Moderna administered first doses of its experimental HIV vaccine

Moderna announced that participants began receiving doses of its experimental HIV vaccine, kicking off phase 1 of its clinical trial.

In a January 28 press release, Moderna said the clinical trial, IAVI G002, is testing whether a two-dose mRNA vaccine can successfully produce “broadly neutralizing antibodies,” a type of antibody that can recognize and block many types of HIV from entering healthy cells. Producing broadly neutralizing antibodies is widely considered to be a goal of HIV vaccination, and this clinical trial is the first step in that process.

An HIV vaccine is a top priority in ending new transmissions of HIV. According to UNAIDS, there were 1.5 million new transmissions of HIV in 2020. Although current medicines make it impossible to transmit HIV, an HIV vaccine could prevent people from acquiring the virus.

Stephen Hoge, president of Moderna, said, “We believe advancing this HIV vaccine program in partnership with IAVI and Scripps Research is an important step in our mission to deliver on the potential for mRNA to improve human health.”

This is not the first clinical trial for an HIV vaccine. In 2021, Moderna ran a proof-of-concept trial—IAVI G001—testing the vaccine in humans. In that clinical trial, 97% of the 48 participants saw successful results, said William Schief, Executive Director of Vaccine Design at IAVI’s Neutralizing Antibody Center, who led the study. (Correction: IAVI G001 did not use the Moderna mRNA vaccine technology but rather used a recombinant protein. IAVI G002 is the first mRNA-based HIV vaccine.)

“We’ve seen promising proof of concept for germline targeting in IAVI G001, and this trial [IAVI G002] lets us take that approach to the next stage,” said Schief.

The first shot in the trial was administered on January 27 at George Washington University in Washington, D.C., according to Moderna.

Currently, “Undetectable = Untransmittable,” or U=U, is the leading global campaign explaining how the sexual transmission of HIV can be stopped, according to the U.S. National Institute of Health.

U=U means that a person with HIV can take daily antiretroviral medicine to suppress the virus so low that it’s undetectable in a blood test. When a person has an undetectable status, it’s impossible to transmit the virus to another person sexually. An undetectable status also means that the virus can’t impact a person’s immune system, providing for a normal, healthy life.

As well as U=U, PrEP is another way to prevent acquiring HIV. Pre-exposure prophylaxis, or PrEP, is a daily medicine for people without HIV who think they may be at risk of HIV exposure. By taking PrEP properly, it’s impossible to acquire HIV.

Post-exposure prophylaxis, or PEP, is also available for people who think they may have been recently exposed to HIV and are not on PrEP.

About the trial

According to the U.S. National Institute of Health, this trial began on November 12, 2021, and is expected to end on April 11, 2023.

In November 2021, 56 healthy, HIV-negative adult volunteers enrolled at four testing sites across the United States. The sites are George Washington University in Washington, D.C., Hope Clinic of Emory Vaccine Center in Atlanta, Fred Hutchinson Cancer Research Center in Seattle, and the University of Texas-Health Science Center at San Antonio.

48 participants will receive one or two doses of eOD-GT8 60mer mRNA Vaccine (mRNA-1644), with 32 of them receiving the boost Core-g28v2 60mer mRNA Vaccine (mRNA-1644v2-Core). An additional eight volunteers will receive the boost immunogen alone. Participants will be monitored for safety for six months after their last vaccination. Participants’ immune responses to the vaccine candidates will be examined in molecular detail to evaluate whether the targeted responses were achieved.

David Diemert, one of the lead investigators at George Washington University, said, “We at GWU School of Medicine and Health Sciences are pleased to be part of this endeavor that aims to induce the next step of B-cell maturation toward the goal of generating antibodies that can neutralize a broad range of HIV variants. Further immunogens will be needed to guide the immune system on this path, but this prime-boost combination could be the first key element of an eventual HIV immunization regimen.” 

The clinical trial was sponsored by the International AIDS Vaccine Initiative, a global not-for-profit working to accelerate the development of vaccines to prevent HIV infection and AIDS.