The future of cancer treatment is targeting: deploying therapies that seek out and destroy cancer cells while leaving other cells unharmed, resulting in few or no side-effects. Many different approaches to achieving this end presently under research and development, and the most advanced have been in clinical trials for a few years now. Using the immune system as a starting point is one of the more promising strategies. After all, why build a whole new set of cell-targeting and cell-killing machinery when you can adapt the sophisticated, adaptive set that already exists?
Even considering only the use of immune cells as therapeutic agents there is still a very broad range of approaches that can be used to produce targeted therapies, and many varieties of potential therapy are presently either under development or in trials. This is a very active field of research, and on the whole things are looking very promising for everyone who is at least a couple of decades away from the stage of life in which developing cancer is likely. The coming generations of new therapies will be highly effective and much less debilitating. When coupled with vastly improved detection and screening technologies, the end result will be that cancer will recede from its present position as one of the principal causes of age-related mortality.
We still need rejuvenation therapies to deal with the underlying causes of degenerative aging, but given the present pace of progress, I don't feel that cancer is something to be greatly concerned about - or at least not in comparison to the other underlying aspects of aging, where there is far less ongoing work and enthusiasm for progress. Here are two recent examples of cancer immune therapies presently in the clinical trial stage of development, both of which show considerable promise:
"THE results are holding up very nicely." Cancer researcher Michel Sadelain is admirably understated about the success of a treatment developed in his lab at the Memorial Sloan-Kettering Cancer Center in New York. In March, he announced that five people with a type of blood cancer called acute lymphoblastic leukaemia (ALL) were in remission following treatment with genetically engineered immune cells from their own blood. One person's tumours disappeared in just eight days. [A] further 11 people have been treated, almost all of them with the same outcome. Several trials for other cancers are also showing promise.
T-cells normally travel around the body clearing sickly or infected cells. Cancer cells can sometimes escape their attention by activating receptors on their surface that tell T-cells not to attack. ALL affects another type of immune cell, the B-cells, so Sadelain takes T-cells from people with ALL and modifies them to recognise CD19, a surface protein on all B-cells - whether cancerous or healthy. After being injected back into the patient, the reprogrammed T-cells destroy all B-cells in the person's body. This means they need bone marrow transplants afterwards to rebuild their immune systems. But because ALL affects only B-cells, the therapy guarantees that all the cancerous cells are destroyed.
Eight of 16 patients participating in a study of an experimental immune system therapy directed against the most aggressive malignant brain tumors - glioblastoma multiforme - survived longer than five years after diagnosis. Seven of the 16 participants still are living, with length of survival ranging from 60.7 to 82.7 months after diagnosis. Six of the patients also were "progression free" for more than five years, meaning the tumors did not return or require more treatment during that time. Four participants still remain free of disease with good quality of life at lengths ranging from 65.1 to 82.7 months following diagnosis.
Results published in January at the end of the study showed median overall survival of 38.4 months. Typically, when tumor-removal surgery is followed by standard care, which includes radiation and chemotherapy, median length of survival is about 15 months. Median progression-free survival - the time from treatment to tumor recurrence - was 16.9 months at study's end. With standard care, the median is about seven months.
Even the most dangerous and challenging cancers are starting to yield in the face of more targeted approaches, and the pace of progress in the laboratory is speeding up. We can look forward to cancer as a controlled, cured condition, no worse a threat for anyone with access to modern medicine than smallpox or tuberculosis.