Unidad de Investigación

• Vanessa Arrieta Paniagua, predoctoral researcher at the Translational Cardiology Unit of Navarrabiomed - IdiSNA will present her doctoral thesis by the Public University of Navarra next Monday, November 28, at 12:00, in the Assembly Hall of Navarrabiomed. 

The doctoral work, entitled "Role of sST2 in myocardial fibrosis in severe aortic stenosis”, has been developed at the University Hospital of Navarra and Navarrabiomed under the direction of Natalia López Andrés, Principal investigator of the Translational Cardiology Unit.

Aortic stenosis is the most common valvular heart disease in Europe and North America affecting 2-7%, depending on the region, in population over 65 years of age. To date, there is no medical treatment that can slow down or reverse the evolution of the disease, so aortic valve replacement (surgical or percutaneous) is the only treatment when symptoms or ventricular dysfunction appear.

This disease produces an abnormal progressive narrowing of the aortic valve that, as a result of pressure overload, causes hypertrophy of the left ventricle. In this process, myocardial fibrosis has an important pathophysiological role, as well as a prognostic role. Initially, myocardial fibrosis is part of a compensatory mechanism, but in advanced stages a focal replacement fibrosis appears, leading to ventricular dysfunction and heart failure. The pathophysiological mechanisms underlying these processes are not fully understood. 

Focal replacement fibrosis can be detected and quantified by cardiac magnetic resonance imaging (MRI) with the delayed enhancement (DE) sequences. The presence of DE in patients with severe aortic stenosis has been shown to be an independent predictor of mortality and unfavourable clinical outcome in this group of patients. However, MRI is an expensive technique with limited availability, so it is not used in the follow-up of this group of patients in routine clinical practice.

The hypothesis of this thesis is that as the levels of soluble ST2 (sST2), a biomarker associated with the process of fibrosis and myocardial remodelling, are elevated in case of aortic stenosis, they may have a prognostic value. Specifically, this study addresses the role of sST2 in myocardial fibrosis in severe aortic stenosis. 
 

Research development 

The work is proposed from a translational point of view, and has a dual goal. First of all, to delve into the pathophysiological role of tSS2 in severe aortic stenosis. To this end, a proteomic study has been carried out to assess the proteins modulated by sST2 in human cardiac fibroblasts and the in vitro effects of sST2 on human cardiac fibroblasts have been investigated. The results have been validated in vitro in a rat model with pressure overload and in myocardial biopsies of patients with aortic stenosis that underwent surgery. 

Likewise, it has been demonstrated that sST2 exerts a deleterious role in human cardiac fibroblasts, on the one hand, affecting the mitochondrial function of the cell and thus increasing oxidative stress and the synthesis of proinflammatory molecules and on the other hand, promoting differentiation to myofibroblasts and increasing the synthesis of profibrotic molecules. These findings were validated in the animal model and in myocardial biopsies of patients with aortic stenosis.

Secondly, from the clinical point of view, a cohort of patients with severe aortic stenosis with surgical indication was analysed to check if the blood levels of sST2 are associated with the DE evaluated by MRI in patients with severe aortic stenosis. Thus, it is observed that patients with severe aortic stenosis with cardiac MRI DE have significantly higher blood levels of sST2 than those without RT. Blood sST2 levels are positively correlated with DE mass and with VI mass in patients with severe aortic stenosis. High levels of sST2 make it possible to identify patients with severe aortic stenosis with DE, without having to perform cardiac MRI, in a simple way that can be applied in routine clinical practice.
 

Dissemination of results 

The work carried out has led to several scientific publications: in 2019, in the journal Clinical Science, “Soluble ST2 promotes oxidative stress and inflammation in cardiac fibroblasts: an in vitro and in vivo study in aortic stenosis”, and in 2020 in the journal Cells, “Soluble St2 Induces Cardiac Fibroblast Activation and Collagen Synthesis via Neuropilin-1”.   

