Role of Physician-Scientists in the Control of Human Immunodeficiency Virus.

Physician-scientists played many important roles in controlling human immunodeficiency virus infection (HIV). They worked in academia, government, and industry, and their research was critical in the following areas: discovering the first active drugs; identifying the virologic, immunologic, and clinical perimeters of efficacy; and conceiving of and executing the subsequent clinical trials that led to the multiple drug regimens that we now have to treat the infection and its complications in all the populations now involved. It is now true that over half of the infected people in the world are under treatment.

In vitro HIV-1 evolution in response to triple reverse transcriptase inhibitors & in silico phenotypic analysis.

Background: Effectiveness of ART regimens strongly depends upon complex interactions between the selective pressure of drugs and the evolution of mutations that allow or restrict drug resistance.

Methods: Four clinical isolates from NRTI-exposed, NNRTI-naive subjects were passaged in increasing concentrations of NVP in combination with 1 µM 3 TC and 2 µM ADV to assess selective pressures of multi-drug treatment. A novel parameter inference procedure, based on a stochastic viral growth model, was used to estimate phenotypic resistance and fitness from in vitro combination passage experiments.

Persistence versus reversion of 3TC resistance in HIV-1 determine the rate of emergence of NVP resistance.

When HIV-1 is exposed to lamivudine (3TC) at inhibitory concentrations, resistant variants carrying the reverse transcriptase (RT) substitution M184V emerge rapidly. This substitution confers high-level 3TC resistance and increased RT fidelity. We established a novel in vitro system to study the effect of starting nevirapine (NVP) in 3TC-resistant/NNRTI-naïve clinical isolates, and the impact of maintaining versus dropping 3TC pressure in this setting.

Phase 2 gene therapy trial of an anti-HIV ribozyme in autologous CD34+ cells.

Gene transfer has potential as a once-only treatment that reduces viral load, preserves the immune system and avoids lifetime highly active antiretroviral therapy. This study, which is to our knowledge the first randomized, double-blind, placebo-controlled, phase 2 cell-delivered gene transfer clinical trial, was conducted in 74 HIV-1-infected adults who received a tat-vpr-specific anti-HIV ribozyme (OZ1) or placebo delivered in autologous CD34+ hematopoietic progenitor cells. There were no OZ1-related adverse events.

Multilocus genetic interactions and response to efavirenz-containing regimens: an adult AIDS clinical trials group study.

Objective: For the HIV-1 reverse transcriptase inhibitor efavirenz, variant drug transporter gene ABCB1 may predict virologic response but not plasma efavirenz exposure. Conversely, variant drug metabolizing enzyme gene CYP2B6 predicts greater plasma efavirenz exposure but not virologic response. We examined whether long-term responses to efavirenz, and/or plasma efavirenz exposure, are better predicted by multilocus genetic interactions than by individual polymorphisms.

Effect of baseline- and treatment-related factors on immunologic recovery after initiation of antiretroviral therapy in HIV-1-positive subjects: results from ACTG 384.

Objective: To assess the effect of baseline- and treatment-related factors on immunologic recovery after initiation of antiretroviral therapy (ART).

Methods: Nine hundred eighty antiretroviral-naive HIV-1+ subjects were randomized to start stavudine/didanosine or zidovudine/lamivudine with nelfinavir, efavirenz, or both nelfinavir and efavirenz.

Results: Greater CD4 cell recovery was associated with age of 40 years or younger, female sex, higher baseline naive/memory CD4 cell ratio, higher baseline virus load (VL), and virologic suppression (VS).

"Wide-open" 1.3 A structure of a multidrug-resistant HIV-1 protease as a drug target.

This report examines structural changes in a highly mutated, clinical multidrug-resistant HIV-1 protease, and the crystal structure has been solved to 1.3 A resolution in the absence of any inhibitor. This protease variant contains codon mutations at positions 10, 36, 46, 54, 62, 63, 71, 82, 84, and 90 that confer resistance to protease inhibitors.

Pharmacogenetics of long-term responses to antiretroviral regimens containing Efavirenz and/or Nelfinavir: an Adult Aids Clinical Trials Group Study.

Background: Efavirenz and nelfinavir are metabolized by cytochrome P-450 (CYP) 2B6 and CYP2C19, respectively, with some involvement by CYP3A. Nelfinavir is a substrate for P-glycoprotein, which is encoded by MDR1. The present study examined associations between genetic variants and long-term responses to treatment.

