6.5.4 Counterclaim of invalidity
Defendants invariably file a counterclaim seeking revocation under Section 64(1) of the Patents Act, 1970. The grounds provided for revocation under Section 64(1) are exhaustive. There is a view that courts retain the discretion not to revoke a patent despite the fulfillment of one or more of the grounds under Section 64(1),124 though this does not seem to be the correct position in law. Proving any one of the grounds under Section 64(1) ought to lead to revocation of the patent.
The grounds for revocation usually taken in a counterclaim include lack of novelty or inventive step and non-patentable subject matter. It is also usual for defendants to support the grounds for revocation, especially in respect of lack of novelty and inventive step, by relying upon claims granted in other jurisdictions. If, in any other foreign jurisdiction, claims granted in corresponding patents are narrower than those granted in India, it is common for defendants in India to question the validity of the Indian patent by referring to such claims. Thus, it is advisable for patentee-plaintiffs in infringement actions in India to check whether the scope of claims in other significant jurisdictions differs, at least broadly, from that of the claims in India. If the patentee narrows the claims in other jurisdictions, it is advisable to make similarly narrower claims in India at the prosecution stage.
The citing of corresponding claims from foreign jurisdictions relates to the concept of “file-wrapper estoppel.” Although patent rights are strictly territorial, defendants argue that the patentee ought to be bound by statements, concessions and amendments made by the patentee before foreign patent offices concerning the same invention. Usually, such narrowing amendments in foreign jurisdictions, without corresponding Indian amendments, could adversely impact the grant of interim relief.
Another ground that defendants often rely upon is noncompliance with Section 8 obligations. Section 8(1) of the Act requires mandatory disclosure of the details of all corresponding foreign applications. Section 8(2) requires the filing of the prosecution history of corresponding foreign applications if so directed by the Indian Patent Office.
An issue frequently agitated in Indian courts, in invalidity challenges to pharmaceutical patents, concerns coverage and disclosure. In Novartis AG v. Union of India,125 the Supreme Court held that a patentee cannot contend that a patent’s coverage is more expansive than its disclosure. The following observation by Justice Jacob in the English case of European Central Bank v. Document Security Systems Inc. is often cited in the Indian context:
Professor Mario Franzosi likens a patentee to an Angora cat. When validity is challenged, the patentee says his patent is very small: the cat with its fur smoothed down, cuddly and sleepy. But when the patentee goes on the attack, the fur bristles, the cat is twice the size with teeth bared and eyes ablaze.126
Since claims are granted only upon an enabling disclosure, courts must presume that a prior patent discloses the claimed subject matter in an enabling manner. However, there have been various opinions expressed that the patent coverage could be wider than the disclosure, leading to multiple patents thereafter. The Delhi High Court has recently considered this issue in a series of interim orders, wherein the preponderance of the view favored the interpretation in Novartis.127 This view is presently the prevalent one.