Cellid, one of the local developers of a homegrown Covid-19 vaccine, updated its plan for a local, late-stage trial.
“Our latest plan for a phase 2b trial benchmarked Janssen’s discussion for a booster shot. We have yet to confirm two doses of the vaccine, but this is one of the many possibilities to advance the marketing approval for the vaccine,” an official at Cellid told Korea Biomedical Review.
On Friday, Cellid applied for a Phase 2b/3 study of AdCLD-CoV19-1, an investigational Covid-19 vaccine, to the Ministry of Food and Drug Safety (MFDS).
It is the third company seeking a late-stage study of a Covid-19 vaccine, following SK Bioscience and EuBiologics.
Cellid’s latest trial plan, however, is somewhat different from the previous one.
In the upcoming phase 2b study, the company said it would divide 125 participants from Korea and overseas into a single-dose group and a two-dose group to compare the vaccine’s immunogenicity and safety results. With the results, the company will decide on the optimal dose for a phase 3 trial.
Cellid promotes that its vaccine candidate AdCLD-CoV19-1 can induce sufficient protective effect with a single shot only.
However, the company said it could change its mind.
Cellid said the plan was only exploratory as booster shots have become the talk of the town. However, industry officials noted that testing two doses in a trial without any license for a vaccine means changing the dose regimen, not adding a booster shot.
Some worried that Cellid’s mentioning of “a strategic decision making to secure flexibility in preparation for a phase 3 trial” could mean its vaccine development may progress slowly.
Cellid admitted that it reviewed changing the dose regimen from a single shot to two jabs in the upcoming trial. However, it emphasized that nothing has been confirmed.
“Just one dose of AdCLD-CoV19-1 can induce an excellent immune response,” an official at Cellid said.
However, suppose vaccination with Janssen’s Covid-19 vaccine, based on the same platform (adenovirus vector), requires two doses. In that case, the regulatory agency might apply the same criteria when reviewing Cellid’s AdCLD-CoV19-1, he explained.
“The phrase, ‘securing flexibility in preparation for a phase 3 trial,’ seems to have caused a misunderstanding in the market,” he went on to say. “The expression means that our company will prepare all the necessary data for comparative trials with a control vaccine or an immunological correlate of protection (ICP).”
The official also mentioned the possibility of a change of the control vaccine in a phase 3 study.
He refused to disclose the name of the vaccine maker but said that Cellid was discussing not only with the MFDS but the Coalition for Epidemic Preparedness Innovations (CEPI).
Cellid plans to compare AdCLD-CoV19-1’s immunogenicity with that of a control vaccine in a phase 3 trial on 4,100 healthy adults (3,100 assigned for AdCLD-CoV19-1 and 1,000 for control vaccine).