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United States Supreme Court affirms invalidating claims for lack of enablement

Executive Summary

In Amgen Inc. v. Sanofi, the United States Supreme Court affirmed the lower courts’ judgment that the asserted claims of U.S. Patent No. 8,829,165 (“the ’165 Patent”) and U.S. Patent No. 8,859,741 (“the ’741 Patent”) are invalid for lack of enablement. The Supreme Court held that a patent covering a class of processes must provide sufficient information to allow those skilled in the art to replicate the full scope of the invention.


PCSK9 is a naturally occurring protein and degrades low-density lipoprotein (“LDL”) cholesterol receptors. (Slip Op. at 4.) Amgen Inc. (“Amgen”) and Sanofi each developed PCSK9-inhibiting drugs that employ distinct antibodies with unique amino acid sequences and received a patent for their respective antibodies in 2011. (Slip Op. at 4-5.)  Each of those patents claims the relevant antibody by its amino acid sequence. (Slip Op. at 5.)

Amgen obtained the ’165 and ’741 Patents in 2014.  Id. Claims 19 and 29 of the ’165 Patent and claim 7 of the ’741 Patent claim the entire genus of antibodies that (1) “bind to specific amino acid residues on PCSK9,” and (2) “block PCSK9 from binding to [LDL receptors].” Id.

Amgen’s patent applications identified the amino acid sequences of 26 antibodies that perform these functions, depicted the three-dimensional structures of two of those antibodies, and described two methods to make other antibodies that perform the claimed functions. Id. The first method, which Amgen calls the “roadmap,” directs scientists to:

  1.  generate a range of antibodies in the lab;
  2.  test those antibodies to determine whether any bind to PCSK9;
  3.  test the antibodies that bind to PCSK9 to determine whether any bind to the “sweet spot”1  as described in its claims; and
  4.  test those antibodies to determine whether any block PCSK9 from binding to LDL receptors. (Slip Op. at 5-6.)  

Amgen’s second method, referred to as “conservative substitution,” requires scientists to:

  1.  start with an antibody known to perform the described functions;
  2.  replace select amino acids in the antibody with other amino acids known to have similar properties; and
  3.  test the resulting antibody to determine if it also performs the described functions.  (Slip Op. at 6.)

Amgen sued Sanofi for infringing the ’165 and ’741 Patents shortly after issuance. Id. Sanofi argued that the asserted claims of these patents were invalid for lack of enablement because they covered potentially millions of unidentified antibodies that perform the claimed functions and neither of the methods described in the patents for generating such antibodies enabled a skilled artisan to do so. Id.  

The district court held that the asserted claims are invalid for lack of enablement, and the Federal Circuit affirmed. (Slip Op. at 6-7.)


The Supreme Court granted certiorari and affirmed the lower courts’ invalidation of the ’165 and ’741 Patents for lack of enablement. (Slip Op. at 19.)  The Court explained that “[i]f a patent claims an entire class of processes, machines, manufactures, or compositions of matter, the patent’s specification must enable a person skilled in the art to make and use the entire class.” (Slip Op. at 13.)  “In other words, the specification must enable the full scope of the invention as defined by its claims.” Id.  Having observed that the ’165 and ’741 Patents claim “every antibody that both binds to particular areas of the sweet spot of PCSK9 and blocks PCSK9 from binding to LDL receptors,” as opposed to just the 26 specific antibodies that were described by their amino acid sequences, the Court concluded that Amgen’s disclosed methods – which it found “amount[ed] to little more than two research assignments” – did not adequately enable a skilled artisan to make and use the claimed class of antibodies. (Slip Op. at 16-17.) Accordingly, the Court affirmed the judgment below. (Slip Op. at 19.)


The “sweet spot” is a sequence of 15 amino acids of PCSK9. (Slip Op. at 4.) An antibody that binds to the “sweet spot” could prevent PCSK9 from binding to and degrading LDL receptors. Id.