Yes it is true.
This cancer "vaccine" is not unique because it targets Telomerase(An enzyme that maintains the length of telomeres in Cancer cells so that they divide continously) but it is unique because of the way it targets this enzyme.
This "vaccine" which works on basic Immunology Principles is being designed by Duke University Medical Centre and Geron has completed its phase 1 and 2 clinical trial on prostrate cancer patients. This is an ex vivo process where the patients dendritic cells(which act as Antigen Presenting cells) are isolated from the blood and pulsed with RNA of the Telomerase protein component (hTERT) and then injected back into the patients body which then instruct T cytotoxic cells to kill tumor cells that expressed telomerase.
I feel this is a very innovative cancer treatment.For more details go to the website: http://geron.com/
Now my question is wether this can be called a VACCINE.
From what I know a Vaccine is given in order to prevent a condition, not when a patient is already having that specific condition. But then if I am wrong then this will be the worlds first Vaccine which is killing Tumors rather than preventing them.
Tell me what do you think?
Waiting for your comments.
I have another question, but that will be after I find the answer for this one.
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7 comments:
your doubt is right that how can it be called a vaccine when it is not preventing the tumour before hand.
My doubt is that:-
when the dendritic cells isolated and pulsed with RNA of the Telomerase enzyme in the outside environment and injected back into the blood stream will there be any sort of compatibility problem as this is foreign?will there be any sort of side effects such as infections?
What I feel is that there should be no issue of compatibility because these cells are autologous. They are from the body and belong to the body, and the same cells being injected back into the same body should not have that issue of compatibility.
The good news is that no compatability problems/infections have been reported so far in Phase 1 and 2 trials and I hope it doesnot affect in the next phases as well.
Am I missing something here?
Do the tumor cells express a different version of the telomerase RNA? If not, how are the dendritic cells specific only to the telomerase RNA of the tumor cells? hTERT is the catalytic component of a telomerase and is required for the existance of cells...
I read thru the website (Dharani, it has to be www.geron.com for the website to work and not just http://geron.com - this didn't work for me, please update)
They do explain things pretty well on their website...
http://www.geron.com/showpage.asp?code=prodcatv
If we look at the procedure directly, vaccine might not seem the right word for this type of treatment. But, looking at it from another point of view, they are taking cells from the patient himself and returning it back to him... so, u r making the patient's cells acquire immunity here when the cells are not being exposed to the disease. So, in a way it is a localized vaccine to the dendritic cells which will immediately get into action after they are back in the body... so, u can call it a vaccine in a way... wat say?
Let me know if I am missing a point here...
Telomerase is highly specific to cancer cells. In healthy cells, humans express telomerase mostly when they are developing from an embryo. In adults with cancer, the enzyme will appear transiently in some stomach lining cells, blood cells, maybe adult stem cells. But it is so rarely expressed that it does not seem to be a problem. Early trials with a predecessor of grnvac1 (called TVAX) by Duke University did not find any "self" targeting in over 50 people. Still, autoimmune issues are a major concern any time you use a naturally occurring substance as a cancer target.
For more info, I would check out the message board at http://www.gerntalk.com, as a few of the posters there are helpful.
Yes Vamsee Sir,
You might be right if you look at it in another dimension. Then dont you think there should be a seperate classification regarding these types of Localized Vaccine or is there any classification that I donot know of(Please Update).
If there isn't then I feel it should be taught in text books. What say!!
And I feel that the tumor cells donot express a different kind of Telomerase. In my view every tumor cell will have more Telomerase and so will express more hTERT and our dendritic cells will target only those cells which express more hTERT and in this way the DC's become highly specific.
Hello Seldeen, Thanks for that weblink, a blog that doesnot have any link with Geron. Thanks very much for sharing that.
Can I know more about you so as to add your name to the list of Viewers of this blog.
Go Ahead only when you feel comfortable. No pressure.
Thanks again for sharing that link. Looking forward for your "Drug of The Week" post(Excuse me for the small font size).
Thanks.
Dharani.
Hi Dharani...
I dont know the classification but, I might want to call it invitro vaccination.
and yes... I read that the amt of hTERT is higher in tumor cells, though I am still not convinced on how only they are targetted. Molecular mechanisms are specific to the levels of a few molecules, so I still don't understand how the body is able to control the flow of the DCs to just the tumor cells and not others...
update if u find something on that...
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