Pfizer Inc. has failed again in enforcing its intellectual property rights in India. The giant pharmaceutical's patent on its rheumatoid arthritis drug, Tofacitinib, was rejected in the country.

According to Business Insider, Pfizer tried to patent a chemical formula for the active compounds in the rheumatoid arthritis drug. However, the Indian Patent Office wants the giant drug maker to prove that the compound they want to patent is more therapeutically effective than the present active compound. Patent Office assistant controller Bharat NS, on September 3, wrote an order stating, "The invention disclosed and claimed in the instant application is not considered as an invention under the provisions of the Act."

Financial Express reported that the Intellectual Property Appellate Board (IPAB) directed the patent office in Mumbai to re-consider Pfizer's application to patent its new rheumatoid arthritis drug, Tofacitinib. The assistant controller said, "For the purposes of this clause, salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of known substances shall be considered to be the same substance, unless they differ significantly in properties with regard to efficacy."

In October last year, IPAB ruled that the assistant controller made a mistake in rejecting Pfizer's patent, saying that there seem to be flagrant violation of principles of natural justice. This was decided upon an appeal by Pfizer. IPAB ordered to reconsider the matter by another assistant controller in the next three months to give an opportunity to Pfizer to argue its case. According to Reuters, the company is currently reviewing its options for its next actions.

Drug patent is a serious issue for international drug makers trying to penetrate India's fast-growing healthcare market. Pfizer isn't the only company struggling to enter the India market. Bayer and Roche also have their own struggles for the past several years to expand their business in India. These companies blame the patent laws, which they claim are designed in favor of for the domestic pharmaceutical companies.

India said its drug patent policy is made to ensure medicines are affordable, since only 15 percent of the country's people have health insurances.