Patentability of Co-crystals

Co-crystals, as a class of compounds, represent compositions of matter which are within the statutory classes of patentable subject matter. Most countries also allow claims for methods of making a co-crystal and often methods of using them, as well as pharmaceutical compositions containing them. The basis for this patentability is that a new co-crystal is a new composition of matter between an API and a co-former(s) with a unique binding interaction between them. The crystalline nature of the co-crystal composition may, and in most countries does, add to co-crystal patentability. 

For an invention, such as a composition of matter, to be patentable it must first be new or novel. Under the EPC, an invention shall be considered to be new if it does not form part of the state of the art. The state of the art comprises everything made available to the public by means of a written or oral description, by use, or in any other way, before the date of filing of the European patent application. In the United States, novelty is defined by categories within the patent statute with reference to, for example, the date of invention or the application filing date, whether or not the prior disclosure was by the inventor or another, and the type of disclosure, for example a publication, a public sale or a patent application. In the United States, novelty-defeating prior art is said to anticipate a claimed invention. An invention is anticipated only if each and every element in the claim is found, expressly or inherently, in the prior art. Thus, when assessing the novelty of an invention, the differences between the invention and the prior art are important. 

The unique combination of an API and a co-former in a co-crystal, with its unique chemical bonding between the API and co-former, typically does not 

To determine inventive step, the European Patent Office (EPO) employs the problem-and-solution approach. In this approach, the EPO takes the view that every invention is the solution to a technical problem. The general analysis of the problem-and-solution approach (1) determines the closest prior art (2) then starting from the closest prior art, establishes the objective technical problem to be solved and (3) assesses whether, in light of the prior art, it would have been obvious to solve the objective technical problem in the way claimed in the patent application.  

The American test for obviousness requires factual analysis of (1) the scope and content of the prior art (2) the differences between the prior art and the claimed invention (3) the level of ordinary skill in the art and (4) any objective evidence of non-obviousness. In its recent decision concerning KSR International, the United States Supreme Court articulated a broad inquiry for determining obviousness. The proper question is whether one of ordinary skill, facing the wide range of needs created by developments in the field of endeavor would have seen the benefit of making the changes in the invention. 

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Effective patenting of co-crystals focuses primarily on two considerations (1) the characterization and proof of actual co-crystal and (2) the properties of the co-crystal. The first is perhaps more important than the second, although as discussed above, the co-crystal must possess practical utility and usefulness. That practical utility is often directly related to the properties of the co-crystal and, sometimes, even the existence of the co-crystal, as a solid-state form of the API, solves the problem of handling, processing, and/or formulating the API. 

This chapter has merely surveyed some ways in which co-crystals may translate into new patents and commercial value and has discussed some considerations for accomplishing this. It is clear that the success of co-crystals in commercialization and as new patents is tied to their unique chemical composition, crystalline structure, and properties. Engineering pharmaceutical properties using co-crystals can create new commercial value for an API and extend its patent life. This value comes from the composition of the co-crystal as well as from its crystalline form. Patenting co-crystals captures that value in the form of intellectual property. Yet, co-crystal patents have their own unique aspects to be addressed as can be seen from the discussion of the definition of cocrystal , the patentability of co-crystals, and the information needed for... 

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