Federal Circuit sends Allergan’s patent dispute back to district court

A district court must revisit its decision that one of Allergan’s patents is valid and was not infringed by a competitor.

In a ruling, published Friday, March 15, The US Court of Appeals for the Federal Circuit found the US District Court for the District of Delaware had erred in its determination that two of the claims of Allergan’s patents were not obvious.

The case concerns Allergan’s antipsychotic medication, Saphris (asenapine maleate). Conventionally, asenapine was developed as a tablet. Saphris is administered sublingually, meaning the formulation is placed under the tongue, where it dissolves.

One of Allergan’s generic competitors, pharmaceutical company Sigmapharm, filed an abbreviated new drug application (ANDA) with the US Food and Drug Administration seeking to market a generic version of Saphris.

Other pharmaceutical companies Hikma, Breckenridge Pharmaceuticals, Alembic and Amneal, also filed ANDAs and were named in the suit.

Allergan sued for patent infringement, asserting that the companies’ proposed generic products would infringe 10 claims of one of its patents (US number 5,763,476).

The US District Court for the District of Delaware found that two claims of the patent were not obvious because Sigmapharm had not established a reason why a person skilled in the art would combine asenapine into a sublingual form.

But, Sigmapharm argued that a person skilled in the art would have been motivated to administer asenapine sublingually to address swallowing difficulties in special patient populations.

Because the court failed to consider whether swallowing difficulties would provide a motivation to combine asenapine into a sublingual form, the Federal Circuit remanded its validity ruling and asked it to address this question.

Additionally, the Federal Circuit determined that the district court erred in its construction of claim 4 of the ‘476 patent.

It said the district court incorrectly perceived the language “excitation” as a disorder, rather than a symptom.

Claim 4 of the patent describes Saphris as “a method for treating tension, excitation, anxiety, and psychotic and schizophrenic disorders”. The Federal Circuit said the use of the conjunction “and” before “psychotic and schizophrenic disorders” indicates that the words “tension,” “excitation,” and “anxiety” are not describing “disorders”.

Because the district court’s interpretation of the claim was wrong, the Federal Circuit said its finding of non-infringement was also incorrect.

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