Question ID: WS-26
Submitted by: Olivera Finn
February 3, 2011
Why are cancer vaccines not considered a priority area to develop for cancer prevention? For reasons that after 30 years in tumor immunology research I still do not understand, tumor immunologists have been saddled with a challenge to develop a therapeutic cancer vaccine. While doomed to failure in this ultimate goal, we have learned a lot about the immune system of a cancer patient and the immune targets on the cancer cell. From numerous small individual efforts we have derived consensus observations. The most important: many targets of therapeutic vaccines are present on premalignant lesions and could be targeted with prophylactic vaccines to prevent progression of these lesions to cancer; if the right prophylactic setting is selected, contrary to naysayers, it would not take 25 years to know that the vaccine was effective – many settings would give this answer in 3-5 years; the best animal models have shown high immunogenicity and complete safety of prophylactic cancer vaccines; the high safety profile supports future vaccination of people at risk.
Average Score: 5.0
 (6 evaluations)Provocativeness - 5.0
Novelty - 4.5
Public Health Significance - 5.0
Feasibility - 4.5
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Comments
Submitted By Toby Hecht
I would like to see more therapeutic vaccine trials in the "no evidence of disease" state.
Submitted By Yong Qian
That cancer prevention targets pre-cancer cells expressing one to a few oncogenes is feasible by whole cell giant liposome analogs made from a tumor post-surgery. The cancer vaccine preserves all tumor associated antigens that will elicit pre-cancer cell and cancer cell specific polyclonal antibody production after vaccinations, and to kill pre-cancer cells and cancer cells without any side effect for the same cancer patient.
Submitted By Pier-Luigi Lollini
In our (preclinical) hands, prophylactic vaccines work very well in the prevention of metastatic growth, i.e. against micrometastases. I don't see a dichotomy between cancer immunoprevention and cancer immunotherapy. After all, adjuvant therapy can be also called "tertiary cancer prevention".
However, we also see a dramatic decrease in efficacy when we use the same vaccines against established lesions, both local or disseminated. M
y conclusion is that vaccines can be used equally well for cancer prevention and for cancer therapy, but it's much better to elicit immune responses before tumor cells entrench in the microenvironment.
Submitted By Wijbe Martin Kast
This is such a relevant question. Especially as evidence from animal models is mounting that therapeutic vaccines can be used very effectively in the cancer preventive setting while they do not work well in the cancer therapeutic setting. It is time to change the paradigm. Don't watchful wait, Vaccinate!
Reply Submitted By Esteban Celis
I totally disagree with Dr. Kast's assertion that "vaccines do not work well in the cancer therapeutic setting". Weak vaccines may not work but potent vaccines do work as recently shown in several mouse models. Unfortunately, we keep using suboptimal vaccines in human studies. Nevertheless, I do agree that the likelihood of a vaccine to work will depend on the disease stage.
Submitted By Masoud Manjili
Neoadjuvant immunotherapy would be another implication of cancer vaccines in preventing tumor relapse after conventional therapies. However, I have found it difficult to get a physician on board who can meet the challenges of patient accrual etc.