In addition, the results have been disclosed at several national and international congresses such as the SEC Congress in Bilbao (in 2015 and in 2017), at the 29th EACTS Annual Meeting in Amsterdam, in 2015 or at the Heart Failure Congress in Paris, in 2017.

Biochemist Jaime Ibarrola Ulzurrun (Pamplona, 1991) has shown for the first time that a hormone is involved in mitral valve prolapse, a heart valve disease that leads to heart failure, and that a series of drugs can have positive effects on this condition. ‘The drugs known as antimineralocorticoids or mineralocorticoid receptor antagonists (MCRAs) are a promising option to reduce mitral valve remodelling. The only existing solution to date was surgery,’ Ibarrola explains. This was the subject of his doctoral thesis at the Public University of Navarra (UPNA).

The mitral valve is the valve between the left atrium and the left ventricle of the heart. Mitral valve prolapse is a condition in which the two valve flaps of the mitral valve do not close smoothly or evenly, but instead bulge (prolapse) upward into the left atrium. Sometimes, the mitral valve does not close tightly, allowing blood to flow backward in the heart. This condition is known as mitral valve regurgitation or mitral insufficiency. Most people with mitral valve prolapse – one of the most common heart conditions, affecting 176 million people around the world – never have problems. They do not need treatment or lifestyle changes. Some, however, do need to be treated. ‘To date, no drugs have been developed for this condition, so the only viable solution is surgery,’ Ibarrola explains. His doctoral advisor was Natalia López Andrés, senior researcher at the Cardiovascular Translational Research Unit of Navarrabiomed, a joint centre of the Government of Navarra and the Public University of Navarra (UPNA).

New therapeutic targets

Ibarrola’s research responds to the need to study ‘new mechanisms and new therapeutic targets in order to find drug treatments for mitral valve prolapse.’ ‘Mineralocorticoids are a class of hormones produced by the human body. The primary mineralocorticoid is aldosterone. The aldosterone/mineralocorticoid receptor (Aldo/MR) pathway can cause cardiac fibrosis. In addition, a large number of studies have shown that the Aldo/MR pathway is involved in a number of heart conditions. MCRA drugs can block the effects of the Aldo/MR pathway. Moreover, significant clinical studies show that they can also improve cardiac function by reducing cardiac fibrosis,’ Ibarrola explains. He conducted his doctoral research project with financial aid from UPNA and a European programme.

Ibarrola worked on the hypothesis that the Aldo/MR pathway could play a role ‘in the development of mitral valve prolapse, modulating cell activation and cellular differentiation.’ ‘Furthermore, the Aldo/MR pathway could become a new therapeutic target in this disease, and blocking this pathway with MCRA drugs could prevent the alterations associated with mitral valve prolapse. For the first time, we were able to show that the Aldo/MR pathway is involved in the development of mitral valve prolapse and that the drugs could have a positive effect on this condition,’ Ibarrola concludes. His doctoral thesis got an A-grade cum laude.

Ibarrola’s résumé

Jaime Ibarrola holds a degree in Biochemistry and a master’s degree in Biomedical Research from the University of Navarra. At present, he is a postdoctoral researcher at the Molecular Cardiology Research Institute (MCRI) at Tufts University (Massachusetts, USA).

As a doctoral student, Ibarrola was twice a visiting scholar at the Cordeliers Research Centre, Sorbonne University, in Paris. He shared his results in eight international conferences in Germany, Spain, France and Ireland. Ibarrola is the author of about a dozen papers published in international scientific journals.

The Microbial Pathogenesis Unit of Navarrabiomed-Public University of Navarra (UPNA) has found a new genetic organisation in bacteria that helps better understand bacterial biology. The study of this genetic architecture was published in Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Research background

In 1961, François Jacob and Jacques Monod discovered that bacteria group the genes that encode the proteins for a certain metabolic pathway in a single transcription unit (which they called ‘operon’). They won the Nobel Prize in Physiology or Medicine in 1965 for their discovery.

