A hepatitis C drug from Santaris targeting a microRNA is now in the early stages of clinical testing, reports Technology Review. The drug, a synthetic nucleic acid, binds miR-122, which the hepatitis C virus needs to reproduce. "Whereas other chemistries invented in the last 20 years as a means to improve the [binding] properties of oligonucleotides [short strands of RNA or DNA] provide one degree of improved binding, locked nucleic acids provide five-fold to ten-fold improvement," Santaris's vice president and chief scientific officer, Henrik Orum, says. "It's really a quantum leap in affinity."