German biotech firm CureVac announced on Monday the start of Phase 2b/3 clinical trial of its COVID-19 vaccine candidate. The trial is expected to include more than 35,000 participants in Europe and Latin America.
The trial will assess the safety and efficacy of the coronavirus vaccine in adults in preventing COVID-19 of any severity as well as preventing moderate to severe confirmed cases of COVID-19 in participants who have never been infected with SARS-CoV-2, CureVac said.
“The clinical safety and immunogenicity data achieved to date look promising and we are hopeful that this trial will continue to demonstrate the impact of mRNA technology and our vaccine to prevent COVID-19, and to help defeat this pandemic,” Chief Executive Franz-Werner Haas said.
CureVac has taken a slightly different route to test mRNA than the BioNTech/Pfizer and Moderna approach. It is using the vaccine’s potency in a 12-µg dose, compared to the 100 µg used by Moderna. This will enable CureVac to make more doses of the vaccine. CureVac is also aiming to trigger balanced immune responses.
This phase of the trial will randomly select 4,000 subjects across two age groups—18 to 60 years and 61 years and older—who will be given two doses of CVnCoV or placebo four weeks apart. 61 years and older participants will number around 1000.
CureVac will move into phase 3 if the data supports the larger study. In phase 3, 32,500 subjects will be recruited to receive the vaccine.
Data on reactogenicity and immunogenicity within this trial will determine start of the phase 3 of the trial. The trial regulators will observe at least 1000 of the receivers for a week after the first dose and make a decision on the phase 3.
CureVac will move into phase 3 if the data supports the larger study. In phase 3, 32,500 subjects will be recruited to receive the vaccine. CureVac plans to pool data from the phase 2b and 3 portions of the clinical trial.
The first review will take place after 56 people have developed COVID-19, with later reviews scheduled for 111 and 185 cases. CureVac estimates the first review will take place around five months after the first vaccination. If seven cases or fewer are in the CVnCoV arm at that point, CureVac will count that as a successful vaccination point and will likely start preparing for regulatory filings.
The German government is supporting three vaccine candidates with about 750 million euros (US$911 million) in total. The European Commission has already secured up to 405 million doses of the vaccine.
The other mRNA vaccines have had nearly 90 plus percent efficacy. CureVac will also need a similar 90 percent efficacy and a good safety profile to join the top tier of COVID-19 vaccines.
Based on the available data, the CureVac candidate’s immune responses compared to other vaccines is similar. A higher proportion of subjects who received 12 µg of CVnCoV had moderate to severe fever, headache and fatigue also seen in the BioNTech-Pfizer phase 3, although the CureVac results come from a small cohort.
The CureVac vaccine does not require very cold temperatures like the BioNTech vaccine, (which needs -70 degree temperature) and can stay stable for at least three months at standard fridge temperatures, the company said. The group will join 13 other drugmakers in proceeding to phase 3 trials, according to the World Health Organization.
The company says it will be able to produce up to 300m doses in 2021, and a further 600m doses in 2022. This is far less than the BioNTech/Pfizer capacity. They have promised nearly 1.3bn doses next year.
