Post by Paul Serbinowski
What must the specification disclose to enable broad functional claim language?
A week ago in Amgen Inc. v. Sanofi, the U.S. Supreme Court considered what the specification must disclose to enable a claim that broadly stated that suitable antibodies for lowering “bad” LDL cholesterol were defined by the ability of an antibody to bind to a “sweet spot” of a certain amino acid sequence of a protein PCSK9 and to block it from binding to LDL receptors. PCSK9 is a naturally occurring protein that binds to and degrades LDL receptors. LDL receptors are beneficial by binding LDL cholesterol and lowering its presence in the blood. LDL cholesterol leads to plaque formation in blood vessels which causes cardiovascular disease, stroke and heart attacks. The “sweet spot” is a region of 15 out of PCSK9’s 692 amino acids. Amgen and Sanofi both obtained other patents not at issue that claimed antibodies having specific amino acids. Antibodies of the immune system are extremely diverse and numerous. An antibody is made of a chain of amino acids, the sequence of which determines its structure. An antibody folds into a complex three-dimensional structure having a shape which serves an important role in its function. Even one change of amino acid in an antibody can disrupt or prevent its function. Experts said that it is not known how replacing one amino acid affects structure and function of the antibody. Knowing the three-dimensional structure of an antibody from knowing its sequence is still not possible.
Amgen’s patent at issue claimed the antibodies not by amino acid sequence (structure) but by their functions of binding the particular amino acid “sweet spot” region of PCSK9 and blocking PCSK9 from binding to LDL receptors. Amgen’s patent specification identified the amino acid sequences of 26 antibodies that perform these two functions, and it depicted the three-dimensional structures of two of these 26 antibodies. The only other information Amgen provided in the specification was to describe two methods (the “roadmap” and “conservative substitution”) to make other antibodies that perform the binding and blocking functions. Sanofi argued that the patent was invalid for lacking an enabling disclosure that described how to make all of the antibodies that performed the two claimed functions. Sanofi argued that Amgen described only 26 antibodies, but its claims covered potentially millions of antibodies that performed the two functions, and its specification did not describe how to obtain them other than by using extensive trial and error discovery. The Court agreed with Sanofi and the U.S. Court of Appeals for the Federal Circ (“CAFC”) and found Amgen’s patent claims invalid for lack of an enabling disclosure.
The Court first noted that the U.S. Constitution requires a “patent bargain” in which the competitive advantage of having a limited patent monopoly is given in exchange for describing new designs and technology for the benefit of all. The public’s interest in this bargain is maintained by requiring that, in the specification of the patent, the invention is described with such particularity that it distinguishes from the prior art as well as enables persons skilled in the art to make and use the invention. This “enablement requirement” states that the patent applicant must provide in the specification “a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art...to make and use the same.” 35
U.S.C. §112(a). To complete the bargain, upon expiration of the patent, the public is entitled to freely use all of the knowledge of the invention for which the patent owner received their monopoly reward. The Court referred to an earlier case stating that “[i]f therefore [the disclosure] be so obscure, loose, and imperfect, that this cannot be done, it is defrauding the public of all the consideration, upon which the monopoly is granted.”
The Court looked to examples from court cases decided over the last 150 years starting with the Morse opinion. The Court noted that it occurred to the inventor Samuel Morse in inventing the telegraph “that, by means of electricity, signs representing figures, letters, or words, might be legibly written down at any distance.” Morse received a patent having 8 claims, 7 of which were upheld as being directed to specific telegraph structures and systems he designed. The claim at issue covered all means of telegraphic communication: “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,” but Morse did not disclose how to make and use them all. The Morse court found the claim invalid, stating that to uphold the claim would lead to the improper result of there being no need for a specification, except to say that “he had discovered that, by using the motive power of electro-magnetism, he could print intelligible characters at any distance.” The Incandescent Lamp opinion involved the prior art technology of gas lamps and arc lamps that were overly bright. Thomas Edison attempted to replace the standard carbon filaments in incandescent lamps which rapidly deteriorated, with metal filaments but they melted. Finally, he found that the oriented fibers of bamboo worked for the filament and obtained a patent. Sawyer and Man patented lamps which used carbonized paper filaments. Their products had limited commercial success. They asserted that Edison’s incandescent lamps having bamboo filaments infringed their patent claims directed to use of a filament of a “fibrous or textile material.” The court agreed with Edison and said that instead of properly limiting their patent to carbonized paper filaments, they tried to cover use of all fibrous and textile material filaments. This broad claim could have been acceptable according to the Incandescent Lamp court, if Sawyer and Man had disclosed “a quality common” to fibrous and textile substances that made them “peculiarly” adapted to incandescent lighting. This would have taught others how to select suitable fibrous and textile materials to make an operable incandescent lamp. Most fibrous and textile materials did not work, and it took “painstaking experimentation” for Edison to find that bamboo worked. The court said that “the fact that paper happens to belong to the fibrous kingdom did not invest [Sawyer and Man] with sovereignty over this entire kingdom.” Lastly in Holland Furniture, the inventor discovered a starched-based glue for adhering wood veneering instead of the prior art use of animal glue. Rather than only claiming its particular starch glue, Perkins claimed a “starch glue which, [when] combined with about three parts or less by weight of water, will have substantially the same properties as animal glue.” Perkins’ specification described that in making the glue one should use a “starch ingredient” with “such qualities” that it would yield a product “‘as good as animal glue’” for wood veneering “when combined with three parts of water and with alkali.” The court found the patent invalid for lack of an enabling disclosure since the specification described the starch ingredient not by its physical or chemical properties but by its use or function. The court would not allow the patent monopoly to extend to every starch that performed as well as animal glue.
