CAFC Affirms Ruling that Blocks Generic Version of Amgen’s Psoriasis Drug Until 2028

Yesterday, in a precedential decision, the United States Court of Appeals for the Federal Circuit (CAFC) affirmed a district court ruling that upheld the validity of several claims in two Amgen patents and barred Sandoz and Zydus from producing generic versions of Amgen’s psoriasis drug Otezla until 2028. The CAFC ruling also upheld the district court’s ruling that three claims in Amgen’s U.S. Patent 10,092,541 were invalid. However, that did not stop Amgen from declaring victory in the case in a press release.

The two patents which were not shown to be invalid were U.S. Patent 7,427,638 and U.S. Patent 7,893,101; all three patents are related to Amgen’s psoriasis drug, Otezla. The pharmaceutical company Sandoz alleged that several claims in the three patents were invalid as obvious.

The legal battle began after Sandoz filed multiple patent applications in order to produce and sell a generic version of Otezla. According to Amgen’s 2022 financial results, the company made nearly $2.3 billion in sales of the psoriasis drug. The company bought the drug from Celgene in 2019 for $13.4 billion.

Sandoz appealed the district court’s ruling that both the ‘638 and ‘101 patents were not invalid. The pharmaceutical company argued that the district court erred in the ‘638 patent ruling by failing to find a reasonable expectation that a mixture could be separated. In the ‘101 patent ruling, Sandoz said that the court erred in ruling that the Amgen patent had a March 2002 priority date.

Amgen also appealed the district court’s ruling on the ‘541 patent by arguing that the court erred in ruling a dosing schedule invalid due to obviousness.

Sandoz’s Appeal

In its discussion of the ‘638 patent, the CAFC said that the ruling came down to the experts from each side. The district court and the appeals court found the expert testimony from Amgen more persuasive.

Additionally, the CAFC wrote, “Dr. Schafer’s [an inventor of the ‘638 patent] credited testimony… is sufficient to establish the presence of unexpected results, and thus to support a finding of nonobviousness.”

The ‘unexpected result’ was key to the CAFC’s determination that the ‘638 patent is non-obvious. The patent is related to the pharmaceutical composition of the drug, including oral formulations and dosing forms. Dr. Schafer found a 20-fold difference between “apremilast alone and the apremilast containing racemic mixture.”

“We hold that the 20-fold difference, when an otherwise two-fold difference would have been expected by the skilled artisan, as shown in this case, suffices to support a finding of an unexpected result and thus to affirm the district court’s finding that claims 3 and 6 of the ’638 patent would not have been obvious,” wrote the appeals court.

In the case of the ‘101 patent, the CAFC agreed with the district court that Sandoz did not provide evidence to prove that a 2002 application did not disclose a crystalline form of the psoriasis drug.

“Sandoz did not produce the results of any experiments showing that Example 2 of the ’515 provisional application did not produce crystalline Form B of apremilast,” the CAFC found.

Amgen’s Cross-appeal

Amgen attempted to appeal a ruling from the district court on the invalidity of the ‘541 patent. If this patent had been ruled valid, Sandoz would be barred from producing a generic version of Amgen’s drug until 2034.

This patent is related to the dosing schedule for the drug, and Amgen argued that the district court erred by analyzing the gist of the invention rather than the invention as it was claimed. The pharmaceutical company continued its appeal by arguing that the district court failed to show that a skilled artisan would have a good reason to pursue its claimed schedule.

On the other hand, Sandoz claimed that the dose modification and scheduling would have been routine to a skilled artisan.

In the end, the CAFC once again affirmed the district court’s ruling, which found claims in Amgen’s patent to be obvious, thus invalidating the patent.

Despite losing the cross-appeal, Amgen hailed the affirmation of the district court’s ruling as a win.

“Today’s decision affirms the permanent injunction entered by the district court prohibiting Sandoz and Zydus from making, using, selling, offering to sell, or importing each of their generic versions of Otezla until February 2028,” wrote Amgen in a press statement.

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Author: billperry