India rejects patents for Gilead’s adefovir (Hespera) & Roche’s erlotinib (Tarceva) salts

Adefovir dipivoxil & polymorph B form of erlotinib are not different from the known substance and so not novel, says Delhi patent office.

The Delhi Patent Office has denied Gilead’s application seeking patent for crystalline form of adefovir dipivoxil citing lack of novelty as reason.

Adefovir dipivoxil is the patented product of Gilead. Adefovir dipivoxil is a diester prodrug of adefovir marketed by Gilead marketed under the brand name Hepsera to treat human hepatitis B virus. Related story: Gilead patent for oseltamivir (Tamiflu) rejected by Indian Patent Office

Ranbaxy, India’s leading drug maker had filed a pre-grant opposition against adefovir dipivoxil  under section 25(1) of the Patents Act, 1970 on 2nd September 2005 arguing that the subject matter of the application is not novel, it lacks inventive step, and has no utility and hence the application could not have been filed under section 5(2) of the previous Act.

On its decision dated 18th March 2008, the patent office in New Delhi said since the compound of the invention adefovir dipivoxil is an ester form of the parent compound PMEA (9-[2-[[bis[(pivaloyloxy)-methoxy]phosphinyl]methoxy]ethyl]adenine, no inventive technical advancement can be attributed to the alleged invention.

Regarding claims on Section 3 (d) of the Indian Patent (Amendment) Act 2005, the patent office pointed out that “the amended section it only declares that the very discovery of a new form of a known substance which does not result in the enhancement of the known efficacy of the substance, will not be treated as invention the position therefore is if the discovery of a new form of a known substance must be treated as invention then the patent application should show that the substance so discovered has a better therapeutic effect.”

Similarly, the Delhi Patent Office rejected OSI Pharmaceuticals patent application for polymorph B form of erlotinib hydrochloride, deciding on a pre-grant opposition.

Erlotinib is the patented drug of Roche sold under the brand name Tarceva to treat lung cancer.

No patent for polymorph B form of erlotinib

The Mumbai-based Cipla Ltd has contested the patent application for the polymorph B form of erlotinib hydrochloride on grounds of prior publication. Cipla also argued that erlotinib is publicly known and used in India and its polymorphic salt lack in inventiveness.

The patent office in its decision stated that the office found application lacking comparative data with respect to known substance to prove improvement in therapeutic and subsequently rejected claims for polymorph B of erlotinib hydrochloride under section 3(d) of the Patents Act, 1970.

It has to be recalled that the Delhi High Court had allowed Cipla to sell generic version of Roche’s patented drug Tarceva (erlotinib) in India, in a very recent judgment.

Erlotinib was granted a patent for erlotinib in India in September 2007. Soon after, Roche started selling the drug for Rs 4,800 ($122) a tablet.

Despite this, Cipla Ltd of Mumbai launched a generic version of Tarceva – erlotinib – the active ingredient in the drug – last year.

While launching the drug, Cipla was quoted as saying that they intended to launch their own version of the drug at far lesser price – Rs 1,600 ($41) a tablet.

Following this, Roche sued Cipla for patent infringement in the Delhi High Court and applied for a temporary injunction. During hearings, Cipla counterclaimed that the patent was invalid and should be revoked.

Cipla claimed that erlotinib (Tarceva) is a derivative of an earlier substance called gefatinib, and therefore should not have been granted a patent, unless increased efficacy can be proved.