Validation of a Triplex Pharmacokinetic Assay for Simultaneous Quantitation of HIV-1 Broadly Neutralizing Antibodies PGT121, PGDM1400, and VRC07-523-LS.

Dan H Barouch,Joseph Nkolola,Jonathan Hare,Nicole L Yates,Sheetal Sawant,Kasey Hernandez,Michelle Rojas,Kelly E Seaton,Jack Heptinstall,David Beaumont,Christine A Arocena,Georgia D Tomaras,Katherine Crisafi,Kelvin T Chiong,Martina S Wesley,Marcella Sarzotti-Kelsoe

doi:10.3389/fimmu.2021.709994

Abstract

The outcome of the recent Antibody Mediated Prevention (AMP) trials that tested infusion of the broadly neutralizing antibody (bnAb) VRC01 provides proof of concept for blocking infection from sensitive HIV-1 strains. These results also open up the possibility that triple combinations of bnAbs such as PGT121, PGDM1400, as well as long-lasting LS variants such as VRC07-523 LS, have immunoprophylactic potential. PGT121 and PGDM1400 target the HIV-1 V3 and V2 glycan regions of the gp120 envelope protein, respectively, while VRC07-523LS targets the HIV-1 CD4 binding site. These bnAbs demonstrate neutralization potency and complementary breadth of HIV-1 strain coverage. An important clinical trial outcome is the accurate measurement of in vivo concentrations of passively infused bnAbs to determine effective doses for therapy and/or prevention. Standardization and validation of this testing method is a key element for clinical studies as is the ability to simultaneously detect multiple bnAbs in a specific manner. Here we report the development of a sensitive, specific, accurate, and precise multiplexed microsphere-based assay that simultaneously quantifies the respective physiological concentrations of passively infused bnAbs in human serum to ultimately define the threshold needed for protection from HIV-1 infection.

Highlights

The rate of Acquired Immunodeficiency Syndrome (AIDS)related deaths is not decreasing, despite the existence of highly efficient drugs that suppress Human Immunodeficiency Virus (HIV) replication and provide patients a life expectancy close to that of healthy individuals [1]
The PK method for the simultaneous detection of three bnAbs was validated for HIV-1 seronegative human serum as well as qualified for HIV-1 seropositive human serum for the measurement of antibody concentrations in human clinical trials
Results demonstrated that the PGDM1400/PGT121/VRC07-523-LS PK BAMA is specific, accurate, sensitive, precise, and capable for repeatable simultaneous quantitation of three bnAbs, namely PGT121, PGDM1400, and VRC07-523-LS

Summary

Introduction

The rate of Acquired Immunodeficiency Syndrome (AIDS)related deaths is not decreasing, despite the existence of highly efficient drugs that suppress Human Immunodeficiency Virus (HIV) replication and provide patients a life expectancy close to that of healthy individuals [1]. This is partially due to the lack of sufficient access to antiretroviral therapy (ART) and due to the fact that ART does not eliminate viral reservoirs from HIV-1 infected individuals. Effective, long-acting prevention strategies with fewer off-target or other side effects may increase trust and acceptance in communities affected by or at high-risk for HIV-1 acquisition

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Results

Conclusion