India has again denied Pfizer Inc a patent on its rheumatoid arthritis drug tofacitinib, the latest setback for a multinational drugmaker seeking to enforce its intellectual property rights in the country. Pfizer sought a patent that covers an important chemical formulation of the active compound in the medicine, but the Indian Patent Office said the company would have to establish that the compound for which it is seeking a patent is therapeutically more effective than the active compound.