The Wisconsin Alumni Research Foundation (WARF) owns the most significant U.S. patents protecting human embryonic stem cell technology. These patents, U.S. Patent Nos. 5,843,780 (claiming primate embryonic stem (pES) cells); 6,200,806 (claiming human embryonic stem cell (hES) cells); and 7,029,913 (hES) (collectively, the Thomson patents) were challenged in a re-examination petition filed July 17, 2006 and granted by the U.S. Patent and Trademark Office on September 29, 2006. The '708 and '806 patents are undergoing re-examination under the conventional (35 U.S.C. § 302-307) ex parte re-examination proceedings (under Serial Nos. 90/008102 and 90/008139, respectively), while the '913 patent is being re-examined inter partes (35 U.S.C. § 311-318), a more recent procedure that permits significantly more participation by a third party re-examination requestor (under Serial No. 95/000154).
Not surprisingly, the Patent Office has rejected all the claims in all the patents in all the re-examinations, in Actions mailed simultaneously on Friday, March 30th. This was not unexpected, since most re-examinations result in rejection of all or some of the claims; indeed, unless the Patent Office is convinced that there is a "substantial question of patentability" raised by the request, re-examination is not permitted.
The third-party requestors, including Dan Ravicher of the Public Patent Foundation (PUBPAT) and The Foundation for Taxpayer and Consumer Rights (FTCR), a California taxpayer group, had cited four prior art references in their re-examination request, including U.S. Patent No. 5,166,065 to Williams. In addition, the requestors included a declaration from Dr. Jeanne F. Loring in the inter partes re-examination. These references, as well as two prior art patents to Hogan (U.S. Patent Nos. 5,453,357 and 5,690,926), formed the basis for rejection under 35 U.S.C. §§ 102 (anticipation) and 103 (obviousness) in each of the Actions mailed on Friday.
The Actions assert that the Hogan patents disclose human embryonic stem cells, although they acknowledge that the methods for producing these cells are different from the Thomson methods. The Actions also assert that the Williams patent discloses both human stem cells and methods for making them that are "identical" to the Thomson methods. These anticipation rejections are all based on the prior art cells "inherently" possessing the properties of "true" embryonic stem cells, as defined in the Thomson patents.
The law of inherent anticipation requires that the claimed composition be produced consistently using the methods disclosed in the art. This means that if the art teaches methods that may or may not produce the claimed composition, or if the composition produced by the art may or may not have the cited properties, then there is no inherent anticipation because the art did not disclose the claimed composition having said properties.
At least one key requirement for the patentee to overcome these grounds of rejection will be to show that the cited prior art was non-enabling. This should require not just that human embryonic stem cells were not produced using the prior art methods, but that they could not be so produced. The characteristics used by Thomson to define hES are considered by the Office to be inherent properties of all hES, including those "disclosed" in the cited prior art. Thus, unless Thomson can show that at least one of these properties would not be inherently possessed by the cells of the cited art, it will be difficult to distinguish the claimed hES cells from those of the cited art. Alternatively, either the way the cells were produced or the way they are maintained may be relevant distinctions. The Office recognizes that the '926 patent teaches different methods for making hES, but characterizes the '065 method for producing hES as being "identical" to the method taught in the Thomson patent.
The rejections based on obviousness utilize the art cited by the re-examination requestor, which art the Office asserts would have provided sufficient motivation to produce primate or human embryonic stem cells to satisfy the requirements of the Federal Circuit's current (but under Supreme Court review) "teaching-suggestion-motivation" test. The Office gives less attention to the second prong of the test, that there must be a reasonable expectation of success in order for the teaching, suggestion, or motivation to render the invention obvious. Thus, there is an opportunity for Thomson to demonstrate that, no matter the motivation provided by the art, the claimed results, primate or human embryonic stem cells, would not have been obvious because the skilled worker would not have had a reasonable expectation of being able to produce them.
An interesting aspect of the inter partes re-examination concerns Dr. Loring's declaration. In her declaration, Dr. Loring opined not only on the prior art but on the legal conclusions regarding the art (i.e., that it rendered the claims obvious) as well as the "public injury" occasioned by the Thomson patents. This declaration produced a patina of expertise for the requestors' public statements regarding the basis for their re-examination requests. In addition, it provided a public-interest rationale for the attempt to garner great economic benefit for at least some of the requestors by eliminating the royalties required by WARF for the type of commercial activity contemplated by California and others. The Examiner handling the inter partes re-examination explicitly condemned this declaration as being improper in a re-examination, which is limited by statute to prior art publications. Such an affidavit can be used to "explain the contents or pertinent dates" of a reference, but does not provide a basis for rejecting a claim during re-examination, according to the Examiner. While undoubtedly true, the Loring affidavit no doubt raised the temperature of the considerations in the Patent Office concerning the original re-examination requests, and thus most likely served its intended purpose.
The patentee has two months to respond to these Actions, and the requestor has another month to reply in the inter partes proceedings. Since re-examinations are conducted with special dispatch in the Office, it can be expected that the Office's next Action will issue by autumn. A final determination is thus foreseeable by the end of this year.
For additional Patent Docs coverage concerning stem cells, please see:
- "NIH Chief Dissents on Federal Stem Cell Funding Ban" - March 20, 2007
- "Limitations on the Usefulness of Adult Stem Cells" - February, 28, 2007
- "Stem Cells a Go! in California" - February 28, 2007
Comments