here at Patent Baristas, we get all giddy when a case comes down the pike involving protein synthesis and gene cloning vectors.  It doesn’t happen all that often and, when it does, we’re treated to BIO 101 introductions explaining how proteins are biomolecules that “are encoded by particular deoxyribonucleic acid (“DNA”) sequences known as genes.”

And so it is with Carnegie Mellon University and Three Rivers Biologicals v. Hoffmann-La Roche (07-1266).  After the district court deflated an infringement suit by Carnegie Mellon University and Three Rivers Biologicals holding that Hoffmann-La Roche et al. did not infringe the patents (and that certain claims were invalid for lack of written description anyway), Carnegie asked the Federal Circuit to intervene.

The patents, U.S. Patents 4,767,708, 5,126,270, and 6,017,745, relate to novel recombinant plasmids for the enhanced expression of an enzyme, to the preparation by gene cloning of the plasmids, to bacterial strains containing the plasmids, and to methods for the conditional control of the expression of the enzyme.

The enzyme of interest is DNA polymerase I (Pol I), which is encoded by the structural gene known as polA.  The prior art showed difficulties cloning polA into multicopy plasmids because the increase in expression of DNA polymerase I above the natural level of expression was found to be lethal to a host bacterium.  The claimed inventions overcome that problem by constructing a novel plasmid containing “the entire and undamaged polA gene coding region enzymatically excised from a DNA molecule,” which “contains essentially none of or at the most only a portion of the activity of its natural promoter.”

The patents disclose that severely damaging the natural polA promoter sequence constituted a “significant discovery of the present invention since it eliminates or greatly reduces the unregulated expression of Pol I, which would otherwise be lethal to the cell.”  By cloning the gene for DNA polymerase I into a vector along with a foreign promoter whose activity is conditionally controlled, one can obtain an amplified amount of DNA polymerase I.

The patents in suit share a common specification, and the claims are directed to recombinant plasmids that contain gene coding regions for the expression of DNA polymerase I from any bacterial source.  The accused product at issue in this appeal involves a recombinant plasmid referred to as pLSG5, which causes host cells to express an enzyme known as Thermus aquaticus (Taq) DNA polymerase.

During a claim construction hearing, the court construed the term “DNA polymerase” as requiring 3’-5’ exonuclease activity so Roche filed motions for summary judgment that some claims were invalid for lack of written description.   The district court agreed holding that there was no genuine issue of material fact as to whether the enzyme in the accused product possessed 3’-5’ exonuclease activity.  Because the undisputed evidence indicated that the accused products lacked that element, the court concluded that summary judgment of noninfringement of the ’708 patent was required.

The court also determined that the specification of the ’270 patent made clear that lethality was an essential feature of the invention and thus, the claims of the patent must contain that feature in order to comply with the written description requirement.  Because the claims omit the feature of lethality, the court concluded that those claims of the ’270 patent were invalid.

The court then concluded that while the claims of the ’708 patent claim recombinant plasmids “containing a cloned complete structural gene coding region from [any] bacterial sources for the expression of DNA polymerase I,” the ’638 application only described recombinant plasmids containing the encoding gene region for E. coli DNA polymerase I and thus failed to adequately support the generic claims of the ’708 patent.

Finally, the court determined that there was no genuine issue of material fact with regard to whether the ’745 patent complies with the written description requirement under 35 U.S.C. § 112 and granted Roche’s motion for summary judgment.

For good measure, Roche additionally asserted that the patents were unenforceable based on inequitable conduct, which is how patent trial lawyers say hello to each other in court.  The district court, however, said that Roche failed to present clear and convincing evidence that appellants committed inequitable conduct.

On appeal, Carnegie challenged the district court’s grant of summary judgment of invalidity and noninfringement of the asserted claims.

The written description requirement is as follows:

The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.

