmei
authors.initials: H
authors.lastname: Mo
authors.forename: Sudthida
authors.initials: S
authors.lastname: Vasavanonda
authors.forename: Lixin
authors.initials: L
authors.lastname: Han
authors.forename: C Thomas
authors.initials: CT
authors.lastname: Lin
authors.forename: Ann
authors.initials: A
authors.lastname: Hsu
authors.forename: Dale J
authors.initials: DJ
authors.lastname: Kempf
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D004359:Drug Therapy, Combination; D006678:HIV / Q000187:drug effects*; D015658:HIV Infections / Q000188:drug therapy; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D061466:Lopinavir; D008826:Microbial Sensitivity Tests; D011744:Pyrimidinones / Q000494:pharmacology*
chemical_list: D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D011744:Pyrimidinones; D061466:Lopinavir