Article
Precision Medicine: What is it and what benefits does it bring?
This type of care grows worldwide and brings significant individual improvements to treatment, but it is also important to assess the benefits and challenges for the healthcare system.
First published in 06/17/2019 - Last updated in 06/15/2023 às 9:48 pm
The discovery of new treatments for human diseases always includes phases of clinical trials, during which, in one of the final stages, individuals affected by the disease undergo the tested treatment. Although the design and implementation of these trials have become increasingly accurate throughout history (though the use of placebos, double-blind studies, and randomized double-blind studies), there is a variability in response between individuals (Figure 1) that cannot be explained solely by variations in age, nutrition, environment, or other commonly analyzed factors. The search for answers to justify ineffectiveness, adverse effects, or death in certain individuals has advanced as studies of the human genome progressed. The answer, it turns out, was in the genes.
Pharmacogenetics was created from a combination of genetics, biochemistry, and pharmacology, and brought evidence of the causal relationship between genotype and drug response, indicating patterns of phenotypic variation of great clinical relevance. Variation in gene sequence translates into variation in target proteins, enzymes or transport proteins, generating variability in drug response. The convergence between pharmacogenetics and human genomics further enhanced these results, generating pharmacogenomics. Data generated from gene sequences and its alterations provide extra information in prevention and in medical intervention. This bunch of genetic information can then be clinically translated as personalized medicine (Ma & Lu, 2011) or precision medicine[1].
Precision medicine combines the data already conventionally used for diagnosis and treatment – signs, symptoms, personal/family history and widely-used complementary exams – with the genetic profile of the individual.
From a treatment standpoint, it allows for a choice of drugs that minimizes adverse effects and produces the best results. From a prevention standpoint, it allows the detection of susceptibility to certain pathologies, even before they manifest clinically, enabling their monitoring and even prevention. From an industry standpoint, it enables the development of alternative treatments for individuals or groups of patients who would not respond to conventional treatments. It can potentially reduce costs and delays of clinical trials.
Table 1 outlines the benefits, potential disadvantages, and need for investment in precision medicine from both an individual and collective perspective, which should be points of discussion, especially in countries where the healthcare system is mixed.
Table 1: Benefits, disadvantages, and the need for investment in precision medicine from an individual and collective perspective
|
|
Individual |
Collective |
|
Short term benefits |
Improvement in the diagnosis and medical management of diseases that are already well-studied. |
Reduces expenses and risks by avoiding the use of practices that have proven to be ineffective. |
| Long term benefits | Improves diagnosis and medical management of a greater number of diseases. | Allows for the characterization of subpopulations. Subpopulations may already be previously defined for clinical trials. It can foster the search for specific drugs for these subpopulations. |
| Possible disadvantages | It can become the sole focus of private institutions with the creation of individualized medical centers. Although it promotes individual benefit, it can be restricted to only those who can afford the costs and that may overshadow the previously idealized collective benefits, such as the reduction of health care treatment costs. | The use of genetic testing in clinical trials for new drugs may identify subpopulations that are unresponsive or at risk to the tested drug. If this subpopulation is too small, it may turn them uninteresting as a market segment for large pharmaceuticals unless there are specific incentives to target them. |
| Public investment | Viable, but high cost due to the need for previous genetic characterization of the individual in order to choose medical management. Need to create reference centers. May require public-private partnerships. | Highly desirable, as it allows for the characterization of populations. Represented by cohort studies of large populations, as exemplified in Europe to identify markers for early detection of disease and preclinical phenotypes (see below). |
| Private investment | Great investment demand, as can be seen in the creation of individualized medical centers that offer the patient a "genetically" personalized treatment, increasing the chances of a cure. | Of interest if there is an advantage or guarantee of exclusive use of data. There are examples like the Murdock Study in Kannapolis, North Carolina, USA. |
According to the National Institutes of Health (NIH), by 2017 there were already over 50,000 genetic tests for 10,000 clinical conditions. That same year, the Centers for Disease Control and Prevention (CDC) estimated two to three new tests per week. These tests allow for the evaluation of the response potential of the therapy of choice for a given disease (Figure 2), and 80% of them guide the therapeutic choice for various types of cancer (Wu et al., 2017).
But cancer is not the only target: there are genetic tests to detect enzyme polymorphisms related to the metabolism of antidepressant drugs, anticoagulants and proton pump inhibitors; chemotherapeutic metabolizing enzymes used to treat leukemias, autoimmune diseases, and to prevent organ rejection; opioid metabolism; and neurodegenerative and infectious diseases.
The list seems inexhaustible, but the different types of cancer are certainly the main target. From an economic standpoint, cancer is the second leading cause of death in the US (behind cardiovascular disease), and it is estimated that $174 billion will be spent on cancer in 2020, according to the CDC. Moreover, cancer is feared for its high lethality, its symptoms and the toxicity of existing therapies, as well as the fact that its prevalence tends to increase with the aging of the population.
Figure 2. Genetic testing as an intermediate step between detection of the disease and choice of treatment, preventing the individual from being directed to something which he or she reacts negatively to, or which presents any sort of risk.