Thus, paragraph 1 of § 112 requires a written description of the invention as a requirement separate and distinct from the enablement requirement.  It has long been the case that a patentee “can lawfully claim only what he has invented and described, and if he claims more his patent is void.”  The written description serves a quid pro quo function “in which the public is given ‘meaningful disclosure in exchange for being excluded from practicing the invention for a limited period of time.’

To satisfy the written description requirement, the applicant must convey with reasonable clarity to those skilled in the art that, as of the filing date sought, he or she was in possession of the invention.

Previously, the Federal Circuit has stated that “[a]n adequate written description of a DNA, such as the cDNA of the recombinant plasmids and microorganisms of the claimed invention, requires a precise definition, such as by structure, formula, chemical name, or physical properties, not a mere wish or plan for obtaining the claimed chemical invention.”  And further  that “[a] description of a genus of cDNAs may be achieved by means of a recitation of a representative number of cDNAs, defined by nucleotide sequence, falling within the scope of the genus or of a recitation of structural features common to the members of the genus, which features constitute a substantial portion of the genus.”

Carnegie argued at the time of the invention, both DNA polymerase I and the polA gene were well known in the art.  Roche argued that the claims of the ’708 patent encompass more than the subject matter described in the specification and thus are invalid.

The Federal Circuit agreed with Roche:

The appealed claims of the ’708 patent are directed to recombinant plasmids that contain a DNA coding sequence that is broadly defined, and only by its function, viz., encoding DNA polymerase I.  Moreover, the generic claims are not limited to a single bacterial species, but broadly encompass coding sequences originating from any bacterial species.  Similarly, the appealed claims of the ’745 patent are broadly directed to recombinant plasmids that contain a DNA coding sequence, again, only defined by function, viz., encoding an enzyme with either DNA polymerase or nick-translation activity.  Those claims are also not limited to a single bacterial species, but cover all bacterial species.

The Guidelines for Examination of Patent Applications under the 35 U.S.C. § 112, ¶ 1, state:

The written description requirement for a claimed genus may be satisfied through sufficient description of a representative number of species . . . by disclosure of relevant, identifying characteristics, i.e., structure or other physical and/or chemical properties, by functional characteristics coupled with a known or disclosed correlation between function and structure, or by a combination of such identifying characteristics, sufficient to show the applicant was in possession of the claimed genus.

A “representative number of species” means that the species which are adequately described are representative of the entire genus.  Thus, when there is substantial variation within the genus, one must describe a sufficient variety of species to reflect the variation within the genus.

* * *

Satisfactory disclosure of a “representative number” depends on whether one of skill in the art would recognize that the applicant was in possession of the necessary common attributes or features of the elements possessed by the members of the genus in view of the species disclosed.  For inventions in an unpredictable art, adequate written description of a genus which embraces widely variant species cannot be achieved by disclosing only one species within the genus.

Driving a proverbial stake through the tiny hearts of Carnegie’s E. coli, the court held:

[A]lthough the written descriptions of the patents emphasize that the recombinant plasmids must be carefully constructed in order to overcome the lethality problem, particularly with regard to the promoter, the patents fail to disclose the nucleotide sequence or other descriptive features for a polA gene (including the promoter sequence) from any bacterial source other than E. coli.

We agree with the district court that the narrow disclosure of the E. coli polA gene is not representative of and fails to adequately support the entire claimed genus under Eli Lilly.  To satisfy the written description requirement in the case of a chemical or biotechnological genus, more than a statement of the genus is normally required.  One must show that one has possession, as described in the application, of sufficient species to show that he or she invented and disclosed the totality of the genus.  In light of the specifications’ disclosure concerning the careful construction of the claimed recombinant plasmids, such that the natural promoter of the polA gene is severely damaged or eliminated, and given the record evidence that the polA gene varied among the numerous bacterial species, as well as the absence of any polA gene sequence for any bacteria other than E. coli, we conclude that that requirement was not met here.

  Print This Post Print This Post  

Comments are closed.