Two plaintiffs, namely, F. Hoffmann-La Roche Ltd. and OSI Pharmaceuticals Inc., filed this suit for permanent injunction restraining infringement of patent by the defendants. The plaintiff No.1 Company claiming to be the world’s leading research-focused healthcare groups in pharmaceuticals and diagnostics stated that it engages into collaborative agreements and alliances with numerous partners and invests huge money for such activities. Plaintiff No.2 jointly owned a patent with Pfizer Products Inc. in respect of a breakthrough small drug molecule known for destroying some types of cancer cells while causing little harm to the normal human cells. This drug is administered in the form of a tablet formulation sold by the plaintiffs under the trademark and name of ‘Tarceva’. The plaintiff No.2 along with Pfizer Products Inc. obtained the grant of patent in respect of this drug and its process. The plaintiffs’ product was registered by the Central Drug Standard Control Organization in the name of plaintiff No.1. Plaintiff No.2 and the plaintiff No.1 had entered into a Development Collaboration and Licensing Agreement wherein the plaintiff No.1 had a licence to use, sell and offer for sale the licensed products including this drug. The plaintiff No.1 was also licensed and authorized to cause enforcement of any intellectual property rights for any of their products. Plaintiff No.1 was actively engaged in manufacture, marketing and sale of the innovative drug Tarceva (Erlotinib) in various countries including India.
The case of the plaintiffs against the defendant was that the defendant being also engaged in manufacture and marketing of pharmaceutical and health care products in India was involved in several actions for violation of intellectual property rights including patent rights as they were allegedly planning to launch a generic version of this drug in India and also export the same to various countries.
The defendant contended that the patent in question was liable to be revoked as it only sought to improve from the existing prior art and was merely a derivative of a known compound and hence not patentable u/s. 3(d) of the Indian Patent Act.
The definition of inventive step u/s 2(ja) once read with grounds of revocation u/s 64 nowhere indicate any special treatment or different tests to be applied for any particular type of invention There are certain essential ingredients of S. 2(ja) in order to call any invention to qualify the threshold of inventive step. The said ingredients are:-
a) That the said invention involves a technical advancement as compared to existing knowledge or economic significance or both; and
b) That makes the invention non obvious to the persons skilled in art.
Beyond the above two ingredients, there is no further ingredient which should be read into in order to enlarge or limit the scope of the Section.
In this case Justice Manmohan Singh at para 220 first noted the submission of the plaintiff in the following words-
“S. 48 provides that infringement analysis has to be assessed upon comparison of the Claims of the suit patent with the accused product or process. Therefore, the test to determine infringement is a 2 step process:
i. First, the claim needs to be interpreted;
ii. Second, the impugned product has to be compared with the claim.
The plaintiffs have cited several authorities wherein the rules of interpretation of the claims in patent are laid down by the courts from time to time. The said authorities relating to several propositions can be discussed in the following manner:
i. Interpretation of a patent is a question of law and not fact. (Markman v. Westview, 517 US 370).
ii. Claims have to be interpreted as on the date of priority of the patent application. (Philips v. AWH, 415 F. 3d 1303)
iii. If the words in the claims are clear and unambiguous then no aid of any other document to interpret is admissible. (Philips v. AWH, 415 F. 3d 1303 at p. 1314; F.H.&B. Corporation v. Unichem, AIR 1969 Bom 255 1968 Indlaw MUM 150)
iv. If the words in the Claims are ambiguous, then the case of Philips v. AWH (415 F. 3d 1303) states that the following documents, in this hierarchy, can be looked into to give meaning:
(a) Patent Specification of the same patent;
(b) Prosecution History of the same patent;
(c) Dictionary and other external sources as on the priority date.
At para 230 it was observed that “such tests appears to be correct so far as it relates to simplicitor infringement cases where the impugned product is straightaway subsumed in the claimed portion of the invention without anything else in the said product.” However, it was noted at para 231 that the said rule of construction is not without an exception. There may arise certain cases where the product which is alleged to be infringing does not completely corresponds to what has been claimed in the patented invention of the product or the product may substantially be containing the patented product but with some parts or variants. For such cases the Courts developed a different rule of construction of the patent claim and specification which is the rule of the purposive construction of the patent claim. This is so that in the cases wherever the need be, the claim in the invention is not construed too narrowly which was never the intention of the inventor and not the purpose of the said invention so that the maximum benefit should be given to the inventor. 