In addition to genetic tests to determine medical management, there are genetic tests focused on predicting individual susceptibility to certain diseases, based on a person's genetic profile.
Cellular and gene therapies can also be included as precision medicine and are currently targeted at degenerative retinal diseases, leukemia and lymphoma.
State of the art in the world and in Brazil
The US stands out for its speed of production and the availability of precision medicine products and services on the market. According to the Personalized Medicine Coalition, the number of available personalized drugs, treatments, and diagnostic teste has risen from 13 in 2006 to 113 in 2014. This same institution has classified as precision treatments 16 out of the 46 new therapies registered by the Food and Drug Administration (FDA) in 2017. Large medical institutions throughout the United States offer a portfolio of molecular markers and individually designed treatments.
To get an idea of the share of spending on precision medicine, according to the OCDE, the United States invested over $35 billion in health research and development in 2016. That same year, funding for precision medicine was $215 million, with $130 allocated to the NIH and $70 million to the National Cancer Institute (Kichko et al, 2016).
In Europe, of note is the European Commission’s project titled Personalized Medicine 2020 and Beyond, which aims to make precision medicine available to the general population, promote the development of strategic research, and implement an innovation agenda, stimulating synergy and avoiding duplication and competition. There are studies focusing on cancer and rare diseases involving several European countries. Countries such as Germany, the United Kingdom, France, and Norway stand out for their investments in the area.
In Germany, although the number of available treatments is lower than in the US market, government efforts are substantial. In 2013, there was €$ 210 million investment for the first ten years of a prospective study of its population aimed at identifying markers for early detection of disease and preclinical phenotypes and seeking tools for prevention (Kichko et al, 2016). This amount represents approximately 0.05% of German health spending, which, according to OCDE, was US$ 4,937 per capita in 2013. Similarly, the United Kingdom invested 60 million pounds in a study aimed at analyzing genotypic and phenotypic biomarkers in cohorts of patients (representing approximately 0.03% of UK health spending, which, according to the OCDE, was US$ 3,841 per capita that same year).
Unfamiliarity about the techniques, however, is still great. A 2018 Personalized Medicine Coalition survey showed that over 60% of the US population was unaware of the term “personalized medicine” or “precision medicine”. Most people react positively to a description of precision medicine, but they also believe that the tests should be covered by insurers. Major concerns are related to coverage, affordability and privacy of the genetic data. These results are similar to a previous version of survey (2016) conducted in both Germany and the United States, which also showed a concern by German physicians about the widespread use of the genetic data in electronic health records.
The implications of individual data collection are big: both positive and negative. The possibility of improved diagnosis and treatment generates ethical discussions about access, from both a public policy perspective and a legal perspective. The data collected, if widely available, could be used to select people to be excluded from health plans or a particular job. The same data, in large numbers, could prompt banks to search for patterns, generating a multiplier effect, further improving diagnosis and treatment selectivity.
The US government funding of precision medicine announced in 2015 goes in the direction of data sharing: participants should make available data generated on sequencing, electronic medical records, personal information, and digital health technologies. Certainly, as precision medicine is implemented in different countries, discussion, regulation, and legislation is required.
In Brazil, there is little material available on the subject. From a research standpoint, several groups focused on pharmacology and genetics created the National Pharmacogenetic Network in 2003, aiming to generate pharmacogenetic data of the Brazilian population. In 2015 Fapesp supported the creation of the Brazilian Initiative on Precision Medicine (BIPMed), which involves public high education and research institutions in the state of São Paulo whose purpose is to create a platform for storing genetic data from five centers based in these institutions. In 2017, the Brazilian Association of Personalized and Precision Medicine was created.
In Brazil, there are a few technology-based companies able to identify new markers and develop new tests. Large, private, clinical analysis laboratories already provide genetic tests in their portfolios and absorb the demand from hospitals that do not yet offer this service. Large private hospitals in São Paulo have initially collaborated with technology-based companies to provide genetic testing and now have their own individualized medicine centers.
This reality, however, seems to be far from reaching Brazil's Unified Health System (SUS), which has not yet been able to implement the electronic medical record in all of its care units. Although the area that benefits the most from molecular diagnostics is oncology, the feasibility of implementing molecular markers prior to the indication of therapies is still unclear.
Conclusion
The combination of technology and acquired knowledge has changed medicine over time. Precision medicine proves to be an exciting reality, changing not only the medical routine, but the economic impacts that the search for new treatment represents. The different reality of countries and their respective health systems brings up a discussion on ethnics and about limitations of a broad access to this new form of treatment and the huge amount of data related to it. In Brazil, this type of medicine is still underdeveloped, but since it is likely to expand, its discussion should be on the agenda.
[1]Literature presents much variability in the definition of these terms. There is a preference for the term "precision medicine”, as the term "personalized medicine" could be misunderstood to mean the treatment and prevention for a single patient without collective benefits. Medical centers offering this type of service often use the term "individualized medicine".
