Generic v. Branded patent battles in India foray into life management diseases too

Patent wars in India between the foreign innovator companies and the Indian generics now seem to be spreading over the life-management diseases segment. Till now the patent infringement cases have revolved and are still revolving over drugs for life-threatening diseases such as HIV, cancer where the public interest has played an important factor in the adjudication of the cases. However, the recent launch of a generic version of Merck’s anti-diabetic blockbuster drug Januvia by Glenmark has opened the gates to India’s first such patent litigation case in the Diabetes market.

Merck sued Glenmark for infringing over it their product patent on Sitagliptin (marketed as Januvia) on April 01st, 2013. Merck sought to obtain an interim injunction against Glenmark seeking to restrain Glenmark from launching its Generic products Zita (generic version of Januvia) and Zita met (generic version of Janumet, a combination of sitagliptin+metmorphin). The Delhi High Court however refused to grant the relief to Merck by its decision of April 5.

The arguments made by Glenmark get the case to follow in a similar direction as Roche v. Cipla. In Roche v. Cipla, Cipla argued that their generic drug Tarceva is a polymorphic form B of Erlotinib Hydrochloride which the valid product patent of Roche does not claim. In addition, Cipla argued that Roche filed a separate Indian patent application on the polymorphic form B which was rejected U/S 3d proving that polymorphic form B is a separate invention not covered in the product patent, on basis of which Cipla was successful in proving non-infringement of the Roche’s patent at the Delhi High Court (the case is now pending at the Supreme Court). One point to be noted is that Cipla sold Tarceva at ~1/3rd of the price of Roche’s marketed drug and that the drug was an anti-cancer agent.

Coming to Merck v. Glenmark, the arguments by Glenmark flowed in a similar direction wherein Glenmark argued that:

  • Merck filed a separate application on Sitagliptin phosphate via 5948/DELNP/2005 which was rejected and affirmatively abandoned by Merck.
  • Merck had also obtained separate US and EP patents on Sitagliptin phosphate wherein Merck admitted that Sitagliptin Phosphate is a new discovery over the main product patent by describing the salt as “novel salt”. Further added that if Sitagliptin phosphate had been not a distinct product from sitagliptin, Merck would not have applied for or obtained a separate patent.
  • Merck suppresses the later Indian patent filing, rejection, and abandonment of 5948/DELNP/2005 covering phosphate salt
  • Merck’s ‘816 patent is for Sitagliptin Hydrochloride only and not for Sitagliptin Phosphate
  • Glenmark’s counsel also placed reliance on Novartis Judgement saying “coverage in a patent cannot be permitted to go much beyond the disclosure made by the patentee and that the scope of a patent cannot be permitted to be determined by the artful drafting of its claim by skillful lawyers instead of the intrinsic worth of the invention”
  • On the basis of the Roche v Cipla judgment, it is further contended that “where the role of variant outweighs the patented claim, there can be no infringement”.

Glenmark, in its arguments, thus relied mainly on separate patent filing on Sitagliptin Phosphate and proving that Merck itself acknowledges that the two are separate inventions and that Glenmark’s selling of the Sitagliptin phosphate salt will not infringe the ‘816 patent.

Merck argued that:

Sitagliptin phosphate being a derivative of Sitagliptin, could not be granted an Indian patent U/S 3d, and that the application was misconceived, which was rejected and later abandoned by Merck itself. Merck contended that there are separate patents in the US, EP, or other countries because there is no section 3d equivalent there. Merck’s counsel also, to allay any influence of the Novartis judgment, contended that there is no price difference in the product of the plaintiffs (Merck) and the defendant (Glenmark) and that it cannot be said that the product of the defendant is considerably cheaper than that of the plaintiffs.

According to Judge,

“To my mind, if the infringing product is made with the same object in view which is attained by the patented article, then a minor variation does not mean that there is no infringement. Trifling and unessential variations are to be ignored. Conversely, a minuscule advancement could be recognized as an invention.”

The Judge further added that if it is proved that Sitagliptin phosphate has a material effect on the ways Sitagliptin works, the defendant would not infringe the plaintiff’s patent.

The Judge highlighted that it was for Merck “to have made a case of Sitagliptin Phosphate being merely a new form of sitagliptin which does not result in the enhancement of the efficacy of sitagliptin”, instead Merck only pleaded that Sitagliptin phosphate is the same as Sitagliptin which they cannot be proved in light of the separate filing of the phosphate patent.

The Judge, therefore, did not find Merck to have made case for grant of interim relief and accordingly has dismissed the application. But the court, of course, gave directions to Glenmark to maintain and file accounts of the manufacture and sales of the infringing products every quarter before the Court and to the counsel for the plaintiffs.

Conclusion

It would be interesting to see how this case unfolds during the trial, especially it would be interesting to see how strongly the Roche v. Cipla case would act as a precedent for this case. There is a similarity of arguments on separate patent application filing and rejection of new form in both cases. There is a difference however in pricing issues and public interest in this case. In Merck v. Glenmark, Plaintiff’s drug (not an anti-cancer or anti-HIV) was already launched in India with 1/5th of the prices in the USA with a current price difference between the plaintiff’s and defendant product being ~30% only, unlike in Roche v. Cipla where the plaintiff’s drug was 3 times more expensive than the defendant’s product and was an anti-cancer agent.

Further in Roche v. Cipla, the original product patent did not disclose polymorphic forms A or B even generically. However, in Merck v Glenmark, ‘816 patent not only discloses pharmaceutically acceptable salts but also mentions phosphoric acid as one of the salt forms among a list of other salts. The Examples though disclose only HCl salt forms.

Wouldn’t the test of infringement involve “reading” a claim of the patent onto the potential infringer’s product, wherein if the claim’s elements are found in the product, said product will infringe. In this case, claim 1 in general and claim 19 specifically covers Sitagliptin and pharmaceutically acceptable salts thereof. And the pharmaceutically acceptable salts are defined in the description as:

The term “pharmaceutically acceptable salts” refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic acids………………………. When the compound of the present invention is basic, salts may be prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include acetic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, panic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic acid, and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric, fumaric, and tartaric acids (emphasis added)

Shouldn’t Sitagliptin phosphate get covered in the ‘816 patent especially due to the fact that phosphoric acid is mentioned not only in just a laundry list, but is mentioned amongst “Particularly preferred” acids in addition to just 7 other acids?

Furthermore, shouldn’t manufacturing Sitagliptin Phosphate include making and using of Sitagliptin, and hence infringe upon ‘816 patent anyways? Shouldn’t Merck prove that manufacturing Sitagliptin Phosphate will infringe its ‘816 patent as the defendant cannot produce Sitagliptin Phosphate without producing Sitagliptin first and thus infringing the ‘816 patent? It might prove to be a better strategy for Merck rather than proving a point that Sitagliptin phosphate and Sitagliptin are the same and are claimed in a single patent because filing a separate patent for the salt, arguing in US/EP prosecution that the salt is a novel one and a new discovery over the main patent may go against Merck keeping in view the Roche v. Cipla case, which the court is very likely to follow in this case.

It would be interesting to see how all these factors will be considered by the court in deciding whether Glenmark infringes or not.

About the Author: Ms. Meenakshi Khurana, Patent Attorney at Khurana & Khurana and can be reached at Meenakshi@khuranaandkhurana.com

Follow us on Twitter: @KnKIPLaw

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