Claim Construction Should Be Well-Grounded in Both Intrinsic and Extrinsic Evidence
| January 15, 2024
ACTELION PHARMACEUTICALS LTD v. MYLAN PHARMACEUTICALS INC.
Decided: November 6, 2023
Before REYNA, STOLL, and STARK, Circuit Judges.
Summary
The Federal Circuit ruled that the patent claim term “a pH of 13 or higher” could not be interpreted solely based on the patent’s intrinsic evidence. The court remanded the case to the district court, instructing it to consider extrinsic evidence to determine the proper construction of this claim limitation.
Background
The case of Actelion Pharmaceuticals Ltd v. Mylan Pharmaceuticals Inc. involves a dispute over patent infringement related to epoprostenol, a drug used for treating hypertension. Actelion Pharmaceuticals, the patent holder, owns two patents of the drug: U.S. Patent Nos. 8318802 and 8598227. These patents disclose a pharmaceutical breakthrough in stabilizing epoprostenol using a high pH solution, which is otherwise unstable and difficult to handle in medical applications.
Mylan Pharmaceuticals, aiming to enter the market with a generic version of epoprostenol, filed an Abbreviated New Drug Application (ANDA). In this process, Mylan certified under Paragraph IV that the patents held by Actelion were either invalid or would not be infringed by Mylan’s manufacture, use, or sale of the generic drug. In response, Actelion asserted these patents against Mylan, claiming infringement.
The key issue in the dispute revolves around the interpretation of the phrase “a pH of 13 or higher” in the patent claims. This particular claim is crucial because the stability of epoprostenol is significantly impacted by the pH level of its solution. Actelion’s patents suggest that the epoprostenol bulk solutions should preferably have a pH adjusted to about 12.5 to 13.5 to achieve the desired stability. However, in the claims, Actelion’s patents only set the limitation as “a pH 13 or higher” as shown in claim 11 of the ’802 patent, a representative of the asserted claims:
11. A lyophilisate formed from a bulk solution comprising:
(a) epoprostenol or a salt thereof;
(b) arginine;
(c) sodium hydroxide; and
(d) water,
wherein the bulk solution has a pH of 13 or higher, and wherein said lyophilisate is capable of being reconstituted for intravenous administration with an intravenous fluid.
The dispute centered on the interpretation of the pH value specified in the patent claims. Actelion contended that the claim should encompass pH values that effectively round up to 13, including values like 12.5. Conversely, Mylan argued for a narrower interpretation, asserting that the claim should only cover pH values strictly at 13 or higher, thus excluding anything below this threshold, such as 12.5.
This interpretation was critical in determining whether Mylan’s generic version of epoprostenol would infringe upon Actelion’s patents. The district court initially adopted Actelion’s interpretation, which led to a stipulated judgment of infringement against Mylan.
Discussion
The Federal Circuit’s analysis began with a de novo review of the district court’s decision. The central question was whether the district court’s adoption of Actelion’s interpretation, which included pH values that could round up to 13 (such as 12.5), was appropriate. This broader interpretation affected the scope of the patent and the potential infringement by Mylan’s generic version of the drug. In scientific and technical contexts, the practice of rounding pH levels, such as rounding 12.5 to 13, depends on the specific requirements of the situation and the level of precision needed. pH is a logarithmic scale used to specify the acidity or basicity of an aqueous solution, and even small changes can represent significant differences in acidity or basicity.
Mylan Pharmaceuticals argued for a narrower interpretation of the term. They insisted that “a pH of 13” sets a definitive lower limit, suggesting that any pH value below 13, even those marginally lower like 12.995, would not fall within the scope of the patent. Mylan suggested that if a margin of error was considered necessary for a pH of 13, it should be minimal, encompassing a range only from 12.995 to 13.004. This interpretation was grounded in the belief that precision was implicit in the claim term, as the absence of approximation language like “about” in the claim suggested an exact value.
In contrast, Actelion Pharmaceuticals argued for a broader interpretation. They argued that the term should include values that round up to 13, thus potentially including values such as 12.5. Actelion’s argument was based on the principle that a numerical value in a patent claim includes rounding, dictated by the inventor’s selection of significant figures, unless the intrinsic record explicitly indicates a different intention. Actelion maintained that rounding was a common practice in scientific measurements and that the absence of specific approximation language did not necessarily dictate a precise value.
One of the key findings of the Federal Circuit was the inadequacy of intrinsic evidence to resolve the dispute conclusively. Intrinsic evidence, which includes the original patent claim language, specification, and prosecution history, is generally the primary resource for interpreting patent claims. However, in this case, these sources did not clearly define the precision of the pH value in question. The specification stated that, “the pH of the bulk solution is preferably adjusted to about 12.5-13.5, most preferably 13.” This language suggested that while the inventor recognized a preferred range (about 12.5-13.5), they specifically highlighted a most preferred value (13). The Federal Circuit also noted that the specification uses both “13” and “13.0” and various degrees of precision for pH values generally throughout the specification. Moreover, the prosecution history shows that the Examiner drew a distinction between the stability of a composition with a pH of 13 and that of 12. However, such distinction does not clarify the narrower issue of whether a pH of 13 could encompass values that round to 13, in particular 12.5.
The specifications and prosecution history left ambiguous whether the term referred exclusively to a pH of 13.0 or could include values that round up to 13. Recognizing this ambiguity, the Federal Circuit emphasized the need for extrinsic evidence to properly interpret the term. This approach is aligned with the Supreme Court’s guidance in Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc., which acknowledged the importance of considering such evidence in certain contexts of patent claim interpretation. The Federal Circuit decided to vacate the district court’s ruling and remand the case for further consideration of extrinsic evidence.
Takeaway
- Precise and specific wording in patent claims is crucial, especially in technical fields, as it defines the scope and protection of the invention.
