Schering Corporation v. Geneva Pharmaceuticals, Inc., et al.

United States Court of Appeals, Federal Circuit
339 F.3d 1373 (2003)

ELI5:

Rule of Law:

A prior art reference inherently anticipates a patent claim, rendering it invalid, if the claimed subject matter is the necessary and inevitable result of carrying out what is described in the reference. Recognition of the inherent subject matter by a person of ordinary skill in the art at the time of the prior art is not required for a finding of anticipation.

Facts:

In 1981, Schering Corporation obtained U.S. Patent No. 4,282,233 ('233 patent), which covered the non-drowsy antihistamine compound loratadine, the active ingredient in its product CLARITIN.
The '233 patent disclosed loratadine and pharmaceutical compositions for administering it to patients.
When a human ingests loratadine, their body necessarily and inevitably metabolizes it, forming a new compound called descarboethoxyloratadine (DCL), which is also a non-drowsy antihistamine.
The '233 patent did not expressly disclose DCL or refer to any metabolites of loratadine.
In 1987, Schering obtained a second patent, U.S. Patent No. 4,659,716 ('716 patent), which included claims covering the DCL compound itself.
After the '233 patent on loratadine expired, Geneva Pharmaceuticals, Inc. and other generic drug manufacturers sought regulatory approval to market generic versions of loratadine.

Procedural Posture:

Several generic drug companies (Geneva Pharmaceuticals, Inc., et al.) filed Abbreviated New Drug Applications with the FDA to market generic loratadine.
As part of the applications, the generic companies certified that Schering's '716 patent (covering DCL) was invalid.
Schering Corporation sued the generic companies in the U.S. District Court for the District of New Jersey for patent infringement.
The parties filed cross-motions for summary judgment on the issue of the '716 patent's validity.
The district court granted summary judgment for the generic companies (defendants), ruling that claims 1 and 3 of the '716 patent were invalid as inherently anticipated by the prior '233 patent.
Schering Corporation (appellant) appealed the summary judgment ruling to the U.S. Court of Appeals for the Federal Circuit.

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Issue:

Does a prior art patent that discloses a compound (loratadine) and its administration to patients inherently anticipate a later patent claiming a metabolite (DCL) of that compound, even if the prior art does not expressly disclose the metabolite and its existence was not recognized at the time?

Opinions:

Majority - Rader, J.

Yes. A prior art patent disclosing a drug inherently anticipates a later patent claim to a metabolite of that drug if the metabolite is a necessary and inevitable result of administering the drug, even if the metabolite was not expressly disclosed or recognized in the prior art. The court reasoned that inherent anticipation does not require that a person of ordinary skill in the art would have recognized the inherent disclosure at the time. Because the record shows that DCL necessarily and inevitably forms from loratadine under normal conditions, the prior art '233 patent, which teaches the administration of loratadine, inherently discloses DCL. The court further clarified that inherency can anticipate the entire claimed invention, not just a single missing limitation. Finally, the court invoked the principle that 'that which would literally infringe if later in time anticipates if earlier'; since ingesting loratadine would lead to the formation of DCL and thus infringe the '716 patent, the prior art teaching of ingesting loratadine must anticipate it.

Analysis:

This decision significantly clarifies and strengthens the doctrine of inherent anticipation in patent law, particularly for the pharmaceutical industry. By holding that prior recognition of an inherent feature is not required, the court made it more difficult to obtain follow-on patents for metabolites of known drugs using broad compound claims. The case establishes that if practicing the prior art (e.g., administering a parent drug) necessarily produces a result (e.g., a metabolite), that result is dedicated to the public domain and cannot be later patented as a compound. This forces patent drafters to use more narrow claim language, such as claiming the metabolite in a 'pure and isolated form' or as a specific pharmaceutical composition, to avoid invalidation.

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