I would check out the work by John Engelhardt.  His group has been one of the most active in the area of gene therapy for CF.

http://www.medicine.uiowa.edu/dept_primary_apr.aspx?appointment=Anatomy%20and%20Cell%20Biology&id=engelhardtj

This is a good review article:

Science. 2009 Jun 19;324(5934):1504-7. doi: 10.1126/science.324_1504.

Genetics. The promise of a cure: 20 years and counting.

Couzin-Frankel J.

http://www.ncbi.nlm.nih.gov/pubmed/?term=couzin-frankel+gene+therapy+cystic+fibrosis

Hello

Over 1600 clinical trials have been conducted using gene therapy approaches. The Journal of Gene Medicine maintains an excellent publicly accessable database of all such studies.

Good Luck

http://www.ndsu.edu/pubweb/~mcclean/plsc431/students98/senn.htm

Dear Manar,

On the site of the UK Cystic Fibrosis Gene Therapy  Consortium  you'll find all the last information about the ongoing gene therapy trials in cystic fibrosis http://www.cfgenetherapy.org.uk/index.php  including the link to the recent paper in The Lancet.

Best regards,