Utility of Pharmacogenetic predictive markers in developing countries versus developed countries
There has been misconception that the implementation of pre-emptive pharmacogenetic predictive marker testing is feasible only in developed countries and is directly related to infrastructure of the service facility and the facilities requiring these services. It is of economical value of course in preventing costs associated with that of adverse drug reactions or therapeutic failure of the drug. The developing countries are also receiving benefits of pharmacogenetic/pharmacogenomic markers from the knowledge transfer, training opportunities, and expanding transnational networks and thus creating opportunities to implement the genome based therapies in wider population. Recent development in genomics and various technologies related to genomics have reformed the clinical practice using appropriate diagnosis and/or predicting the inherited diseases as well as the optimal usage of drug. Further, the genome-wide studies where the next generation sequencing are used for the target gene or genome sequencing analyses, added fuel for this newer approach to detect or treat various diseases.
Currently, many developed countries such as USA, and Western Europe are gradually adopting this powerful approach to implement the genomic medicines into routine clinical practices. These countries developed guidance documents related to the usage of genome based therapies. Pharmacogenetic tests are generally used to find the genetic, molecular, and cellular level information from individual patients and mainly focuses on the identification of specific biomarkers or genetic mutations (Scott, 2011, Mini and Nobili, 2009, Plöthner et al., 2016). Often, biomarkers add information on prognostic and predictive purposes. The DNA testing offers enormous opportunities for the prevention of diseases by means of identification of patients who could be in high risk of developing the diseases. Studies showed that the mutation is the epidermal growth factor receptor (EGFR), breast cancer susceptibility gene I and II (BRCA I, BRCA II), and the Kirsten RAS (KRAS) are useful to predict resistance to treatment. Thus, these predictive biomarkers are very much advantageous for identifying the susceptible population and clinical effectiveness by improving the efficacy and safety. In recent years, many pharmacogenetic therapies have been approved and many of these approved drugs require a genetic test prior to the administration. The sustainability of these therapy always depends on the cost effectiveness of the therapy. The healthcare resources are finite and therefore an appropriate evaluation of cost-effectiveness is an important aspect. Economic evaluation between two interventions is a useful instrument for the policy or decision making as well as expenditure in the healthcare (Verbelen et al., 2017). The pace of implementation of pharmacogenetic driven therapies and genetic biomarkers for identification suitable population is always remained faster in the developed countries as a result of the organized healthcare system, political willingness, available resources as well as technology and transfer of knowledge. In contrast, this is not always same in the developing and resource limited countries where many hindrances exist.
Approximately 85% of the world’s population live in the resource limited countries and therefore, genome driven medicines in these regions represent a huge opportunity and also challenges (Mitropoulos et al., 2015). It is true that the, limited resources countries are burdened by poverty, poor political will, lack of appropriate infrastructure and lack of required knowledge among the healthcare professionals. However, one must also think that may be pharmacogenetics has of greater importance in limited resource settings where the infrastructure and human resources have to be prioritized to offer the services. There are have been many successful examples of implementation of pharmacogenetic or pharmacogenomic medicines in recent years and these could be further replicated in many other developing countries. In regard to this, pharmacogenetic success story of HLA-B*1502 testing for the prevention of carbamazepine-induced Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis in Southeast Asia is worth to mention. This has led the Thai government to provide this testing in the standard care and decrease the healthcare cost by means by reducing the carbamazepine-induced severe adverse drug reactions. Therefore, implementing pharmacogenetics/pharmacogenomic testing could easily allow us to prioritize or channelize resources based on the stratification after pharmacogenetics testings and improving the cost effectiveness. This will also help to enhance and allocate resources in an appropriate way without diluting the delivery of services. Overall, it can have more economical impact and can facilitate personalized care implementation.
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