Pharmacokinetics of nelfinavir and efavirenz in antiretroviral-naive, human immunodeficiency virus-infected subjects when administered alone or in combination with nucleoside analog reverse transcriptase inhibitors.

Pharmacokinetic studies were conducted with human immunodeficiency virus-infected patients receiving efavirenz, nelfinavir, or both agents at weeks 4 and 32. Reductions of 25% and 45% were observed in the mean nelfinavir area under the concentration-time curve and minimum concentration of the drug in serum, and there was a 31% more rapid half-life for patients receiving both drugs compared to patients receiving nelfinavir alone. There were no significant differences in efavirenz pharmacokinetics.

Antiviral activity of lamivudine in salvage therapy for multidrug-resistant HIV-1 infection.

Background: Maximum suppression of virus replication is often not achievable for persons infected with multidrug-resistant human immunodeficiency virus type 1 (HIV-1). Available data suggest that lamivudine contributes to partial viral suppression, despite the presence of M184V mutations and high-level phenotypic lamivudine resistance.

Methods: Selective lamivudine withdrawal was studied in 6 subjects who had incomplete viral suppression during antiretroviral treatment for multidrug-resistant HIV-1 infection.

New two-amino acid insertion near codon 70 of the HIV type 1 protease gene.

A two-amino acid insertion near codon 70 of the HIV-1 protease gene was found in an individual failing protease inhibitor therapy. Susceptibility of this strain to protease inhibitors was similar to that of non-insert-containing strains with comparable resistance mutations and one or more other major PI mutations.

Rare one and two amino acid inserts adjacent to codon 103 of the HIV-1 reverse transcriptase (RT) affect susceptibility to non-nucleoside RT inhibitors.

HIV-1 strains that possess a one or two amino acid insert between codons 102 and 103 of the reverse transcriptase (RT) gene were identified in three HIV-1-infected individuals. Each strain also had one or more known mutations associated with nucleoside RT inhibitors (NRTIs) and non-nucleoside RT inhibitors (NNRTIs). Recombinant viruses from these strains had reduced susceptibility to efavirenz and nevirapine, and homology modelling predicted a loss of binding contacts with efavirenz.

Nonnucleoside reverse transcriptase inhibitor phenotypic hypersusceptibility can be demonstrated in different assays.

Background: HIV-1 isolates harboring multiple nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations are more susceptible ("hypersusceptible") to the nonnucleoside reverse transcriptase inhibitors (NNRTIs) than isolates lacking NRTI resistance mutations, but this has only been reported with a single-cycle replication phenotypic assay. In fact, there was a report that a commercial multicycle assay did not readily detect hypersusceptibility.

Objective: To see whether NNRTI hypersusceptibility can be demonstrated in other types of phenotypic assays, including multicycle assays and enzyme inhibition assays.

Human immunodeficiency virus type 1 infection in Oman: antiretroviral therapy and frequencies of drug resistance mutations.

Highly active antiretroviral therapy (HAART), consisting mainly of two nucleoside reverse transcriptase inhibitors (NRTIs) and one protease inhibitor (PI), is offered to < 10% of HIV-infected subjects in Oman. The aims of the present study were to determine the frequency of resistance-associated mutations in these patients, and to assess the contribution of drug resistance to treatment outcome. Among 29 patients on HAART for > or =6 months, virological, failure was observed in 27 (93%).

Association of a novel human immunodeficiency virus type 1 protease substrate cleft mutation, L23I, with protease inhibitor therapy and in vitro drug resistance.

We observed a previously uncharacterized mutation in the protease substrate cleft, L23I, in 31 of 4,303 persons undergoing human immunodeficiency virus type 1 genotypic resistance testing. In combination with V82I, L23I was associated with a sevenfold reduction in nelfinavir susceptibility and a decrease in replication capacity. In combination with other drug resistance mutations, L23I was associated with multidrug resistance and a compensatory increase in replication capacity.

HIV type 1 genotypic resistance in a clinical database correlates with antiretroviral utilization.

We established a database of HIV-1 reverse transcriptase (RT) and protease (PR) sequences and mutations to monitor the prevalence of antiretroviral drug resistance and mutational patterns in clinical samples submitted for testing to a major U.S. reference laboratory.