The Amgen Court stated that these cases supported the rule 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. In other words, the specification must enable the full scope of the invention as defined by its claims. The more one claims, the more one must enable.” The Court said this does not mean that each and every embodiment of the class must be disclosed (“it may suffice to give an example (or a few examples) if the specification also discloses some general quality running through the class that gives it a peculiar fitness for the particular purpose.” Incandescent Lamp). The Court also reiterated that it is permissible for the specification to require a reasonable amount of experimentation to make and use the invention. The patent in the Wood opinion claimed a method of making bricks by mixing coal dust with clay. The Amgen Court approved of the decision in Wood in which the specification “required use and offered two alternative proportions where the clay has some peculiarity.” The validity of the claim was upheld by the Wood court since varieties of clay can result in some differences in proportions sometimes being needed. In the Minerals Separation opinion, the court dismissed a challenge to a claim to a method of separating metal from mineral ore. That court found that the specification’s use of some preliminary testing of the mineral ore in separating metal from the ore was acceptable to adapt the process to any particular ore. The court in Minerals Separation said that the “the certainty which the law requires in patents is not greater than is reasonable.” It also noted that because the “composition of ores varies infinitely,” it was “impossible to specify in a patent the precise treatment which would be most successful and economical in each case.” The Amgen Court also approved of an earlier opinion stating that “the definiteness of a specification must vary with the nature of its subject. Addressed as it is to those skilled in the art, it may leave something to their skill in applying the invention." However, the Amgen Court cautioned that “in that much tolerance, courts cannot detract from the basic statutory requirement that a patent’s specification describe the invention in such full, clear, concise, and exact terms as to enable any person skilled in the art to make and use the invention.”
Turning to the particular facts of the case, the Amgen Court said there was an enabling disclosure in the specification, by its listing of the amino acid sequences of 26 amino acids, for the invention of those antibodies. The structure of the antibodies was able to be determined from specifying the definite amino acid sequences. However, other claims of Amgen’s patent seek 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. This class of antibodies does not include just the 26 that Amgen has described by their amino acid sequences, but additional antibodies that may include at least millions of candidates.” The Court said that just like Morse tried to monopolize all means of telegraphic communication, Sawyer and Man sought to monopolize all fibrous or textile materials for incandescent filaments and Perkins tried to monopolize all starch glues that performed as good as animal glues in wood veneering, Amgen sought to monopolize all antibodies that inhibit PCSK9 to lower LDL cholesterol. The Court was not persuaded by Amgen giving a “roadmap” for others to follow using trial and error by which scientists come up with a wide range of antibody candidates and then screen antibodies that bind to the amino acids of the sweet spot of PCSK9 protein and block it from binding LDL receptors. The conservative substitution of Amgen’s specification also failed to teach how to arrive at the antibodies in a meaningful way by merely substituting amino acids of antibodies that work and then testing to determine their effectiveness. The Court was not persuaded by Amgen’s arguments that this decision would stifle groundbreaking inventions, that it was applying a higher enablement standard for such inventions in which an entire genus of molecules were defined by their function, or that the CAFC was insisting on improperly evaluating how much time and effort would be needed to make all of the antibodies satisfying the broad scope of the claim. The Court found Amgen’s broad claims using functional language to describe the antibodies were invalid as not supported by an enabling disclosure since the insufficient guidance in the specification required scientists to carry out “painstaking experimentation” to determine suitable antibodies, providing nothing more than a “hunting license.”
The Amgen case represents a culmination of years of the CAFC and U.S. Patent and Trademark Office being dissatisfied with use of broad functional wording in claims. The Court is using the enablement requirement to deter broad claiming of a class using functional language by insisting that it is part of the “patent bargain” for the inventor to show examples of the claimed structure as well as to provide useful guidance for how others can find other suitable structures falling within the claim by showing the exception to the rule is satisfied. The Court said that under the exception it is not requiring that each and every embodiment of the class must be disclosed (“it may suffice to give an example (or a few examples) if the specification also discloses some general quality running through the class that gives it a peculiar fitness for the particular purpose). Patents should be drafted using structural wording where possible (describing the invention by “what it is, rather than what it does”). If patent claims use broad functional wording to cover structure the patent specification should disclose a general quality running through the class that gives it a peculiar fitness for the particular purpose. It is expected that many future cases before the CAFC will revolve around whether this exception is satisfied.