The Delhi Patent Office lately refused the Application Number 924/DELNP/2006 filed by Boehringer Ingelheim claiming polymorphic form II of anticoagulant drug dabigatran etexilate mesylate, marketed under the brand name Pradaxa. The Application was refused on the grounds of lack of inventive step and not patentable under S.3 (d). During the prosecution, Boehringer tried to substantiate the inventive step in terms of better solubility resulting into higher bioavailability and argued that none of the cited prior art documents provide any hint that mesylate salt have better solubility and exists in different polymorphic modifications. The Patent Office was of opinion that Boehringer’s argument of higher bioavailability lack experimental and comparative data. In its post hearing reply, Boehringer argued to substantiate and validate that bioavailability translates in enhanced efficacy a clinical trial in human beings would be required and for which regulatory approval is needed. Boehringer argued that such a regulatory permission just for the sake of complying efficacy requirement under S.3 (d) would hardly be granted.