Everyone has their own treatment
MEPhI talked about the role of biomarkers in the individual treatment of cancer
Personalized and precision medicine (PM) is becoming the main direction of the development of medical science and practice. Its main task is to determine which medications will be effective for the patient, taking into account his genetic characteristics and individual form of the disease, as well as for his closest relatives. Over time, personalized medicine with the use of biomarkers will become an important part of the preventive and curative work of oncologists and will help reduce the threat of disease for people at risk.
What is a biomarker? This is a characteristic that can be objectively evaluated in order to identify a pathological or physiological process in the human body. Biomarkers are used, for example, to assess the stage of the disease, predict the course and choose an individual treatment regimen, depending on the molecular type of tumor.
For example, in patients suffering from breast cancer or lung cancer, tumors contain typical gene mutations. In this regard, in the world oncological practice, it is customary for such patients to carry out targeted genomic scanning and determine an individual range of biomarkers in order to adequately form targeted therapy. Biomarkers are of three main types, Professor Sergey Suchkov, Head of the Department of Translational Medicine at the MEPhI National Research University, told MIA "Russia Today". "Predictive biomarkers predict the possible risks of the disease and the most likely response to planned and ongoing treatment. Prognostic give information about how the disease can proceed regardless of the type of treatment, that is, determine the prognosis of the disease. Diagnostic tools allow you to make the right diagnosis at the right time," he explained. Numerous studies have identified a number of biomarkers associated with tumors. Their determination in a single package (multifactorial screening and monitoring) increases the accuracy of the diagnosis and even precancerous condition, as well as the reliability of the prognosis, while optimizing the procedure for detecting metastases.
The study of auxiliary biomarkers is becoming a mandatory part of treatment and diagnostic protocols for cancer patients and preventive and preventive protocols for people at risk. This method gives the oncologist a unique tool for clinical orientation and helps patients achieve the longest possible life without relapses.
Right on target
Biomarkers can significantly improve the diagnosis of malignant neoplasms, making it easier for the doctor to design the most effective treatment regimen. It was biomarkers that gave a real impetus to the development of the concept of targeted therapy. The researchers realized the need to create special, "targeted" drugs that can be introduced into the key links of pathogenesis and correct them.
In 2011, the U.S. Food and Drug Administration (FDA) approved a number of regulations on targeted cancer therapy. Two of them, related to the drugs krizotinib and vemurafenib, have become unique. For the first time, the choice of treatment methods was based not on the subjective views of the attending physician, but on objective principles of biomarking.
Now, before prescribing crizotinib therapy, doctors must conduct a test based on a unique fluorescence method (FISH method). This test helps to identify genomic permutations that indicate that this particular patient can and should receive special benefits from treatment with crizotinib.
"The use of a new and extremely reliable method for rapid screening of biomolecules associated with cancer has allowed scientists to construct a unique panel of biomarkers of the early stages of the tumor process (biopredictors). This panel not only helps to choose a highly effective therapy for breast cancer, but also provides an error–free diagnosis of the disease at the very beginning of development," said Sergey Suchkov.
Examples of success
Metastatic melanoma is a dangerous disease with an unfavorable prognosis for most patients. Therefore, the decision to include the drug vemurafenib in clinical protocols, which helps about 40-60% of patients with this diagnosis, has become unique in importance. The use of vemurafenib for the first time provided a significant increase in survival from this deadly disease. However, the drug is not active in some patients, so all of them must undergo a preliminary examination for the presence of an appropriate biomarker.
Another example is related to the drug brentuximab vedotin, intended for the treatment of patients with Hodgkin's lymphoma. Previously, these patients were treated with autologous stem cells, but many of them died. And brentuximab, which combines targeted monoclonal antibodies with an artificially created small molecule, gives a powerful medicinal effect, causing the death of cancer cells and suppressing their reproduction. Already in clinical trials with Hodgkin's lymphoma, the frequency of positive effect was 73%, and almost 32% of patients achieved complete remission.
The identification of certain biomolecules in the seminal fluid of the patient, in turn, phenomenally helps early and accurate diagnosis of prostate cancer and assessment of the severity of the tumor process, said Sergey Suchkov. "For comparison, in the past, due to numerous false positive results, biopsies were taken unnecessarily in patients. They were prescribed inadequate therapy even with benign forms of the tumor that could be left untouched," he explained.
Identification of biomarkers such as single transformed cells in the blood helps to assess the cumulative risks of metastasis, monitor the effectiveness of treatment and predict possible relapses, as well as conduct preclinical diagnostics of a latent precancerous condition. It is a new, highly informative and reliable biomarker for the diagnosis and prediction of cancer, capable of predicting the survival of patients with metastatic cancer at various stages during treatment.
"In recent years, biomarkers of the next generation are also gaining popularity – families of so-called microRNAs found in blood plasma in breast cancer, lung cancer, intestinal cancer and other oncological diseases. The use of these biomarkers helps the chemotherapist to determine the patient's sensitivity to various types of targeted therapy, including the latest combinatorial protocols. This practice is common so far only in clinics in the USA and Europe. In Russia, it still exists in its infancy," said the head of the Department of MEPhI.
In search of the perfect biomarker
The ideal biomarker, according to experts, must meet a number of criteria, depending on how it is used:
(a) it is desirable to determine it by non-invasive methods, and it should indicate the existence of a tumor before the first clinical symptoms appear;
(b) he must be sensitive to shifts in the tumor process itself (for example, to the response to therapy or surgical interventions);
(c) it should easily pass from model systems to clinical practice as an interpreted parameter, without causing doubts in the doctor.
To implement biomarkers, it is necessary to develop a process for their validation and standardize the procedure for preparing biological samples, creating sets of reliable methods for screening and evaluating biomarkers as a strategic participant in personalized and precision medicine.
Today, the market for technologies related to biomarkers, including for oncological diseases, is rapidly growing in the world. This is influenced by the rapid growth of cancer incidence in the population, combined with success in diagnosis and treatment.
"The search for new biomarkers is extremely necessary, and the scale of such a search should be gradually expanded, affecting the "silent" (seemingly "non-working" today) regions of the genome. To do this, it is necessary to develop cooperation between academic and university science, on the one hand, biopharmaceutical and medical diagnostic companies, on the other, attracting venture and grant funds during the development of initiatives," Sergey Suchkov believes.
At the same time, in his opinion, all interested groups of persons should participate in decision-making or determine ways to use intermediate and final research results. This is necessary for the development of targeted medicines of fundamentally new generations.
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