In two different verdicts, the India's Patent Office rejected patent applications of two big pharma companies for two different products in the country. The rejected applications are for Caduet, a therapeutic combination of amlodipine and atorvastatin from Pfizer Ltd and another application for a rosiglitazone salt from GlaxoSmithKline.

The decision against Caduet, a combination Pfizer's Norvasc (amlodipine besylate) and Lipitor (atorvastatin calcium), is in favour of a pre-grant opposition filed by the Ahmedabad-based Torrent Pharmaceuticals Ltd. Torrent has filed its opposition against Pfizer's patent application number 2571/DEL/1998 for exclusive marketing rights of Caduet in the country.

The Delhi Patent Office found that though the invention of the drug is novel over the prior art, there is lack of inventive step with respect to the prior art and publications available. The official opined that the application failed to justify the sufficiency of description to a certain extent and the drug is not patentable under section 3(d) and 3(e).

The patent office also opined that the claim of synergism of the two ingredients was never substantiated by the applicant and expressed suspicion whether such effect was at all known to the applicant either at the time of filing. "I therefore cannot agree that the combination of the present invention has synergistic effect and which was not clearly predicted by prior art in different analysis and report," explains the decision.

According to the unaudited annual report of Pfizer in 2008, global market for Caduet is estimated as USD 589 million, in which USD 120 million is from non-US markets. The figures show that the global market for the product has seen a four per cent increase in the financial year from USD 568 million recorded in year 2007. Interestingly, the sales of Caduet have dipped by six per cent in US in 2008 whereas the international market sales have shown an increase of 68 per cent.

In another development, the Delhi Patent Office has rejected the patent application of SmithKline Beecham PLC, England, for ethane sulphonate salt of its anti-diabetic drug rosiglitazone after finding that the company failed to establish that the rosiglitazone derivative has better efficacy than the known patent compound.

The patent office explains that the publication papers submitted by the company to support the claims of the company on better efficacy of the thiazolidione derivative (ethane sulphonate salt) with respect to the patent compound as known in prior art, failed to meet the purpose. As per Section 3(d) of the Patents Act 1970, the derivatives of known parent compounds are not patentable unless they differ significantly in properties with regard to efficacy.

"The applicants could not establish that the compound as claimed in the instant Patent Application is better in terms of the efficacy with respect to the parent compound as known in prior art, hence in lack of the efficacy the instant Patent Application can not be allowed. Accordingly the instant Patent Application No. 00295/DELNP/2003 is refused," ordered the patent office.

Avandia, the rosiglitazone formulation of Glaxo and the generic versions manufactured by Indian companies including Sun Pharmaceuticals, Dr Reddy's Lab and Torrent Pharma along with almost 25 other companies were warned by the Drug Controller General of India (DCGI) on the possible cardiac problems related to the drug. Rosiglitazone is used by an estimated seven to 10 million people in India, according to the official reports announced in the end of 2008.

Earlier, the company's 060701 application for exclusive marketing rights (EMR) for its blockbuster anti-diabetic drug Rosiglitazone and its derivative, Rosiglitazone maleate has been rejected by the patent controller of India in 2002.

The company has then filed its patent application for the derivative form, eyeing the fast growing anti-diabetes market which was recorded at USD 480 million in 2008 with a compound annual growth rate of 16 to 20 per cent (according to a recent report from Intelligence provider Grail Research).