Effect of foreign patent proceedings on U.S. patent litigation

Craig Metcalf

In today’s global marketplace, it is common for patent owners to file for patent protection in multiple countries around the world. In addition to the U.S., it is common for companies and inventors to seek parallel protection for their inventions in countries and jurisdictions such as the European Union, Japan, China, Canada, India, Brazil and other countries. Most of these countries have highly developed patent systems of their own. It is possible to obtain patent protection and enforce patents through patent infringement litigation in these jurisdictions. There is, therefore, a question as to whether patent prosecution and litigation proceedings in foreign jurisdictions can impact similar ongoing proceedings in the U.S.

One of the primary functions of courts in patent litigation is to interpret the language of the patent claims in order to determine whether an accused product infringes. Generally courts rely on intrinsic evidence, such as the claims themselves, the patent specification and the patent prosecution history. In cases where the courts deem it necessary or desirable, however, they may be open to receiving extrinsic evidence beyond the patent itself.

If a similar patent has been prosecuted in a foreign jurisdiction, there may be a question as to whether a court can rely on statements made during the foreign prosecution for the purposes of interpreting the claim language. There have been cases where the courts have allowed the introduction of representations made to a foreign patent office and have found those statements to be relevant evidence. At other times, the courts have declined to allow such evidence due in part to the varying legal and procedural standards applied in foreign patent offices. Nevertheless, it is useful to keep in mind that statements made during foreign prosecution could be raised in a related U.S. litigation. Accordingly, care should be taken in foreign patent prosecution.

Another question is whether a judgment in a related foreign patent litigation can be introduced as evidence in the U.S. litigation. This issue was raised in a recent case in the Court of Appeals for the Federal Circuit. In that case, a German patent litigation had been conducted involving a related German patent and similar accused product. The German courts found infringement and issued an injunction. The plaintiff in the related U.S. action argued that the U.S. court should adopt the German judgment “as an admission of infringement of a virtually identical claim.” The Federal Circuit refused to do so, stating that “foreign patent determinations are not binding in litigation concerning United States patents and patent law.” Finally, the Federal Circuit stated that “the German decision has no application in this Court and is not entitled to any deference.” Even in view of this holding by the Federal Circuit, parties should be aware that foreign patent litigation will certainly be monitored and considered by their opponents in U.S. litigation, and there may be an effort to introduce into evidence some aspect of the foreign proceedings.

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