Sanofi partnered with Translate Bio in a deal worth up to US$800 million to develop mRNA vaccines against up to five infectious disease pathogens.

mRNA vaccines are an emerging new vaccine modality in which patients are treated with mRNA oligonucleotides that encode either an antigen of interest or an antigen as well its viral replication machinery. Although their application has been limited by the instability and inefficient in vivo delivery of mRNA, a recent review in Nature Reviews Drug Discovery summarized how technological advances have now largely overcome these issues.

“Currently, mRNA vaccines are experiencing a burst in basic and clinical research. The past 2 years alone have witnessed the publication of dozens of preclinical and clinical reports showing the efficacy of these platforms. Whereas the majority of early work in mRNA vaccines focused on cancer applications, a number of recent reports have demonstrated the potency and versatility of mRNA to protect against a wide variety of infectious pathogens,” the authors write. The authors also caution that two recent trials found that immunogenicity in humans may be more modest than anticipated and side effects can be non-trivial with at least some mRNA vaccine platforms.

Translate Bio, formerly called RaNA Therapeutics, and Sanofi have not yet disclosed what pathogens they will be working on. But several companies have advanced infectious disease mRNA vaccines into the clinic. Argos Therapeutics and partner Kyowa Hakko Kirin are testing AGS-004 in phase II HIV trials, and Curevac is testing its CV7201 in a phase I rabies trial. Moderna's mRNA-1388, mRNA-1851, mRNA-1325, mRNA-1647 and mRNA-1653 are in phase I trials for chikungunya virus, influenza, zika virus, cytomegalovirus, human parainfluenza virus and human metapneumovirus, respectively.

Companies are also working on mRNA cancer vaccines that train the immune system to find and kill cancer cells, and on mRNA-based therapeutics that can replace or supplement aberrant proteins.