Singapore has embarked on a cell-based clinical trial that may have far-reaching implications for future cancer research and treatments.
The trial, currently ongoing, involves up to 35 patients of advanced nasopharyngeal cancer (NPC) and will likely be completed in late-2009, says Dr. Toh Han Chong (pictured), Senior Consultant, Department of Medical Oncology at the National Cancer Centre (NCC), Singapore.
Explaining the ground-breaking nature of this trial, Dr. Toh says, "What we're doing is to extract T-cells from the patient's own blood, then 'educate' these cells to recognize certain viral proteins. These T-cells will be expanded into large numbers in the lab and returned back to the patients to fight the cancer."
T-cells belong to a group of white blood cells (WBCs) called lymphocytes. There are a number of different types of T-cells that act in many ways to identify, directly attack, and destroy infectious agents and potentially even cancer cells. Along with other WBCs, they play a major role in the immune system, which guards the body against infection.
Likening the entire operation to growing an army, Dr. Toh elaborates, "If we see the T-cells as fresh recruits, what we're trying to do is train them up to recognize a specific enemy. Once this is done, we then build up this fighting force from platoon to battalion to division strength. When they reach the battle field, they would know how to 'seek and destroy' the enemy while sparing the innocents in their midst."
The process itself is logistically simple for the patient. All that is needed is about 350 ml of blood, about the volume of a coca-cola can. The culturing of T-cells will take a few months and the programmed new cells will be returned over a series of intravenous infusions. It is hoped that this process, coupled with a course of chemotherapy, will significantly extend survival rates.
According to Dr. Toh, nasopharyngeal cancer was selected for two reasons: It is the sixth commonest cancer in Singapore, and is endemic in southern China and South East Asia. It also has a detectable weakness - Epstein-Barr related viral proteins are expressed on the surface of NPC cancer cells, which are useful as therapeutic targets.
Epstein-Barr virus or EBV is a member of the herpes virus family. Most people become infected with it at some point in their lives. Of those affected, the majority suffer nothing more than mild afflictions, such as fever, sore throat, or swollen lymph glands. However, some carriers of the virus eventually develop nasopharyngeal carcinoma, or cancer.
To date, only two studies have been done on using T-cells to fight NPC. The first was done by the Center for Cell and Gene Therapy at Baylor College of Medicine in Houston, Texas, while the second was done in Pavia, Italy.
"Singapore is extremely well-placed to perform this trial because NPC is so common in Asia. We can truly become a hub of excellence in this area," says Dr. Toh, whose clinical and research team is in frequent contact with the Center for Cell and Gene Therapy in Houston.
"We are very grateful to be partnering the Center for Cell and Gene Therapy. They are actively involved with us in ramping up capabilities, technologies, clinical trials development using adoptive T-cells to fight NPC. Conventional chemotherapy alone for patients with advanced NPC does not provide a cure. This is an alternative new treatment strategy," said Dr. Toh.
Dr. Toh's team, comprising scientists, clinicians, clinician-scientists, researchers, and trained nurses, will build up a bench-to-bedside T-cell therapy facility, which is arguably the only one of its kind in Asia.
"T-cell therapy will provide Singapore with a unique opportunity to distinguish ourselves in the region, if not the world. We have the manpower, regulatory framework, infrastructure, the training, and the resources, and we are ready to proceed," says Dr. Toh.
Illustration: National Cancer Centre (NCC), Singapore.
Singapore Medicine News Release (10/28/08)
Press Release Newswire (10/29/08)
National Cancer Centre (NCC), Singapore
Parkway Cancer Centre