First-of-its-Kind mRNA Vaccine Trial Reinvigorates Hope for Effective HIV Vaccine

The first trial for an mRNA vaccine against HIV vaccine will soon be underway as Moderna is set to begin recruiting trial of two experimental vaccines.

The vaccines — mRNA-1644 and mRNA-1644-v2-Core— are built on the same mRNA platform used for Moderna’s COVID-19 vaccineas well and Pfizer and BioNTech’s COVID-19 vaccine. With mRNA vaccines, patients are not exposed to the virus. Instead, the vaccines consist of engineered messenger RNA that results in the production of an antigen — in the case of COVID-19, the virus’ spike protein — that provokes an immune response.

Moderna is aiming to enroll just over 50 patients between the ages of 18 and 50 years in its phase 1 trial. In this early stage of development, the company will first test the safety of the vaccines among healthy patients and how their immune systems respond before initiating trials that test the efficacy of the candidates. The trial will split the patients into four group. Some of the study volunteers will receive just one of the vaccines and others, both. 

The study is scheduled to be completed in sometime in the spring of 2023. Sponsors and collaborators of the study also include the International AIDS Vaccine Initiative, The University of Texas at San Antonio, Fred Hutchinson Cancer Research Center, George Washington University, and Emory University.

Researchers are hopeful that this new approach to HIV vaccines, which use mRNA technology, can turn the revive hopes of developing an HIV vaccine. In stark contrast to the speed at which COVID-19 vaccines were developed, researchers have been unsuccessfully in develop an HIV vaccine. The HIV/AIDs pandemic began in the early 1980s.

Moderna’s vaccines aim to overcome what has proven to be the biggest barrier to developing an effective HIV vaccine: producing enough neutralizing antibodies that fend off pathogens like the HIV virus. WHIV directly attacks the immune system which allows the virus to affect the body before the immune system can react and protect itself.

To date, all other HIV vaccine trials have assessed the potential of adenovirus vaccines—vaccines that inject an altered form of a virus to trigger an immune response and produce antibodies against the virus.

One trial of an experimental HIV vaccine to date has shown promise. The trial, RV-144 (also known as the phase 3 Thai trial), was conducted in Thailand. More than 10,000 people were enrolled in the study, and results were just shy of being statistically significant, protecting against HIV in 31% of patients over 3.5 years.

Subsequent analyses of the trial have shown that the protective efficacy was actually 60% in the first year, prompting future trials to try and build on the results and create more lasting responses.