Moving to expand its vaccine pipeline after some slip-ups last year, Sanofi is betting on Translate Bio's mRNA platform in up to five undisclosed infectious disease targets.

In an R&D deal (PDF) disclosed this week, Sanofi will pay Translate $45 million upfront, plus up to $760 million in potential milestones. The companies will work to advance mRNA vaccines under an initial three-year agreement. Additional payments could come from development, regulatory and sales milestones, or if Sanofi exercises options in additional disease areas. Translate Bio is also eligible for sales royalties if the programs make it to market.

Under the deal, Sanofi agreed to pay for all R&D costs and will retain worldwide marketing rights for the shots. For its part, Translate Bio will manufacture supplies for clinical tests under a separate agreement that the companies haven't yet established.

For Translate Bio, the deal comes right on the heels of its move to file for an IPO worth $115 million. Formerly known as RaNA Therapeutics, the company is seeking to advance cystic fibrosis and ornithine transcarbamylase deficiency candidates based on an mRNA therapeutic platform it acquired in 2016 from Shire.

The deal provides Sanofi a chance to grow its vaccine pipeline after setbacks in 2017. In November, Sanofi warned of an increased risk of severe dengue in people vaccinated with Dengvaxia who haven't had prior exposure to the virus. The revelation sparked a safety controversy that is still playing out in the Philippines, the only country to undertake a full-scale vaccination program with the vaccine. Sanofi agreed to refund unused doses, and issues with the vaccine cost the drugmaker €158 million in the fourth quarter last year.

Aside from dengue, the company also pulled the plug on its late-stage C. difficile shot after an interim analysis determined it wasn't likely to succeed.

In a statement, Sanofi Pasteur senior vice president of R&D John Shiver said the company believes mRNA technology holds "significant potential for rapid and versatile manufacturing, reduced industrialization costs for multiple vaccines, and the improved breadth of immune response for infectious disease vaccines." For its part, Translate believes the deal validates its program and allows it to expand its platform beyond cystic fibrosis and OTC deficiency, CEO Ronald Renaud said in a statement.

Other biotechs working on mRNA vaccines include Moderna, CureVac and BioNTech.