BioWorld International Correspondent

LONDON - A UK start-up company has been granted a U.S. patent on the production of stem cell-derived cell lines for the treatment of central nervous system diseases, a patent it said is so broad that all the other companies currently in the field are likely to infringe it.

The patent, granted to CellFactors plc, includes claims covering the immortalization of neural stem cell lines using any gene or other immortalizing agent, and the use of any mechanism to control the proliferation of the cells after administration.

CEO Iain Cubitt told BioWorld International, "I think a lot of people will be caught by our patents." He expects the company, based in Cambridge, to have significant income from licensing in the short term, as it progresses the development of cell therapies.

Although CellFactors completed its first-round funding of £1.1 million (US$1.6 million) as recently as November, the patent was filed by the scientific founders in 1994. Co- founder Bradley Stringer said he was not surprised at the breadth of the patent. "We have a priority date of 1994. We are lucky because we got into the field before there was widespread interest." Stringer was helped in the drafting of the patent by the fact that he spent two years as a biotechnology specialist at the UK patent office.

Cubitt said he is working on raising second-round funding, but was unable to say how much he aims to raise, or by what route. "The U.S. patent is a milestone, and I don't expect to have problems raising money, but it's a question of what sort of investors and shareholder structure to go for."

CellFactors' lead product, Skeletex, for bone regeneration, is not a cell line but a cartilage matrix containing a mixture of the growth factors and other proteins that initiate the process of bone formation in humans. "In vitro we have got phenomenal data, and this is because we are replicating the natural physiology of bone formation," Stringer said. "Skeletex is the same material as the body uses to induce new bone to form."

The company is in the process of setting up a GMP production line for Skeletex, and aims to start two Phase IIa clinical trials next year at the University of Sheffield, where Stringer is based. The product will be tested as a treatment for periodontal disease, to see if it can regenerate bone to prevent teeth loss, and as a means of prompting new bone to grow around dental implants. Because there are no live cells in Skeletex, Stringer said there are no immunological considerations in the therapy.

Although its precise composition is unknown, Cubitt said preliminary discussions with the UK Medicines Control Agency indicate Skeletex could be registered as long as the major components are identified.

CellFactors' first target in CNS diseases will be Parkinson's disease. Co-founder George Foster said, "We have many clones of human neural cells to screen for the one we want to go with." Having reached this stage, "It is just a handle-turning exercise to make the selection."

Cubitt said CellFactors' technique for identifying and culturing human cell lines could be applied to produce replacement cells to treat a broad range of diseases. "It is conceptually very simple growing human cells once you know how to do it," he said. The company intends to concentrate on CNS diseases, where immunogenicity is not an issue.

There is one other significant UK company, ReNeuron Holding plc, working on cell therapies to treat CNS diseases. The company raised £21.4 million when it floated on the Alternative Investment Market (AIM) of the London Stock Exchange in November, and it hopes to start trials in treating stroke patients later this year. CEO Martin Edwards told BioWorld International, "[CellFactors'] IP was known to our patents attorney and it was concluded there was no overlap. We each employ patent lawyers who are expert in the field and we obviously got different opinions." Edwards said "it is very unlikely" ReNeuron will need to take a license from CellFactors.