Composite or composition? Drawing a subtle line on PTE eligibility
Australia’s patent term extension (PTE) provisions, while relatively uncomplicated in comparison to their US PTE and European Supplementary Protection Certificate (SPC) counterparts, are not without their subtle nuances. For example, in the recent Pharma Mar S.A.  APO 8 decision, the Patent Office considered the subtle yet significant distinction between composites and compositions in assessing PTE eligibility.
PTE eligibility criteria
A pharmaceutical patent may be eligible for an extension of up to 5 years in Australia where one or more of the following is in substance disclosed in the complete specification and in substance fall within the scope of at least one of the claims:
(a) a pharmaceutical substance per se; or
(b) a pharmaceutical substance when produced by a process that involves the use of recombinant DNA technology.
Further, goods containing, or consisting of, the relevant substance must be included in the Australian Register of Therapeutic Goods (ARTG) and the period of time elapsed between the date of the patent and first regulatory approval date for the substance must be at least 5 years.
Pharma Mar is the owner of a patent covering the goods APLIDIN (plitidepsin), which is used in combination with dexamethasone for the treatment of patients with relapsed and refractory multiple myeloma. Relevantly, claim 1 of the patent is directed to:
A pharmaceutical composition of a didemnin compound, comprising firstly a lyophilised didemnin preparation including water-soluble material and secondly a reconstitution solution of mixed solvents.
Pharma Mar applied for PTE based on the ARTG registration of APLIDIN, identifying plitidepsin (a didemnin compound) as the relevant pharmaceutical substance per se. Several notices of deficiency were issued in relation to the PTE application on the basis that plitidepsin per se does not in substance fall within the scope of claim 1 (or any other claim of the patent). Unable to overcome this deficiency, Pharma Mar requested a hearing to decide the PTE application.
The relevant goods
APLIDIN is a composite pack comprising a vial containing lyophilised plitidepsin (in the form of a powder) and an ampoule containing a mixture of solvents. APLIDIN must be reconstituted by combining the contents of the vial and the ampoule, and further diluted prior to administration.
Pharma Mar argued that although the APLIDIN product is in the form of a composite pack, the reconstituted product immediately prior to administration is also included in the ARTG. In support of this argument, Pharma Mar referred to the Product Information sheet, which refers to administration by ‘intravenous infusion’ – clearly a reference to the reconstituted product since a power cannot be administered by injection – among other references to properties of the reconstituted product.
However, as stated by the Federal Court in H Lundbeck A/S v Alphapharm Pty Ltd  FCAFC 70, the enquiry into whether the relevant substance is included in the ARTG should go no further than ‘a simple comparison of the pharmaceutical substance with the “ingredients” of the goods on the ARTG.’ In this regard, the ‘ingredients’ in APLIDIN are a vial containing lyophilised plitidepsin and an ampoule containing a mixture of solvents. Accordingly, the Delegate found that the relevant goods listed on the ARTG are APLIDIN in the form of a composite pack and do not extend to the reconstituted (composition) product.
Does plitidespsin in substance fall within the scope of the claims?
The Delegate construed the claims as encompassing a two-part combination of separate components having the prima facie nature of a kit claim; plitidepsin per se was not ‘included among the things claimed.’ Rather, what the Delegate considered to in substance fall within the scope of the claims was a two-part combination of first, a didemnin preparation (comprising a lyophilised didemnin and water soluble material) and second, a reconstitution solution of mixed solvents.
Pharma Mar put forward an alternative construction of claim 1 as including the components of the claim ‘in separate vials, in mixture immediately prior to reconstitution, after reconstitution, or otherwise’ (i.e., both the composite and combination products). However, the Delegate did not consider it necessary to consider this alternative construction, since it would not give rise to PTE in any case because the goods APLIDIN do not contain the reconstituted mixture.
Is PTE available for kit claims?
While there are no court decisions on whether claims directed to a kit or composite product are eligible for PTE, the Patent Office found some claims of this type to be ineligible for PTE in Children’s Medical Center Corporation  APO 80. In that case, the patentee sought to extend the term of a patent claiming a combination of two drugs in separate dosage forms. However, this manifestation was not considered a pharmaceutical substance per se because it was not claimed ‘by or in itself, intrinsically, essentially’ or ‘taken alone; essentially; without reference to anything else’ (per Boehringer Ingelheim International GmbH v Commissioner of Patents  FCA 647).
As stated by the Delegate in Children’s Medical Center, the definition of pharmaceutical substance in the Patents Act requires it to have a therapeutic use whose application involves:
(a) a chemical interaction, or physico‑chemical interaction, with a human physiological system; or
(b) action on an infectious agent, or on a toxin or other poison, in a human body.
In that case, the claimed components could not be considered a single pharmaceutical substance per se simply because of the interaction they have in the human body following separate administration.
In Pharma Mar, the Delegate acknowledged that the difference between a composite and a composition is a subtle one, but could not reconcile the wording of the Patents Act and the relevant case law with recognising a ‘deconstructed’ formulation intended for later reconstitution as a pharmaceutical substance per se for the purpose of PTE.
What claims are eligible for PTE?
The types of claims that may be eligible for PTE include:
- an active pharmaceutical ingredient (API);
- a pharmaceutical composition comprising an API;
- a combination/admixture of APIs;
- crystalline polymorphs of an API;
- single enantiomers or diastereomers of an API;
- a new formulation of a known API; and
- an API when produced by a process involving the use of recombinant DNA technology.
In contrast, kit or composite claims, Swiss-style and other ‘use’ claims, claims to modes of administration or dosing regimens, and product-by-process claims that do not involve the use of recombinant DNA technology, for example, cannot currently form the basis for PTE because a relevant pharmaceutical substance does not in substance fall within the scope of such claims.
If you would like to know more about PTE in Australia, please do not hesitate to contact Claire Gregg at CGregg@davies.com.au or your regular Davies Collison Cave contact.