Full Court Rejects Inventive Step Attack on Veterinary Formulation Patent
In Boehringer Ingelheim Animal Health USA Inc v Intervet International BV 2022 FCAFC 88 the Full Court dismissed Boehringer’s appeal of the primary Judge’s rejection of Boehringer’s opposition to Intervet’s patent application on the basis of lack of inventive step.
Intervet’s patent application relates to injectable formulations of a macrocyclic lactone and levamisole and their use for controlling parasites and has a priority date of 24th June 2010. As examination was requested several days before the 15th April 2013 commencement of the Intellectual Property Laws Amendment (Raising the Bar) Act 2012, the case applied the pre-Raising the Bar test for inventive step.
The use of macrocyclic lactones for controlling parasites in animals was well known, but there were concerns around the emergence of resistant strains of parasites. Similarly, the use of levamisole as an anti-parasitic was also well known. While macrocyclic lactones and levamisole had been co-administered, attempts to formulate a stable combination of those active ingredients had been unsuccessful for several reasons including: they tend to react with each other when combined; they are individually stable at different pH ranges; and differences in solubility profiles. Those skilled in the art recognised that a stable formulation for such a combination would be desirable in relation to the concerns around resistant strains of parasites. Intervet’s patent application alleges to solve that formulation problem by using a macrocyclic lactone solution formulation comprising levamisole in a particulate form in a non-aqueous solvent system. Claim 1 defines the invention as follows:
An injectable formulation of a macrocyclic lactone and levamisole in a non-aqueous solvent system comprising oil and an organic solvent, wherein the macrocyclic lactone is in solution and the levamisole is a salt in a particulate form, and wherein the levamisole salt is present in the range of between 10-35% w/v.
The trial Judge found that the person skilled in the art to which the patent application was directed consisted of a team with experience in the field of animal health including a pharmaceutical formulator and parasitology expert. An expert giving evidence for Boehringer claimed that it would have been obvious to make a suspension formulation in which the macrocyclic lactone is in solution and the levamisole HCl is in particulate form, making routine adjustments to enhance viscosity, and that he would expect such a formulation to be stable. Intervet’s expert counter responded that the use of a suspension could affect the release profile of the levamisole in the formulation and that there could be issues with achieving even dispersion or preventing agglomeration. It was also noted that in a 2005 patent application Boehringer’s above noted expert made a statement about the difficulty of making liquid formulations containing mixtures across different classes of active compounds.
The trial Judge rejected Boehringer’s expert’s lack of inventive step pleading for several reasons including: the departure from existing formulations; the lack of commercially available formulations; the above noted differences between the actives; Boehringer’s expert’s claims to the contrary were essentially speculative and unlikely to be established by way of routine testing; uncertainty as to the efficacy of levamisole in such a formulation; and long-standing need for such a formulation.
Boehringer also argued for lack of inventive step on the basis of a prior Chinese patent application in combination with the common general knowledge. The trial Judge also rejected that attack on inventive step, finding that the patent application: did not address stability issues or provide the skilled addressee assistance in addressing the known incompatibilities; and did not specify whether the levamisole would be in particulate form.
On appeal Boehringer contended that the trial Judge erred in rejecting its first inventive step attack. Given that claim 1 does not require a formulation within its scope to have any particular release profile or absorption rate or other measure of efficacy, Boehringer contended that the trial Judge gave too much emphasis to the uncertainty as to the efficacy of levamisole in such a formulation and point away from its adoption. The Full Court disagreed, finding that the trial Judge rightly recognised that for pharmaceutical compositions the skilled team would be seeking a formulation that is safe and efficacious. Boehringer also argued that the trial Judge wrongly held that the invention could be arrived at through routine testing. The Full Court disagreed finding the testing involved would be exploratory rather than confirmatory in nature and more importantly it was the selection of the formulation that was inventive, irrespective of the routineness or otherwise of testing it. Boehringer sought to downplay the formulation difficulties acknowledged in the above noted 2005 patent application by arguing that a different approach may have been taken by that expert in 2010. However, this too was rejected as there was no evidence to support that contention.
Regarding the trial Judge’s rejection of Boehringer’s second inventive step attack the Full Court found no error in the trial Judge’s conclusions. While the Chinese patent application qualified as prior art, it was found the notional skilled team would derive little assistance or expectation of success from it given its lack of stability or efficacy data. Nor did it contain information from which the skilled reader could infer whether the levamisole was present in particulate form or in solution.
As earlier noted the opposition to the related New Zealand patent application was also unsuccessful. That opposition was not appealed beyond the Assistant Commissioner’s decision. Given that the New Zealand opposition was conducted under the provisions of the now repealed Patents Act 1953 establishing lack of inventive step was harder than under the Australian pre-Raising the Bar legislation.
Renewed Efforts Towards Harmonisation of Substantive Patent Law
The UKIPO recently opened a short consultation period on substantive patent law harmonisation initiatives in relation to the interrelated issues of grace periods, prior user rights and conflicting applications.
