It is axiomatic that, when construing patent claims, it is improper to read a limitation from the specification into the claims. Phillips v. AWH Corp. 415 F.3d 1303, 1323 (Fed. Cir. 2005)("to avoid the danger of reading limitations from the specification into the claim—is sound"). On the other hand, claims are to be read in light of the specification, which is the "single best guide to the meaning of a disputed term." Id. at 1316 (Fed. Cir. 2005) (quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed.Cir.1996). At times, these two principles come into conflict. In the recent case of Medicines Co. v. Mylan, Inc., 853 F.3d 1296 (Fed. Cir. 2017), the Federal Circuit, while acknowledging the tension between these two principles of claim construction, decided to import process limitations into a claim that contained no explicit mention of any process. Does this decision represent a doctrinal shift in claim construction whereby limitations will be more readily imported from the specification into the claims? We first examine the Medicines case in detail and then consider how some recent district court cases have dealt with that decision to determine the answer to that question.
There were two patents at issue in Medicines, both of which were directed to pharmaceutical "batches" of a drug product comprising bivalirudin, a synthetic peptide used to prevent blood clotting in patients undergoing cardiac catheterization. Bivalirudin is usually sold as a dry powder that has to be compounded with a base to adjust the pH to a clinically acceptable level, then reconstituted before intravenous administration to a patient. The patents in suit, the '727 and '343 patents, are directed to minimizing impurities in bivalirudin batches that have been compounded with a base. The prior compounding process had produced localized regions of high pH during the mixing process which led to the formation of a particular impurity, "Asp9." The inventors of the patents-in-suit developed an improved, "efficient mixing" process that avoided the creation of the high pH "hot spots." The improved mixing process produced bivalirudin batches that consistently satisfied the FDA's limit on Asp9 levels in the plaintiff's commercial bivalirudin drug product.
The two patents-in-suit were filed on the same day with largely the same specification. Although only the claims of the '343 patent expressly contain the words "efficiently mixing", the claims of both patents recite "pharmaceutical batches" of a bivalirudin drug product "wherein the batches have a maximum impurity level of [Asp9] that does not exceed about 0.6%." The specification defined "pharmaceutical batches" to refer to "material produced by a single execution of a compounding process of various embodiments of the present invention." Medicines at 1300. The specification also noted that the term "batch" may refer to a single batch that is representative of all commercial batches with respect to impurities and reconstitution time, and "batches" may include all batches prepared by a same compounding process. Id.
The defendant in Medicines, Mylan, filed an ANDA seeking FDA approval to market a generic bivalirudin product prior to the expiration of the '343 and '727 patents. Mylan represented to the FDA that it would limit the Asp9 levels in its product to less than 2%, which encompassed a level higher than the ceiling allowed by the FDA for Plaintiff's commercial product and higher than the level recited in the asserted patent claims. The district court construed the term "pharmaceutical batches" to refer to either (1) a single batch, wherein the single batch is representative in terms of impurities and reconstitution time of all commercial batches made by a compounding process, or (2) all batches prepared by a same compounding process. Medicines at 1301. Both parties consented to that construction, which requires preparation of the batches by a compounding process. Id. The district court also construed the term "efficiently mixing" to exclude the inefficient mixing conditions that were disclosed in Example 4 of the specification. Id.
Based on these constructions, the district court held on summary judgment that Mylan's ANDA did not infringe the '343 patent because it used an "inefficient" mixing process. Because the '727 patent did not recite the "efficiently mixing" limitation, the district court tried all issues regarding the '727 patent, ultimately holding that Mylan's ANDA product infringed the '727 patent.
On appeal, the Federal Circuit held that the claims of the '727 patent required "efficient mixing" as defined by the process parameters of Example 5 of the specification even though "efficient mixing," let alone the Example 5 process parameters, were not explicit limitations of the claim. The Federal Circuit instead focused on the term "pharmaceutical batches," which did appear in the asserted claims of the '727 patent. According to the Federal Circuit, given the definition of "pharmaceutical batches" that appeared in the specification, the pharmaceutical batches limitation was properly construed to require the use of a compounding process that achieves batch consistency. In fact, at oral argument before the Federal Circuit, the patentee had agreed that batch consistency is what distinguished the claims over the prior art. Id. at 1303. The Federal Circuit noted that its decision "does not impermissibly add a process limitation to a product claim that does not require a process because the specification's definition of "batches" by itself injects a compounding process as a limitation in the asserted claims." Id. at 1304 (emphasis added). Not surprisingly then, the Federal Circuit rejected the patentee's argument that the pharmaceutical batches limitation is not necessarily limited to a compounding process that achieves batch consistency: "Under Medicines' interpretation, proof of infringement would necessitate forward-looking assessments of whether an accused infringer's production of future or 'potential' batches would be likely to generate Asp9 levels greater than 'about 0.6%.'" Medicines at 1303. This uncertainty with respect to the determination of infringement was unacceptable to the Federal Circuit.
