Serial Killer Cells

A ray of light has emerged in the global fight against cancer which presents some fascinating science, and shows just how far we have come in our ability to engineer our own cells to fight this deadly disease.

A current trending video (shown below) has highlighted an ongoing clinical trial that has been having some miraculous results. It focuses on the story of Emma, a girl who had seen her leukaemia return twice, and who was looking for some sliver of hope that would be nothing short of a miracle.

But the journey did not start with Emma. In 2010, Dr Carl H. June, of the Perelman School of Medicine at the University of Pennsylvania, enrolled a patient, who had for years been receiving various forms of treatment for chronic lymphoid leukaemia (CLL), in a clinical trial for a newly devised treatment for cancer.[i]

This treatment involved harvesting T-cells from the leukaemia sufferer, and modifying them to target and kill the cancerous cells in the body. This is done by using a viral agent to “infect” the T cells with new genetic information, effectively recoding them to attack Cancer cells.

The best viruses for the job are what are known as lentiviruses, one of which, the one that was used for this purpose, was the HIV virus. These viruses are adept at getting their own genetic code into host cells, and as such are the perfect vehicle for the modification of patient T cells. 

The HIV virus was of course modified to prevent it from infecting the patient, and as such is not HIV as we know it, but a genetically modified version that still has viral qualities but which are not harmful to the patient. Thus a patient given this treatment does not have HIV.

The newly modified cell is known as a chimeric antigen receptor. “Chimeric antigen receptors have theoretical advantages over other T-cell–based therapies. They use the patient’s own cells, which avoids the risk of graft-versus-host disease. They can be created quickly, and the same chimeric antigen receptor can be used for multiple patients.”[ii]

Each cell can kill over 1000 tumour cells, and with the advances made in the field, the cells can now successfully both attack cancer cells and proliferate within the patient, something which the first generation CAR’s could not do, producing only “transient cell division”[iii].

With all this destruction going on in the body and the pile-up of dead tumour cells, there are inevitably potent side-effects to the treatment. These include fever, blood pressure difficulties, and a whole host of issues that can bring the patient close to death.

Ongoing research will hopefully reduce the severity of these symptoms, and answer questions such as “how many T cells should a patient be given” and “how many treatments are needed to ensure complete remission”? Also, like the original bone marrow transplant option, this treatment would need to be a worldwide option, not just in a few “boutique cancer clinics”.[iv]

Still, Emma’s example, and those of the other cancer sufferers who have survived as a result of this new cutting edge treatment, should give us all new hope for the future in the fight against Cancer. 

Check out the moving video below for Emma’s story.

References:

[i] “Chimeric Antigen Receptor–Modified T Cells in Chronic Lymphoid Leukemia”. David L. Porter, M.D., Bruce L. Levine, Ph.D., Michael Kalos, Ph.D., Adam Bagg, M.D., and Carl H. June, M.D. N Engl J Med August 25, 2011 365 pp 725-733
[ii] “Redirecting T Cells” Walter J. Urba, M.D., Ph.D., and Dan L. Longo, M.D. N Engl J Med August 25, 2011 365;8 pp 754-7
[iii] Ibid.
[iv] “New Therapy Unleashes 'Serial Killer' Cells in Leukemia” Interview With Carl H. June, MD by Alice Goodman, Medscape News Today May 14, 2013