reasonable expectation of success
Subscribe to reasonable expectation of success's Posts

Obvious to Try Requires Reasonable Expectation of Success Tethered to Claimed Invention

Addressing obviousness in the context of method of treatment claims using particular drug dosages, the US Court of Appeals for the Federal Circuit affirmed a Patent Trial & Appeal Board (Board) final written decision holding that Teva failed to prove obviousness because it failed to show a reasonable expectation of success. Teva Pharms., LLC v. Corcept Therapeutics, Inc., Case No. 21-1360 (Fed. Cir. Dec. 7, 2021) (Moore, C.J.)

Corcept filed a New Drug Application (NDA) for Korlym, a 300 mg mifepristone tablet administered to certain patients with Cushing’s syndrome. The US Food and Drug Administration (FDA) approved Corcept’s application but required a drug-drug interaction clinical trial to determine drug safety when co-administered with strong CYP3A inhibitors such as ketoconazole (Lee memorandum). Corcept conducted the drug-drug interaction study and received a patent relating to methods of treating Cushing’s syndrome by co-administering mifepristone and a strong CYP3A inhibitor based on the data from the Lee memorandum.

Teva sought post-grant review of the patent after Corcept asserted it against Teva in district court. Teva argued that the patent would have been obvious in view of Korlym’s label and the Lee memorandum and submitted a supporting expert declaration. The Board held that Teva failed to prove that a skilled artisan would have had a reasonable expectation of success for safe co-administration of more than 300 mg of mifepristone with a strong CYP3A inhibitor, and thus failed to prove that the patent was obvious. Teva appealed, arguing that the Board erroneously required precise predictability rather than reasonable expectation of success in achieving the claimed invention, and that the Board did not apply Federal Circuit prior art range precedents.

The Federal Circuit affirmed the Board’s decision. Turning first to reasonable expectation of success, the Court explained that the analysis must be tied to the scope of the claimed invention. Because the patent required safe administration of a specific amount of mifepristone, the Board did not err in requiring Teva to show a reasonable expectation of success for a specific mifepristone dosage. Applying this correct standard, the Court found that the evidence supported that a skilled artisan would have had no expectation as to whether co-administering dosages of mifepristone above the 300 mg/day threshold set forth in the Korlym label would be successful. The Federal Circuit also agreed with the Board that Teva’s expert testimony supported a finding of no expectation of success in achieving the claimed invention based on inconsistent testimony before and after institution.

Turning next to the applicability of Federal Circuit prior art range precedents, the Federal Circuit found that Teva had failed to prove that the general working conditions disclosed in the prior art encompassed the claimed invention. Substantial evidence supported the Board’s finding that there was no overlap in ranges because the prior art (Korlym label and industry publications) capped the range of co-administration dosages at 300 mg/day. The Court also noted that Teva’s reliance on mifepristone monotherapy dosages to create an overlap in the claimed ranges failed because the patent claims [...]

Continue Reading

Federal Circuit Makes Clear: Prior Failures in the Art May Demonstrate Non-Obviousness

Addressing the issue of obviousness of a patent directed toward a method of killing antibiotic-resistant bacteria using only visible light with no photosensitizer, the US Court of Appeals for the Federal Circuit reversed the Patent Trial & Appeal Board’s (PTAB) decision, finding no obviousness where the asserted prior art did not disclose a successful method that did not use a photosensitizer. University of Strathclyde v. Clear-Vu Lighting, LLC, Case No. 20-2243 (Fed. Cir. Nov. 4, 2021) (Stoll, J.) The Court held that the PTAB erroneously found a reasonable expectation of success where “[t]he only support for such a finding [was] pure conjecture coupled with hindsight reliance on the teachings in the [asserted] patent.”

Gram-positive bacteria, such as Methicillin-resistant Staphylococcus aureus (MRSA), are known to negatively affect health but effective methods of killing (or inactivating) such bacteria have been elusive. Photoinactivation is a way to kill antibiotic-resistant bacteria, and previous methods involved applying a photosensitizing agent to the infection and then activating the agent using light. Through experimentation, scientists at the University of Strathclyde discovered that application of visible (blue) light of wavelengths in the range of 400 – 420 nm was effective at inactivating bacteria such as MRSA without using a photosensitizing agent. The challenged patent claimed this method of using a photosensitizer for inactivating MRSA and other Gram-positive bacteria.

After Clear-Vu Lighting petitioned for inter partes review, the PTAB found the patent invalid as obvious in view of prior art disclosing methods of photoactivation using visible light. The university appealed.

The Federal Circuit reversed, finding that the prior art did not disclose all claim elements and there was no reasonable expectation of success in reaching the claimed invention by combining the prior art.

The Federal Circuit first addressed the PTAB finding that the prior art disclosed all claim limitations, finding that neither of the asserted prior art references taught or suggested “inactivation” of the bacteria without using a photosensitizer—as required by the claims. The Court noted that it “fail[ed] to see why a skilled artisan would opt to entirely omit a photosensitizer when combining [the] references,” finding it “particularly relevant” that one of the references actually “disclosed such a photosensitizer-free embodiment and was wholly unsuccessful in achieving inactivation.”

The PTAB also found that, based on a prior art teaching that “blue light may” inactivate “other bacterial cells that produce porphyrins,” a skilled artisan would have expected that MRSA could be inactivated by blue light without a photosensitizer due to the presence of porphyrins. In defense of the PTAB’s findings, Clear-Vu argued that support for the reasonable expectation of success could be found in the challenged patent itself. Citing its 2012 decision in Otsuka Pharm. v. Sandoz, the Federal Circuit harshly criticized this position, reiterating that the inventor’s own path to the invention is not the proper lens through which to find obviousness; “that is hindsight.”

The Federal Circuit explained that “not only is there a complete lack of evidence in the record that any bacteria were inactivated after exposure [...]

Continue Reading