Shionogi & Co., Ltd. announced that it has initiated a Japanese Phase 3 active control neutralizing antibody comparative clinical trial of a prophylactic vaccine candidate for COVID-19 (code No. S-268019), caused by the novel coronavirus (SARS-CoV-2) infection. Past development of COVID-19 vaccines has usually entailed large-scale clinical trials to evaluate the onset prevention effect.

However, as effective vaccines have become broadly distributed and more and more of the population has been vaccinated, it has become difficult to carry out onset prevention studies. At the same time, substantial demand remains for additional, and even initial, vaccine doses globally; therefore, it is necessary to develop safe and effective new vaccines. Under these circumstances, to progress the development of a new vaccine against COVID-19, the neutralizing antibody titer after vaccination can be used as a substitute index for the onset prevention effect.

After discussions at the International Coalition of Medicines Regulatory Authorities (ICMRA), neutralizing antibody titer comparison trials to evaluate a new vaccine in comparison to approved vaccines has been recognized as a viable evaluation method.1 The phase 3 clinical trial that started in Japan is a neutralizing antibody titer comparison study using an approved vaccine as a control. For adults and the elderly, the study compares the neutralizing antibody titer against the SARS-CoV-2 28 days after the second inoculation of S-268019 or the control vaccine (jRCT No.:2051210151). will continue to consult closely with the Ministry of Health, Labor and Welfare, Pharmaceuticals and Medical Devices Agency (PMDA) and other organizations regarding applications for approval based on the progess and results of the ongoing clinical trial.

2, 3, 4, 5 Shionogi's key focus and commitment is to protect people worldwide from the threat of infectious diseases. are working toward total care for infectious diseases through awareness building, epidemiological surveillance, prevention, diagnosis, and addressing exacerbations, as well as treating the infection itself. As SARS-CoV-2 continues to have a major impact on people's lives and represents a global threat, will seek to contribute to re-establishing the safety and security of society by developing, delivering, and producing a vaccine for COVID-19 in Japan.

will keep all stakeholders informed regarding the progress of efforts.