24 May 2015

On Extensions of Patent Term and Genetic Technologies

Recombinant formation of plasmidsTwo recent decisions issued by the Australian Patent Office address the requirements for extending the term of a patent encompassing a pharmaceutical substance ‘when produced by a process that involves the use of recombinant DNA technology’: ImmunoGen, Inc. [2014] APO 88 and Novartis Vaccines and Diagnostics S.r.l. [2015] APO 2.

What is interesting about both these cases is that, while recombinant DNA techniques are employed in manufacturing the pharmaceutical products, neither patent directly claims a new product resulting from the use recombinant DNA technology.  In both cases, the patent claims are principally directed to processes for making the products, and extensions of term have nonetheless been granted. 

The decisions relate to the anti-cancer drug KADCYLA, and the meningitis vaccine BEXSERO, both of which will now enjoy an extended term of patent protection in Australia.

An Anti-Cancer Drug

The first of the two recent decisions (ImmunoGen) relates to a patent covering an anti-cancer drug marketed under the name KADCYLA.  The drug is used to treat advanced or metastatic (spreading) breast cancer in patients who have tested positive for a protein known as ‘human epidermal growth factor receptor 2’ (HER2), which is found in large amounts on the surface of some cancer cells.  KADCYLA contains the active ingredients trastuzumab, a monoclonal antibody, and emtansine, an anti-cancer substance.

As I understand it, the antibody in KADCYLA targets the HER2 receptor.  In practice, this antibody is made by a process which involves using recombinant DNA techniques (i.e. the ‘joining together’ of DNA molecules) to ‘humanise’ mouse antibodies.  However, the humanised mouse antibodies are just a step along the way, and not the final active ingredient that goes into the drug.

A Vaccine Against Meningitis

The second recent decision (Novartis) relates to a vaccine called BEXSERO, which was approved for use in Australia in August 2013.  The vaccine protects recipients (primarily infants and young children) against Meningitis B (‘MenB’), which is the most common cause of bacterial meningitis.  MenB disease can kill within 24 hours of onset, and about one in 10 of those who contract the disease will die, even with appropriate treatment.  Furthermore, survivors may suffer from devastating, life-long disabilities such as brain damage, hearing impairment or limb loss.

BEXSERO contains four active antigenic ingredients, three of which are proteins produced using recombinant DNA techniques.  The fourth active ingredient is an extract prepared from MenB bacterial cells.  However, the Novartis patent does not claim any of the individual antigens as an invention.  Rather, it claims a mixture of the antigens with ‘an aluminium salt and histidine’, which are additives provided to improve the immune response to the antigens.

The Policy Behind Extensions of Patent Term

Drugs and other therapeutic products may take a long time, and a great deal of money, to develop, trial, prove, and gain approval for sale.  At the same time, corresponding patents must be filed early in the process to ensure that the applicant is first-to-file, and that the claimed product is novel in view of subsequent disclosures occurring during the product development, trial and approval process.

By the time a drug is actually on the market, a significant proportion of the term of the associated patent may already have passed, and the period within which the patentee is able to capitalise on its investment is then significantly reduced.

Many jurisdictions – including Australia – therefore allow patentees of pharmaceutical inventions to apply for an extension of the patent term beyond the usual 20 years from filing.  There are various time limits and procedural requirements, but in essence the expiry of the patent may be extended by a period commensurate with the delay associated with obtaining regulatory approval, usually subject to some cap (e.g. a five-year maximum in Australia).

Extensions and Recombinant DNA

Generally, extensions of term are available only for patents covering new and inventive compounds.  Patents on new processes for making known compounds, or for new treatments based on existing compounds, cannot usually be extended.

The Australian patent law, however, provides an exception to this general rule, in relation to recombinant DNA technologies.  In particular, section 70 of the Patents Act 1990 permits an extension when either one (or both) of the following conditions are satisfied:
  1. one or more pharmaceutical substances per se must in substance be disclosed in the complete specification of the patent and in substance fall within the scope of the claim or claims of that specification;
  2. one or more pharmaceutical substances when produced by a process that involves the use of recombinant DNA technology, must in substance be disclosed in the complete specification of the patent and in substance fall within the scope of the claim or claims of that specification.
The first of these conditions in the ‘general rule’, while the second is the limited exception.

