Geron yesterday announced the issuance of US patent #7,326,572, helping to extend their patent protection around their embryonic stem (ES) cell platform technology in the area of treating type 1 diabetes. Currently, Geron owns an exclusive license from the Wisconsin Alumni Research Foundation (WARF) for James Tomson’s original ES patents. This license allows Geron the right to develop and commercialize pancreatic islet cells, cardiomyocytes, and neural cells that are derived from ES cells for therapeutic applications. Patent #7,326,572 covers important and frequently used culture conditions for creating endoderm tissue from ES cells, a critical intermediate cell type on the differentiation pathway towards insulin-secreting islet cells.

It is always a good idea to look up a patent and actually read what is claimed. The claims are often wordy and difficult to understand, but the more you read the easier they are to interpret. The primary claim of this patent reads:

• A method for generating endoderm cells from human ES cells or human embryonic germ (EG) cells, comprising culturing the hES cells or hEG cells in a medium comprising a sufficient amount of Activin A to cause differentiation of said cells into endoderm, thereby generating endoderm cells, wherein the endoderm cells express the markers Sox 17, HNF313 and HNF4a.

Activin A is a very common signaling factor necessary for differentiation of ES cells into endoderm, and they have a broad claim stating “a sufficient amount of Activin A”, not limiting them to an optimal dose. They have also covered the endodermal cells with very generic endodermal markers, making this difficult to get around unless their competitors (like Novocell) can come up with ways to do this without Activin A. According to a recently published article in Stem Cells by Novocell scientists, Activin A is a critical component of their process of differentiating ES cells towards endoderm as well. What this patent does not block are technologies that are able to generate endodermal cells using a starting material other than ES or EG cell starting material.

This is a good patent to illustrate how a company builds what is called a “patent fence” around their base intellectual property (IP). IP is considered a property that is owned just as land is owned. To protect your land you can construct a fence, and IP may be protected in a similar fashion (thus extending the analogy). If the original WARF patents for ES cells is their base technology that they want to protect, and Geron has made the strategic decision to pursue type 1 diabetes as a clinical indication, then building a fence around this base ES cell technology with methods patents on both manufacturing (culturing in this case) and use are important. This patent and the previously issued US patent #7,033,831 cover methods to culture ES or EG cells that differentiates them into an important endodermal cell intermediate – helping to provide the freedom to operate and potentially block competitors in using ES cells for diabetes applications. Therefore, if another company is able to get around the initial WARF patent for ways of making ES cells, then there are still barriers to using ES cells as a starting material for creating insulin-producing cells. Furthermore, by patenting these methods Geron is protecting themselves from having competitors patenting over them and creating patent fences that Geron would then need to go around or license.

Geron has done a great job at establishing and executing on their patent strategy and has been active in gaining access to complimentary patents from other institutions. This provides Geron with multiple paths for addressing the therapeutic indications that they are going after, as well as limits IP available to competitors to create work-around strategies. Geron patent velocity (the number of patent applications filed per year) has slowed in recent years and they have not been filing as many patents around their ES cell technology – likely due to the maturation of the technology. However, they are still prosecuting multiple patents that were filed in the early 2000’s, and they should still be expecting more patents to issue over the next few years.