The first doses of LUNAR-COV19, an investigational self-replicating mRNA SARS-CoV-2 vaccine, developed by Duke-NUS and Arcturus Therapeutics, were administered to a group of healthy volunteers in a trial in Singapore, the company announced today.
The first group of younger volunteers, aged 21 to 55, had all been injected with a dose of the vaccine candidate which became better known as ARCT-021. This marked the beginning of the Phase I/II trial to evaluate the safety of the vaccine. As well as safety, the longitudinal immune responses and T-cell response data would be monitored and inform which dose regimens would be selected for the second phase of the study. That phase would include cohorts in both younger and older adults, aged 56 to 80.
The trial had been brought forward from its original September start date due to promising results from preclinical trials. The preclinical data showed that a single 2µg dose of ARCT-021 was sufficient to trigger the production of neutralising antibodies in 100 per cent of the vaccinated animals. It also induced a type of immune cell known as CD8 T cells, which help the body fight invading pathogens. In the face of a respiratory infection, these cells help to clear viral particles from the lungs by bringing about a robust immune system response.
With the start of this new phase, the Duke-NUS team that had completed much of the preclinical testing shifted gears to receive the clinical trial samples. That meant running the same set of tests for each of the more than 100 trial participants at each time point.
While the work became repetitive after some time, the team was acutely aware of their mission: to generate the data needed to deliver a vaccine that could save lives as fast as possible. The stakes could not have been higher.
“It was a highly stressful time. We had to be extremely rigorous and detailed for these clinical trials,” reflects Dr Ruklanthi de Alwis, a then senior research fellow with the Viral Research and Experimental Medicine Centre at SingHealth Duke-NUS (ViREMiCS). “We kept a good track of samples that came in pretty much every day. Everything was very tightly organised.