AIDS Clinical Trials Group Launches Study of New CMV Vaccine

The AIDS Clinical Trials Group (ACTG) recently announced the commencement of A5355, a clinical trial of a novel cytomegalovirus (CMV) vaccine for adults living with both HIV and CMV.

The goal of the trial is for the vaccine, Triplex, to elicit a CMV-specific immune response in HIV-positive participants, safely and successfully suppressing CMV replication.

Most people living with HIV are also living with CMV, conditions associated with chronic inflammation that can cause severe comorbidities such as heart disease, diabetes, strokes, and neurological problems.

According to ACTG chair Judith Currier, MD, MSc, “Because almost all individuals living with HIV have also been exposed to CMV and they both persist across the lifetime, CMV is an important research focus as we seek to curtail the impact of other chronic diseases associated with HIV.”

Triplex is a modified vaccinia ankara (MVA)-based vaccine, encoding the 3 full-length CMV antigens pp65 (UL83), IE1-exon4 (UL123), and IE2-exon5 (UL122). Prior stage 1 and 2 studies demonstrated Triplex as safe and capable of preventing CMV-related disease in over 100 adults with hematologic stem cell transplants.

A5355 is a phase 2, randomized, double-blind, placebo-controlled study to evaluate the safety and immunogenicity of 2 Triplex injections. Included participants are 18-65 years of age and living with both HIV and CMV. All patients must have undetectable HIV RNA on antiretroviral therapy (ART), with current CD4+ cell count >250 cells/μL and nadir CD4+ cell count ≥100 cells/μL). Approximately 25% or more of participants will be cisgender or transgender women.

The participants will be randomized 2:1, with 60 receiving Triplex and 30 receiving placebo at the study launch and at week 4, as administered through 2 intramuscular deltoid injections. Participant follow-up will continue for 92 weeks after the week 4 injections, for a total study duration of 96 weeks.

“The ACTG is eager to gain insights from this first-of-its-kind study into Triplex’s potential ability to reduce systemic inflammation among people living with HIV, which can be linked to a number of health issues that impact their quality of life,” Currier said.