US-based messenger RNA (mRNA) medicines company Arcturus Therapeutics and Australian vaccines producer CSL Seqirus have entered into a licensing deal worth more than $4.5bn for the former’s late-stage self-amplifying mRNA vaccines.

Under the terms of the deal, Arcturus and CSL Seqirus will support the research, development, manufacturing, and commercialisation of the US firm’s self-amplifying mRNA technology for SARS-CoV-2, pandemic preparedness, influenza, and three other prevalent respiratory infectious diseases in the world.

CSL Seqirus will pay Arcturus $200m upfront and an additional $1.3bn for certain development milestones and over $3bn in payments for achieving commercial milestones. Arcturus will also be eligible for a net profit share of 40% for COVID-19 vaccine products along with double-digit royalties for the vaccines.

CSL chief operating officer Paul McKenzie said: “This collaboration is an exciting opportunity to complement CSL’s own next generation mRNA program with a partner who developed a platform to deliver late stage clinical supplies at scale.”

The partnership will combine the global vaccine commercial and manufacturing infrastructure of CSL Seqirus with the manufacturing expertise of Arcturus as well as its STARR self-amplifying mRNA vaccine and LUNAR delivery platform technology.

Arcturus will contribute to the collaboration of its experience in mRNA design and expertise in modification. The firm will also bring its know-how in LUNAR lipid nanoparticle (LNP) technology, which helped it produce the low-dose, lyophilised, and long-lasting self-amplifying mRNA COVID-19 vaccines.

Arcturus CEO and president Joseph Payne said: “We are excited to embark on this collaboration with CSL Seqirus, a respected world leader in the development, manufacture and commercialisation of vaccines.

“We look forward to a long and fruitful partnership as we work together to develop next generation self-amplifying mRNA vaccines to protect against the most prevalent infectious diseases.”