Photo/Illutration Unigen Corp., a manufacturer of bio-pharmaceuticals, in Ikeda, Gifu Prefecture, is getting its factory ready to produce a COVID-19 vaccine being developed by Shionogi & Co. (Provided by Shionogi & Co.)

Shionogi & Co. looks set to put its COVID-19 vaccine into practical use by the end of March 2022 following a government decision to change clinical trial methods that put Japanese vaccine developers trailing foreign rivals at a disadvantage.

Like other domestic drug companies, it had faced difficulties accomplishing the final phase of clinical trials involving tens of thousands of participants due to the regulations.

However, the government recently gave pharmaceutical companies a break by announcing they can use other means to speed up the development of homegrown vaccines. 

Japan, which until very recently had been grappling with a rapid surge in COVID-19 cases nationwide, has relied on imports and domestic production of vaccines developed overseas to accelerate its vaccine rollout.

Osaka-based Shionogi said it tinkered with the formula of a vaccine it is jointly developing with the National Institute of Infectious Diseases and a university to allow it to carry out the final phase of testing under the new procedure.

The company said Aug. 2 it aims to enter the final phase of clinical trials by the year-end and start supplying doses by the end of fiscal 2021 once it gains the go-ahead from the government.

Shionogi said it is also gearing up to increase production capacity by the end of this year to manufacture enough doses to inoculate up to 60 million people a year.

The company started clinical trials in Japan involving 300 participants last December.

Currently, pharmaceutical firms are obliged to recruit tens of thousands of test subjects for the final phase of clinical trials to evaluate the efficacy of their vaccines and assess the severity of possible adverse reactions from receiving jabs.

Half of the participants are administered doses of a vaccine candidate, while the other half receive shots of a placebo.

But the procedure poses an ethical problem in administering placebo jabs as millions of people in Japan have already been inoculated with COVID-19 vaccines developed by overseas companies.

In response, the government decided to introduce an alternative method to confirm the effectiveness of vaccines under development.

Under the procedure, drug companies compare the amount of neutralizing antibodies, which are believed to be effective in preventing infections, in blood samples taken from people who received shots of a vaccine candidate with that in recipients of authorized vaccine doses.

The government is making final arrangements with the International Coalition of Medicines Regulatory Authorities (ICMRA) to formally adopt the method.

The new procedure requires only several thousands of participants, thereby shortening the study period, according to the health ministry.

Shionogi has already changed the type of an adjuvant, a substance that helps bolster the vaccine’s efficacy, to increase the volume of neutralizing antibodies it produces. The company said experiments on monkeys confirmed that those inoculated with the vaccine had the same volume of antibodies that COVID-19 survivors did, and sometimes more, in their blood.

The company was forced to restart its clinical trial for the vaccine from an early phase in July because of the change in the adjuvant.

In addition to the new method, Shionogi said it is also preparing to conduct the final phase of clinical trials using conventional methods by recruiting participants in Asian and African countries. The company said it hopes to begin the final phase by whichever method meets its requirements first.

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