As Justice Heerey put it in Boehringer lngelheim International v Commissioner of Patents [2000] FCA 1918 (at [14]-[15]):

Broadly speaking, a claim in relation to a pharmaceutical substance can be made in three ways:
(i) a new and inventive product alone;
(ii) an old or known product prepared by a new and inventive process;
(iii) an old or known product used in a new and inventive mode of treatment.

What is clear in s 70 is that only the first type of claim to a pharmaceutical product is to be subject to extension rights. So far as a new process is concerned, it is only when the new process answers the particular description in s 70(2)(b) (recombinant DNA process) that it can be the subject of an extension. As counsel for the Commissioner submitted, the policy to be deduced in the light of the legislative history is that Parliament has decided that what is intended to be fostered is primary research and development in inventive substances, not the way they are made or the way they are used, with the sole (and important) exception of recombinant DNA techniques, this being an area particularly worthy of assistance for research and development.

KADCYLA Patent Extension

There are two preconditions for a patent to be eligible for an extension of term, which can broadly be characterised as ‘disclosure’ and ‘claiming’, i.e.:
  1. one or more pharmaceutical substances when produced by a process that involves the use of recombinant DNA technology, must in substance be disclosed in the complete specification of the patent; and
  2. the one or more substances must in substance fall within the scope of the claim or claims of that specification.
Regarding the first precondition, the Hearing Officer readily concluded that:

In simply requiring a process “that involves the use of recombinant DNA technology” the legislation appears to encompass a range of scenarios including the present one where the processes described includes forming a conjugate from an antibody produced by known recombinant techniques.

It is less apparent that the second precondition is satisfied, because the patent includes claims directed to a process for making the pharmaceutical substances, but not to the resulting substances themselves.  However, the Hearing Officer found that:
  1. ‘falling within the scope of a claim’ in a patent specification means ‘included amongst the things claimed’; and
  2. under Australian law (though it must be said that this is not the law in many other jurisdictions) a claim to a product made by a particular process is substantially indistinguishable in scope from a claim to the particular process used to make the product, both being limited by the features of the process.
If this seems quite generous, I note that it is consistent with the use of the language ‘substances when produced by a process’ in section 70.  This is kind of language that is often used in a patent claim to distinguish an otherwise known product on the basis that it has been produced by the specified process.  Such a claim is considered novel if the process itself is new, but is infringed only by a product that has been made using the claimed process.

BEXSERO Patent Extension

In the case of BEXSERO, the Hearing Officer found that the ‘pharmaceutical substance’ for the purpose of the preconditions set out in section 70 is

…the mixture of protein antigens … OMVs, aluminium hydroxide and histidine. It is this pharmaceutical substance, when produced by a process that involves the use of recombinant DNA technology, that must in substance be disclosed in the complete specification of the patent and in substance fall within the scope of the claim or claims of that specification.

The Hearing Officer further found that the specification identifies suitable antigens and that, even though the details are disclosed principally by reference to other documents, ‘it is reasonable to conclude that the complete specification discloses the three protein antigens in the pharmaceutical substance as the products of recombinant DNA technology’.  Thus the first precondition was satisfied.

Claim 1 of Novatis’ patent (in similar manner to the KADCYLA patent) is directed to a process for making the pharmaceutical substance.  However, the Novatis patent also includes claims (added, as it happens, by recent amendment) directed to the product ‘obtained by a process according to’ claim 1.  The Hearing Officer accepted that, in line with the decision in ImmunoGen, either form of claim satisfied the second precondition for an extension of term to be granted.

Conclusion – ‘Recombinant DNA’ Patents Are Broadly Extendible

These two decisions confirm that when, as a practical matter, recombinant DNA technologies are employed as some part of the process of making a pharmaceutical substance, a patent covering the process will commonly satisfy the preconditions in section 70 of the Australian Patents Act for the grant of a term extension.

It does not matter that the products may not themselves be novel.  Nor does it matter that the claims may not explicitly recite recombinant process steps.  And it does not matter that the claims may be directed only to the process, and not to the products of the process (although ‘product by process claims’ can typically be added by amendment of such patents, even after grant).

It is enough for a product made by a process including steps involving recombinant DNA technology be included among the things claimed.

This, it seems to me, is a fairly generous incentive provided by the Australian government for researchers and company to engage in R&D relating to the use of recombinant DNA technology for the production of pharmaceuticals.

Image credit: ‘Minestrone Soup ’ (Own work) [CC-BY-SA-3.0], via Wikipedia


Post a Comment

Copyright © 2014
Creative Commons License
The Patentology Blog by Dr Mark A Summerfield is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Australia License.