South Korea’s COVID-19 vaccine candidates can be evaluated through comparison with previously authorized vaccines. This means domestic vaccine developers will no longer have to recruit large control groups for a phase 3 clinical trial.

According to the Ministry of Food and Drug Safety on Wednesday, the government has revised guidelines for phase 3 clinical trials in a bid to accelerate the development of homegrown vaccines against COVID-19.

Under the new rules, drugmakers would need just 4,000 volunteers to conduct a phase 3 clinical study of a vaccine candidate. Based on the findings, they can compare the immunogenicity of an already authorized vaccine with one under development to prove its efficacy.

Cross-platform comparisons between already authorized vaccines and a candidate of a different type are also allowed.

Several South Korean firms are developing vaccines now, including Genexine, which is developing a DNA vaccine against the novel coronavirus. There are currently no DNA-based COVID-19 vaccines anywhere, meaning that Genexine has no authorized DNA vaccine that the company can compare with its vaccine candidate.

The Health Ministry said vaccine developers should consult with the ministry when designing cross-platform comparisons to decide the proper vaccine for comparison.

The minimum number of participants needed for a phase 3 clinical study was previously 10,000.

In terms of a cross-platform comparison, vaccine developers will need to secure 3,000 subjects to be administered with a new vaccine and 1,000 subjects who have been already vaccinated with an existing vaccine, according to the ministry.

The revision is expected to help local pharmaceutical companies speed up development of COVID-19 vaccines and ease difficulties in securing placebo-controlled subjects who have not been vaccinated, the ministry expected.

Domestic firms have experienced difficulties in recruiting enough test subjects, particularly placebo-controlled subjects, as more and more people are getting vaccinated these days.

The ministry expects that the new guideline will also help local firms save on spending for their clinical studies.

Meanwhile, the Health Ministry has also set up new articles in the guideline that allow for vaccine developers to be able to test their vaccines against COVID-19 variants.