Pharmacogenetics
The development of new medicines
6 The application of pharmacogenetics to the development of new medicines has implications for the way in which basic research and clinical trials are designed and managed, and for the cost of undertaking clinical trials. The application of pharmacogenetic analysis could, in some cases, identify those individuals participating in research who are less likely to respond or who are at risk of adverse reactions, at later stages of clinical trials. These individuals could then be excluded from participating in the trials, which could lead to better protection of participants in research. The selection of smaller groups of genetically homogenous participants in clinical trials may be advantageous, leading to more robust and reliable scientific findings regarding the group of patients who might eventually be prescribed the medicine. There may be regulatory and legal pressures to incorporate pharmacogenetic analysis into clinical trials (paragraph 3.5) but such analysis will not always be feasible, nor will such an approach necessarily be appropriate, given available pharmacological evidence. We recommend that the appropriate use of pharmacogenetic analysis in clinical trials should be promoted. Regulators should be encouraged to promote the collection and storage of samples in clinical trials such that they could be subjected to pharmacogenetic analysis either during the trial, or subsequently (paragraph 3.12).
Using pharmacogenetics to improve existing medicines
7 Pharmacogenetics could be used to improve the prescribing of existing medicines, whether by reducing the incidence of adverse reactions, or by restricting prescription to those patients likely to benefit. Some potential examples include the medicine clozapine, used to treat schizophrenia, and the medicine warfarin, used to prevent the formation of blood clots (paragraphs 3.21-23). It is by no means certain that research would successfully identify genetic variants which could form the basis of a clinically useful test. Factors that will affect whether a test is likely to be of use in clinical practice include the scale of the negative effects experienced, the size of the patient population, the likely clinical value of the pharmacogenetic test, and the existence of other treatments. Nevertheless, in some cases, the development of a test could make a significant contribution to improving the prescription of existing medicines. It is not clear that the private sector will be motivated to pursue pharmacogenetic research in relation to medicines not covered by patent protection. We therefore recommend that efforts should be made to encourage pharmacogenetic research on existing medicines, where there is reason to believe that such research could significantly improve efficacy or safety. Funding and support should be made available within the public sector and public–private partnerships encouraged. We welcome the recent announcement by the Department of Health that £4 million will be directed towards research in pharmacogenetics over the next three years (paragraph 3.26).1
The use of pharmacogenetic information collected in research
8 There are numerous codes of practice and guidance regarding the conduct of clinical research. It is common practice to require consent for the collection and banking of tissue and DNA samples of participants in research, especially if it is intended to combine genetic information with other information from the patient’s medical record. Most researchers obtain written consent from participants and are required to provide written information in advance of obtaining consent. In the context of pharmacogenetic research, as in other forms of research, the nature of the information likely to be revealed and its implications for the patient should be set out for prospective participants as part of the standard process of obtaining consent. Two important areas of concern are the voluntary nature of the consent and the privacy of the information which is obtained and stored.
Footnotes1 Department of Health (2003) Genetics White Paper. Our inheritance, our future – realising the potential of genetics in the NHS (Norwich: The Stationery Office, CM 5791).