The Delhi High court in its recent Judgment dated 20 July, 2021 denied injunctions to AstraZeneca AB and AstraZeneca Pharma India Limited (Appellants) against nine generic drugmakers (Respondents –Zydus Healthcare Limited & ANR, Alkem Laboratories Ltd, Intas Pharmaceuticals Ltd, Eris Lifesciences Limited, USV Private Limited, Torrent Pharmaceuticals Limited, MSN Laboratories Private Limited, Micro Labs Limited and Ajanta Pharma Limited) for manufacturing Dapagliflozin (an anti-diabetic drug) owned by the Appellants. This article throws light on how disclosure of the genus patent can be used to invalidate a species patent.
In the present case, the Indian Patent office had granted two separate patents for single invention one relating to genus patent IN 205147 (IN 147) and the other patent IN 235625 (IN 625) relating to species patent. The species patent relates to the compound Dapagliflozin, which forms a part of the Markush structure claimed in the genus patent. The defendants argued that two patents cannot be granted for a single invention and allege that the genus patent anticipated the species patent.
Obviousness under section 2(1)(ja)
The Delhi High Court rejected an interim injunction to AstraZeneca as the species patent was obvious, in light of the genus patent as it disclosed the methods to prepare the compound DAPA of the species patent. Although, Example 12 of the genus patent disclosed methods to prepare the compound DAPA with methoxy substitution, a person skilled in the art can replace the methoxy group with ethoxy group to obtain the compound DAPA. Further, there was no technical advancement of the claimed compound compared to the genus or economic significance that would make the synthesis of DAPA an “inventive step” under section 2(1)(ja).
Relevant excerpts from the Delhi High Court's judgement:
12.7 According to the plaintiff there is no motivation to look at Example 12 when 80 examples have been given of which Examples 1 and 2 were synthesized on a large scale, there is no motivation to change methyl group, there are no teachings towards substitution with ethoxy, efficacy data of Example 12 was not known, the teaching of IN ‟147 were to have hydrogen on central phenyl ring and no ethoxy on the distal phenyl in any of the 80 examples. As noted above, for preparation of the structure in Example 12, four methods have been noted and in the said example though methoxy was used and even though there was no teaching towards ethoxy, there were no teachings even away from ethoxy. Both ethoxy and methoxy being lower alkyl, a person with ordinary skill in the art would have been motivated to bring this single change of substitution of methoxy to ethoxy to find out if predictable results ensue. Consequently, this Court is of the prima facie opinion that the suit patent is vulnerable on the grounds of obviousness in view of Example 12 of IN ‟147.
On the contrary, in Natco's post-grant opposition to Novartis's Ceritinib patent, IPAB had found that although Ceritinib was encompassed in the Markush structure of the genus patent, the disclosure of the genus patent failed to teach a person skilled in the art to arrive at the specific combination necessary to create Ceritinib. Therefore, the species patent could not be invalidated.
It can be concluded that the description or disclosure of a genus patent may be a game changer for the grant or revocation of the species patent. A species patent for any compound may be granted depending on the details provided in the description of the genus patent.
Double patenting is not allowable in any jurisdiction. Section 10 (5) of the Indian patent act prohibits patenting of obvious variations of each other in two separate patents, the expiration of the parent patent resulting in an improper extension of the patent rights due to the unexpired second patent.
The court contended that the appellants had filed terminal disclaimer (disclaims the portion of the 20-year term of the second patent that extends beyond the earlier patent's term) in the USPTO to overcome obviousness type double patenting objection. The appellant had agreed to the validity of US patent equivalent to IN 625 ending on the same day as the validity period of the US patent equivalent to IN 147. The appellants are not entitled to claim different periods of validity for the two patents.
Relevant excerpts from the decision:
We are also of the prima facie view, that once the appellants/plaintiffs, before the USPTO applied for and agreed to the validity period of US patent equivalent of IN 625 ending on the same day as the validity period of the US patent equivalent to IN 147, the appellants/plaintiffs, in this country are not entitled to claim different periods of validity of the two patents.
In a scenario, where the genus patent discloses the compound of the species patent in its disclosure, such that a person skilled in the art is motivated to arrive at the compound of the species patent, one may consider of filing a divisional application to seek protection for both the genus and species patent. However, the divisional application must be filed before the grant of the parent application. This approach stops any third party from making, using, offering for sale, selling or importing the patented invention for the purpose of using, selling and offering for sale without the approval of the patentee until the expiry of the said patent. Further, the Patent Statute states that a patent issuing on either the original application or a divisional application cannot be employed as a reference against the other. However, if the disclosure of the genus patent fails to motivate the person skilled in the art to arrive at the compound of the species patent, then one may seek protection for genus and the species patent separately.
Further, the patent office also must take utmost care while examining a species patent. Any erroneous decision of the IPO may lead to prolonged litigation process, which could have been avoided, if the applications were examined scrupulously. Such litigation process incurs huge expense for both the parties as well as additional litigation process may burden the court which could have been avoided.
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