The Canadian Intellectual Property Office (CIPO) has proposed new patent examination guidelines for pharmaceutical solid forms, including polymorphs, salts, hydrates, solvates, desolvates and co-crystals.1 The proposed guidelines are intended to provide "certainty and consistency" in the patent examination process but signal more stringent examination requirements for these solid forms.
What You Need To Know
- If approved, the proposed patent examination guidelines will appear in the Manual of Patent Office Practice (MOPOP). The MOPOP is a guide outlining Canada's patent examination practice, and does not have the force of law.
- The proposed guidelines address the tests for anticipation, obviousness, utility, indefiniteness and unity of invention in relation to crystalline forms of small molecules, and provide specific commentary with respect to polymorphs, salts, hydrates, solvates, desolvates and co-crystals.
- Compared to current examination practices, the proposed guidelines set heightened requirements with respect to non-obviousness and utility of certain inventions relating to crystalline forms of small molecules.
- The proposed guidelines are open for public consultation until August 10.
Some of the more important aspects of patentability addressed in the proposed guidelines are discussed below.
The proposed guidelines stipulate that where a particular crystalline form of a small molecule has not been disclosed and enabled in the prior art, either explicitly or inherently, a claim to the crystalline form will be considered novel. If the crystalline form is already known, a claim to the process used to prepare the form may still be novel if it can be distinguished from the prior art.
According to the proposed guidelines, a crystalline form (e.g., a polymorph) of a small molecule will be considered non-obvious (inventive) if:
- the form can only be produced using an inventive process (generally beyond the mere application of common general knowledge and routine experimentation), or
- the form provides an unexpected benefit, such as a beneficial physicochemical property, attributable to the form itself.
CIPO takes the position that the unexpected beneficial property must be explicitly or implicitly disclosed in the originally filed application and that the crystalline form must have been prepared and tested in order to ascertain that it possesses the property. The proposed guidelines also specify that predictable benefits over an amorphous form (e.g., easier isolating, purifying, drying, handling and formulating) are not generally sufficient to support a finding of non-obviousness. Where the specification comprises statements indicating a solid form "may" have a particular benefit or "has at least one" benefit selected from a list of benefits (without clearly stating which it has), CIPO will consider this to be an inexplicit indication of a potential benefit and such statements will not be considered during an obviousness assessment.
CIPO acknowledges that utility will often be self-evident for polymorphs of a known small molecule with a previously established utility. However, where the subject-matter of the invention as claimed has a utility that is different from other known form(s) of the same small molecule, the guidelines stipulate that the utility must be established by demonstration rather than sound prediction. CIPO takes the position that the specific physicochemical properties of a particular crystalline form are generally unpredictable since the form must be prepared and tested before its physical properties can be ascertained. Furthermore, where experimental data serves as the basis for the demonstration of utility, the data must have existed at the filing date but need not have been disclosed in the description.
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