The persistence of the patent applicant pays off

in the Taiho Pharmaceutical Co Ltd [2022] NZIPOPAT 1 several grounds for refusal put forward by the examiner were either absent or upheld, with the applicant being given the opportunity to make appropriate amendments.

The application in question is a divisional application of a PCT national phase entry claiming priority from a Japanese application, with a priority filing date of 27 March 2013. The New Zealand claims are in Swiss format, while the entries in the national or regional phase other jurisdictions later granted use other claim formats. The New Zealand application in question has 8 claims, with claim 1 being the only independent claim, as follows:

1. Use of trifluridine and tipiracil hydrochloride in a molar ratio of 1:0.5 in the manufacture of an antitumor drug for the treatment of solid cancers, – wherein the antitumor drug is adapted to contain trifluridine and tipiracil hydrochloride in a dose im range of 35 to 70 mg/m2/day to be administered, and – wherein the antitumor drug is adapted to contain trifluridine and tipiracil hydrochloride in combination with irinotecan hydrochloride hydrate at a dose in the range of 45 to 130 mg/m2/ day to administer.

There were several outstanding objections from the examiner. Namely:

Section 40/Regulation 58/Section 33(5) – whether the amendment is supported in the priority document Section 39(2)(b) – whether claims are clear Section 14(b)(i) – whether the claimed invention lacks novelty Section 14 (b) )(ii) – whether the claimed invention involves an inventive step Section 14(a) – whether double patenting

entitled to support: The Assistant Commissioner dismissed the examiner’s objection of lack of support for claim 1 after finding that the upper range value of 130 mg/m2/day was a slight rounding up of the dosages given in the priority specification.

clarity: The examiner’s clarity objection to claim 1 concerned the absence of one of the active ingredients – namely irinotecan hydrochloride hydrate – in the preamble of the claim. While the inventors found that the use of the three named active ingredients is advantageous in the manufacture of a medicament for the treatment of solid cancer diseases, only two of these active ingredients are mentioned in the preamble of the claim. The Deputy Commissioner upheld this objection, stating that the claim did not conform to the acceptable format of a Swiss claim and ordered the claim to be amended to conform to an acceptable claim format.

The examiner also raised a clarity objection to claim 7 as being dependent on claim 6 but containing the phrase “the administration regimen” which only precedes claim 5. Claim 7 reads as follows:

7. Use according to claim 6, wherein the patient has received irinotecan hydrochloride hydrate within one cycle of the regimen.

While claim 6 may be dependent on claim 5, it may also be dependent on any of claims 1-4. Thus, if claim 6 is dependent on any one of claims 1 to 4 but is not also dependent on claim 5, then claim 7 has no precedent for the phrase “the schedule of administration”. The Deputy Commissioner also confirmed this clarity objection and gave the applicant the option to either amend the claims so that claim 7 is dependent on claim 6 when it is dependent on claim 5, or make claim 6 dependent on claim 5 only.

novelty: The Deputy Commissioner dismissed the examiner’s novelty objections, noting that none of the prior art documents “raised the flag” since they did not disclose the use of irinotecan hydrochloride hydrate with the other two active ingredients and one of the documents disclosed a different chemical Structure revealed for tipiracil hydrochloride.

Obviousness: In addition to the above differences, the objection of lack of inventive step also considered other differences. The first document (Temmink) gave the best chance of establishing the obvious, but used higher dosages of trifluridine and tipiracil hydrochloride and even taught to refrain from lower dosage. While the higher dosage ranges in Temmink would be within the common general knowledge of a person skilled in the art, the Deputy Commissioner stated that it would not be obvious to a person skilled in the art to use the dosage range given for these active ingredients in claim 1.

While Temmink did not disclose the use of irinotecan hydrochloride hydrate with the other active ingredients mentioned therein, it did indicate that the combination of irinotecan hydrochloride hydrate with the disclosed active ingredients might be worth trying. The examiner considered that this represents a realistic expectation of success for the combination of the three active ingredients claimed in Taiho’s application. However, the Assistant Commissioner dismissed this claim on the grounds that Temmink was merely speculating about the combination as it contained no studies on the effect of using the combination. At best, that was motivation to try the combination, but even then, the Deputy Commissioner felt that establishing the dosages would require a certain amount of inventiveness, especially given the dosages used, which are lower than what is commonly known to those skilled in the art would be in art. Consequently, the obviousness ground was rejected.

Double patenting: The examiner had raised a double patenting objection in relation to a patent also granted in the name of Taiho with the same priority and international filing dates and with very similar claims. Despite the similarities, the Deputy Commissioner noted that Rule 82’s prohibition on double patenting does not apply because the patents are not related in the parent-division relationship required by Rule 82. However, the Deputy Commissioner pointed to the precedent in the UK Applications of Dreyfus (1927) 44 RPC 291 that if an applicant has two applications with the same priority date and directed to the same invention, only one of the applications will be admitted for grant. However, after comparing the claims, the Assistant Commissioner concluded that there is no double patenting as neither the patent nor the application claim fully falls within the scope of the other. In particular, claim 1 of the granted patent contains a regimen and contains a higher dosage range for irinotecan hydrochloride hydrate which does not fully contain the range for this active ingredient in the application.

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