First self-amplifying mRNA vaccine approved in Europe

BELGIUM – Arcturus Therapeutics and CSL’s COVID-19 vaccine, Kostaive, has been approved for marketing in the European Union, making it the first self-amplifying mRNA (sa-mRNA) vaccine to achieve this milestone.

While the COVID-19 vaccine market has significantly shrunk since the pandemic’s peak, Kostaive is being hailed as an advancement over traditional mRNA vaccines like Moderna’s Spikevax and Pfizer/BioNTech’s Comirnaty, offering longer-lasting immunity.

Unlike conventional mRNA vaccines, which rely on a fixed amount of mRNA to stimulate the immune system, sa-mRNA vaccines direct the body to produce more mRNA and protein, boosting the immune response over time.

This allows the immune system to maintain protection for a longer duration without the need for additional doses.

Arcturus and CSL have shared clinical trial data showing that Kostaive (formerly ARCT-154) provides superior immune response and antibody persistence for up to 12 months after vaccination, compared to traditional mRNA vaccines.

The vaccine is specifically aimed at the JN.1 subtype of the Omicron variant BA.2.86, which remains one of the main circulating strains in Europe.

The vaccine is formulated with lipid nanoparticles and is administered in two doses, 28 days apart.

Kostaive has proven effective against multiple strains of the SARS-CoV-2 virus, which causes COVID-19. In phase 3 trials, it demonstrated over 95% efficacy in preventing severe COVID infections.

While Kostaive has been approved in the EU, it is not the first market where it has received approval.

The vaccine was also approved in Japan and is being distributed by Meiji Seika Pharma, starting with the 2024/25 COVID-19 vaccination campaign.

Additionally, the first sa-mRNA vaccine, Gemcovac, developed by Gennova Biopharmaceuticals, was launched in India in 2022.

However, CSL plans to make some adjustments to Kostaive’s formulation before launching in Europe. Jonathan Edelman, head of CSL’s vaccine innovations unit, stated that the changes aim to “better meet the needs of healthcare professionals and their patients.” He added,

“As COVID-19 remains an unpredictable global threat, CSL is dedicated to completing these technical enhancements and making this innovative vaccine available in Europe as soon as possible.”

CSL acquired the rights to Kostaive from Arcturus in 2022, paying US $200 million upfront to access Arcturus’ sa-mRNA platform for COVID-19 and other respiratory diseases, including influenza.

If development and commercial goals are met, Arcturus stands to receive over US $4.3 billion in milestone payments, along with a 40% net profit share for COVID-19 vaccines.