But the Federal Circuit's analysis did not stop there. The next step was to determine what the compounding process required by the pharmaceutical batches limitation entailed. Based on the specification and prosecution history of the '727 patent, which repeatedly referred to efficient mixing as part of the claimed invention, the Federal Circuit held that the requisite compounding process must use efficient mixing. Id. at 1306. So, the next question became: what is "efficient mixing?" In answering this question, the court rejected the Plaintiff's position that "efficient mixing" was any mixing that attained Asp9 levels of less than 0.6%: "Medicines' construction is problematic because it amounts to a mere recitation of the results obtained from 'efficient mixing' rather than a definition of what the efficient mixing process is." Medicines at 1306. The Federal Circuit turned to the specification of the '727 patent for guidance, but found the specification's description of efficient mixing to be vague and unhelpful. Lacking any clear definition in the specification, the Federal Circuit determined that "efficient mixing" must require the specific efficient mixing process conditions described in Example 5 of the specification:
As the only embodiment of efficient mixing, Example 5 is "highly indicative of the scope of the claims. . .." Example 5, however, is not merely the only disclosed embodiment of efficient mixing—it is the only description of efficient mixing in the patents in suit that casts light on what efficient mixing is and that enables one of ordinary skill in the art to achieve the objects of the claimed invention. Although the specification provides that Example 5 is "non-limiting,". . . no other part of the patents' written description sufficiently teaches the affirmative steps that constitute efficient mixing. In this circumstance, we think it entirely appropriate to limit the term "efficiently mixing" to the sole portion of the specification that adequately discloses "efficient mixing" to the public.
Id. at 1309 (footnote and citations omitted). Under that construction, Mylan did not infringe either the '727 patent or the '343 patent because it used one paddle mixer and added the pH-adjusting solution all at once instead of using multiple mixers and adding the pH-adjusting solution continuously using a peristaltic pump as described in Example 5. Id. at 1310.
In Medicines, the Federal Circuit thus imported the specific process conditions of Example 5 into a claim of the '727 patent that did not recite any "efficient mixing" limitation or, for that matter, any process limitation. At least one decision has cited Medicines to support adding a limitation from the specification in the claims. See IYM Techs. LLC v. Advanced Micro Devices, Inc., 2017 BL 386430 at 3 (D. Del. Oct. 27, 2017)(citing Medicines and holding that "the use of linear equations to construct a system of constraints as shown in figure 1 . . . and its description in the specification" and the exclusive use of linear equations in cited art support the conclusion that "a person of ordinary skill in the art would rely on this evidence to achieve the objects" of the patent-in-suit). But other cases have distinguished Medicines on both factual and procedural grounds. A recent case from the District of New Jersey, In re Certain Consol. Roflumilast Cases, 2017 BL 186169 (D.N.J. June 2, 2017), although marked "not for publication," is illuminating because it distinguished Medicines and highlighted the many specific facts of Medicines that compelled its result.
In Roflumilast, the Defendants sought reconsideration of the court's construction of the term "roflumilast." The court had construed the term in accordance with its plain and ordinary meaning to refer to the drug defined by the chemical name (N-(3,5-dichloropyrid-4-yl)-3-cyclopropylmethoxy-4-difluorormethoxybenzamide). The patents-in-suit claim methods of treatment of an airway disorder using highly pure roflumilast or a chemical composition primarily composed of roflumilast, but share a specification with a patent directed to processes for the production of highly pure roflumilast. Defendants argued that, based on alleged disavowals of claim scope made in the specification and prosecution history, the term "roflumilast" should be limited to the product of the process to produce roflumilast disclosed in the specification. After issuing its Markman claim construction decision, the court granted the Defendants' request for reconsideration and supplemental briefing to argue the significance of the Medicines decision (called ''TMC'' by the court) and to cite to new deposition testimony of the named inventor. But the court rejected Defendants' attempt to modify its claim construction decision.
