Hijacking The Messenger

Exosomes have evolved over millennia to deliver macromolecules in their native, active forms from one cell or one tissue to another. The small lipid-membraned sacs are filled with a soup of nucleic acids and proteins: messages, signals or instructions that emerge from one cell to journey to a nearby or distant destination. Now a handful of biotech companies are repurposing exosomes as off-the-shelf treatments for various diseases, and engineering them using ligands or antibodies to route them to various tissues in the body. These exosomes can be decorated or filled, Trojan-horse style, with anything from traditional small molecules to biologics to various flavors of oligonucleotide, and sent off to hit membrane-based or even intracellular targets.

Exosomes may prove to be potent therapies – and they might solve some of the thorniest delivery problems that have...