By: Laurence MacPhie and Noel Courage
ACROSS CANADA
STEM CELL
PATENTS Securing Intellectual Property for Regenerative Medicine
Stem cells are at the centre of research into regenerative medicine. They are also a valuable tool for drug discovery and development. The transition to successful clinical treatments using stem cells has been slow and difficult.
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However, there is still commercial optimism as the use of stem cells becomes more established and therapeutic applications of stem cells start to enter the market. For example, Hemacord™, a cord blood hematopoietic progenitor cell therapy, was recently the first stem cell product approved by the FDA. Also, Prochymal™, a formulation of adult cultured mesenchymal stem cells, recently received regulatory approval in Canada for the treatment of acute graft versus host disease in children. Since the discovery of stem cells in Toronto by Drs. Ernest McCulloch and James Till in the 1960s, Canadian scientists have been at the forefront of stem cells and regenerative medicine research. More recently, specialized institutions like the Centre for Commercialization of Regenerative Medicine and the Ontario Stem Cell Initiative have been formed to encourage collaboration and commercial ventures for moving innova-
tions forward towards patient care. Obtaining effective patent protection for inventions related to stem cells is vital as the practical commercial and clinical applications of stem cells start to come of age.
Criteria for Patentability Any invention must meet certain key criteria for patentability in the U.S., Europe and Canada. It must be “patentable subject matter,” meaning that it must be a type of invention that is eligible for patenting. For example, abstract ideas or scientific principles are not patentable. Methods of surgery are patentable in the U.S., but not in Europe and Canada. The boundaries of what is considered patentable subject matter differ in each patent office. An eligible invention must also be new, useful and inventive compared to previously known information (called “prior art’). For stem cells, there can be difficult issues in drafting patent claims, since they are a complex living system, unlike pharmaceuticals, proteins or nucleic acid molecules that have a readily describable chemical structure. Proving to patent offices that an isolated stem cell is new and inventive compared to previously known cells, and therefore patentable, can be a challenge. The new stem cell may produce different cell lineages with variable expression patterns of biological markers depending on the culture conditions. Prior art stem cells are also dynamic and even the same cell type will have some inherent differences if taken from a genetically different tissue source. It can be difficult to compare and reconcile each researcher’s limited data set and make direct comparisons to show that a new cell is a patentably unique stem cell. Inventors should be prepared to provide detailed evidence to patent offices. Another important criteria for patentability is that the patent application must disclose the invention in sufficient detail to show a skilled person how to make and use the invention (called “enablement” or “support”). In brief, it is usually readily satisfied for methods of isolating stem cells or using cells for drug screening. Enablement becomes a challenge for patent claims on medical applications of stem cells because stem cells are highly unpredictable and difficult to use successfully in treatment. Patents are also normally filed well in advance of any experimental use in humans. However, the necessary level of data to support a patent claim is generally significantly less than what may be required for regulatory approval for clinical treatment. Demonstrating a particular effect in vitro or in a model organism that
