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26. On this issue, the learned Single Judge has placed significant reliance on expert testimony of two kinds - first, on X-ray diffraction tests which establish that Tarceva is Polymorph B alone and second, that the tablet form of Erlotinib Hydrochloride does not follow directly from the claims in IN ‗774 (on account of the fact that further reactions of the product from IN ‗774 are required to produce Tarceva).

27. This has lead the learned Single Judge to a construction of Claim 1 of IN ‗774 to understand whether it subsumes Polymorph B of Erlotinib Hydrochloride, which is admittedly Erlocip.

99. Sh.Pravin Anand, learned counsel for Roche admitted in all fairness that the Learned Single Judge correctly notes that DW-2 analyzed the compound of Roche's drug Tarceva and concluded that the said drug is based on Polymorph B of Erlotinib Hydrochloride which corresponds to US ‗221 (the Polymorph B patent). However, Sh.Pravin Anand urged that the Learned Single Judge has erred in not appreciating that the X-ray diffraction of Tarceva was wholly irrelevant to the lis in the present instance, which was for infringement of Claim 1 of IN ‗774 by Cipla product Erlocip. It was urged that it was not Roche's case that Tarceva is not Polymorph B of Erlotinib Hydrochloride but in fact it is Roche's case that the compound in Tarceva is Erlotinib Hydrochloride which corresponds to Claim 1 of IN ‗774. Learned counsel urged that the Learned Single Judge failed to appreciate that new chemical entities (NCE) such as Erlotinib Hydrochloride can be identified and characterized by Chemical Name, International Union of Pure and Applied Chemistry (IUPAC name), Chemical Structure and International Non-Proprietary Names (INN). Having been so described in Claim 1 of the suit patent, it was sufficient for Roche to show that Cipla had admittedly the same Chemical Name, IUPAC name, Chemical Structure and INN for its compound. X-ray diffraction analysis, urged Sh.Pravin Anand, is meant to describe the crystal lattice or the manner in which various molecules are arranged or packed together and this is only relevant when an invention is claimed in a new Polymorphic form. According to learned counsel, the invention does not relate to the physical characteristics of Erlotinib Hydrochloride but to the basic chemical substance itself. Learned counsel urged that if any third party uses, makes, sells etc. a compound or drug and identifies the same by Chemical Name, Chemical Structure or INN name, it is admitted that infringement has occurred. In fact, in the United States, Tarceva is covered by US ‗498 (being the Basic patent) and US ‗221 (being the Polymorph B or improvement patent) amongst other patents.

106. At this stage it is important for us to make some observations on X- ray diffraction as a methodology to ascertain infringement. X-ray diffraction is a method to determine and understand the crystalline structure of a compound. It is primarily used for the following broad purposes:

 In the regulatory field or during drug development, to identify a compound.

 To distinguish between amorphous and crystalline compounds.  To identify the fingerprints of various polymorphic forms of a compound.

109. It is an incorrect analysis of product patent infringement in a case like the present, to use methodologies like X-Ray diffraction to ascertain whether the competing products are identical in nature. The correct test of infringement in this case is to map Cipla product against the Roche's patent claims, which we find has not been done by the learned Single Judge, and this is the third infirmity on this aspect of the dispute.

110. If Roche's patent was for a polymorphic form of Erlotinib Hydrochloride and not the molecule itself and Cipla had argued that theirs was a ‗new substance‟, then alone the Court could have relied on evidence of use of the X-Ray diffraction technique and a consequential analysis of the peaks of both to ascertain whether they are identical or dissimilar compounds. However in that situation too, the comparison would have to be between a product made on the basis of Roche's patent claim and Cipla's product and not between Roche's product as sold in the market and Cipla's product. This subtle distinction is important to be kept in mind because the holder of a patent is by no means limited to only manufacture and sell only those products that are disclosed in the claims of the patent and hence a different polymorph manufactured by the patent holder which is not the subject of the registered patent cannot be used for the purpose of comparison with the infringer product; the very product disclosed in the patent claims must be used.