Some biotech investors had probably never heard of exosomes until Codiak’s chief executive, Doug Williams, made his pitch at the JP Morgan conference two weeks ago. But the area has been gaining traction, and Jazz’s $56m up-front payment to Codiak is its biggest endorsement to date. Roche and Boehringer Ingelheim have also bought into rival technologies, which broadly seek to use exosomes as delivery vehicles for proteins, small molecules, RNA and other therapeutics. Naturally occurring exosomes are vesicles that bud off from many mammalian cells and are subsequently internalised by other cells, along with their cargo, hence their role in cell-cell communication.