LadyBio

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Richard,
You asked where I got the following from:
a.)"Professor Durrant has discovered special modified versions of over 100 cancer and pathogen epitopes."
and
b.)"It is hoped that for every natural epitope there is a Moditope, enough to allow T Cells to home in on every known cancer and virus."

a.) was announced at the company's AGM on 7th November 2012.
and
b.) is an extrapolation of the science itself. At the moment Scancell uses natural cancer epitopes in its ImmunoBody cancer vaccines and other companies using ImmunoBody under licence to make vaccines to combat infectious diseases, such as Immbio, use natural viral epitopes. It is hoped that Scancell and other companies like Immbio will be able to incorporate the more powerful Moditope epitopes in their vaccines instead. And that of course for every natural epitope in use a more effective Moditope equivalent can be discovered and patented.

You queried further:
"It appears to me that Scancell are not patenting the individual epitopes at the moment. Am I wrong?"

To answer this (aside from referring to the AGM presentation) here are some extracts from Scancell's announcement to market on 15th August 2012:

"Scancell has identified and patented a series of modified epitopes."
"Not only do these unique epitopes stimulate a CD4 killer T cell response, we have also shown in tests that cancer patients can produce an immune response to these epitopes. The Moditope epitopes can be used to develop both DNA and peptide vaccines and could become an important component of many therapeutic vaccines in the future, both under development at Scancell and other companies.”

Source:
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It would be misleading to imply, in a simplistic fashion, that one of these two Scancell platforms is superior to the other. We shall see in the argument, developed below, that in fact either platform could one day be used to complement the other.

DENDRITIC CELL VACCINES REMAIN THE ONLY ONLY GAME IN TOWN, FOR NOW.
ImmunoBody is Scancell's dendritic cell vaccine platform. It is still generally accepted that the best way to safely stimulate the immune system is via dendritic cells. This is the way that Nature herself proceeds. In fact the only therapeutic cancer vaccine to gain approval for commercial use from the FDA is a dendritic cell prostate cancer vaccine known as Provenge made by Dendreon. Its acceptance made Dendreon the industry leader in therapeutic cancer vaccines and dendritic cell vaccines the only game in town.

But there is a serious flaw in Dendreon's business model. This is because Dendreon has to extract each patient's dendritic cells first before treating these cells with cancer antigens (to teach the immune system to home in on the cancer that these antigens are found in). Then they have to re-infuse the treated cells back into the patient they were taken from. So a different batch of Provenge has to be made for each individual patient, making it extremely expensive. More than $90,000 per treatment cycle!

Other companies have tried to follow Dendreon while at the same time seeking ways to reduce the costs of their respective vaccines to their potential end users. But all of them have come up against the same stumbling block - having to extract the patient's own dendritic cells first. Scancell has found a way round that.

SCANCELL GETS INTO THE SOFTWARE BUSINESS
Scancell's answer to these unaffordable and individually made dendritic cell vaccines was to enter the biological software business. By constructing a DNA program, Scancell found that it could introduce this program into dendritic cells while they were still in the patient's body. The ImmunoBody program then instructs the patient's dendritic cells to manufacture epitopes (that piece of a cancer or virus antigen that the immune system actually recognises). Finally the dendritic cells present these cancer epitopes on their surface to passing T Cells, which recognise the epitopes as foreign and go off to destroy any cancer cells that contain them.

Scancell's ImmunoBody dendritic cell vaccines are therefore able to elicit an immune response against cancer without having to extract the patient's dendritic cells first. This means that unlike Scancell's competitors ImmunoBody vaccines can be mass produced to treat any number of patients from a single manufactured batch. A much more sustainable business model than the competition.

ImmunoBody is also more powerful than other dendritic cell vaccines. ImmunoBody's DNA encodes intentionally for cancer epitopes that stimulate Helper as well as Killer T Cells. The Helper T Cells greatly increase the population of Killer T Cells and aid their onslaught at the tumour site. Some of the epitopes that ImmunoBody instructs the dendritic cells to make escape from these cells altogether and get picked up by their neighbours. This process, known as cross presentation, serves to increase the population of Killer T Cells even more. This all leads to an intensely powerful T Cell response: what Scancell describes as 'high avidity.' This is believed to be the reason why Scancell's SCIB1 vaccine has the ability to shrink tumours, something that other dendritic cell vaccines have been unable to do without the addition of a toxic additive.

