The Expanding Blocking Patent Doctrine: a Reversal of Burden of Proof?

Nathan Potter, Blog Editor, University of Cincinnati Law Review

I. Introduction

Overcoming obviousness is becoming increasingly difficult in some industries due to competitors seeking “blocking” patents.[1] A blocking patent is obtained by one patentee to restrict the make, use, sale, and/or export of an earlier patent owned by a different patentee. This may prohibit both patentees’ use of their respective patents due to the likelihood of infringement. Because a blocking patent may dissuade a competitor from pursuing innovation, it can be difficult to apply the objective indicia of nonobviousness (including commercial success, long felt but unsolved needs, and failure of others) listed in Graham v. John Deere Co.[2] This conflict has been brought to the Supreme Court of the United States in Acorda Therapeutics, Inc. v. Roxane Laboratories, Inc.[3] This petition has been distributed for conference on October 1, 2019.[4]

II. Background

A patent must be a nonobvious invention over prior art.[5] 35 U.S.C. § 103 evaluates nonobviousness from the perspective of a person having ordinary skill in the art (a “PHOSITA”). If a PHOSITA would determine that a potentially patentable invention is an obvious variation or addition to prior art, then the invention is not patentable. When determining whether a potentially patentable invention is obvious, the PHOSITA will use the four Graham factors: (1) the scope and content of the prior art; (2) the differences between the prior art and the claims at issue; (3) the level of ordinary skill in the art; and (4) secondary considerations (or the indicia of nonobviousness).[6]

These “secondary” considerations have become increasingly important since Graham. The Federal Circuit has emphasized the importance of secondary considerations in “guard[ing] as a check against hindsight bias.”[7] The Federal Circuit has also used secondary considerations to reverse district courts’ findings of obviousness.[8] The Federal Circuit has even commented on the necessity of analyzing secondary considerations before pronouncing an invention at issue in a case as obvious.[9]

III. Acorda Therapeutic, Inc. v. Roxane Laboratories, Inc., et al.

Acorda centers on four patents that claim the administration of a medication that is used to improve walking in individuals with multiple sclerosis.[10] Acorda was granted an exclusive license for another patent (the Elan patent) from Elan Corporation.[11] The Elan patent discouraged other companies from researching the administration of medication as detailed in the Acorda patents because of the likelihood that those developments would infringe the Elan patent.

One of Acorda’s arguments was “that the district court improperly applied a categorical rule that a blocking patent (the Elan patent) negates any findings in favor of Acorda on the objective indicia of commercial success, failure of others, and long felt but unmet need.”[12] The Federal Circuit sided with the district court, stating the ruling was based on the factual findings of the case, not a categorical ban.[13] The Federal Circuit continued, stating that a blocking patent, by itself, does not discount evidence of commercial success as a secondary consideration, but it requires a more fact-specific inquiry.[14] However, the existence of a blocking patent does lead to the logical conclusion that competitors may be less commercially motivated to pursue similar research.[15] After losing its appeal to the Federal Circuit, Acorda raised its case to the Supreme Court.

A. Petitioner’s Brief

Acorda’s brief asks whether objective indicia of nonobviousness may be partially or entirely discounted by the existence of a blocking patent, and, if so, whether the defendant must prove implicit or actual blockage.[16] The brief alleges that the Federal Circuit’s opinion is in direct conflict with Graham and opens the obviousness inquiry to hindsight bias.[17] The brief also alleges that the Federal Circuit has overridden the Supreme Court’s decision in Microsoft Corp. v. i4i Limited Partnership, which said that patents are presumed valid under 35 U.S.C. § 282(a) and that it is up to the challenger to prove invalidity, based on obviousness, by clear and convincing evidence.[18]

Acorda argues three key points against the concept of blocking patents within the pharmaceutical industry.[19] First, that 35 U.S.C. § 271(e)(1)’s safe harbor provision will protect researchers from being accused of infringement.[20] Second, that the defendants were capable of researching the art in the Elan patent outside the U.S.[21] And third, that the blocking patent could have been licensed to the defendants for a share of the profits.[22] Acorda then concludes, under these points, that any finding of blockage would have to be implicit.[23]

Acorda also argues that the Federal Circuit improperly applied the “clear and convincing evidence” standard.[24] Further, Acorda stated that the defendants did not have to overcome this standard because the Federal Circuit negated Acorda’s evidence of commercial success and other indicia of nonobviousness.[25] Acorda concludes that the blocking patent doctrine improperly shifted the burden of proof to Acorda.[26]

B. Respondents’ Brief

The Respondents’ brief alleges that the district court correctly found Acorda’s patents to be obvious in light of published studies and other evidence.[27] Respondents also point out that the Federal Circuit’s review was to consider whether the district court’s factual findings were clearly erroneous.[28] They stated that the Federal Circuit correctly sided with the district court while also rejecting any categorical rules regarding blocking patents.[29]

The Respondents’ brief argues that Acorda’s accusation of the creation of a categorical rule in the blocking patent doctrine is incorrect and “illusory.”[30] The brief goes on to say that there is no conflict between the outcome in the present case and any decision by the Supreme Court.[31] In this fact-specific inquiry, the Court must consider that the long felt need and commercial success are due to the blocking patent preventing competitors from devoting resources to do research based off the claimed invention.[32] Finally, Respondents surmise that even with the evidence of objective indicia of nonobviousness, Acorda’s patents would be held obvious under the prior art.[33]

IV. Discussion

The Petitioner and the Respondents both presented compelling arguments. There is no evidence of actual blockage. Licensing is common in the pharmaceutical industry. The Respondents never said they sought a license from Elan or Acorda of the Elan patent. Acorda admits that it was given an exclusive license, but there is no mention whether Acorda was permitted to assign that license. But, is it necessary to show actual blockage when the facts of a case strongly lead to an implicit conclusion?