First addressing the Defendants' argument that the patentee had disavowed claim scope, the court reasoned that it had previously rejected the disavowal argument, and that even if it were to reconsider the issue, it would reach the same conclusion on the basis of the intrinsic evidence. Notably, even though the specification disparaged certain prior art processes of producing roflumilast, the court noted that "the law does not support that disparagement of some embodiments in the specification evinces an express intent to limit the claim." Id. at 5. Furthermore, the court found that, during prosecution, the inventors purposely chose not to limit the claims to roflumilast produced by a particular process. Id.
The court then held that the Federal Circuit's Medicines decision did not affect its construction of "roflumilast," and provided a detailed analysis of that decision. In fact, the court pointed out that the circumstances of the Medicines case were "extremely different" than those of the case at hand. Id. at 6. We discuss the different circumstances that have been or could be used to distinguish Medicines, below.
The Medicines Specification Defined "Pharmaceutical Batches" in Terms of a Process
First, in the Medicines case, the definition of "pharmaceutical batches" in the patent specification specifically referred to the use of a particular process to make the highly pure bivalirudin. But in Roflumilast, such limiting language is absent from the specification. On the contrary, the specification in the Roflumilast case did not tie the claimed compositions to any process or the consistency of any such process. Roflumilast at 7.
The importance of a clear definitional statement also was noted in a recent Northern District Illinois case. In Sunoco Partners Mktg. & Terminals L.P. v. U.S. Venture, Inc., 2017 BL 143786 (N.D. Ill. Apr. 28, 2017), the patents-at-issue covered "several variations of an invention that allows butane to be accurately blended into gasoline near the end of the distribution process." Id. at 2. Certain claims required a lending unit to be "in fluid connection" with the gasoline and butane tanks and with a downstream dispensing unit. Id. at 4. Other claims required "dispensing the blend" to transport vehicles. Id. The defendant sought to impose a temporal immediacy requirement on both the "fluid connection" and "dispensing" claim limitations based on the language of the claims and statements in the specification, including, for example: "A system and method is provided for blending butane with gasoline at petroleum tank farms, immediately before distribution to tanker trucks." Id. at 7. But the court interpreted the word "immediately" in the context of the specification to refer to a direct connection in the order of process steps, not a temporal limitation. And while the court acknowledged that a limitation that consistently appears in the specification can limit a claim, it distinguished Medicines on the ground that the specification did not dictate a construction of the term "immediately" as used in the specification to require a temporal limitation in the claims. Id. at 9.
The Medicines Patentee Agreed to a Process Limitation
Significantly, the patentee agreed to the process limitation in the Medicines case, a fact which was not lost on the court in Roflumilast. In fact, the patentee in Medicines had admitted that, when viewed in the context of the specification, the term "pharmaceutical batches" refers to the compounding process that was described in the specification. In contrast, the court in Roflumilast expressly pointed out that there was no such consent in Roflumilast. In fact, in Roflumilast, the patentee consistently maintained that the term ''roflumilast'' did not include any process limitation. Roflumilast at 7.
The Medicines Patentee Distinguished the Claimed Invention on the Basis of Consistent Impurity Levels Provided by a Particular Process
Moreover, the patentee in Medicines had distinguished the claimed invention over the prior art on the basis of consistency of impurity levels attained by using the improved process. In contrast, the Roflumilast patentee did not distinguish its claimed compositions over the prior art based on the process by which they were made, but instead submitted a declaration during prosecution showing that the claimed compositions were not in the prior art. Roflumilast at 7.
The Medicines Claims Were Construed to Avoid Uncertainty as to Infringement
In Medicines, the patentee had urged a construction of "pharmaceutical batches" that was not tied to the specific process parameters of Example 5 of the '727 patent, but instead was met whenever an accused infringer consistently produced batches having the requisite purity level. But the Federal Circuit found such a construction "unworkable" because a defendant would not know whether any of its batches infringed until all of its batches were produced having the requisite purity level—"if even one of the batches was determined to have an Asp9 level higher that 0.6 percent, none of the batches would infringe." Medicines at 1303. Furthermore, individual batches with the claimed purity level were already in the prior art. Thus, the invention claimed in the Medicines case was "dependent upon consistently producing batches with impurity levels below 0.6 percent." Roflumilast at 7. And that consistency was attained by using the process of Example 5. In contrast, the Roflumilast case's claimed composition of roflumilast (and its 4-hydroxy compound) was itself novel, such that consistency in its production was not necessary. Id.
