A new approach to heal cancer with the body's own immune system to attack metastatic tumors is truly a "paradigm shift" in treatment of the disease.
T-cell therapy works best on the "liquid" tumors of the blood and bone marrow. Scientists believe its strength lies in the fact that T-cells can live and proliferate within the body for months or even years after they have been transfused back into patients.
T-cells form an important arsenal in the body's immune defenses. They help to identify invading viruses and bacteria and can keep a "memory" of previous infections in order to launch a rapid immune response when the body comes under a repeat attack.
Various trials have been conducted to ensure the effect and feasibility of the treatment. In one trial of a patient's own T-cells - a type of white blood cell - that were engineered in the laboratory to identify and attack tumor cells, more than 90 percent of the 35 patients with acute lymphoblastic leukemia went into complete remission.
In two other clinical trials involving about 40 patients with either non-Hodgkin's lymphoma or chronic lymphocyte leukemia, more than 80 percent of patients responded to the treatment.
"In the laboratory and in clinical trials, we are seeing dramatic responses in patients with tumrs that are resistant to conventional high-dose chemotherapy," said Dr Stanley Riddell, of the Fred Hutchinson Cancer Research Centre in Seattle.
Dr Riddell's team has developed a method of making chimaeric antigen receptor (CAR) T-cells that are highly stable and consistent, which lowers the risk of a toxic reaction, known as a cytokine storm, which can result in fatal fevers and falls in blood pressure.
"Our approach has been to try to formulate a T-cell product of defined composition in every patient, so it is the same in every patient. It removes a big variable," said Dr Riddell. "These cells have the capacity to proliferate. They have the capacity to survive long term as memory cells, and they have the capacity to differentiate to the effective lineages that are necessary to mediate anti-tumor activity."