Enrollment in Early Phase Trial of HIV Vaccine That Uses a Cytomegalovirus Vector Is Underway

Enrollment in a phase 1 trial of HIV vaccine that uses a cytomegalovirus (CMV) vector has started it the United States and South Africa, the National Institute of Allery and Infectious Diseases (NIAID) announced in a press release yesterday.

The vaccine, provisionally called VIR-1388, has been developed by Vir Biotechnology, a San Francisco company, and Vir is sponsoring the trial, with NIAID and Bill & Melinda Gates Foundation providing financial support. NIAID has provided scientific and financial support throughout the lifecycle of this HIV vaccine concept, the press release said.

The trial is being conducted through the NIAID-funded HIV Vaccine Trials Network (HVTN) and has been designated study HVTN 142.

Study volunteers are being enrolled at sites in six cities the United States (Birmingham, Alabama; Decatur, Georgia; Boston, Philadelphia, Pittsburgh and Seattle) and four in South Africa. The goal is to enroll 95 HIV-negative participants. The volunteers will be randomly assigned to one of four groups, three of which will each receive a different dose of the vaccine and the fourth, a placebo. To optimize participant safety, this study will only enroll people already living with asymptomatic CMV. Initial results are expected in late 2024, and an optional long-term sub-study will continue to follow volunteers for up to three years after their first vaccine dose.

CMV has been present in much of the global population for centuries, according to the NIAID press release, and most people living with the infection experience no symptoms and therefore are unaware that they are living with the virus. However, CMV remains detectable in the body for life, which suggests it has the potential to deliver and then safely help the body retain HIV vaccine material for a long period, potentially overcoming the waning immunity observed with more short-lived vaccine vectors, said the press release.

The vaccine is designed to provoke the production of T cellls that will recognize the HIV virus and stir up an immune system response that will keep the virus from taking hold and becoming a chronic infection, the press release says.