The consultation stems from September 2020 proposals by the Industry Trilateral (IT3), which was formed in 2003 for stakeholders to engage with the Trilateral Offices (EPO, JPO and USPTO) on substantive and procedural issues of patent law. IT3 is composed of representatives from four associations: American Intellectual Property Law Association (AIPLA), Intellectual Property Owners Association (IPO), BusinessEurope and the Japan Intellectual Property Association (JIPA). The proposals concern the above three areas of substantive patent law as well as the definition of prior art and having applications published at 18-months from the priority date. Given there is currently significant patent law harmonisation in respect of the latter two issues the consultation is focussed on the three initially noted issues.
In the early 2000’s WIPO’s Standing Committee on the Law of Patents (SCP) made concerted attempts to formulate a Substantive Patent Law Treaty (SPLT), but this was dropped as an active work program in 2004 after a lack of consensus. In 2014 the IT3 started working on key elements of what could form a SPLT resulting in its proposals being released to a select group (Group B+) of industrialised nations at the delegation level. The consultation also takes into account various position papers on these issues by the patent attorney organisations AIPPI (International Association for the Protection of Intellectual Property) and FICPI (International Federation of Intellectual Property Attorneys).
Grace Period: Currently there are a number of variations for grace periods. Amongst industrialised countries or countries with moderate to high patenting activity the strictest grace period provisions are those in the EPC. Currently the EPC only allows novelty to not be affected by disclosures resulting either from displaying the invention at an officially recognised exhibition or due to evident abuse of the rights of the inventor / applicant / assignee and only if such disclosures occurred no more than 6-months prior to the patent application filing date. As recently discussed the EPO conducted a select stakeholder consultation on its grace periods. Given the high use of the EP in patenting activity, if the EPC moves to a more general grace period, then other countries with similar grace period provisions to the EPC’s may also move to a more general grace period as there will no longer be a risk in not matching the strictness of the EPC grace period provisions.
Many countries apply a general grace period in respect of any disclosures by the inventor / applicant / assignee or due to evident abuse of their rights. However, there is variation as to whether the grace period is for a period of 6-months or 12-months and whether that time period precedes the priority date or the filing date. The vast majority of countries with a general grace period apply a 12-month term, with just over a dozen jurisdictions applying a 6 month term. Of those applying a 12-month term the majority have that time period preceding the priority date, although more highly developed countries generally have that time period preceding the filing date.
Other grace period issues for consideration are whether the applicant needs to declare any such disclosures when filing the application or can they be made at any stage during the life of the patent. If no such declaration is filed should a third party who started using the invention before the filing date after being aware of a pre-filing disclosure be able to claim a defence of intervening user and continue to use the invention? Should third party prior uses within the grace period that are the same or significantly similar to the claimed invention be presumed to be due to a pre-filing disclosure by the applicant? If the applicant invokes the grace period when filing should the application be subject to any early or additional publication requirements?
Prior User Rights: The defence of intervening user just mentioned is a subset of prior user rights. Broader prior user rights are in general allowed for where a third party independently and prior to the priority or filing date either is secretly and commercially using the invention or has begun investing in the invention with the intention of commercially exploiting it. Prior user rights are considered an important part of a balanced patent system that encourages early filing and also recognises the freedom of an inventor to choose between patent protection and trade secret protection. In general the burden of proof is on the party claiming the prior user right. In addition to the defence of intervening user issues, other issues for consideration include to what extent the prior user can, post-filing, modify their use without infringing and whether the right is only available in the country in which the prior use or significant preparations therefore took place.
Conflicting Applications: Where different applications disclose common subject matter but one is filed before but published after the filing of the second application there is variation in how jurisdictions consider the first filed application affects the scope of the second filed application. Although there is increasing harmonisation in the determination being made on a ‘whole of contents’ approach, rather than just being restricted to the claims of the earlier application. Many countries follow the European approach where such secret prior art is only relevant for novelty, while the USA also allows it to be relevant for inventive step. In Europe there is no anti-self-collision provision, meaning an applicant’s prior but unpublished application can be prior art for a subsequent application by the same applicant covering the same or significantly similar subject matter. In the USA there is an anti-self-collision provision, which incentivises first-mover advantage.
Another issue for consideration is the prior art status of PCT applications filed within the secret prior art window. In Europe a PCT application filed within such a window of time only counts as prior art if it subsequently enters European regional phase. Other jurisdictions such as the UK, Japan and South Korea likewise only recognise such PCT applications as prior art if PCT national phase is entered in that country. The rationale for this being that if such regional or national entry is not made then there will be no double patenting to be avoided. However, for the USA if the USA remains designated when the PCT application is published at 18-months then it counts as prior art whether or not national phase is entered. Australia also applies the approach taken in the USA. In a recent New Zealand case on this point, amongst other reasons, it was argued that New Zealand’s patent legislation requires PCT applications to enter New Zealand national phase to count as whole of contents secret prior art. However, the Assistant Commissioner’s decision found New Zealand’s patent legislation on this point to be more in line with the approach taken in the USA and Australia.