Finally, another special feature of ImmunoBody which makes it far superior to the competition is its unique 'plug & play' function. This is the ability to swap out the epitopes of one type of cancer and replace them with those of another type of cancer, simply by making small alterations in its DNA software code. This allows a small lab to develop a new vaccine to treat a different type of cancer in just a couple of weeks, ready for manufacturing. Scancell's ImmunoBody vaccines can therefore be reprogrammed to treat any type of cancer. They can even be programmed to treat infectious diseases by swapping in viral epitopes instead.

MODITOPE: VACCINE COMPONENTS THAT CAN DIRECTLY INDUCE CANCER KILLING T CELLS
As we have seen DNA vaccines such as Scancell's ImmunoBody don't use complete cancer antigens only the active bit of an antigen, its epitope. These 'peptides,' as they are classed chemically, are much shorter than the protein molecules which form antigens so are more convenient to code for. Apart from DNA vaccines there is also another type of vaccine that uses epitopes. They consist simply of epitopes mixed with an adjuvant which is meant to provoke the interest of the immune system. These paired down vaccines are appropriately called 'peptide vaccines.'

When Scancell announced its discovery of Moditope we were told that Moditope consisted of a series of modified epitopes that had the power to stimulate the production of Killer T Cells that destroyed tumours without toxicity. Furthermore that these Moditope epitopes could be used to develop both DNA and peptide vaccines; which makes sense as epitopes are vital components of some DNA vaccines and all peptide vaccines. Additionally we were told that Moditope epitopes could become an important component of many therapeutic vaccines in the future, both under development at Scancell or at other companies.

To understand the significance of this discovery we need to consider a vaccine format where epitopes are in use without the complex delivery machinery used in Scancell's ImmunoBody or other DNA vaccines, namely peptide vaccines.

The typical peptide vaccine consists of a number of epitopes derived from cancer or viral antigens. But with epitopes on their own very little would happen so some kind of immune system stimulant such as the crushed cell walls of bacteria is added in the hope that the immune system will be aroused and take up the vaccine's epitopes and process them. If antigen presenting cells can take up these epitopes then Killer T Cells could be stimulated enough to attack the cancer or the virus that their epitopes have been derived from. But this is in practice a very hit and miss affair and peptide vaccines as a result have met with very little success.

MODITOPE TO THE RESCUE
Nevertheless it seems that salvation is at last at hand for the humble peptide vaccine with the discovery of Moditope. Moditope's specially modified epitopes have the unique ability, unaided, to attract, stimulate and proliferate Killer T Cells. Tests have also shown that the T Cell response they initiate is uniquely powerful; even more powerful than Scancell's ImmunoBody vaccine SCIB1.

From the above it will be immediately evident that the use of Moditope epitopes in peptide vaccines should make these attractively simple vaccines work reliably. Not only could Moditope peptide vaccines work every time but should do so with hitherto unknown power and efficacy.

WHERE DOES THIS PUT IMMUNOBODY?
Fortunately Moditope is not only good news for peptide vaccines but also for ImmunoBody as well, in fact for any future vaccine that uses epitopes. ImmunoBody is also in the especially fortunate position of being able to swap out existing epitopes for different ones at a moment's notice via its 'plug & play' feature.

As pointed out earlier Scancell believes that Moditope epitopes could be included in the vaccines it has currently under development, such as the ImmunoBody vaccines SCIB1 for melanoma and SCIB2 for lung cancer. So what would such a vaccine look like?

SCIB1 incorporating Moditope could have swapped in a Moditope version of the epitope for the Tyrosinase-Related Protein 2 (TRP2) melanoma antigen. TRP2 is currently being used by SCIB1 to stimulate Killer T Cells. The two epitopes used by SCIB1 to stimulate a Helper T Cell response can be left just as they are. We would then get a vaccine that generated, as usual, a powerful high avidity Killer T Cell response but added to that would be the extra proliferation of Killer T Cells provided by the substituted Moditope epitope in the place of TRP2. The result would be a vaccine far more powerful than either SCIB1 unmodified or Moditope used on its own as a peptide vaccine. A great deal of its power and efficacy will still arise from its ImmunoBody design but you would definitely want to see 'Moditope Inside' stamped on the syringe.

Navid - Yes I am aware of your question. But because you posted your question on the Scancell Forum as well as here I thought I better put my non technical description of Moditope on the forum first. I shall supply my answer shortly.