With large vaccine studies harder to carry out, regulators look for alternatives

A cross-border coalition of medicines regulators has begun exploring alternatives to large-scale clinical trials when it comes to evaluating the efficacy and safety of coronavirus vaccines, as it is becoming difficult for latecomers to secure enough study participants.

If the International Coalition of Medicines Regulatory Authorities finds other effective ways, drugmakers in Japan and other countries trailing the United States and European countries in COVID-19 vaccine development would be able to accelerate their development and production.

The authorization or approval of vaccines generally requires a large-scale clinical study with the involvement of tens of thousands of participants — in groups receiving a vaccine or a placebo — to assess their safety and efficacy by comparing their data.

However, since vaccination campaigns using those developed by U.S. and European firms have already begun in a number of countries, it has become difficult for some nations to recruit a sufficient number of test subjects who have no immunity against the coronavirus.

The move by the coalition comes as calls have been mounting from many countries to review the policy of requiring large-scale clinical trials.

In Japan, for example, several companies including Shionogi & Co. have been engaged in the development of coronavirus vaccines, but a large-scale clinical study is a major hurdle for the completion of domestic vaccines.

With highly contagious virus variants spreading in the country and elsewhere, the government is scrambling to find other ways to evaluate vaccine efficacy while not turning a blind eye to health risks, including the assessment of potential side-effects, at the same time.

“We are not at a stage to disclose concrete methods yet,” a health ministry official said. “It is essential to collect reliable data not only on efficacy but also on safety.”

The authorities are studying various approaches based on data from already available vaccines developed by U.S. pharmaceutical giant Pfizer Inc. and others.

One alternative is to figure out the relationship between the amount of antibodies generated after vaccination and its effectiveness in preventing symptoms of the disease using the available data.

This method may allow other drugmakers to evaluate the efficacy of their vaccine candidates by studying the amount of antibodies in small-scale clinical studies.

Other ideas include comparing data of people who have received vaccines still under development and those who have received authorized vaccines of U.S. and European firms. This method does not require data of those who received a placebo.

If the coalition, which plans to discuss the matter several times a month, can establish an alternative capable of evaluating COVID-19 vaccines swiftly, it would apply to the development of modified vaccines against coronavirus variants as well.