The Indian Patent Office rejected Cipla’s patent application for its HIV drug composition comprising combination of “ritonavir” and “darunavir”. The application, in particular, was directed to a pharmaceutical composition comprising a solid unit dosage form comprising: (i) ritonavir; (ii) darunavir; (iii) a water insoluble polymer and/or water soluble polymer, wherein the ratio of the weight of the ritonavir or darunavir to the weight of the polymer is from 1:1 to 1:6. Further, the claimed composition was a tablet composition comprising ritonavir and polymer in first layer and darunavir in second layer. The first layer is obtainable by hot melt extruding, and the second layer is obtainable by direct compression or by wet granulation.
The application was rejected on the grounds of lack of inventive step in view of the prior published documents. The controller cited 6 prior art documents and heavily relied on one particular D6: US 2005/0048112 in his inventive step analysis which describes that solid pharmaceutical dosage forms comprising ritonavir and, a second species of HIV protease inhibitor, including TMC-114 (darunavir). Therefore, according to the Controller, D6 provides strong motivation to formulate a solid pharmaceutical dosage form that comprises both ritonavir and darunavir. D6 additionally discloses that dosage may be provided as dosage forms consisting of several layers and such “multilayer forms have the advantage of processing two active ingredients which are incompatible with one another or controlling the release characteristics of the active ingredient(s). The claims were therefore considered obvious by the Controller. in addition to this, the Controller held that the claimed subject matter does not clearly show advantage/surprising effect over prior art composition to show non-obviousness (no comparative data being provided by the Applicant).
The Controller also rejected the application under section 3(d) as he considered the new layered form of a known combination of prior art, as being statutorily barred from the patentability u/s 3 (d).