The standard is clear and convincing evidence, not actual proof. The Respondents provided several secondary sources which backed their opinion that a blocking patent severely inhibits the commercial incentive for the Respondents to have pursued invention based on the Elan patent. However, this is still not concrete proof that the Elan patent actually blocked the Respondents’ research in the area.

Secondary considerations, or the indicia of nonobviousness, carry more weight today than they did in 1966, when Graham was decided. This was due to the recognition that those factors are best suited to tipping the scales on whether a patent is invalid due to obviousness. However, when there is significant research in the field and a patent which blocks others’ commercial viability, the court must view any secondary considerations in the light of the facts surrounding a case. To do otherwise, would allow one patentee to dominate a particular area of a field of research. Therefore, the existence of a blocking patent will almost always negate the effectiveness of secondary considerations in an obviousness analysis.

Acorda understates the importance of Federal Circuit’s standard of review. The Federal Circuit could only overturn the district court if it found the ruling to be clearly erroneous. This provided a great deal of deference to the district court, which tried the case based on the facts. Even though the Federal Circuit reviewed those facts, they came to the same conclusion. 

V. Conclusion

Acorda lost its appeal to the Federal Circuit on the facts of the case. It is undeniable that a blocking patent heavily weighs against a court’s consideration of the indicia of nonobviousness. This is the correct approach. Requiring a defendant to show proof of actual blockage is unrealistic in the world of pharmaceuticals. To suggest that a company is welcome to research the claimed invention outside the U.S. is a weak argument. The district court gave the Acorda patents their presumption of validity; however, the respondents overcame this presumption. Acorda relied too heavily on the indicia of nonobviousness to prove their patents were valid, and so those patents were found invalid. The Supreme Court does not need to grant certiorari on this issue because the Federal Circuit has already provided a correct decision. Requiring a defendant to show proof of actual blockage is too heavy a burden and potentially impossible.


[1] 35 U.S.C. § 103. A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.

[2] 383 U.S. 1, 17 (1966).

[3] 903 F.3d 1310 (Fed. Cir. 2018, cert. pending, Apr. 8, 2019).

[4] Acorda Therapeutics, Inc. vs. Roxane Laboratories, Inc., No. 18-1280 (U.S. Apr 08, 2019).

[5] Prior art is any evidence that your invention is already disclosed to the public. Prior art could be disclosed by the inventor or someone else and does not need to be fixed in a tangible medium.

[6] Graham, 383 U.S. at 17.

[7] In re Cyclobenzaprine Hydrochloride Extended-Release Capsule Patent Litig., 676 F.3d 1063, 1079 (Fed. Cir. 2012). See also Apple Inc. v. ITC, 725 F.3d 1356, 1365 (Fed. Cir. 2013).

[8] See Transocean Offshore Deepwater Drilling, Inc. v. Maersk Drilling USA, Inc.,699 F.3d 1340 (Fed. Cir. 2012); Plantronics, Inc. v. Aliph, Inc., 724 F. 3d 1343 (Fed. Cir. 2013); Leo Pharm. Prods., Ltd. v. Rea, 726 F.3d 1346 (Fed. Cir. Aug. 12, 2013).

[9] Apple, 725 F.3d at 1365.

[10] Acorda, 903 F.3d at 1313.

[11] Id.

[12] Id. at 1328.

[13] Id. at 1337.

[14] Id. at 1338 (citing Merck Sharp & Dohme Corp. v. Hospira, Inc., 874 F.3d 724 (Fed. Cir. 2017).

[15] Id

[16] Brief for Petitioner at i, Acorda Therapeutics, Inc. vs. Roxane Laboratories, Inc., No. 18-1280 (U.S. Apr. 8, 2019) (https://www.supremecourt.gov/DocketPDF/18/18-1280/95384/20190404120304062_Acorda%20Petition%20TO%20FILE.pdf).

[17] Id. at 2.

[18] Id. at 3.

[19] Id. at 20.

[20] Id.

[21] Id.

[22] Id.

[23] Id.

[24] Id. at 22.

[25] Id.

[26] Id. at 23.

[27] Brief for Respondents at i, Acorda Therapeutics, Inc. vs. Roxane Laboratories, Inc., No. 18-1280 (U.S. Apr. 8, 2019) (https://www.supremecourt.gov/DocketPDF/18/18-1280/102277/20190607120933242_18-1280%20Brief%20in%20Opposition.pdf).

[28] Id.

[29] Id.

[30] Id. at 1.

[31] Id.

[32] Id. at 14.

[33] Id.at 18.

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