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Inventor’s Motivation to Combine Does Not Control Obviousness

The US Court of Appeals for the Federal Circuit affirmed a district court decision rejecting claims of a patent application directed to a dosing regimen for a cancer treatment, finding the claims to be obvious where the motivation to use the claimed dosing was not the same as the inventor’s motivation. ImmunoGen, Inc. v. Coke Morgan Stewart, Case No. 23-1763 (Fed. Cir. Mar. 6, 2025) (Lourie, Dyk, Prost, JJ)

The claims at issue involved a dosing regimen for administering IMGN853, an already-patented antibody drug conjugate used for treating certain cancers, at a claimed dose of six milligrams (mg) per kilogram (kg) of adjusted ideal body weight (AIBW) of the patient.

ImmunoGen argued that it was undisputed that, at the time of the invention, a person of ordinary skill in the art would not have known that IMGN853 caused ocular toxicity in humans and that without a motivation to address the problem of ocular toxicity, the claimed dosing limitation could not have been obvious. Therefore, according to ImmunoGen, the district court erred in its motivation-to-combine analysis. The Federal Circuit disagreed, stating, “that the specific problem the inventors . . . purported to solve via the claimed dosing regimen was unknown does not necessarily mean that the dosing regimen itself was not obvious.” The Court also noted that because ocular toxicity was a well-known adverse event in the administration of drugs containing a payload included in IMGN853, “a person of ordinary skill in the art, despite not knowing of IMGN853’s ocular toxicity, would have nonetheless been motivated to monitor for those side effects when administering the drug to a human.”

ImmunoGen also argued that the district court erred in finding that a person of ordinary skill in the art would have been motivated to use AIBW dosing to eliminate ocular toxicity. The Federal Circuit again disagreed, reasoning that although AIBW dosing has not been used for drugs such as IMGN853, it would still have been within the range of knowledge of a person of ordinary skill in the art when addressing dosing-induced ocular toxicity. The Court explained that AIBW was well known, had been used for drugs both smaller and larger than IMGN853, and had proven effective in reducing ocular toxicity.

The Federal Circuit concluded that the district court did not clearly err in determining that a person of ordinary skill in the art would have been motivated to select the claimed dose of six mg/kg AIBW with a reasonable expectation of success. The claimed dose had already been described in the literature for patients at their ideal body weight, regardless of whether a doctor was aware of AIBW dosing specifically. The Court also noted that the district court was not required to find that a person of ordinary skill in the art would have had a reasonable expectation of eliminating ocular toxicity using the claimed dose, as “the obviousness inquiry is generally agnostic to the particular motivation of the inventor” and the claims made no reference to ocular toxicity.

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Private Sale Means Public Fail

The US Court of Appeals for the Federal Circuit affirmed a Patent Trial & Appeal Board decision that a private sale of a product embodying the claimed invention did not qualify as a “public disclosure” under 35 U.S.C. § 102(b)(2)(B). Sanho Corp. v. Kaijet Technology Int’l Ltd, Inc., Case No. 23-1336 (Fed. Cir. July 31, 2024) (Dyk, Clevenger, Stoll, JJ.)

Sanho owns a patent directed to a port extension apparatus designed to enhance connectivity of end-user devices (such as laptops) with other devices (such as printers). Kaijet petitioned for inter partes review (IPR) challenging certain claims of Sanho’s patent, arguing that the claims were obvious based on a prior art reference. The Board found that the patent claims were invalid because of the prior art reference’s earlier effective filing date. Sanho argued that a prior sale of its HyperDrive device by the inventor of the patent should disqualify the reference as prior art. However, the Board determined that Sanho failed to demonstrate a public disclosure of the HyperDrive sale before the prior art reference’s effective filing date. Thus, the patent was invalidated. Sanho appealed.

The Federal Circuit affirmed, explaining that the America Invents Act (AIA) redefined prior art, shifting from a first-to-invent to a first-inventor-to-file system. Under the AIA, prior art includes patents and applications filed before the patent’s effective filing date subject to exceptions for public disclosures by the inventor. Sanho argued that the HyperDrive sale fell into this exception.

The Federal Circuit dismissed Sanho’s argument that the phrase “publicly disclosed” in § 102(b)(2)(B) should encompass all types of disclosures described in § 102(a)(1), including private sales. The crux of the issue was whether placing an invention “on sale” was tantamount to a “public disclosure” under § 102(b)(2)(B). The statute states that a disclosure is not prior art if the subject matter was publicly disclosed by the inventor before the effective filing date of the prior art. Sanho argued that “publicly disclosed” includes any disclosure, even private sales. The Court disagreed, explaining that the statute’s use of “publicly” implies a narrower scope than just “disclosed.” The Court noted that the purpose of this exception is to protect inventors who make their inventions available to the public before another’s patent filing.

The Federal Circuit also relied on legislative history in support of the conclusion that “public disclosure” in § 102(b)(2)(B) means the invention must be made available to the public. Sanho argued that as long as there are no confidentiality requirements, all disclosures, even private sales, should constitute public disclosures. Again, the Court rejected that argument, noting that the statute differentiates between “publicly disclosed” and general “disclosures,” implying different meanings.

The Federal Circuit determined that § 102(b)(2)(B) protects inventors who publicly disclose their inventions from subsequent disclosures by others, ensuring that prior public disclosure by the inventor prevents a third party’s disclosure from becoming prior art. This provision aims to encourage inventors to share their innovations with the public.

Practice Note: For a disclosure to qualify as “public” under the [...]

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