Sandoz fails in Enbrel patent challenge, but Fed Circuit split

Amgen has won a key patent victory over  Sandoz in a dispute over biologic Enbrel (etanercept).

The  US Court of Appeals for the Federal Circuit’s ruling, issued yesterday, July 1, means Sandoz cannot market a competitor version of the drug, which is used to treat autoimmune diseases like rheumatoid arthritis.

Amgen, which exclusively licenses the patents covering Enbrel from Roche, brought the case.

Amgen accused Sandoz of infringing two patents after the German company filed an application for Erelzi, a biosimilar version of Enbrel.

The patents-in-suit were first licensed from Roche by the biologics developer Immunex more than 30 years ago. After Amgen acquired Immunex in 2002, it entered into an ‘accord and satisfaction’ agreement with Roche, which gave Amgen the exclusive right to prosecute the patents, as well as the first right to sue for infringement and retain any damages.

The US District Court for the District of New Jersey ruled in favour of Amgen after Sandoz could not prove that the patents were invalid.

Sandoz then appealed the New Jersey court’s decision to the Federal Circuit, which yesterday upheld the infringement finding by a majority of 2-1.

The German company claimed that the patents should be invalid under the judicial doctrine of “obviousness-type double patenting”—designed to prevent applicants from filing separate patents that claim obvious variants of the same subject matter, so as to extend the life of their patent protection.

Sandoz said the two asserted patents should be invalid under this theory in light of two other Immunex patents, not asserted in the suit. This doctrine only applies to patents which are “commonly owned” by the same party.

In its appeal, Sandoz argued that the patents were all commonly owned by Amgen because the ‘accord and satisfaction’ agreement transferred “all substantial rights” in the IP to the company.

But the Federal Circuit disagreed, on the basis that Roche retained a secondary right to sue for infringement, and a veto over the assignment of the patents to an unrelated third party.

“As such, the Immunex patents and the patents-in-suit are not ‘commonly owned,’ and obviousness-type double patenting does not apply,” the Federal Circuit ruling stated.

Dissenting from the majority opinion, Circuit Judge Jimmie Reyna argued that Amgen’s subsidiary Immunex owns all substantial rights in the patents.

Reyna highlighted a clause in the accord that allows Amgen to acquire all outstanding rights in the patents for a payment of $50,000.

The judge argued that Roche’s rights in the patents were therefore “illusory”, and should be considered commonly owned by Amgen.

In a statement, Sandoz US president Carol Lynch said the company would “continue its efforts to make Erelzi available to US patients with autoimmune and inflammatory diseases”.

"Our company respects valid IP, however Sandoz continues to believe the patents asserted by Amgen are not valid, and that it should not be able to use them to extend the drug’s exclusivity,” Lynch added.

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