NIH Announces HIV Vaccine Clinical Trial Begins

The National Institutes of Health announced today that clinical trials are beginning in the United States and South Africa of a preventative HIV vaccine. The Phase 1 trial of a novel HIV vaccine candidate called VIR-1388 is called HVTN 142 and aims to assess the vaccine's safety and its ability to stimulate an HIV-specific immune response. VIR-1388 employs a cytomegalovirus (CMV) vector to deliver the vaccine material. The National Institute of Allergy and Infectious Diseases (NIAID) provides scientific and financial support for the study. CMV is a long-lasting virus, which may help maintain HIV vaccine material in the body over an extended period, potentially addressing issues of waning immunity observed in shorter-lived vaccine vectors. The first results are expected in late 2024, with an optional long-term substudy tracking participants for up to 3 years after their initial vaccine dose.

According to the announcement, “VIR-1388 is designed to instruct the immune system to produce T cells that can recognize HIV and signal an immune response to prevent the virus from establishing chronic infection. VIR-1388 uses a cytomegalovirus (CMV) vector, meaning a weakened version of CMV delivers the HIV vaccine material to the immune system without causing disease in the study participants. CMV has been present in much of the global population for centuries.” Many individuals who have CMV do not display any symptoms and may not even know they have the virus. CMV can persist in the body indefinitely, indicating that it may be able to effectively deliver and maintain HIV vaccine material for an extended period. This could potentially overcome the decreasing immunity often seen with shorter-lasting vaccine vectors.

HVTN 142 is being conducted at 6 locations in the United States and 4 in South Africa, involving the enrollment of 95 HIV-negative participants. These participants will be randomly assigned to 1 of 4 study groups, with 3 groups receiving different doses of the vaccine, while one group will receive a placebo. To enhance participant safety, the trial specifically recruits individuals already living with asymptomatic CMV.

Since 2004, NIAID has been instrumental in funding the discovery and development of the CMV vaccine vector. The current trial is being funded in collaboration with the Bill & Melinda Gates Foundation and Vir Biotechnology, headquartered in San Francisco. The study, designated as HVTN 142, is sponsored by Vir and is conducted through the NIAID-supported HIV Vaccine Trials Network (HVTN).

According to the announcement, "Additional information about the trial is available on ClinicalTrials.gov under study identifier NCT05854381."