IP Law Daily Court affirms validity of Amgen’s patents for rheumatoid arthritis drug Enbrel
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Monday, August 12, 2019

Court affirms validity of Amgen’s patents for rheumatoid arthritis drug Enbrel

By Brian Craig, J.D.

The court concluded the patent claims are not invalid based on challenges for lack of written description and obviousness.

Following a two-week bench trial, the federal district court in Newark, New Jersey, has concluded that Amgen’s patents for the blockbuster drug Enbrel used to treat rheumatoid arthritis are not invalid. The court decision blocks the launch of a biosimilar version of Enbrel called Erelzi by Sandoz Inc. In the suit, where Sadonz did not contest infringement but only challenged the validity of the patents, the court found that the patent claims are not invalid based on challenges for lack of written description, obviousness, or obviousness-type double patenting(Immunex Corporation V. Sandoz Inc, August 09, 2019, Cecchi, H.).

Immunex Corp., Amgen Manufacturing, Limited, and Hoffman-La Roche, Inc. ("Amgen") own patents covering the active ingredient and manufacture of Enbrel, a biological drug primarily used to treat rheumatoid arthritis. Enbrel is the brand name for etanercept, the first FDA approved fusion protein, first approved in 1998. In August 2016, the FDA approvedSandoz’s biosimilar version of Enbrel called Erelzi. Amgen then filed a patent infringement suit against Sandoz over certain claims for U.S. Patent Nos. 8,063,182 (the ’182 Patent) and 8,163,522 (the ’522 Patent) covering Enbrel. The court held a two-week bench trial in September 2018. Sandoz did not contest infringement of the patents. The only remaining issues were whether the patents are invalid based on: (1) lack of written description and enablement; (2) obviousness; and (3) obviousness-type double patenting. In a lengthy 85-page opinion, the court issued its factual findings and conclusions of law.

Written description and enablement. First, the court concluded that the patents are not invalid based on lack of written description and enablement. The specification must reasonably convey to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date. The level of detail required varies depending on the nature and scope of the claims and on the complexity and predictability of the relevant technology. As to enablement, the patent specification must describe the manner and process of making and using the invention to teach a person of ordinary skill in the art how to make and use the full scope of the claimed invention without undue experimentation.

Here, the court found that the specifications meet the written description requirements, including examples within the specifications. The requisite components of the fusion protection were disclosed in the specifications and known prior to August 1990. Furthermore, amendments to the prosecution file history did not add new material. The amendments were proper and do not alter the written description.

Sandoz also failed to show by clear and convincing evidence that the patents do not meet the enablement standard. The patents explain how to prepare a cDNA encoding the extracellular region of the known p75 protection. The court found Amgen’s experts credible that the patents sufficiently describe the manner and process of making the invention. Thus, the patents are not invalid based on lack of written description and enablement.

Obviousness. Next, the court found that patents are not invalid based on obviousness. There are four basic inquires on obviousness: (1) the scope and content of the prior art; (2) the level of ordinary skill in the art; (3) the difference between the claimed subject matter and the prior art; and (4) secondary considerations of non-obviousness. The prior art would not have motivated a person of ordinary skill in the art to select the individual component of etanercept and in fact taught away from using certain components. It would not have been obvious to a person of ordinary skill in the art to combine the prior art references. Amgen also submitted evidence of unexpected results supporting nonobviousness. The court found ample evidence of praise and clinical success for Enbrel, which has been widely prescribed since its approval in 1998 and has changed the practice of medicine. Furthermore, Immunex obtained licensing from Roche and submitted evidence of a long-felt need, which supported nonobviousness. The argument of simultaneous invention failed to support obviousness. Therefore, the argument that the patent claims are invalid based on obviousness failed.

Obviousness-type double patenting. Finally, the court concluded that Sandozfailed to demonstrate by clear and convincing evidence that the patents are invalid for obviousness type double patenting. The purpose of the rule against double patenting is to prevent an inventor from effectively extending the term of exclusivity by the subsequent patents of variations that are not patentable distinct from the first-patented invention.

Here, the court found that the ’182 Patent is not an invalid patent on Roche’s p55 fusion protein patent for U.S. Patent No. 5,610,279 (the ’279 Patent) issued in 1997. The safe harbor provision protects the claims of the ’182 Patent in view of the ’279 Patent because the ’182 Patent was (1) the result of a divisional application; (2) based on a restriction requirement issued by the USPTO; and (3) in consonance with that restriction requirements. The court concluded the claims of the ’279 Patent are patentably distinct from the ’182 Patent. Additionally, the patents are not invalid over the Immunex’s other patents. Sandoz failed to establish common ownership or inventorship to support invalidity of the patents under the doctrine of double patenting with other patents owned by Immunex and Roche. Accordingly, the court affirmed the validity of Amgen’s patents.

This case is No. 2:16-cv-01118-CCC-MF.

Attorneys: Liza M. Walsh (Walsh Pizzi O’Reilly Falanga LLP) for Immunex Corp. Eric I. Abraham (Hill Wallack, LLP) for Sandoz Inc.

Companies: Immunex Corp.; Amgen Manufacturing, Limited; Hoffman-La Roche, Inc.; Sandox Inc.; Sandox International GmbH; Sandox GmbH

MainStory: TopStory Patent NewJerseyNews

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