Gene therapy alone has been given to patients whose disease had recurred following radiation therapy. Gene therapy prevented development of lung metastases. Mice with existing metastases were given gene therapy and the gene therapy prevented the growth of the existing metastases. The gene by itself does not kill the cancer cell. In order to kill the cancer a drug by the name valacyclovir must be administered as well.
Thymidine kinase causes a reaction with the valacyclovir that kills the cancer.
The gene therapy causes an immunological response that kills the cancer cell. The killing of the cancer cell by two different mechanisms is the reason why gene therapy is thought to have such an exciting future in the treatment of cancer. There is no added cost to the patient for the gene therapy. Yes, biopsies will have to be done. One biopsy will be done during hormonal therapy if hormonal therapy is part of the protocol.