Cyclacel Receives US Patent On Novel Drug Target Of The Cancer Cell Cycle

DUNDEE - 8 October 2001 - Cyclacel Limited, the UK-based cancer therapeutics company, announced today that it was granted United States Patent 6,242,201 covering the cancer drug target PCNA (Proliferating Cell Nuclear Antigen).

Cyclacel's CYC102 programme is seeking to prevent cancer cell proliferation through drugs acting on PCNA. The CYC102 studies are based on the understanding that inhibition of PCNA prevents DNA replication, a prerequisite to cancer cell division. Cyclacel is working on this target because it is associated with the body's own tumour suppression systems, such as the p21 protein that prevents cancer cell division by inhibiting PCNA.

Cyclacel's new US patent specifically covers both substances that mimic the structure and activity of the p21 tumour suppressor protein and screening assays for such compounds. An equivalent patent is already granted in Europe as European Patent 0789711. A further European Patent 0871655 has been granted to Cyclacel claiming mimetics and assays relating to PCNA's interaction with Fen1, another protein with similar function to p21.

The inventors on these patents include Professor Sir David Lane, Cyclacel's Chief Scientific Officer, and Professor David Glover, Chief Scientist of Cyclacel's Polgen target discovery division.

Professor Glover said, "It is gratifying to see that our early academic insights on this key cancer target are validated by recent evidence. PCNA is an excellent example of a novel cancer target that can be evaluated in model organisms, such as the Drosophila fruit fly, which formed the basis of Cyclacel's Polgen Division."

Professor Lane said, "Cyclacel is continuing to demonstrate that peptidomimetic targets are accepted as potentially "druggable". Earlier this year we entered into a collaborative research agreement with AstraZeneca to develop macromolecular substrate inhibitors against one such target arising from our CYC103 programme. The grant of patent protection on our CYC102 programme is setting the stage for commercial exploitation of this target. I believe that our set of discovery tools including cellular and in vitro assays in combination with our evolving structural information on human PCNA will enable the use of rational drug discovery approaches to develop inhibitors of this unique target."

Dr Howard Marriage, Executive Director of Business Development, said, "Cyclacel is looking for a CYC102 drug discovery and development collaboration in which Cyclacel would apply its established expertise in rational drug design, including its in silico screening platform, to identify small molecule inhibitors of PCNA. Our intention is to strike a partnership that will take this programme from a gene target to the clinic."