The Merck/Moderna collaboration is one of several combining powerful drugs that unleash the immune system to target cancers with mRNA vaccine technology.
BioNTech SE (22UAy.DE) and Gritstone Bio Inc (GRTS.O) are working on competing cancer vaccines based on mRNA technology.
Barr said it took about eight weeks to design a personalized mRNA vaccine for each patient.
In the past, similar experimental cancer vaccines were developed targeting a single tumor mutation, or neoantigen.
With mRNA technology in combination with Keytruda, "we can create this shotgun approach ... that can create a more potent immune response," Barr said.