Last month, Europe’s Committee for Medicinal Products for Human Use approved a gene therapy for a rare genetic disease, the first time a Western regulatory agency has okayed such a treatment, though gene therapies have been approved in China.

The virus-mediated treatment, called Glybera, which is being developed by Amsterdam-based UniQure, introduces a normal version of a gene needed to properly break down fats in the blood. Though the condition is rare, patients with dysfunctional copies of this gene have dramatically increased levels of fat in their blood, which can lead to fatal inflammation of the pancreas.