In a unanimous decision published on May 18, 2023, the U.S. Supreme Court invalidated two of Amgen’s patents for its cholesterol drug, Repatha, making it more difficult for patentees to obtain broadly worded patents.[1]  The case – Amgen Inc. v. Sanofi – involves a dispute between the two pharmaceutical companies over the “enablement” requirement of 35 U.S.C. Section 112,[2] specifically how much a patent must disclose in order to “enable” a skilled person to make and use the claimed invention without undue trial and error.  The Supreme Court held that Amgen failed to provide enough detail to recreate the full scope of its claimed invention, and that if a patent claims an entire class of processes, machines, manufactures or compositions of matter then the patent must include sufficient information that enables a person skilled in the art to make and use the entire class.

Amgen’s patents at issue claimed an entire genus of antibodies that bind at specific places to a protein called PCSK9 and prevent the protein from binding to and degrading naturally occurring LDL receptors (which extract LDL cholesterol from the bloodstream).  The patents incorporated what is known as functional claims, where an invention is defined by its function instead of its physical components.  Most important is that Amgen identified the specific amino acid sequences of 26 antibodies that could achieve this function of stopping PCSK9, but the patents claimed all antibodies that achieve the same function. 

Amgen sued Sanofi for patent infringement based on Sanofi’s cholesterol drug that utilizes the same function claimed in Amgen’s patents, but using a different antibody from the 26 specifically described in the Amgen patents. 

The Court’s decision in this case shows that, in exchange for the limited monopoly afforded by a patent, the patentee must ensure that others can accurately and reliably create the entire invention.  By claiming an entire class of things defined by their function, but describing only some of the embodiments of that function, a patentee would be claiming rights over future discoveries without making such discoveries on its own.  The Court rejected Amgen’s arguments that requiring a patentee to describe every enablement would create a heightened enablement standard for patent claims defined by function.  The Court emphasized that there is one standard for enablement, but the broader a patent is, the more the patentee must enable.  In so ruling, the Court compared this case to other inventions from the 19th and 20th century where the enablement requirement was tested.  The Court observed that each of those cases stands for the proposition that if 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. 

Here, the Court determined that the two methods described for discovering antibodies – beyond the 26 specifically identified – required significant experimentation.  The Court did not rule out the possibility that a patent could claim an entire class of processes, so long as the description reliably allows a person skilled in the art to utilize all of the claimed class.  Limited experimentation would still be permitted. 

Future cases may turn on just how much experimentation and testing is permissible, and that will depend on the nature of the invention and underlying art.   Inventors pursuing patents that describe a class of processes, for example in the biotechnologies or software industries, now have a clear burden to fully describe that entire class.  And they will need to tread carefully when experimentation is necessary, perhaps incrementally patenting specific instances in a wider class, rather than risk invalidation because the entire class of inventions cannot be adequately described.  Inventors should also consider whether to protect certain discoveries as trade secrets instead of trying to patent them through broad claims that are now likely to be struck down.

Key Takeaways:

  1. The standard for patent enablement has not changed and applies equally to all patents, but patents that describe a class of processes by their function will necessitate more disclosure for enablement because of the broad claims.
  2. Patents that describe a class of processes must sufficiently enable a person skilled in the art to create the entire class described in the patent claim, without unreasonable experimentation or testing.
  3. Patents that contain broad claims based on the function of a class of processes are at particular risk of being challenged due to lack of enablement.

[1] The full text of Amgen Inc. et al. v. Sanofi et al. can be found here.

[2] Requiring patent applicants to describe inventions in “clear, concise, and exact terms as to enable any person skilled in the art … to make and use [the invention].” 35 U.S.C. §112(a)