title: Sequential versus simultaneous combination antiretroviral regimens for the treatment of human immunodeficiency virus type 1 infection in vitro.
abstract: Two-, three-, and four-drug antiretroviral combinations in either simultaneous or sequential regimens were evaluated for their ability to suppress human immunodeficiency virus (HIV) type 1 replication in vitro. Zidovudine, lamivudine, saquinavir, and nevirapine were used at IC(90)s, IC(99)s, or IC(> or = 99)s in a CD4-positive human lymphoblastoid cell line (H9 cells) acutely infected with HIV-1. In sequential regimens, drugs were added at weekly intervals. In simultaneous regimens, all drugs were added on day 0. Increasing the number of drugs in a combination regimen both increased the degree of viral inhibition and delayed the time of breakthrough viral replication. Simultaneous regimens provided more profound and earlier viral inhibition than did sequential regimens. However, sequential addition provided relatively more durable viral inhibition than did simultaneous regimens when drug concentrations were low. The relative effectiveness of different HIV-1 therapeutic strategies depends on both the numbers and concentrations of the drugs used.
authors.affiliation: Infectious Disease Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
authors.forename: M
authors.initials: M
authors.lastname: Oh
authors.forename: D P
authors.initials: DP
authors.lastname: Merrill
authors.forename: L
authors.initials: L
authors.lastname: Sutton
authors.forename: M S
authors.initials: MS
authors.lastname: Hirsch
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage*; D015496:CD4-Positive T-Lymphocytes / Q000821:virology*; D002460:Cell Line; D004334:Drug Administration Schedule; D016655:HIV Core Protein p24 / Q000096:biosynthesis; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D014779:Virus Replication / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D016655:HIV Core Protein p24