We have recently witnessed IP Australia Examiners issuing lack of support and enablement objections that require at least 10 XRPD peaks in a claim to appropriately support and define a novel/inventive polymorph.
The Support Objections
The support objections raised by Examiners are based on sub-sections 40(3) and 40(2)(a) of the Patents Act 1990 (Cth) and typically take the following form:
Sub-section 40(3) – that the claims are drafted so broadly that their scope extends beyond the disclosure of the specification to encompass possibilities which cannot be readily predetermined or assessed by what is disclosed, and that the specification does not provide sufficient directions as how to put the claimed invention into practice; and
Sub-section 40(2)(a) – the specification does not provide sufficient information to enable the skilled addressee to perform the invention over the full width of the claims without undue burden or the need for further invention.
To support the assertion that claims defining fewer than 10 2θ peaks are not adequately supported across their full scope, Examiners have relied on the U.S Pharmacopeia general chapter on x-ray diffraction as referred to in the 1st edition of Polymorphism in Pharmaceutical Solids, by Brittain, H.G., Ed., 1999, pages 235-238, particularly page 236 ('Brittain').
Relying on the disclosure of Brittain, the objections generally assert that in the general chapter on x–ray diffraction, the U.S. Pharmacopeia states that identity is established if the scattering angles of the ten strongest reflections obtained for an analyte agree to within ±0.20 degrees with those of the reference material, and if the relative intensities of these reflections do not vary by more than 20 percent.
Prior to this latest practice at IP Australia, it has usually been acceptable to define a novel polymorphic form by defining less than 10 of the major characteristic peaks.
Overcoming the objections
Guidance from 2nd Edition Brittain
Although the objections are based on the 1st edition text of Brittain, the updated 2nd Edition (published some 10 years after the 1st edition) provides more explicit guidance as to the skilled person's knowledge in this field, and also makes reference to a further updated version of the US Pharmacopeia (USP 32nd revision).
Although the 2nd edition still contains the same paragraph as referred to by IP Australia, this paragraph is followed by a further paragraph describing the importance of "where different XRD patterns of polymorphs are used for patentability purposes". The paragraph goes on to provide the example of two polymorphs of ibandronate sodium, which are the subject of (now) granted patents US 7,714,158 and US 7,582,789, as well as EP patents EP1848727, EP1848728 and EP2662380.
Specifically, the 2nd edition of Brittain notes that: "although the XRD patterns of these are somewhat similar (referring to Fig. 11), a sufficient number of differences in scattering peak angles exist so as to permit their identification. In the patent applications, some of the claims define the two polymorphs on the basis of five characteristic XRD scattering peaks, which enables one to tabulate the data and determine whether or not a given sample of ibandronate sodium is within the scope of these XRD claims".
So, contrary to the position taken by IP Australia, the 2nd edition of Brittain clearly illustrates that there are circumstances, particularly in the context of patent applications, where significantly fewer than 10 peaks are sufficient to characterize a given polymorph.
The IP Australia objections often also specify a requirement that the relative intensities of reflections do not vary by more than 20 percent. The 2nd edition of Brittain also debunks that requirement, stating: "Older versions of the general test contained an additional criterion for relative intensities of the scattering peaks, but it has been noted that relative intensities may vary considerably from that of the reference standard, making it impossible to enforce a criterion based on the relative intensities of corresponding scattering peaks". This is also clearly set out in updated versions of the USP.
Guidance from Europe
The Australian support requirements are intended to align with those of major overseas jurisdictions, and when assessing the ground of support, Australian Examiners are often persuaded if the same scope of claims has proceeded to allowance in a corresponding case in a major jurisdiction. The main reason for this is that during the Parliamentary debate surrounding the introduction of the support requirements, it was considered that the test should only elevate the level of support to be in line with equivalent requirements of Australia's major trading partners. Accordingly, as the support test is a subjective one, Australian Examiners' are typically mindful that the requirement does not extend beyond those required by, for instance, the EPO, JPO or USPTO.
In this regard we have found it useful to refer to the decision of the Boards of Appeal of the European Patent Office (T 0833/11), where claims to polymorphs of a compound were defined by only one or two 2θ angles, and where sufficiency of disclosure (i.e. a clear enough and complete enough disclosure) was upheld. In that particular instance, Form 1, 2 and 3 polymorphs were defined by peak angles at 18.9°; 18.4 and 21.5; and 18.6 and 19.2 respectively. Specifically, it was noted at 4.2:
"In order to assess whether the requirement of sufficiency of disclosure is fulfilled, it must be assessed whether the patent in suit as a whole, that is, the claims, description and figures, makes available to the skilled person, in the light of his general common knowledge, all the information necessary for obtaining the desired polymorphs without undue burden.
In the present case, it has not been contested that examples 1 to 3 of the patent in suit contain clear instructions as to how to prepare the polymorphs designated at Forms 1 to 3, respectively. Moreover, it has not been disputed that these forms are distinguishable by means of their complete XRPD patterns as shown in overlaid Figure 1."
Thus, the Board of Appeals accepted that a sufficient number of differences in scattering peak angles existed so as to permit their identification and that claims to polymorphs defined by only one or two XRPD peaks were sufficiently disclosed.
By submitting arguments based on the analysis presented above, we have successfully overcome a number of support objections raised by IP Australia in relation to claims directed to polymorphs, and have secured acceptance of claims that define new crystalline polymorphs with reference to fewer than 10 XRPD peaks.
Originally published 10 December 2020
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