Sanofi and Translate Bio have announced the launch of a phase 1/2 trial evaluating their mRNA-based COVID-19 vaccine candidate MRT5500.
The randomised, placebo-controlled trial will evaluate the safety, tolerability and immunogenicity of MRT5500 and is expected to enrol 415 healthy adults aged 18 years and older.
Participants taking part in the phase 1/2 trial will receive one dose of MRT5500 or two doses administered 21 days apart. Sanofi and Translate will investigate three different dose levels of the vaccine candidate – 15µg, 45µg or 135µg.
The companies added that preclinical studies are also ongoing and are set to continue over the coming months.
These studies will evaluate if MRT5500 and additional mRNA vaccine candidates can induce neutralising antibodies against emerging SARS-CoV-2 variants.
“Our mRNA vaccine candidate is the result of our expertise in infectious diseases coupled with the innovative technologies of our partner,” said Thomas Triomphe, executive vice president and global head of Sanofi Pasteur.
“Initiating the phase 1/2 trial represents an important step forward in our goal of bringing another effective vaccine to the ongoing fight against the COVID-19 pandemic,” he added.
In October, Sanofi and Translate published findings from preclinical studies of MRT5500.
The preclinical data showed the vaccine candidate induced high antibody levels in preclinical studies, leading to the production of neutralising antibodies in mice and macaques.
Neutralising antibody titers were observed across all dose levels tested – 0.2, 1, 5 and 10 µg per dose – after a two-dose administration regimen.
However, in the higher dose groups, titers were detected after one shot of MRT55000 and were stronger following the second administration.
In macaques (non-human primates), the majority of subjects developed neutralising antibodies reactive to the SARS-CoV-2 spike protein after the first administration of MRT5500, with the antibodies enhanced following a second dose.
Researchers also tested a specific immune reaction – Th1-biased T cell response – which in previous studies has been found to accelerate in patients with mild cases of COVID-19.
In the preclinical study, all mice and macaques immunised with MRT5500 exhibited a Th1-biased T cell response against SARS-CoV-2.
Sanofi and Translate are expecting interim results from the phase 1/2 clinical trial of MRT5500 in the third quarter of 2021.
The companies are also working on ‘improving’ the temperature stability of MRT5500, with the aim of achieving a -20°C storage temperature for late-stage clinical trials and potential launch.