Short-term safety and antiretroviral activity of T-1249, a second-generation fusion inhibitor of HIV.

T-1249 is a 39-aa synthetic peptide that inhibits fusion of human immunodeficiency virus (HIV) to the host target cell. A 14-day open-label, phase 1/2 dose-escalation monotherapy study of the safety and antiretroviral activity of T-1249 was performed on 115 HIV-1-infected adults. At baseline, the majority of the patients had advanced HIV disease (baseline median CD4(+) cell count, 57 cells/microL) and had extensive pretreatment (i.

Crystal structures of a multidrug-resistant human immunodeficiency virus type 1 protease reveal an expanded active-site cavity.

The goal of this study was to use X-ray crystallography to investigate the structural basis of resistance to human immunodeficiency virus type 1 (HIV-1) protease inhibitors. We overexpressed, purified, and crystallized a multidrug-resistant (MDR) HIV-1 protease enzyme derived from a patient failing on several protease inhibitor-containing regimens. This HIV-1 variant contained codon mutations at positions 10, 36, 46, 54, 63, 71, 82, 84, and 90 that confer drug resistance to protease inhibitors.

Granulocyte-macrophage colony-stimulating factor induces modest increases in plasma human immunodeficiency virus (HIV) type 1 RNA levels and CD4+ lymphocyte counts in patients with uncontrolled HIV infection.

Background: Studies have reported that plasma human immunodeficiency virus type 1 (HIV-1) RNA levels and CD4+ lymphocyte counts in HIV-infected patients improved after treatment with granulocyte-macrophage colony-stimulating factor (GM-CSF).

Methods: In AIDS Clinical Trials Group Protocol 5041, 116 patients were enrolled in a double-blind, randomized, placebo-controlled clinical trial of 16 weeks of 250 microg of GM-CSF administered subcutaneously 3 times/week, followed by open-label treatment for an additional 32 weeks. Patients had stable baseline plasma HIV-1 RNA levels of > or =1500 copies/mL and received constant antiretroviral regimens through at least the first 16 weeks of the study.

Comparison of four-drug regimens and pairs of sequential three-drug regimens as initial therapy for HIV-1 infection.

Background: It is unclear whether therapy for human immunodeficiency virus type 1 (HIV-1) should be initiated with a four-drug or two sequential three-drug regimens.

Methods: In this multicenter trial we compared initial therapy involving four-drug regimens containing efavirenz and nelfinavir in combination with either didanosine and stavudine or zidovudine and lamivudine with therapy involving two consecutive three-drug regimens the first of which contained either efavirenz or nelfinavir.

Results: A total of 980 subjects were followed for a median of 2.

Comparison of sequential three-drug regimens as initial therapy for HIV-1 infection.

Background: The optimal sequencing of antiretroviral regimens for the treatment of infection with human immunodeficiency virus type 1 (HIV-1) is unknown. We compared several different antiretroviral treatment strategies.

Methods: This multicenter, randomized, partially double-blind trial used a factorial design to compare pairs of sequential three-drug regimens, starting with a regimen including zidovudine and lamivudine or a regimen including didanosine and stavudine in combination with either nelfinavir or efavirenz.

Correlation of single photon emission computed tomography parameters as a noninvasive alternative to liver biopsies in assessing liver involvement in the setting of HIV and hepatitis C virus coinfection: a multicenter trial of the Adult AIDS Clinical Trials Group.

Performing a liver biopsy in patients infected with HIV and hepatitis C virus (HCV) is considered the standard of practice to assess hepatic involvement but carries risks to patients. This pilot study was designed to identify single photon emission computed tomography (SPECT) parameters that correlate with liver disease stage. HIV-coinfected and HCV-coinfected individuals undergoing a liver biopsy had a SPECT scan performed.

HIV-1 protease variants from 100-fold drug resistant clinical isolates: expression, purification, and crystallization.

High-resolution X-ray crystallographic structures of HIV-1 protease clinical variants complexed with licensed inhibitors are essential to understanding the fundamental cause of protease drug resistance. There is a need for structures of naturally evolved HIV-1 proteases from patients failing antiretroviral therapy. Here, we report the expression, purification, and crystallization of clinical isolates of HIV-1 protease that have been characterized to be more than 100 times less susceptible to US FDA approved protease inhibitors.