Importance of expert testimony in patent cases

The grant of a patent invariably follows a thorough examination by expert patent examiners of the patent offices. In some jurisdictions, this grant carries with it the presumption of validity. In India, however, the validity of a patent is not guaranteed by the grant according to section 13(4) of the Patents Act, 1970. When the grant of a patent is challenged it requires evidence to prove the grounds of invalidity taken by the opponent. Most of these patent invalidity challenges, by nature of being technical, require opinions of expert witnesses.

The Intellectual Property Appellate Board (IPAB), in a number of cases, have remanded the cases back to the controller on this ground alone. Non-consideration of expert evidence was treated as a violation of the principle of natural justice. Appeal courts are harsh to the decisions taken by lower courts, or IPAB, or controllers without appreciating expert evidence.

Judges’ discretion

The usefulness, scope and extent of technical expert testimony in the patent disputes will be tested in future cases. As we are still in the process of evolving the precedence on role of experts in patent disputes, it will take some time for intellectual property litigators to break the shackles placed on trial courts on whether an expert view is essential. As stated by American judge Learned Hand in Kohn v Eimer, “We have not the slightest wish to minimize the vital importance of expert testimony in patent suits, or to suggest that we are not absolutely dependent upon it within its proper scope; but that scope is often altogether misapprehended … when the judge has understood the specifications, he cannot avoid the responsibility of deciding himself all questions of infringement and anticipation, and the testimony of experts on these issues is inevitably a burdensome impertinence.”

When is it essential?

In the recent Renadyl (formerly known as Kbow Biotics) appeal case, Madras High court stressed the need for expert evidence in support of the petition for the revocation of a patent. The court held: “The petitioner has not produced any evidence of an expert before the third respondent appellate board to substantiate its plea that the invention is a mere “admixture” or that the patent was liable to be revoked on the grounds stated in the petition filed by it”.

DPS Parmar is a special counsel with LexOrbis’s IPAB practice group.

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