A specification is not required to describe each and every embodiment of a claim; Opinion In Merck v. Watson

On Aug 31, 2015 Judge Andrews stated that Watson was failed to prove by clear and convincing evidence that claim 4 of the U.S. Patent No. 6,441,168 (“the ‘168 patent”) is invalid. C.A. Nos. 13-978 – RGA & 13-1272-RGA

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Background:
Watson filed two Abbreviated New Drug Applications seeking approval to engage in the commercial manufacture, importation, use, or sale of generic versions of Safyral® and Beyaz® (Drospirenone; Ethinyl Estradiol; Levomefolate Calcium). Merck and Bayer (Plaintiff) filed a suit against Watson Laboratories (Defendant) alleging infringement of US ‘168 patent. The infringement action centers on one ingredient of the proposed drugs (Levomefolate Calcium), the Type I crystal form of calcium 5-methyl-(6S)-tetrahydrofolate (“MTHF”).

US ‘168 claims Type I crystalline form of calcium salt of 5-methyl-(6S)-tetrahydrofolic acid, having a water of crystallization of at least one equivalent per equivalent of 5-methyltetrahydrofolic acid. Further, this patent also claims a process for the conversion of type I to type II, III & IV crystals.

The above lawsuit was mainly brought on the infringment of claim 4 of US ‘168, wherein the claim 4 of the patent recites: A crystalline calcium salt of 5-methyl-(6S)-tetrahydrofolic acid with 2 theta values of 6.5, 13.3, 16.8, and 20.1 (Type I) said crystalline salt having a water of crystallization of at least one equivalent per equivalent of 5-methyltetrahydrofolic acid.

Watson Arguments & the Final Decision:
Watson argued that claim 4 is invalid under the following grounds:
i) 35 U.S.C. § 102(b)-Disclosures made 1 year or less before the effective filing date of the claimed invention;
ii) 35 U.S.C. § 102(a)-lack of novelty;
iii) 35 U.S.C. § 103(a)-obviousness; and
iv) 35 U.S.C. § 112-lack of written description.

Ground I:
The ‘168 patent was filed in Apr 2000 claiming the priority from Apr 1999 and the patent was issued on August 27, 2002. Watson argues that Merck and Weider Nutrition International were exploring a strategic partnership to introduce dietary supplements with Merck ingredients into the United States, IN Sep 1998 Merck wrote to Weider saying that the MTHF to be delivered would be from Lot ESF-118. Merck stipulated that

1) Lot ESF-118 is within the scope of claim 4 of the ‘168 patent;
2) the x-ray diffraction pattern of Lot ESF-118 is disclosed in Figure 1 of the patent; and
3) the x-ray diffraction pattern of Lot ESF-118 was obtained by Merck at least as of August 25, 1998.

By showing the above statements Watson argued that the MTHF was actually ready for patenting by September 1998, and it also argued that the September 9, 1998 and September 16, 1998 communications constitute a commercial sale.

Merck argued that there was no commercial sale or offer for sale in light of§ 5.2 of the CDA was maintained.

Ground II:
Watson argued that claim 4 of the ‘168 patent is anticipated by the US 5,350,850 (‘850 patent). Watson maintains that Example 3 of the ‘850 patent details a method of obtaining a crystalline pentahydrate of MTHF. Watson further argued that the ‘850 product had a moisture content of 15.27%, which corresponds to a pentahydrate, wherein the Type I crystal is the only currently known pentahydrate polymorph of MTHF.

Merck argues that the ‘850 product and the claim 4 crystals have different solubilities, and it further argued that Watson did not followed the ‘850 process to produce the final API.

Ground III & IV:
Watson argues that claim 4 is obvious in light of the ‘850 patent alone or in combination with U.S. Patent No. 5,006,655 (the ‘655 patent). The ‘655 patent discloses the pentahydrate calcium MTHF. Watson argues that a person of skill in the art would have a reasonable expectation of producing Type I crystals by combining the pentahydrate calcium MTHF with the recrystallization process taught in the ‘850 patent. Watson maintains that crystalline MTHF was known and preferred, and there was motivation in the industry to find and characterize crystalline forms.

However, Watson has not demonstrated that a person of skill in the art would have a reasonable expectation of success of producing Type I crystals in light of the prior art.

Further, Watson argues that claim 4 lacks written description because the specification does not disclose any information from which a person of skill could conclude that the inventors possessed an MTHF polymorph with one water of crystallization.

Merck responds that the patent states, “the Type I modification typically contains ≥3 equivalents of water.” “Typically” is not limiting, meaning that sometimes Type I crystals have fewer than three waters of crystallization.

After considering the hearings from both the parties the Judge stated that Watson did not prove by clear and convincing evidence that claim 4 of the ‘168 patent is invalid. Merck is directed to submit an agreed upon final judgment within two weeks.

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