An experimental 
vaccine study that seems to prolong life of those diagnosed with chronic lymphocytic (CLL) leukaemia, offers a glimmer of hope to patients who otherwise have just a bleek hope for treatment. Phase I of human clinical trials are underway to test the safety of the vaccine and standardize the best possible CLL treatment.
Chronic lymphocytic leukaemia is a type of cancer that did not respond or was resistant to initial treatment or harbours a particular chromosomal abnormality called a 17p deletion. In most of these cases, the cancer has failed to respond to further conventional therapy. The new vaccine offers a tailored approach towards targeting leukaemia cells by boosting the patient’s own immune system. Cancer vaccines differ from conventional vaccines in the sense that they don’t prevent diseases, but act as an adjuvant in a treatment given to someone who already has cancer.
In this clinical trial, patients will receive a vaccine of an immune-boosting molecule, ISF35 (Immune Stimulatory Factor 35) followed by three courses of rituximab, a monoclonal antibody, and the chemotherapy drugs fludarabine and cyclophosphamide (FCR). The vaccine therapy approach makes it possible to target the cancer cells and activate the immune system by making the cancerous leukaemia B cells more visible. The activated immune system can then find and eliminate the cancer cells. ” The immune system is made to see something as foreign and can then destroy it itself. This has the chance to be curative,” said Professor Farzaneh of the University College of London.
CLL can be especially hard to treat, as the rate of remission is very high. Though chemotherapy can beat back the disease initially, the disease invariably returns, frequently resistant to further treatment. The American Cancer Society estimates that about 15,100 new cases of CLL will occur this year in the United States, with about 4,390 deaths from the disease.
According to Januario E. Castro, M.D., assistant clinical professor of medicine at the UC San Diego School of Medicine and the Moores UCSD Cancer Centre, “The vaccine also has the potential to treat a range of blood cancers including lymphomas and even certain types of breast and lung cancers and melanoma.”
Muzaffar Qazilbash, MD, associate professor in the department of stem cell transplantation and cellular therapy at the University of Texas M.D. Anderson Cancer Centre, conducted a trial on 66 people with leukaemia over three years of follow-up. Of the 53 patients with active leukaemia, 25 (47%) had an immune response to the treatment (as determined by lab tests) and 28 did not. Those that had an immune response experienced a longer period of event-free survival from their disease during the study, an average of 8.7 months compared with 2.4 months among those who didn’t respond to the vaccine. Dr. Qazilbash further adds that, “Immunotherapy works best for low level of disease, so patients with low leukaemia burden may get the maximum benefit.”
Although the initial results look very promising and could pave a way for the vaccine to be incorporated in routine leukaemia treatment, researchers point out that the results need to be validated in bigger multicentre trials before drawing any conclusions.
Article by Snigdha Taduri for Biomed-ME