The bacteria they chose for their study was Escherichia coli, which normally lives in the intestines of healthy people; specifically, they studied the set of genes E. coli bacteria need to transport lactose (milk sugar) and break it down. E. coli only produces the three proteins it needs to digest lactose when the sugar is available. To simplify transcription regulation, the three genes involved are adjacent in the genome and under a single regulation system. Similar transcriptional regulation systems are found in other metabolic pathways in all bacteria.

Research at Navarrabiomed

In 2018, the team of researchers at Navarrabiomed coordinated by Iñigo Lasa Uzcudun, Head of the Microbial Pathogenesis Unit and Director of the biomedical research centre, described a new way genes are organised in bacteria. This regulation system has a higher level of regulation in operon structure, which the authors of the study named ‘non-contiguous operon’.

The bacterial model analysed has a group of four genes that are transcribed as a transcription unit despite the existence of a separate gene between the second and third genes that is transcribed in the opposite direction.

This transcriptional architecture results in an antisense transcript that acts as a mutual regulation system for the expression of the genes in the operon and the gene that produces this antisense transcript. Therefore, the concept of non-contiguous operon includes not only the genes transcribed from the same transcription unit but also overlapping genes whose expression is coordinated with that of the genes in the operon.

This finding deepens the understanding of bacterial biology and may trigger novel developments in the fields of synthetic biology and bacterial biotechnology.
The study was carried out as part of the scientific activity done at the Navarra Medical Research Institute (IdiSNA).

• Paper published in PNAS.

• El estudio, financiado por el Ministerio de Economía, ha sido publicado por la prestigiosa revista Nature Communication.

Un equipo científico del centro de investigación biomédica Navarrabiomed -centro mixto del Gobierno de Navarra y la Universidad Pública de Navarra (UPNA)- ha conseguido caracterizar el sistema sensorial que las bacterias utilizan entre otras cosas para multiplicarse en el cuerpo humano y causar infección.

El avance, que ha sido publicado por la revista científica Nature Communications y cuenta con financiación del Ministerio de Economía, Industria y Competitividad, permite comprender mejor cómo las bacterias se adaptan a las diferentes condiciones ambientales y posibilitará el desarrollo de antibióticos más específicos y eficaces.
El estudio ha contado con el liderazgo del doctor Iñigo Lasa, director de Navarrabiomed e investigador responsable del Grupo de Patogénesis Microbiana del centro. Asimismo, han colaborado investigadores del Instituto de Agrobiotecnología (UPNA-CSIC-Gobierno de Navarra), del Instituto de Biomedicina de Valencia (CSIC) y del Institute of Infection, Immunity and Inflammation, University of Glasgow.

Bacterias superresistentes

Actualmente, la aparición de bacterias farmacorresistentes, que no responden a tratamientos con antibióticos, constituye uno de los problemas sanitarios a escala mundial priorizados por la Organización Mundial de la Salud (OMS).

Las bacterias detectan, responden y se adaptan a los cambios en su entorno utilizando unos elementos sensoriales denominados sistemas de dos componentes. Este tipo de sistemas sensoriales están presentes en bacterias, hongos y plantas, pero no se encuentran en células animales. En el caso de las bacterias, regulan procesos celulares tan importantes como la virulencia o su propio crecimiento, lo que los convierte en dianas para el diseño de nuevas terapias antimicrobianas.

El objetivo del trabajo ha consistido en eliminar todos los sistemas de dos componentes, es decir el sistema sensorial completo, en Staphylococcus aureus, uno de los principales patógenos humanos según la OMS y, posteriormente, en la generación de una colección de bacterias cada una de las cuales contiene un único sistema de dos-componentes. Esta estrategia ha permitido simplificar una compleja red sensorial en cada uno de sus elementos para comprender cuál es la función individual de cada uno de los sistemas y la relación existente entre ellos. 

