Long-term efficacy of the peptide-based COVID-19 T cell activator CoVac-1 in healthy adults
Claudia Tandler, Jonas S. Heitmann, Tanja Michel, Maddalena Marconato, Simon U. Jaeger, Christian M. Tegeler, Monika Denk, Marion Richter, Melek Tutku Oezbek, Yacine Maringer, Sarah M. Schroeder, Nicole Schneiderhan‐Marra, Karl‐Heinz Wiesmüller, Michael Bitzer, Natalia Ruétalo, Michael Schindler, Christoph Meisner, Imma Fischer, Hans‐Georg Rammensee, Helmut R. Salih, Juliane S. Walz
Abstract
BackgroundT cell immunity is key for the control of viral infections including SARS-CoV-2, in particular with regard to immune memory and protection against arising genetic variants. Method: We recently evaluated a peptide-based SARS-CoV-2 T cell activator termed CoVac-1 in a first-in-human trial in healthy adults. Here, we report on long-term safety and efficacy data of CoVac-1 until month 12.ResultsCoVac-1 is well tolerated without long-term immune-related side effects and induces long-lasting anti-viral T cell responses in 100% of study participants, with potent expandability of CD4+ and CD8+ T cells targeting multiple different CoVac-1 T cell epitopes. T cell responses were associated with stronger injection site reaction. Beyond induction of T cell immunity, 89% of subjects developed CoVac-1-specific IgG antibodies which associated with the intensity of the T cell response, indicating that CoVac-1-specific CD4+ T cells support the induction of B cell responses. Vaccination with approved COVID-19 vaccines boosted CoVac-1-specific T cell responses. Overall, a low SARS-CoV-2 infection rate (8.3%) was observed.ConclusionTogether, a single application of CoVac-1 elicits long-lived and broad SARS-CoV-2-specific T cell immunity, which further supports the current evaluation of our T cell activator in patients with congenital or acquired B cell defects.