HIV Vaccine: Phase 1 Clinical Trial Tests mRNA Technology Against HIV

Moderna and the nonprofit science research organization IAVI have administered the first doses in a Phase I clinical trial of an experimental HIV vaccine, delivered by messenger RNA (mRNA) – the technology that revolutionized vaccines against COVID-19.

The trial kicked off last week at George Washington University School of Medicine and Health Sciences in Washington, D.C. It is partially funded by the Bill & Melinda Gates Foundation.

The Phase I trial, IAVI G002, is testing the hypothesis that sequential administration of priming and boosting HIV immunogens delivered by messenger RNA (mRNA) can induce specific classes of B-cell responses and guide their maturation to generate broadly neutralizing antibodies (bnAb) that would protect against disease, a joint statement by Moderna and IAVI explained.

The immunogens being tested were developed by scientific teams at IAVI and the Scripps Research Institute, and will be delivered via Moderna’s mRNA technology.

“The search for an HIV vaccine has been long and challenging, and having new tools in terms of immunogens and platforms could be the key to making rapid progress toward an urgently needed, effective HIV vaccine,” said Mark Feinberg, CEO of IAVI – whose board includes prominent names from industry, research, The Global Fund, and the Africa Centers for Disease Control.

More than 36 million people have died of AIDS-related illnesses

As of June 2021, 28.2 million people were using antiretroviral therapy for the treatment of HIV, according to UNAIDS, and 37.7 million people were living with the disease in 2020.

Some 680,000 people died of AIDS-related illnesses in 2020. A total of 36.3 million people have died of AIDS since the virus exploded into a pandemic in the late 1980s.

Photo: UNAIDS/Sydelle Willow Smith

The mRNA vaccine strategy centers on stimulating the immune system to produce bnAbs against HIV, a process known as “germline-targeting.” Antibodies are produced by B cells, which start out in a “germline” state.

BnAbs are believed to be capable of neutralizing different HIV strains by binding to hard-to-reach but consistent regions of the virus surface. If it works, the germline targeting strategy could offer protection against millions of different HIV strains circulating in various parts of the world.

Last year, Dr William Schief, a professor at Scripps Research Institute and executive director of vaccine design at IAVI’s Neutralizing Antibody Center – who developed the HIV vaccine antigens  being evaluated in mRNA formats in this study – announced results from the IAVI G001 clinical trial, showing that an adjuvanted protein-based version of the priming immunogen induced the desired B-cell response in 97% of recipients.

Until now, no HIV vaccine candidate has been able to induce a protective bnAb response in humans.

The release said that “given the speed with which mRNA vaccines can be produced,” using the platform could shave off years from typical vaccine development timelines – like it did for the development of an emergency coronavirus vaccine.

“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,” said Moderna’s president Dr Stephen Hoge.

Image Credits: Moderna, UNAIDS/Sydelle Willow Smith.

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