Written by: Tanner Murphy

Infringement Disputes

For nearly a decade, Amgen Inc. and Sanofi had been embroiled in a patent infringement dispute over Amgen patents covering broad classes of antibodies beneficial to human blood cholesterol levels. The antibodies that Amgen claimed are defined by their function—an ability to bind to a certain protein and subsequently block the protein from binding to LDL receptors. At trial court and at the Federal Circuit, Amgen’s claims were held invalid because they were not enabled by the patent’s specification, as 35 U.S.C. § 112(a) requires. In our last article, we discussed the procedural history of Amgen’s patent infringement suit against Sanofi, the Federal Circuit decision, and the arguments presented to the Supreme Court.

On May 18, 2023, the Supreme Court unanimously affirmed the Federal Circuit’s decision invalidating Amgen’s functional genus patent claims for lack of enablement. The decision was highly anticipated, in part because the issue before the Court—enabling functional genus patent claims—affects many patentees. Some feared a sweeping change for functional genus claims. For example, would the Court declare that one cannot satisfy the Patent Act’s enablement requirement for functional genus claims without expressly describing how to make each possible embodiment of the claimed genus? That could be an impossible task in many circumstances. As we discuss below, that did not happen. 

Although the Court’s decision hardened the Federal Circuit’s enablement standard that “to be enabling, the specification of a patent must teach those skilled in the art how to make and use the full scope of the claimed invention without undue experimentation,”¹ it did not provide an explicit test for enablement beyond the statutory language of 35 U.S.C. § 112.  

The Fight Against “Bad” Cholesterol

Low-density lipoprotein (LDL) cholesterol, commonly referred to as “bad” cholesterol, contributes to the build up of plaque in arteries, sometime causing serious cardiovascular complications. Benevolent laborers, “LDL receptors” work to remove LDL cholesterol from the body. However, the laborers are met with opposition in the form of PCSK9, a naturally occurring protein that binds to and degrades LDL receptors, preventing the receptors from performing their instrumental function. Enter the Pharmaceutical industry. Beginning in the mid-2000’s pharmaceutical companies began the search for antibodies capable of binding to the “sweet spot” of PCSK9, thereby preventing PCSK9 from binding to and degrading LDL receptors. In simpler terms, a cure for “bad” cholesterol.

In 2011, Amgen obtained a patent for a specific antibody capable of the binding and blocking process. The patent describes the antibody by its amino acid sequence. In 2014, Amgen obtained two additional patents that relate back to the 2011 patent. The claims in those patents, however, do not disclose a particular antibody by its amino acid sequence. Rather, the claims disclose “all antibodies with the functions of (i) binding to particular PCSK9 residues and (ii) blocking PCSK9 from binding to LDL receptors, regardless of whether Amgen could even make (let alone teach others to make) those antibodies.”² 

Equipped with patent claims covering every antibody capable of the binding and blocking functions, Amgen filed suit against Sanofi alleging that Sanofi’s cholesterol fighting drug, Praluent, infringed Amgen’s patent. Sanofi responded asserting that the claims at issue were invalid because Amgen failed to enable a person skilled in the art to make all of the antibodies that perform the binding and blocking functions.

The Supreme Court’s Decision

In holding that Amgen’s specification did not teach a person skilled in the art to make and use the claimed invention, the Court relied on the statutory enablement requirement outlined in 35 U.S.C. § 112, but it also noted that a specification need not always describe with particularity how to make and use every single embodiment within a claimed class.³ “It may suffice to give to give an example if the specification also discloses some ‘general quality running through’ the class that gives it ‘a peculiar fitness for the particular purpose.’”⁴ Furthermore, the Court held a specification is not inadequate merely because the skilled artist must engage in “some measure of adaptation or testing.”⁵ More tersely put, “the more a party claims, the more it must enable.”⁶

The Court analogized Amgen’s patent claims to those at issue in three earlier enablement cases: O’Reilly v. Morse, The Incandescent Lamp Patent, and Holland Furniture Co. v. Perkins Glue Co.

