Unlike obviousness, the test for anticipation in patent law is generally pretty simple—does the prior art disclose the same thing as the challenged patent claims. But as our latest case of the week shows, that simple test can sometimes involve subtle, and more complicated, issues.
Case of the (recent) week: Mylan Pharmaceuticals Inc. v. Merck Sharp & Dohme Corp., No. 21-2121
Panel: Judges Lourie, Reyna, and Stoll, with Judge Lourie writing the opinion
You should read this case if: you have a matter involving anticipation of a species when the prior art discloses a genus
In this week’s case, the patentee obtained a patent to a chemical formula that can be used for treating non-insulin-dependent diabetes. The fancy name for the claimed chemical is a sitagliptin dihydrogenphosphate salt with a 1:1 stoichiometry. If that’s all gibberish to you, the relevant point to know is that the claimed compound can be formed from sitagliptin and phosphoric acid. And the relevant prior art in the case discloses sitagliptin and “pharmaceutically acceptable salts thereof,” while also identifying phosphoric acid as a preferred acid for forming such a salt. Open and shut invalidity, right?
The Board thought not and the Federal Circuit affirmed. The Federal Circuit reasoned that the prior art discloses sitagliptin only as part of a class of 33 compounds related to possible diabetes treatment. Yet nothing in the art “directs a skilled artisan to sitagliptin from among the 33 listed” compounds. The prior art similarly teaches phosphoric acid for salt formation only as part of a group of 8 potential acids. But again, nothing in the art “singles out phosphoric acid or any phosphate salt.” Plus, the art’s description of salts “comes 44 pages earlier in the specification” before the description of sitagliptin. These facts were enough to support the Board’s finding that the art did not expressly disclose the claimed chemical.
The Federal Circuit similarly saw sufficient evidence to support the Board’s finding of no-inherent anticipation. The challenger relied on precedent holding that disclosing a class could anticipate individual species within the class when a skilled artisan may “at once envisage each member of the limited class.” The Federal Circuit rejected that argument because the challenger in this case had failed to show the prior art discloses a “limited” class. The Court pointed to unrebutted testimony that the combination of 33 potential compounds and 8 potential acids for forming salts amounted to a class of “957 salts, some of which may not exist.” That class size “is a far cry from the 20 compounds ‘envisaged’ by the narrow genus” in the relevant precedent. The Court explained that it “cannot provide a specific number defining a ‘limited class’” because the number “depends on the ‘class.’” But on the facts in this case, it held that the Board’s no-anticipation conclusion was reasonable.
OTHER WEEKLY STATS
Precedential opinions: 0
Non-precedential opinions: 8
Rule 36: 4
Longest pending case from argument: Novozymes North America, Inc. v. Danisco US Inc., No. 21-2184 (173 days)
Shortest (non-Rule 36) pending case from argument: Penley v. McDonough, No. 21-2088 (3 days)