Pharmacogenetics
The development of pharmacogenetic tests
3.16 A potential barrier to the development of pharmacogenetic tests concerns the application of intellectual property rights. Pharmacogenetic tests may be developed in a number of ways. The pharmaceutical company which is developing the medicine may also develop the pharmacogenetic test. Alternatively, a third party, such as another company or researchers from the public sector may develop the test independently. For example, in the case of Herceptin (Box 2.3: Case study 2), two independent companies produce the diagnostic tests which are used to assess the suitability of patients to receive the medicine.9 It seems most likely that companies producing diagnostic tests will be involved in developing and marketing pharmacogenetic tests, since not all pharmaceutical companies will have the necessary skills, manufacturing capabilities and marketing force to successfully undertake production themselves.
3.17 What kind of patents might be used to protect pharmacogenetic tests? It is likely that the majority of pharmacogenetic tests will be based on the use of a small number of SNPs to identify the genetic variants which correlate with the response to treatment with one or more medicines. Individual SNPs are not patentable since they consist only of a single nucleotide base. Opinions differ as to whether a new variant of a known gene, in which the novelty is the identification of a SNP, will meet the necessary legal criteria for patentability.10 Variants in DNA sequence are more likely to be patentable when, for example, a particular SNP in coding DNA leads to an amino acid change which alters the response to a medicine, in other words, when a direct causal link has been demonstrated between the SNP and the phenotypic response. Patents which claim the substance(s) itself are called composition of matter or product patents and confer the most protection on biological molecules. It seems likely that patent protection will generally focus on claims which relate to the use of SNPs rather than the SNPs themselves.11 It is currently unclear to what extent particular groups of SNPs associated with the pharmacogenetic response for different medicines will overlap. It may be that some groups will be specific to individual medicines while others may be generally applicable to a number of medicines in one class.
3.18 In broad terms, three types of patent claims can be expected: those relating to methods of testing, those relating to methods of treatment and those related to novel dosage forms of the medicine. These claims will be predicated on the identification of a novel association between genetic markers and a response to treatment with a specific medicine. Claims which relate to methods of testing will enable the identification of patients who are predicted to have a defined response to treatment through the testing for specific genetic variants, usually in the form of SNPs. Other novel features of the test will also be claimed. Claims which relate to methods of treatment, involving the administration of the medicine to patients of a defined response phenotype, are only strictly allowable in the US.12 Claims which relate to the dosage of a medicine will specify the appropriate dosage for patients with particular genetic variants.
3.19 It may be necessary for companies or others developing pharmacogenetic tests to obtain a number of licences from other parties in order to develop their particular test. For example, there may be existing patents which assert property rights over DNA sequences within which the genetic variant of interest is found. It has even been suggested that the complexity of obtaining licences and the uncertainty of protection may adversely affect the development of the science.13 It is too early to judge whether this will prove to be the case. However, we consider that it would be undesirable if the development of pharmacogenetic tests were to be inhibited by the need for complex cross-licensing arrangements. We recognise that the granting of protection of inventions through patents can be an important means of promoting development and innovation in healthcare, but it is important to ensure that they do not achieve the opposite effect.
Footnotes9 The two tests produced to determine whether a patient is suitable for treatment with Herceptin are the HercepTest, manufactured by Dako, and PathVysion, manufactured by Visis. The two tests determine whether the patient’s tumour cells overexpress HER2. However they do so in different ways. HercepTest measures the protein in cancerous tissue while PathVysion measures the number of copies of the HER2 gene found in the tumour cells.
10 Nuffield Council on Bioethics (2002) The ethics of patenting DNA (London: Nuffield Council on Bioethics).
11 Personal communications: Andrew Sheard, Patent Attorney, and Mike Stott, Corporate Intellectual Property, GSK, Brentford.
12 In Europe such claims have been limited to the so-called ‘Swiss claims’ which provide patent protection for the industrial aspects of preparing a compound for a particular use. Swiss claims are being superseded by ‘compound for use’ claims which will provide broadly the same degree of protection.
13 Personal communication (2003) Duncan McHale, Senior Scientist, Pfizer Ltd.