By Ilan Zipkin
Staff writer

Cystic fibrosis was seemingly the perfect test case for gene therapy approaches: the disease results from a well characterized defect in a single known gene - CFTR, a transmembrane chloride channel - and activity is required in one tissue for a straightforward biochemical purpose. However, even as the tenth anniversary of the cloning of CFTR approaches, difficulties with delivery and vectors have kept CFTR gene therapy products in early clinical development with no strong signs of efficacy.