Antibody-Mediated Prevention (AMP) Studies

Antibody-Mediated Prevention (AMP) Studies

The AMP studies are the first to test whether an infusion of antibodies, received every eight weeks, is safe and can prevent HIV infection. Both studies, a collaboration between the HIV Prevention Trials Network (HPTN) and HIV Vaccine Trials Network (HVTN), investigated a broadly neutralizing antibody (bNAb) known as VRC01. (To learn more about this approach to HIV prevention, visit our Antibodies for Prevention page.)

AMP consists of two Phase IIb trials and their results were presented at HIV R4P Virtual on January 26, 2021. VRC01 did not significantly reduce the overall risk of HIV acquisition in participants who received the antibody compared to those who received the placebo. However, VRC01 did safely and effectively reduce the risk of acquiring HIV from strains of the virus that are classified as “highly-sensitive” to VRC01. The trials suggest a single bNAb, such as VRC01, does not offer sufficient protection against a broad range of HIV, and a combination of bNAbs is likely needed to achieve broad protection.

AMP investigators say that the results confirm the utility of TMZ-bl, an assay (test) used in the trial to measure how well VRC01 blocked the activity of different types of HIV. The team says that the assay can be used in future trials to help select future bNAB candidates or combinations for testing.

Understanding AMP

Putting the Research in Context

AMP-ticipation: Context and concepts for understanding the AMP Trials
This article by AVAC founder Bill Snow summarizes the antibody-mediated prevention (AMP) trials and some concepts to understand and related issues to watch as the AMP data come in.

A Look at the Broadly Neutralizing Antibody Pipeline – What Happens After AMP
At AVAC’s Research Literacy Zone (RLZN) at AIDS 2020 Virtual, researchers Devin Sok & Olayinka Fagbayi of IAVI discuss bNAb research for HIV prevention and the implications of the AMP Trials.

HIV-Specific Neutralizing Antibodies – Targets and research status
Broadly neutralizing antibodies that target various regions of HIV’s Env protein are being developed for HIV prevention, and this graphic showcases the range of bNAbs under study and their targets.

Broadly Neutralizing Antibody Combinations
As with antiretroviral combinations used in treatment, passive immunization (infusions) of broadly neutralizing antibodies for prevention may require two or more bNAbs that target different parts of the virus. This graphic outlines the bNAb combinations being explored in early clinical studies.

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