Aplicación clínica de la investigación

En relación a la aplicación clínica, Iñigo Lasa apunta al desarrollo de nuevos antibióticos más específicos. “El hecho de que los sistemas de dos componentes estén presentes en todas las bacterias patógenas y no en las células de nuestro organismo nos puede permitir desarrollar fármacos que bloqueen estos sistemas, evitando así el desarrollo de la bacteria durante la infección, sin causar ningún efecto secundario sobre nuestras células”.

En este sentido, las bacterias generadas en este estudio han sido patentadas y actualmente el equipo analiza diversos compuestos marinos que puedan incorporarse en el tratamiento y control de infecciones en la práctica clínica.

La investigación forma parte de la actividad científica del Instituto de Investigación Sanitaria de Navarra (IdiSNA), agrupación público-privada para el fomento de la investigación biomédica en la Comunidad Foral y de la que son miembros Navarrabiomed y la UPNA.

• Información adicional sobre el paper: Behind the paper - Nature Microbiology: "Life without sensing. Can Staphylococcus aureus live without two-component sensorial system?"

High-cholesterol levels, or hypercholesterolemia, affects nearly 1500-2500 people in Navarra, and less than 20 per cent of them are not aware that they suffer from this condition. Hypercholesterolemia is considered to cause 22 per cent of coronary events, most of which could be prevented with early diagnosis and treatment. The biomedical research centre Navarrabiomed has launched NAGENCOL, a project to address this issue using whole-genome sequencing as a diagnostic tool to offer personalised treatment to patients who suffer from hypercholesterolemia. The project is framed within NAGEN, a global strategy aimed at applying genomic medicine in the Navarra Health System-Osasunbidea (SNS-O).

Currently, hypercholesterolemia poses a real challenge to the public health system, because the life expectancy of untreated patients can decrease by 25 years, and 50 per cent of them are more likely to have a heart attack before the age of 55. NAGENCOL addresses this problem, offering a new model that uses genomic information, together with other clinical and demographic data, to bring precision medicine to individual patients.

This ambitious public health project has a budget of 2 million Euro, contributed by the Department of Economic Development at the Directorate-General for Industry, Energy and Innovation of the Government of Navarra, within the framework of the Genomics and Advanced Medicine project (GEMA) and the Intelligent Specialisation Strategy S3.

The NAGENCOL activities are managed by five strategic partners specialising in clinical practice, scientific and technical services, and research. They include the Navarra Hospital Complex (CHN), Nasertic, Tracasa Instrumental SL and Navarrabiomed as the leader of the study. The project is headed by Dr Ander Ernaga and Dr Juan Pablo Martínez from the Endocrinology Service at CHN.

NAGEN Strategy

Since 2016, Navarrabiomed has been leading the Genomic Medicine Strategy (NAGEN) of the Navarra Health System-Osasunbidea. With the support of the Government of Navarra, Navarrabiomed has since coordinated two strategic projects: NAGEN 1000 (best precision medicine project award winner in 2018) and Pharmanagen.

The two initiatives, along with NAGENCOL, are being used to set up, in the SNS-O patient care units, the infrastructure required for using genomic data as a powerful diagnostic tool and to determine the best personalised treatment for each patient.

Navarrabiomed has led the NAGEN: Navarra Genome 1000 project since 2016. The project focuses on whole genome sequencing for a new approach to rare genetic disorders in the Navarra Health System-Osasunbidea (SNS-O). So far, thanks to collaboration with doctors from 18 medical specialties at the Navarra Hospital Complex (CHN), the study includes data about 400 patients and their relatives, precise diagnoses for 25 per cent patients and identification of possible causes for another 25 per cent.

The patients that are part of the study had not been accurately diagnosed, despite having been treated by several specialists and having taken a large number of traditional tests. Angel Alonso, the coordinator of the project, highlighted the project’s relevance to healthcare services: ‘Making genomic analysis available to the public health system is revolutionary. It means a significant change in the clinical approach to patients with rare genetic disorders.’

Impact on the patient and their family

On the occasion of Rare Disease Day on the last day of February, it is worth mentioning that about 6 per cent of the global population are individuals with rare diseases. In Navarra, their number amounts to 38,000. At present, there are 7000 types of rare diseases, most of them of genetic origin.

