After about a year and half since trial initiation, the WHV138 clinical team has recently administered the trial’s final vaccination of the investigational product PDPHV, a polyvalent DNA/Protein HIV Vaccine that includes five DNA plasmids encoding for HIV Env A, B, C, AE and gag C with matched protein gp120 Env antigens. WHV138 is currently the only in-human clinical trial testing a heterologous HIV vaccine candidate that targets all four major circulating subtypes of HIV-1. The administration of the trial’s final vaccination without the occurrence of any major safety concerns thus far is therefore a promising and exiting milestone for the whole HIV vaccine research community.
The single-site, randomized, placebo-controlled phase 1b trial WHV138 started screening in June of 2021 and enrolled a total of 42 volunteers into two groups. Both groups received the DNA and the Protein products of PDPHV as a co-administration regimen in repeated doses but at slightly different vaccination schedules. While Group 1 volunteers received four doses of the DNA and the adjuvanted Protein vaccine in two different arms over the course of twelve months, Group 2 volunteers received five doses of a mix of the DNA and the Protein vaccine without an adjuvant into both arms over the course of eight months. All active volunteers will continue the trial for a 12-month safety observation period following their final vaccination.
The previously conducted phase 1a HVTN124 trial assessed the safety and immunogenicity of PDPHV using a DNA prime – Protein boost approach which has shown remarkable immune responses according to preliminary analyses that were presented at the 2022 Keystone Symposium on Next Generation HIV Vaccines and Therapies earlier last year. Exploratory immunogenicity studies of WHV138 will be conducted once the trial concludes towards the end of this year.
