Friday, March 5, 2010
Researchers in the Netherlands have shown for the first time the feasibility of using dendritic-cell based immunotherapy in the treatment of mesothelioma patients. They hope the research will lead one day to a vaccine to give people who have been exposed to asbestos to help prevent asbestos-related diseases. Mesothelioma is an incurable cancer of the lining of the lung or abdomen closely associated with asbestos.
While most western countries have banned asbestos or restricted its use, the incidence of mesothelioma is still increasing worldwide because of the disease’s long incubation period of 20 to 50 years from initial asbestos exposure. In many developing countries including Mexico and India, asbestos is still in wide use so incidence of mesothelioma is expected to increase further in coming decades.
The expected spread of mesothelioma has spurred new research into ways to treat the fatal disease. Chemotherapy consisting of the drugs permatrexed and cisplatin is considered the standard treatment for selected patients, but only extends patients’ lives about three months. On average, patients survive about a year from the first signs of the disease.
One promising new method of treating cancer is immunotherapy which uses the body’s own immune system to target and destroy cancer cells. The aim of immunotherapy is the harness the potency of the immune system in a specifically focused attack on cancer cells, while avoiding the broader toxic effects of chemotherapy.
One type of immunotherapy uses injections of immune system dendritic cells laced with tumor-associated antigens to provoke the immune system to generate antibodies to fight the mesothelioma cell. Dendritic cells are a form of immune system cell.
“This is the first human study on dendritic cell-based immunotherapy in patients with mesothelioma,” said Dr. Joachim Aerts, a pulmonary physician at Erasmus Medical Center in the Netherlands and lead author of a study published online in the American Thoracic Society’s Journal of Respiratory and Critical Care Medicine.
Having shown in animal studies that immunotherapy allowed cancer-stricken mice to survive longer, Dr. Aerts and his colleagues at the Erasmus Medical Center in the Netherlands selected 10 human patients recently diagnosed with mesothelioma who had responded well to chemotherapy. They gave the patients —males ages 56 to 78—three injections of dendritic cells laced with tumor-associated antigens at two-week intervals. The patients tolerated the vaccinations well overall and none had severe toxic reactions.
The researchers said they observed distinct immune responses and anti-tumor responses in the 10 mesothelioma patients. They observed shrinkage of tumors in three patients after the third round of immunotherapy. They cautioned however that a delayed reaction to the earlier chemotherapy could also have contributed to the tumor reduction, and further research was needed on this point. The median survival of the 10 patients was 19 months. Nine patients died of the disease and one patient remained alive after 34 months.
While the size of the study was small, the researchers said the results suggest that selected patients may benefit from dendritic cell immunotherapy without major adverse effects.
“We hope that by further development of our method it will be possible to increase survival in patients with mesothelioma and eventually vaccinate persons who have been in contact with asbestos to prevent them from getting asbestos related diseases,” Dr. Aerts said in a press release.
Read more about alternative treatments for mesothelioma here
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With thanks to Dan for bringing this to attention.
