9.8.5 Predictable improvements resulting from amorphous forms as compared to crystalline forms

In T 777/08 (OJ 2011, 633) the claims in question related to a particular polymorph (form IV) of crystalline atorvastatin hydrate. The board considered that the amorphous form of atorvastatin, as obtained according to the processes of documents (1) and (2) represented the closest state of the art. The appellant defined the problem to be solved in view of this prior art as lying in the provision of atorvastatin in a form having improved filterability and drying characteristics. Having regard to the experimental results reported in document (25), which demonstrated shorter filtration and drying times for form IV compared to the amorphous form, the board was satisfied that this problem had been solved. It also found that the skilled person in the field of pharmaceutical drug development would have been aware of the fact that instances of polymorphism were commonplace in molecules of interest to the pharmaceutical industry, and have known it to be advisable to screen for polymorphs early on in the drug development process. Moreover, he would be familiar with routine methods of screening. Consequently, in the absence of any technical prejudice and in the absence of any unexpected property, the mere provision of a crystalline form of a known pharmaceutically active compound could not be regarded as involving an inventive step.

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