In Morse, inventor Samuel Morse had obtained a patent related to his telegraph invention. That patent’s first seven claims related to the actual structures and systems Morse had designed, and the Court held those claims enabled with little difficulty. But the eighth claim covered the entire essence of the invention class, claiming “the use of the motive power of the electric or galvanic current…however developed for marking or printing intelligible characters, signs, or letters at any distances.”⁷ Morse’s eighth claim was not sufficiently enabled because it “covered all means of achieving telegraphic communication, yet Morse had not described how to make and use them all.”⁸ The Court held that “if [Morse’s eight claim] can be maintained, there was no necessity for any specification, further than to say that [Morse] had discovered that, by using the motive power of electromagnetism, he could print intelligible characters at any distance.”⁹ The Court held that Morse’s eighth claim could derive no aid from the specification filed, and the claim was not valid.¹⁰

In Incandescent Lamp, the patent at issue claimed an “electric lamp” with an “incandescing conductor made of carbonized fibrous or textile material.”¹¹ The patentee brought an infringement suit against Thomas Edison after Edison began using bamboo (a fibrous material) as a conductor in his lamp designs. The Court held that the patent claims at issue “made a broad claim for every fibrous and textile material”; they claimed an entire class of things. But the patent did not teach others how to select materials within that class. Nor did it disclose any quality common to the class that made materials peculiarly adapted to the function (incandescent lighting). Rather, the patent’s specification left others skilled in the art (like Edison) to engage in “painstaking experimentation” to discover what materials “answered the required purpose”—just as Edison had actually undertaken to discover that bamboo did what the patent claimed.¹² That claim was also not enabled.

In Holland Furniture, Perkins Glue Company developed and patented a starch glue as an alternative to animal glue.¹³ The patent claimed all “starch glue which, [when] combined with about three parts or less by weight of water, will have substantially the properties as animal glue.”¹⁴ But the specification described the key ingredient—starch—only in terms of its function and not its chemical or other physical properties. That claim was not enabled because “[o]ne attempting to use or avoid the use of [the invention] as so claimed and described functionally could do so only after elaborate experimentation” with various starches.¹⁵

In comparing the above patent claims to the Amgen claims, the Court stated, “Amgen seeks to monopolize an entire class of things defined by their function – every antibody that both binds to particular areas of the sweet spot of PCSK9 and blocks PCSK9 from binding to LDL receptors”¹⁶ and that “decisions in Morse, Incandescent Lamp, and Holland Furniture reinforce the simple statutory command [that a] specification must enable the full scope of the invention as defined by its claims.”¹⁷

While the Court’s opinion did not provide a steadfast rule, it reinforced the quid pro quo of the “patent bargain”: an inventor receives a limited term of “protection from competitive exploitation” in exchange for bringing “new designs and technologies into the public domain through disclosure.”¹⁸ What Thomas Jefferson called the “embarrassment of an exclusive patent”¹⁹ requires enabling a skilled workman to use the same.

1. MagSil Corp. v. Hitachi Glob. Storage Techs, Inc., 687 F. 3d 1377, 1380 (Fed. Cir. 2012).

2. Brief for Respondents at 10, Amgen v. Sanofi (Feb. 3, 2023) (No. 21-757).

3. Amgen Inc. v. Sanofi, No. 21-757, 2023 WL 3511533, at 13 (U.S. May 18, 2023).

4. Id.

5. Id. at 14.

6. Id. at 16.

7. O’Reilly v. Morse, 56 U.S. 62 , 15 How. 62 (1853) (emphasis added).

8. Amgen, 21-757, 2023 WL 3511533 at 10.

9. Morse, 15 How. at 119.

10. Id. at 119-120.

11. Consolidated Electric Light Co. v. McKeesport Light Co., 159 U.S. 465, 466 (1895).

12. Id. at 475-476.

13. Holland Furniture Co. v. Perkins Glue Co., 277 U.S. 245 (1928).

14. Id. at 250.

15. Id. at 257.

16. Amgen, 21-757, 2023 WL 3511533 at 16.

17. Id. at 13.

18. Bonito Boats, Inc. v. Thunder Craft Boats, Inc. 489 U.S. 141, 150.

19. Graham v. John Deere Co. 383 U.S. 1,9 (1966) (quoting letter from Thomas Jefferson to Isaac McPherson (Aug. 13, 1813), VI THE WRITINGS OF THOMAS JEFFERSON, at 181 (H.A. Washington ed. 1854)).