Oslo, 11th December 2008 – PCI Biotech Holding ASA, the Norwegian drug delivery company, today announced the results of a study demonstrating the efficacy of its photochemical internalization (PCI) technology for delivery of siRNA. The study which is being published in the journal Current Pharmaceutical Design, was conducted at the University of Utrecht and focused on the barriers and challenges in trafficking of siRNA upon local delivery in general and in particular on endosomal escape. The researchers found that PCI greatly increases the efficacy of RNAi, by enabling the efficient release of siRNA molecules from endosomes.
The 2006 Nobel Prize in Physiology or Medicine was received for the discovery of RNA interference (RNAi). The siRNA technology aims to exploit this discovery in medicine and there is a common understanding in the pharmaceutical industry regarding the potential, even though the technology is not yet fully developed. There are more than 20 companies currently developing RNAi therapeutics and there has been significant deal activity in this field. One of the main challenges of this technology is the ability to transport the siRNA into target areas on a cellular level, where it needs to be delivered in order to silence a gene. Various different methods have been developed for ensuring successful uptake of siRNAs into cells, but many leave the siRNA encapsulated in endosomes within the cell, making them ineffective. This study shows that by pre-treatment with a photosensitizing agent designed for specific sub-cellular localisation in the endosomes of the cells, endosomal escape of siRNA can be greatly increased using PCI. The study specifically looked at the intratumoral injection of siRNA lipoplexes targeted to silence the gene encoding the Epidermal Growth factor Receptor (EGFR), a well known target for cancer therapy. It was shown that PCI increased the degree of gene silencing to 80%, compared to 30% achieved without PCI. Despite the transient nature of siRNA-mediated gene silencing, there were also indications that tumor growth was slowed, indicating the potential of PCI-mediated siRNA delivery in tumor therapy.
Per Walday CEO of PCI Biotech, said: “This study is another major step forward for the company. Efficient and specific delivery is the key issue in siRNA therapeutics at the moment and these results point to the potential of photochemical internalization in this area. We will now continue with our previously announced strategy of preparing a full preclinical package for potential licencees.
PCI Biotech
PCI Biotech is a Norwegian biopharmaceutical company developing a novel light directed drug delivery system based on its patented photochemical internalisation (PCI) technology. Originating from world leading research at the Norwegian Radium Hospital, the PCI method involves first injecting target cells with a photosensitiser. Therapeutic molecules are then delivered to the cells and when these are illuminated the cells’ endosomes are ruptured to allow successful delivery of the drug.
PCI can enhance the delivery of all molecules taken into the cell by endocytosis. This includes most types of macromolecules, drugs carried by antibodies or nanoparticles, as well as some small molecule drugs. In addition, PCI can facilitate the use of efficient, but very toxic anti-cancer compounds, by restricting their effects to the target site.
PCI Biotech follows a dual strategy of using its technology to improve the effect both of existing drugs and of emerging treatments such as gene therapy. PCI Biotech’s first clinical study combines the proprietary photosensitiser AmphinexTM with the cytotoxic agent bleomycin and is scheduled for start in 2008.
For more information visit: www.pcibiotech.no