In many cases, genetic testing enables the patient and their family to get a deeper knowledge of their condition and its progression, to understand how a genetic disease is inherited and to learn about the risks for other family members. The emotional significance of finding answers to the questions posed by the symptoms – which sometimes have remained unanswered for too long – means putting an end to uncertainty and isolation for most patients with rare diseases.

NAGEN 1000: a pioneering project in Spain

NAGEN 1000 is a ground-breaking project at the national level, placing Navarra at the forefront of genomic analysis and technology. The project was introduced last year at the Senate Presentation of Genomic Studies, whose conclusions were approved in 2019, thus green-lighting the development of a national strategy for personalised medicine.

Currently, the project’s methods, procedures and infrastructure are being transferred to daily clinical practice in SNS-O, to the benefit of the people of Navarra.

NAGEN 1000 is financed by the Economic Development Department at the Directorate-General for Industry, Energy and Innovation within the framework of the Intelligent Specialisation Strategy S3. It is being developed by a consortium made of CHN, Nasertic (a company run by the Government of Navarra), Avantia and Navarrabiomed, leader and coordinator of the project, with the support of the Directorate-General for Information Technology, Telecommunications and Public Information (DIGITIP), and the cooperation of the Centro Nacional de Análisis Genómico (CNAG-CRG) and the Clinical Bioinformatics Research Area into Rare Diseases (CIBERER) of Instituto de Salud Carlos III (ISCIII).

• Since 2015 the associations annual investment in research has been increased by 65%

On October 27th, 2019 Breast Cancer Association of Navarre SARAY collected 75,000 euros in the solidarity race celebrated in Pamplona. 49,970 euros will fund two studies developed by Navarrabiomed on metastatic breast cancer.

One of the projects is focused on liquid biopsy in this type of cancer, and it is led by Natalia Ramírez Huerto, the head of the Hematological Oncology Unit of Navarrabiomed. SARAY´s contribution for the second year of the project development raises to 24,970 euros. Other study lead by Cancer Signaling Unit head Imanol Arozarena Martinicorena will receive 22,000 euros. His project aims to develop new adjuvant therapies to treat brain and bone metastases from these tumors. The additional funds will be donated to the Chronos Hope Project from Solti Foundation.

On the 25th of June SARAY decided to allocate the incomes in a face-to-face and online assembly among 725 associates (event delayed three months later due to the COVID-19 crisis). During the last years, the organization shows a strong commitment with biomedical research performed in Navarre. Therefore, it is relevant to highlight that since 2015 SARAY has increased by 65% its annual investment in oncology research.

Imanol Arozarena, senior researcher from the Cancer Signalling Unit at the Navarrabiomed biomedical research centre and a member of Instituto de Investigación Sanitaria de Navarra (IdiSNA), has recently published a melanoma review with University of Manchester Professor Claudia Wellbrock.

The two scientists were asked by the renowned scientific journal Nature Reviews: Cancer to write an article on the latest findings in melanoma cell distinct phenotypes and their relevance for melanoma development and response to therapy.

As many as 4000 new melanoma cases are diagnosed in Spain every year. Malignant melanoma is a serious type of skin cancer that is usually metastatic. It is notorious for its intra- and inter-tumour heterogeneity.

Such variability results from the ability of melanoma cells (melanocytes) to adjust to changing environmental conditions by reprogramming their genetic expression. Thus, melanocytes develop resistance to both targeted therapy and immunotherapy, and their plasticity plays a role in metastasis development.

In their article, the authors reveal the importance of combining recent developments in genomic technologies and the availability of large gene expression datasets for a precise definition of the gene signatures that characterise changes in each patient’s tumours and the prognostic relevance for tumour development and response to therapy.

According to Arozarena, ‘By understanding the molecular mechanisms that adapt melanoma cells to anti-tumour drugs, we will be able to prevent both therapy resistance and the progression of metastatic melanoma.

