Expert opinion in biological therapy: update on developments in lung gene transfer.

INTRODUCTION: Gene therapy may be suitable for a large number of acquired and inherited lung diseases, and research efforts in the field are vast. Although gene transfer to the lung has proven more challenging than initially anticipated, significant progress has been made over the last 10 years. AREAS COVERED: Here, we will first review viral and non-viral gene transfer agents that have been assessed for lung gene therapy and discuss key barriers to pulmonary gene transfer. We will then review progress in gene therapy for various lung diseases. EXPERT OPINION: In our view, one of the most significant developments in recent years is the generation of lentiviral vectors which efficiently transduce lung tissue. Focused and coordinated efforts assessing lentivirus safety and scaling up lentivirus production will be required to move this vector into clinical lung gene therapy studies. Although market authorization for a lung gene therapy product is not yet available, we are optimistic that this key milestone can be achieved in the next few years.