This week has started from another great news in the world of cancer research!
The scientists from Dr. Riddell’s lab at the Fred Hutchinson Cancer Research Center (Seattle) have demonstrated that engineered T- cells (which normally act to destroy cancer cells) after being re-introduced to people with the Acute Lymphoblastic Leukemia (ALL) (blood cancer) caused a complete remission in more than 90% of terminally ill patients. Moreover, the response rate was 80% and no signs of tumor cells was in more than 50% of patients suffering from other blood cancers (Non-Hodgkin’s Lymphoma (NHL) and Chronic Lymphocytic Leukemia (CLL)).
The method used is called CAR T-cell immunotherapy which can be divided into three big steps (Figure 1):
- Individual’s T- cells are extracted;
- In a lab, T-cells are modified (by adding a synthetic molecule- chimeric antigen receptor (CAR), specific for patient’s tumor cells);
- Engineered T-cells are introduced back to the patient.
Then patients are monitored for a disease response, for instance, by CT scans. The presence and the number of T-cells is also evaluated by performing biochemical analysis, such as RT-PCR.
Figure 1: The method of CAR T-cell immunotherapy. The picture taken from: https://en.wikipedia.org/wiki/Chimeric_antigen_receptor#/media/File:CAR-Engineered_T-Cell_Adoptive_Transfer.jpg
You can find a video from the lab and the story of discovery at: https://www.fredhutch.org/en/news/center-news/2016/02/immunotherapy-remission-blood-cancer-AAAS-riddell.html
CONS against the therapy
Although this is a very promising treatment option against the ALL and some other types of blood cancers, experts in the field believe that people put too many hopes to this treatment option.
For instance, Cai Xuan a pharma analyst from Global Data believes that the price for this type of therapy ($300,000-$500,000) is higher than for the existing stem cell transplantation ($100,000-200,000) . Therefore, more studies should be done to prove the advantages of the emerging type of the treatment (from: http://pharmatimes.com/Article/16-02-18/T-cell_hype_ignoring_cost_and_safety_concerns_say_experts.aspx).
Dr. Alan Worsley from Cancer Research UK in the interview to BBC confirmed that “…although this is exciting, it is still the first step“. The reasons are as usual: price, expertise and time. Biomedical scientists are needed, who are the experts in immuno-oncology. Although this is a growing field, some time is needed to “get” such people, so that this method can be widely used. Also, the technique itself requires a significant amount of time, so that cells can grow in a lab. For more information: http://www.bbc.co.uk/news/health-35586834
Another aspect we need to put attention to is the safety of a technique. As Dr.Worsley says: “This is especially important, as for instance, in chemotherapy, as soon as the drug is not administered, the treatment is finished”. However, here is a different mechanism of action: as soon as the cells are infused back to the patient, “they go and live”. Therefore, we need to ensure that “they go after THE right (cancerous) cells… targeting THE right things”.
There are treatment options available (e.g.: chemotherapy, oncovin or doxorubicin) to cure the ALL; however, these have unpleasant side- effects, such as hair loss. As for majority of the drugs, during the clinical trials of CAR T-cell immunotherapy unfortunately, people also developed adverse reactions, such as very low blood pressure or neurological syndrome. However, Dr. Riddell believes that these can be overcome by reducing the number of T-cells infused back to the patient.
Finally, Dr. Worsley mentions that normally, in the ALL condition chemotherapeutics are given and these are effective in 70-70% of cases. However, in the described clinical trial, the treatment was used in patients, who developed resistance to other drugs. Now the questions remain, whether it can be used as a first-line therapy or applied to different cancers.
Dr. Riddell’s group has initiated clinical trials for some type of breast, lung and pancreatic cancers, sarcoma and melanoma. However, only the time will show, whether this will be an effective form of the treatment in these cases.
Although this is a very exciting and promising news, some experts believe that currently we are too far away from the time, when CAR T-cell immunotherapy will be used as a regular treatment option.
Nevertheless, the amount of research and clinical trials in immunotherapy has significantly increased in the last years and hopefully, in the near future the technique of re-engineering T cells could be optimized and become a treatment option not just for blood cancer(s), but also for other types of malignancies.
Finally, there always were and would be those, who are in favor of conservative methods of treatment (such as chemotherapy). However, without trying to improve and/or optimize new medicinal options, we would not be able to make a step forward. Therefore, I believe, although we might be not quite there (yet) to make CAR T-cell immunotherapy as a form of a first-line treatment, this IS a big step forward in the field of immuno-oncology and hopefully, one day this will stand in a line with chemo- and radiotherapies.
Thank you very much for your time! I hope, you found this post interesting and as always, I wish you a LOT of HEALTH !!!
Figure: T-cells surrounding cancer cell. Taken from: flickr.com