RAC Approves Gene Therapies For Cancer, CF

The US National Institutes of Health's Recombinant DNA Advisory Committee (RAC) met earlier this month to review several applications for new gene therapy protocols for cancer and cystic fibrosis. The panel approved in principle Genzyme's adenovirus-mediated gene therapy for cystic fibrosis (pending submission of further safety data) and Vical's interleukin-2 lipid complex protocol for solid tumors or lymphomas, but deferred approval of Genetic Therapy's Herpes simplex thymidine kinase vector protocol for head and neck cancer.

Genzyme's protocol, which is the first to utilize aerosolized delivery of CF gene therapy to the lungs, is in two parts. In the first part of the procedure, investigators will directly administer an adenovirus vector that contains the normal cystic fibrosis transmembrane receptor (CFTR) gene into one lobe of each patients lungs using a bronchoscope. In the second part, the patients will inhale the adenovirus vector in aerosol form. Around 20 patients will be included in each arm of the trial.

There were some concerns raised at the panel meeting regarding the safety of aerosolized administration of vectors, particularly with regard to contamination of the surrounding environment. Genzyme's protocol includes three levels of protection, including isolation in a room, a canopy within the room and a hood within the canopy. The committee voted to approve the protocol once data from experiments testing viral contamination following aerosolization have been reviewed by an RAC subcommittee.