Ark’s Platform Increases Efficacy of Anti-cancer Therapies

Ark Therapeutics Group plc has announced that its gene-based drug targeting platform technology, Scavidin^® has been shown to be effective in stopping tumour development in two cancer treatment models, using low doses of existing anti-cancer agents which would be sub-therapeutic if administered conventionally. 

Scavidin^® was used to target and concentrate intravenous doses of as little as one-tenth the conventional levels of the radioisotope Yttrium90 in one model, and the chemotherapy drug paclitaxel in another, to tumours growing under the skin. 

Scavidin^® is a two-part drug targeting technology originating from the DNA which expresses the scavenger receptor on white blood cells. 

This natural receptor usually collects undesired fats and damaged cells and membranes from the blood, taking them into the white blood cells and releasing them for destruction as part of the body’s natural 'clean up' system.  

By modifying the DNA sequence for such receptor types, Ark has developed a new family of receptors which bind only to the protein biotin. 
 
The Scavidin^® DNA is put into the tumour where it expresses the new drug targeting receptor. The therapeutic agent, pre-tagged with biotin, is then given intravenously at low doses.  

As the therapeutic agent circulates round the body, Scavidin^® extracts it from the blood by binding to the biotin tag, taking it into the cell and releasing it. The receptor then goes back and collects more. 

This 'molecular shuttle' system concentrates the therapeutic agent from a low and ineffective dose in the blood to a high therapeutic dose specifically in the target tissue. 

In this way an important and effective therapeutic, which could have a poor safety profile (such as chemotherapy with high unwanted side-effects) at a traditional dose, may be given in a low and safe dose systemically, with Scavidin^® concentrating it specifically at the disease site where its treatment effect is needed. As such, it has enormous potential across many disease areas.
 
These latest results are from two cancer treatment models where aggressive tumours developed rapidly under the skin. Scavidin^® DNA in a viral delivery vector was transfected into the growing tumours. 

Two different treatments were then given intravenously at sub-therapeutic doses, biotin-tagged Yttrium 90 (a radio isotope) and biotin-tagged paclitaxel (a potent generic chemotherapy).  

Each treatment eliminated tumour growth during the respective 7-10 day study periods with a clear treatment response quickly evident.  Tumours in non-treated controls showed a three to five fold increase in size in the same period.  No side-effects were observed.
 
Nigel Parker, CEO of Ark, commented, "These results indicate that Scavidin^® has the potential both to improve the therapeutic effect and to reduce the unpleasant side-effects of a wide variety of drugs, most obviously chemotherapy and other potent anti-cancer agents, but also in many other therapies where the side-effects are high and thus dose-limiting."

"This is another ground-breaking step forward in DNA-based medicine at Ark, which is now clearly establishing itself as a global leader in this important and rapidly emerging area of medicine."
 
Professor Seppo Ylä-Herrtuala, Ark’s Director of Molecular Medicine, added, "Scavidin^® targeting technology offers the possibility of cancer patients being given up to a 10 times lower dose of radiation or chemotherapy than in conventional treatment approaches, which could markedly reduce the side-effects and enable the treatment to be repeated more easily." 

"An additional advantage is that the anti-cancer drug can be concentrated into the tumour at higher levels and thus its biological cancer 'killing' efficacy can be very substantially increased."