On the feasibility of a “universal” cancer vaccine (but first in prostate cancer)


As some readers may be aware, one of the great biologic discoveries of the late 20th Century was the association between the length of the telomere (a piece of repeating DNA at the tips of each chromosome) and the ability of an individual cell to divide and replicate. Three American scientists shared a Nobel Prize for this discovery in 2009.

Under normal circumstances, most cells can only divide a limited number of times because each time they divide they use up one of the repeating pieces of DNA at the telomere of each chromosome, and when there are no longer enough pieces of this repeated DNA, cell division can no longer be accomplished. However, in many cancer cells an enzyme known as telomerase can add new pieces of the repeat DNA, which allows the cancer cells to become, effectively, immortal, which is (one of the reasons) why they are able to continue to grow and divide. The enzyme telomerase is activated (“up-regulated”) in about 90 percent of human cancers.

It has been proposed for some time now that if it was possible to down-regulate telomerase in some way (i.e., make it much less able to continuously extend the telomeres) in cancer cells, then it might be possible to use such a mechanism to control or stop cancer growth, and (at least in theory) this mechanism ought to work in many different types of cancer.

However, readers should be aware that the actual biologic controls over telomere length are a great deal more complicated than we currently understand. The actual length of the telomere is clearly a key aspect of cell replication and division, but how telomere length is controlled under specific circumstances is probably very complicated indeed, and the idea that all cells conform to a simple process of only being able to divide a specific number of times based on the telomere length is already known to be “just a nice idea” which does not apply under all circumstances.

Why do we raise this topic? Because of a media release from Adamis Pharmaceutical Corp. related to acquisition of technology underlying the development of an investigational product known as TeloB-VAX. Adamis is suggesting that the technology behind TeloB-VAX offers the opportunity to develop a “potential universal cancer vaccine” by exercising control over the expression of the enzyme telomerase.

At present TeloB-VAX is in development exclusively as a potential treatment for castration-resistant prostate cancer (CRPC). A single Phase I clinical trial of TeloB-VAX has been completed to date, so there is a long way to go before we will know if this agent has real clinical potential in the management of CRPC, let alone whether such technology can actually be developed into a form of cancer vaccine that comes anywhere close to “universal” utility in the development of treatments for all forms of cancer.

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