Long-term Follow-up of Patients with Malignant Pleural Mesothelioma Receiving High-Dose Adenovirus Herpes Simplex Thymidine Kinase/Ganciclovir Suicide Gene Therapy
Saturday, October 15th, 2005.
Clinical Cancer Research. 2005 Oct 15;11(20):7444-53. [Link]
Sterman DH, Recio A, Vachani A, Sun J, Cheung L, Delong P, Amin KM, Litzky LA, Wilson JM, Kaiser LR, Albelda SM.
Authors’ Affiliations: Thoracic Oncology Research Laboratory.
Abstract
Purpose: Delineation of the long-term follow-up data on a series of patients with malignant mesothelioma, who received a single intrapleural dose of a nonreplicative adenoviral (Ad) vector encoding the herpes simplex virus thymidine kinase "suicide gene" (Ad.HSVtk) in combination with systemic ganciclovir.
Experimental Design: This report focuses on the 21 patients receiving "high-dose" therapy, defined by an intrapleural dose of vector (>/=1.6 x 10(13) viral particles), where transgene-encoded tk protein was reliably identified on immunohistochemical staining. In 13 patients, the vector was deleted in the E1 and E3 regions of the Ad; in the other eight patients, the vector had deletions in the Ad genes E1 and E4. Safety, immunologic responses, transgene expression, and clinical responses were evaluated.
Results: Both the E1/E3-deleted vector and the E1/E4-deleted vector were well tolerated and safe, although production of the E1/E4 vector was more difficult. Posttreatment antibody responses against the tumors were consistently seen. Interestingly, we observed a number of clinical responses in our patients, including two long-term (>6.5 year) survivors, both of whom were treated with the E1/E4-deleted vector.
Conclusions: Intrapleural Ad.HSVtk/ganciclovir is safe and well tolerated in mesothelioma patients and resulted in long-term durable responses in two patients. Given the limited amount of gene transfer observed, we postulate that Ad.HSVtk may have been effective due to induction of antitumor immune responses. We hypothesize that approaches aiming to augment the immune effects of Ad gene transfer (i.e., with the use of cytokines) may lead to increased numbers of therapeutic responses in otherwise untreatable pleural malignancies.
Glossary
- therapy
- any of the measures taken to treat a disease. Unproven therapy is any therapy that has not been scientifically tested and approved. Use of an unproven therapy instead of standard (proven) therapy is called alternative therapy. Some alternative therapies have dangerous or even life-threatening side effects. For others, the main danger is that a patient may lose the opportunity to benefit from standard therapy. Complementary therapy, on the other hand, refers to therapies used in addition to standard therapy. Some complementary therapies may help relieve certain symptoms of cancer, relieve side effects of standard cancer therapy, or improve a patient's sense of well-being. The ACS recommends that patients considering use of any alternative or complementary therapy discuss this with their health care team.
- oncology
- (on-call-o-jee) the branch of medicine concerned with the diagnosis and treatment of cancer.
- gene
- a segment of DNA that contains information on hereditary characteristics such as hair color, eye color, and height, as well as susceptibility to certain diseases. Women who have BRCA1 or BRCA2 gene mutations (defects) have an inherited tendency to develop breast cancer.
- cancer
- malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.
- antibody
- a protein in the blood that defends against foreign agents, such as bacteria. These agents contain certain substances called antigens. Each antibody works against a specific antigen. (See also antigen.)
- virus
- very small organisms that cause infections. Viruses are too small to be seen with a regular microscope. They reproduce only in living cells.
- mesothelioma
- a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.
