Daiichi takes mRNA COVID-19 vaccine into clinic as Japanese R&D belatedly fires up

Office building showing Daiichi Sankyo logo
The Daiichi Sankyo trial is part of a flurry of studies of Japanese COVID-19 vaccines.

Daiichi Sankyo has begun (PDF) a phase 1/2 clinical trial of an mRNA vaccine against COVID-19. The vaccine is set to come to market well after leading prophylactics but gives Japan a chance to establish its own countermeasures for COVID-19 and future health crises. 

Japan has played a small role in the development of COVID-19 vaccines so far. AnGes took a vaccine candidate into the clinic last year, but the rest of the local industry has lagged well behind. Japanese companies have struck deals to make foreign vaccines, such as Daiichi’s deal with AstraZeneca, but home-grown innovation has been lacking.

Daiichi signaled its intent to bring a home-grown vaccine to market in August when it was selected to take part in government initiatives to develop COVID-19 prophylactics and build production capacity. The vaccine covered by the agreements, DS-5670, is now in the clinic.

Investigators are enrolling 152 healthy adults, including elderly individuals, in the phase 1/2 trial. The study will assess the safety and immunogenicity of the mRNA vaccine to determine a recommended dose for further development. 

Daiichi is yet to share a timeline for further development of the vaccine but, based on the speed at which other products came to market, the product is unlikely to win approval until late this year at the earliest. Japan’s vaccination campaign has ramped up relatively slowly—0.44% of people had received at least one dose as of March 19—but with jabs from AstraZeneca and Moderna waiting to join the Pfizer-BioNTech product on the market, it is possible Daiichi will arrive too late to play a big role in the initial immunizations.

By then, attention may have turned to protecting the population against variants. Japan has reported cases of infection with variants featuring E484K, the mutation that is thought to make the virus more resistant to antibodies. E484K is found in the variants first identified in Brazil and South Africa. The start of work on DS-5670 predates the emergence of the variants, suggesting it may be less effective against them than it is against the original coronavirus. 

In the longer term, the development of DS-5670 may ensure Japan is equipped to respond faster to new or mutated pathogens. Vaccines from Moderna and Pfizer-BioNTech have pointed to the power of mRNA to protect against pathogens, suggesting Daiichi’s technology could be used in response to future health crises if validated against COVID-19. The capacity Daiichi is establishing is intended for use in the responses to infectious diseases other than COVID-19.

The Daiichi trial is part of a flurry of studies of Japanese COVID-19 vaccines. Shionogi became the second company to trial a Japan-originated COVID-19 vaccine late last year, and KM Biologics disclosed the initiation of its study on the same day as Daiichi.