- Although intrinsic evidence (claim language, specifications, and prosecution history) is primary in patent interpretation, it may not always be sufficient. In cases where intrinsic evidence is ambiguous or lacks clarity, extrinsic evidence such as expert testimonies, scientific literature, and other technical documents becomes crucial for a comprehensive understanding of the claim.
FUNCTIONAL CLAIMS REQUIRE MORE THAN JUST TRIAL-AND-ERROR INSTRUCTIONS FOR SATISFYING THE ENABLEMENT REQUIREMENT
| January 5, 2024
Baxalta Inc. v. Genentech, Inc.
Decided: September 20, 2023
Moore, Clevenger and Chen. Opinion by Moore
Summary:
Baxalta sued Genentech alleging that Genentech’s Hemlibra product infringes US Patent No. 7,033,590 (the ‘590 patent). Genentech moved for summary judgment of invalidity of the claims for lack of enablement. The district court granted summary judgment of invalidity. Upon appeal to the CAFC, the CAFC affirmed invalidity for lack of enablement citing the recent Supreme Court case Amgen v. Sanofi.
Details:
Baxalta’s patent is to a treatment for Hemophilia A. Blood clots are formed by a series of enzymatic activations known as the coagulation cascade. In a step of the cascade, enzyme activated Factor VIII (Factor VIIIa) complexes with enzyme activated Factor IX (Factor IXa) to activate Factor X. Hemophilia A causes the activity of Factor VIII to be functionally absent which impedes the coagulation cascade and the body’s ability to form blood clots. Traditional treatment includes administering Factor VIII intravenously. But this treatment does not work for about 20-30% of patients.
The ‘590 patent provides an alternative treatment. The treatment includes antibodies that bind to Factor IX/IXa to increase the procoagulant activity of Factor IXa which allows Factor IXa to activate Factor X in the absence of Factor VIII/VIIIa. Claim 1 of the ‘590 patent is provided:
1. An isolated antibody or antibody fragment thereof that binds Factor IX or Factor IXa and increases the procoagulant activity of Factor IXa.
The ‘590 patent describes that the inventors performed four hybridoma fusion experiments using a prior art method. And using routine techniques, the inventors screened the candidate antibodies from the four fusion experiments to determine whether the antibodies bind to Factor IX/IXa and increase procoagulant activity as claimed. Only 1.6% of the thousands of screened antibodies increased the procoagulant activity of Factor IXa. The ‘590 patent discloses the amino acid sequences of eleven antibodies that bind to Factor IX/IXa and increase the procoagulant activity of Factor IXa.
Citing Amgen Inc. v. Sanofi, 598 U.S. 594 (2023), the CAFC stated that “the specification must enable the full scope of the invention as defined by its claims, allowing for a reasonable amount of experimentation. Citing additional cases, the CAFC stated “in other words, the specification of a patent must teach those skilled in the art how to make and use the full scope of the claimed invention without undue experimentation.”
Baxalta argued that one of ordinary skill in the art can obtain the full scope of the claimed antibodies without undue experimentation because the patent describes the routine hybridoma-and-screening process. However, the CAFC stated that the facts of this case are indistinguishable from the Amgen case in which the patent at issue provided two methods for determining antibodies within the scope of the claims. In Amgen, the Supreme Court stated that the two disclosed methods were “little more than two research assignments,” and thus, the claims fail the enablement requirement.
The CAFC described the claims in this case as covering all antibodies that (1) bind to Factor IX/IXa; and (2) increase the procoagulant activity of Factor IXa, and that “there are millions of potential candidate antibodies.” The specification only discloses amino acid sequences for eleven antibodies within the scope of the claims. Regarding the method for obtaining the claimed antibodies, the specification describes the following steps:
(1) immunize mice with human Factor IX/IXa;
(2) form hybridomas from the antibody-secreting spleen cells of those mice;
(3) test those antibodies to determine whether they bind to Factor IX/IXa; and
(4) test those antibodies that bind to Factor IX/IXa to determine whether any increase procoagulant activity.
The CAFC stated that similar to Amgen, this process “simply directs skilled artisans to engage in the same iterative, trial-and-error process the inventors followed to discover the eleven antibodies they elected to disclose.”
The Supreme Court in Amgen also stated that the methods for determining antibodies within the scope of the claims might be sufficient to enable the claims if the specification discloses “a quality common to every functional embodiment.” However, no such common quality was found in the ‘590 patent that would allow a skilled artisan to predict which antibodies will perform the claimed functions. Thus, the CAFC concluded that the disclosed instructions for obtaining claimed antibodies, without more, “is not enough to enable the broad functional genus claims at issue here.”
Baxalta further argued that its process disclosed in the ‘590 patent does not require trial-and-error because the process predictably and reliably generates new claimed antibodies every time it is performed. The CAFC stated that even if a skilled artisan will generate at least one claimed antibody each time they follow the disclosed process, “this does not take the process out of the realm of the trial-and-error approaches rejected in Amgen.” “Under Amgen, such random trial-and-error discovery, without more, constitutes unreasonable experimentation that falls outside the bounds required by § 112(a).”
Baxalta also argued that the district court’s enablement determination is inconsistent with In re Wands. The CAFC disagreed stating that the facts of this case are more analogous to the facts in Amgen, and the Amgen case did not disturb prior enablement case law including In re Wands and its factors.
Comments
When claiming a product functionally, make sure your specification includes something more than just trial-and-error instructions. The CAFC suggested in this case that the enablement requirement may be satisfied if the patent discloses a common structural or other feature delineating products that satisfy the claims from products that will not. The CAFC also suggested that a description about why the actual disclosed products perform the claimed functions or why other products do not perform the claimed function would be helpful for satisfying the enablement requirement.