The problem of forward-looking assessments of infringement—i.e., the possibility that determination of one's infringement status today is dependent upon testing that can only be completed in the future—was also raised in a District of Delaware case. In GlaxoSmith-Kline LLC v. Glenmark Pharms. Inc., USA, 2017 BL 196843 (D. Del. May 24, 2017), the court was called upon to construe the term "said maintenance period is greater than six months" in the context of method of treatment claims that required administration of "daily maintenance dosages for a maintenance period." Id. at 3. The Defendants argued that "said maintenance period is greater than six months" should mean that infringement would begin only after a period of six months of treatment had already passed. The Plaintiffs, however, urged that infringement begins as soon as the daily maintenance dosage was given for the first time, as long as the treatment period reaches six months. The court adopted Plaintiffs' position, and distinguished Medicines:
[In Medicines], in the absence of requiring the use of a particular compounding process that utilized efficient mixing, . . . "proof of infringement would [simply be dependent on] forward-looking assessments" of whether an accused infringer's production of future batches would be likely to generate the requisite impurity levels. Here, in contrast, there are clear markers in the claims that provide the requisite reasonable certainty as to what is infringing conduct. . . .[E]ven if one does not infringe the Claims until administrating carvedilol for the time period set out therein, the claims make very clear the particular, multi-faceted process that must be followed in order to get to infringement. GlaxoSmithKline at 7-8 (citation omitted).
The Medicines Claims Were Construed to Cover Process Limitations, Not a Particular Result
There is another factor worth mentioning that was not highlighted in the Roflumilast decision. One of the problems with the Medicines Plaintiff's claim construction position—whereby "efficient mixing" referred to any process that attained the claimed purity level—was that it cast a claim limitation in terms of a result, and not in terms of the process required to attain that result. Medicines at 1306. That proposed construction, therefore, impermissibly encompassed all solutions to the problem, beyond that justified by the specification's disclosure and without describing the entire range of solutions to that problem. Id. at 1306-07. This problem of results-oriented claim construction was also raised in Reckitt Benckiser Pharms. Inc. v. Dr. Reddy's Labs. S.A., 2017 BL 307394 (D. Del. August 31, 2017). In that case, the asserted claims were directed to sublingual film drug delivery systems that, among other things, resulted in substantially uniform stationing of the active pharmaceutical ingredient in the film, and processes for making such films. Id. at 2-3. The claims included "drying" limitations that were construed to refer to unconventional drying techniques. The Plaintiff urged any controlled process that avoids rippling of the film and achieves drug content uniformity should automatically amount to an unconventional drying technique. The court, however, noted that a finding of infringement of the "drying" limitations based on whether rippling was avoided and drug uniformity achieved "would put too much focus on whether drug content uniformity is achieved, and would gloss over whether the parameters employed are actually unconventional." Id. at 6-7. The court further noted the similarity to Medicines, where the patentee unsuccessfully argued that "efficient mixing" covered all solutions to the impurities problem, but the specification failed to describe the entire range of solutions to that problem. Thus, both the Medicines and the Reckitt Benckiser decisions rejected a results-oriented approach to claim construction.
Conclusion
In short, there are many factors underlying the Medicines decision. As such, it is unlikely to portend a major shift in the Federal Circuit's approach to claim construction. Instead, the Medicines decision and the subsequent district court cases discussed above together demonstrate that claim construction is highly dependent upon the unique collection of facts presented. The Medicines case highlights the important role that statements and definitions in the specification can play in claim construction, and the consequences of agreeing (during prosecution or litigation) to certain language as part of the construction of a claim term. Notwithstanding the result in Medicines, it still would appear that the construction "'that stays true to the claim language and most naturally aligns with the patent's description of the invention will be, in the end, the correct construction.'"GlaxoSmithKline at 4 (quoting Renishaw PLC v. Marposs Societa' per Azioni, 158 F.3d 1243, 1250 (Fed. Cir. 1998).
Previously published in BNA's Pharmaceutical Law & Industry Report
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
