Daiichi Sankyo has initiated a trial in Japan to investigate a booster dose of DS-5670, an mRNA vaccine against Covid-19. The trial is being conducted as a phase 1/2/3 study to evaluate the safety and efficacy of DS-5670 in healthy Japanese adults, including an elderly population, who completed initial vaccination (1^st and 2^nd shots) against Covid-19 with vaccines approved in Japan after at least 6 months following last vaccination. The first part of the study will determine the recommended booster dose of DS-5670 followed by a controlled study in 4,500 adults comparing DS-5670 to other vaccines approved in Japan.

About DS-5670

DS-5670 is an mRNA vaccine against Covid-19 using a novel nucleic acid delivery technology discovered by Daiichi Sankyo. It is anticipated to be safe and efficacious by targeting the receptor binding domain (RBD) of the new coronavirus. In addition, DS-5670 in animal models induced neutralizing activities against the Omicron variant to a certain extent following the initial vaccination, and the additional dose further increased neutralizing activities, demonstrating a potential booster effect.

The clinical development of DS-5670 is being conducted through “Vaccine development project” promoted by Japan Agency for Medical Research and Development (AMED) and “Urgent improvement project for vaccine manufacturing systems” supported by Ministry of Health, Labour and Welfare (MHLW).