CureVac gets OK to start testing mRNA COVID-19 vaccine in humans

CureVac has received regulatory clearance to start a phase 1 trial of its COVID-19 vaccine. The start of the 168-subject study comes days after the German government invested €300 million ($337 million) in CureVac to support its efforts to develop and manufacture a vaccine against the coronavirus.

To date, CureVac has been outshone by its mRNA rivals in the COVID-19 vaccine race. Moderna got into the clinic first. CureVac’s compatriot BioNTech landed a deal with Pfizer and followed Moderna into the clinic. CureVac, in contrast, has made more headlines for a reported approach by the Trump administration and the departure of its CEO than for its COVID-19 vaccine.

That may now start to change. Wednesday, CureVac said regulatory agencies in Belgium and Germany have authorized it to start a phase 1 clinical trial of CVnCoV, a COVID-19 vaccine featuring mRNA that encodes for the spike protein formulated with lipid nanoparticles.

“During the last few months our team has put a lot of efforts into the preclinical validation of several vaccine candidates to select an optimal construct. We are confident that our early optimization work will provide a safe and effective low dose vaccine,” Franz-Werner Haas, acting CEO of CureVac, said in a statement.

The phase 1 dose-escalation study, which is set to start “promptly,” will enroll 168 people aged 18 to 60 years. Participants will receive doses of CVnCoV ranging from 2 µg to 8 µg to determine the optimal dose of the vaccine and assess its safety and immune profile. Moderna, the biotech with the most advanced mRNA COVID-19 vaccine, selected 100 µg as the dose for its phase 3 clinical trial. 

CureVac will start the process of assessing whether its vaccine works in humans at Ghent University Hospital in Belgium, the Tübingen Institute for Tropical Medicine, the Tropical Institute of the University Hospital Munich and the Hannover Medical School in its native Germany.

The activation of a trial site in Belgium gives the mRNA specialist the chance to enroll participants in a nation that was hit relatively hard by COVID-19 and continues to report more cases than Germany. At the peak of its outbreak, Belgium was averaging around 120 cases per million people a day. Germany, in contrast, barely saw more than 60 cases per million people.

Belgium has since dramatically reduced the number of cases, but, with the caveat that confounding variables could affect the analysis, still appears to have a higher rate of new infections than Germany. Over the past week, Belgium averaged nine cases per million people compared to four cases per million in Germany.

Such differences could matter as CureVac begins to test whether its vaccine prevents infection with SARS-CoV-2 and improves outcomes in people carrying the virus. The primary purpose of the phase 1 is to assess the safety and immune profile of the vaccine, but CureVac will need to assess efficacy at some point. 

In countries where SARS-CoV-2 is less prevalent, such as Germany, trial participants will be less likely to come into contact with the virus; by extension, it will take studies longer to generate efficacy data. The time-pressured nature of COVID-19 vaccine development is leading companies to try to avoid such delays, for example by enrolling healthcare professionals and other groups more likely to be exposed to the coronavirus in efficacy studies.