At para 233, it was further observed that-
“The said rule of purposive construction was used for a long period of time in the Court of appeal in England and time and again the same was approved to accord the benefit wherever possible to the inventor of the patent. However, the Courts have from time to time thereafter also faced a situation where the resort was taken to such construction of the patent claim in order to enlarge the scope of the patent, which was never the intent or the purpose of the said invention, the Courts also came across the cases where the properties and characteristics of the product significantly varied from what has been claimed in the patented invention. Those were the cases where the alleged infringing product contained some additional variant or the part in addition to the product or process under patent, the Courts in such a case answered the said question by laying down that much shall dependent upon the role of the said variant in the said product. The cases in which the role of the said variant is inconsequential in nature and does not change the nature and characteristics of the article, then in those cases, the product in question is an infringement of the patent, in all other cases, where there is a role of such variant which may alter the characteristics and quality of the said product or process, there is no infringement of the patent. However, what is a role of such variant in each case is essentially a question of the fact and same shall depend upon case to case basis”.
Also, the observation made in this case at para 235 is noteworthy as the test laid down by Lord Diplock in Catnic Case holds the field and is a good law. The said case of Catnic has been followed by the Indian Courts time and again while evaluating the patents in India so far as it relates to obviousness and infringement claims. The extract from para 235 is reproduced below-
“From the reading of the aforementioned quoted illuminating observations of Lord Diplock in Catnic (supra), the following propositions can be deduced:-
(a) That there are exceptions to the rule of purposive construction of patent claim which was aimed at giving the benefit to the inventor even in cases where the product impugned does not strictly fall within the ambit of the patent claim.
(b) That much shall be dependent upon the role of variant attached with the invention which is claimed in the patent in order to arrive at the impugned product.
(c) There is a compartmentalization of variants, viz major variants and minor variants has been done by Lord Diplock in order to define as to the permissible extent of applicability of rule of purposive construction of the patent claim.
(d) In cases where the variant attached to the invented work which is in the form of product or process under challenge would have material bearing upon the working of the invention. In such cases, the rule of purposive construction is not applicable as in those cases the variant attached its role thereof would exclude the product in question from the ambit of the patented claim and thereby there will be no infringement of patent.
(e) The said rule of purposive construction is also not applicable where the invention itself is obvious to the person skilled in art.
(f) There is thereafter an exception to exception which is laid down by Lord Diplock so as to determine in which cases where variant is present, the said rule of purposive construction can still be applicable.
Those are the cases where it is proved on record that from the reading of the patented claim the patentee could not have intended to exclude the minor variants which to the knowledge of him as well as readers of the patent could have no material effect in the way in which the invention worked. The said exception can be sub-categorized into the following fact finding enquiry:-
(i) That one has to show by an evidence as to what is missing in the patented claim and the product in question is a minor variant;
(ii) That there could not have been intention of the patentee to exclude such minor variant from the ambit of invention;
(iii) That the said minor variant could have no material effect on the way in which the invention worked.”
The Court at para 239 observed that the approach laid down in Catnic is not alien to the Indian context and consequently can be conveniently relied upon by the courts in India. It was further observed at para 243 that-
“From the above observations of Justice Laddie, it is clear that the wordings of the claims and specifications are important but are not necessarily determinative one and if the court has to conduct an enquiry in view of Catnic approach as to whether the benefit which was aimed by Lord Diplock by propounding the rule of purposive is to be given, all the attending facts and circumstances are to be given due respect besides the strict reading of the claims in order to objectively arrive at the conclusion as to what actually the patentee intended to include within the ambit of his patented claim.”
On the contention of the plaintiff that Court has to the see the specification and not to rely on other documents to draw the inference, it was observed that the tests vary from case to case basis and where there is a product containing variants, the tests laid down in Catnic (supra) are applicable.
It was held that fictions engrafted under the statute are to be given effect to by the Courts but by confining the scope, ambit and purposes for which the said fictions are enacted in the statute and not beyond the same. Even if the fiction is engrafted u/s. 3(d) to treat the Polymorphic version as a same substance, the said treatment has been accorded by the law only for the purposes of applicability of S. 3(d). The said limited fiction nowhere states and construed to mean that for all other reasons too including for the purposes of measuring the infringement of the patent, the said Polymorphic version B shall be deemed to be the same substance. Reading the said explanation in the manner in which the plaintiffs are reading would amount to extending the scope of the fiction beyond the purpose which is impermissible in law.
Plaintiffs in this case failed to discharge the onus of the proof as to show the infringement of its patent. Accordingly it was held that the defendant was not infringing the impugned patent. No permanent injunction was therefore granted to the plaintiff.
 As Quinazoline compounds are known to inhibit growth have been used as anti cancer treatment and are available in the market for treatment of various cancers
 newly inserted in the Patents Act (Amendment) 2005
 by not interpreting the patent claim in a pedantic manner and giving the same an effect which was the real purpose for which the product was invented in furtherance of the practical approach. Para 232
 Para 239
 Para 239