Cipla is again in news. This time it is for the revocation of a cancer patent owned by a multinational company. The patent is an Indian Patent IN209251 and it was granted to Pfizer/ Sugen for their cancer drug Sunitinib.

The Patent for Sunitinib was granted to Pfizer/ Sugen on 23-08-2007 with an allotment no. IN209251 and published in the Patent Office Journal U/S 43 (2) of India on 05-10-2007. The opponents (i.e. Cipla) filed an opposition U/S 25 (2) on 01-09-2008 for the revocation of said Patent.

Grounds of opposition

Cipla claimed that the invention was already in public domain when the Patent was filed for the invention.
Cipla also claimed that the invention is obvious and doesn’t involve any inventive step.
Cipla also stated that this invention was not patentable in India.
Cipla also said that the patentee has failed to disclose the information to the controller required by Section 8.
Section 8:Information and undertaking regarding foreign applications

(1) Where an applicant for a patent under this Act is prosecuting either alone or jointly with any other person an application for a patent in any country outside India in respect of the same or substantially the same invention, or where to his knowledge such an application is being prosecuted by some person through whom he claims or by some person deriving title from him, he shall file along with his application –

a statement setting out the name of the country where the application is being prosecuted, the serial number and date of filing of the application and such other particulars as may be prescribed; and
an undertaking that, up to the date of the acceptance of his complete specification filed in India, he would keep the Controller informed in writing, from time to time, of details of the nature referred to in clause (a) in respect of every other application relating to the same or substantially the same invention, if any, filed in any country outside India subsequently to the filing of the statement referred to in the aforesaid clause, within the prescribed time.
(2) The Controller may also require the applicant to furnish, as far as may be available to the applicant, details relating to the objections, if any, taken to any such application as is referred to in sub-section (1) on the ground that the invention is lacking in novelty or patentability, the amendments effected in the specifications, the claims allowed in respect thereof and such other particulars as he may require.


Cipla cited three documents to show lack of inventive step (or obviousness) in the granted patent. These were

1. US 5886020 (D1)

2. WO/98/50356 (D2)

3. WO/99/61422 (D3)

According to Cipla, document D1 disclosed an extremely similar structure as compared to the granted claims. In particular, the compound as described in D1 possess an amide substituent at position 4 of a pyrrole ring, as well as D1 teaches an amide function at the 4 position of the pyrrole ring. Additionally, D1 also taught compounds that were useful to treat unregulated TKS transduction / cancer. Hence it would have been obvious to one of ordinary skill in the art, to experiment with replacing an alkyl substituent with something similar and possessing similar qualities. Similarly document D2 also disclosed similar compounds (to the granted patent) where an alkyl substituent could be replaced. A similar argument was made for D3.

Pfizer sought to distinguish the claims from the cited prior art documents. In particular, it discussed that the basic backbone or core of the compounds as disclosed by Dl is an indolinone and not a pyrrole substituted indolinone compound. Therefore, Dl did not envisage pyrrole substituted indolinone compounds as disclosed by the patent and specifically Dl did not recognize the advantages of attaching a pyrrole substituent at the 3rd position of the indolinone ring.

The affidavit submitted on behalf of opponents stated “Sunitinib is a novel tyrosine kinase inhibitor and is therapeutically potential in the treatment of renal carcinoma and gastrointestinal stromal tumors (GIST)”. It is apparent from this affidavit that the metabolization occurs at the terminal N atom and not at the position of the (Alkyl) group. Therefore I observe that the disclosures in Dl or D2 could be modified to introduce the polar group Z as taught by D3 to formulate a compound which does not possess the (Alkyl) group but retains the protein tyrosine kinase inhibitory activity.”


Dr. Nilanjana Mukherjee (Assistant Controller of Patents and Designs) concluded that the invention doesn’t involve an inventive step, as it can be seen from the documents and exhibits cited by the opponent. She also concluded that this invention is obvious to the person skilled in art, hence this invention is not patentable u/s 2 (1) (j) of Patent Act, 1970.


With this revocation Cipla has got two major decisions in their favor in last two months. First one was the case where Cipla was sued for patent infringement by Swiss pharma giant Roche where they came out victorious and now this one where Cipla have been successful in revoking Pfizer’s patent.

MNCs are now afraid of Indian Patent system. First Roche lost to Cipla and now Cipla have revoked Pfizer’s patent and also IPAB holds an important decision in compulsory license for another cancer drug ‘Nexavar’.