Gene Therapy To Treat Deadly Cancer

The world's first gene therapy trial to treat patients with pancreatic cancer is being launched in the UK. The therapy uses a "Trojan horse" technique to hit cancer cells with large doses of toxic drugs. MetXia, developed by UK company Oxford BioMedica, consists of a retrovirus which has been modified to carry a gene for an enzyme that normally occurs in the liver. Retroviruses only replicate in dividing cells, so the treatment mainly targets cancer cells. Once in the cell, the virus inserts the gene for the enzyme and the cell starts producing it. The enzyme then converts an inactive drug into a toxic form. This obliterates the tumour cells, without harming normal ones. It also means a hugely increased dose of chemotherapy can be delivered to tumours, without patients suffering greater harmful effects.