• www.navarra.es
• Review Article - Phenotype plasticity as enabler of melanoma progression and therapy resistance

• The Carlos III Health Institute finances two projects in Navarre through Spain's COVID-19 Fund and grants the full amount applied for in both cases. 

The Spanish Ministry of Science and Innovation, through the Carlos III Health Institute (ISCIII), has awarded €232,000 to develop two public research projects within the context of the Navarre Health Research Institute (IdiSNA). David Escors Murugarren, a researcher at Navarrabiomed, and Jesús Castilla Catalán, a researcher at the Institute of Public and Occupational Health of Navarre (ISPLN), have received 100% of the amounts they applied for from the COVID-19 Fund, a mechanism approved by Royal Decree-Law 8 of 17 March 2020 on urgent extraordinary measures for dealing with the economic and social impact of COVID-19.

David Escors, the principal investigator at the Navarrabiomed Oncoimmunology Research Unit, began his scientific career working on coronaviruses at the Spanish National Biotechnology Center (CNB-CSIC), along with researcher Luis Enjuanes. He then continued his work at University College London (UCL) by applying lentiviral vectors and gene therapy in immunotherapy. He is a coronavirus specialist and the positive evaluation received from the ISCIII will enable him to obtain the €115,000 he applied for to develop the project “Platforms for developing biosafe SARS-CoV-2 vaccines.”

The aim of the initiative is to develop a platform for engineering biosafe vaccines for the virus that causes COVID-19 disease. The focus will be on the expression of viral proteins that may activate immunity. This line of research was started up specifically for COVID-19, given the current health emergency, but is based on the European ISOLDA Project - Horizon 2020 for generating more effective and safer virus vaccines (yellow fever, influenza and coronavirus) for adults over 65. Navarrabiomed has worked on this project since 2019 in coordination with professionals from the Spanish National Research Council (CSIC) and with Dutch, German and Italian collaborators.

Institute of Public and Occupational Health of Navarre

At the Institute of Public and Occupational Health of Navarre’s Group of Infectious Diseases and Vaccines, Jesús Castilla will lead the study “Infection, Hospitalization, ICU Admissions and Deaths Caused by SARS-CoV-2 in a Population Cohort.” To carry out the study, he will also receive the total amount applied for from the ISCIII: €117,000.

His proposal focuses on estimating the effect of sociodemographic characteristics, chronic diseases and other conditioning health factors on the risk of infection, hospitalization and severe forms of COVID-19. This will involve calculating the incidence of suspected cases, infections confirmed using PCR, hospitalizations, ICU admissions, assisted ventilation and mortality. The mortality rate will also be calculated in confirmed cases and hospitalizations. Antibody seroprevalence will also be evaluated in a sample of patients from the sentinel physician network and/or donors.

This is the second SARS-CoV-2 initiative for Jesús Castilla, given the ISPLN’s participation in the European project I-MOVE-COVID-19, with the involvement of 11 countries and 20 organizations. It is one of the European projects funded through the fast-track call of Horizon 2020, the European Union’s research and innovation program to promote research of different aspects of the SARS-CoV-2 virus.

Both research projects financed by the ISCIII will form part of the scientific activity of the IdiSNA, a public-private partnership for promoting biomedical research in Navarre. Both the ISPLN and Navarrabiomed are partnership members.

El Dr. Hugo Arasanz, oncólogo del Complejo Hospitalario de Navarra e investigador de la Unidad de Inmunomodulación de Navarrabiomed - IdiSNA, recibió ayer en Madrid la Ayuda Clínico Junior de la Asociación Española Contra el Cáncer (AECC). La financiación recibida (120.000 €) se destinará al proyecto "Subpoblaciones linfocitarias como biomarcador predictivo de respuesta a inmunoterapia anti-PD1/PDL1 en carcinoma no-microcítico de pulmón avanzado en 1º línea de tratamiento". Este estudio se desarrollará durante los próximos cuatro años y contará con la dirección del Dr. David Escors. 

El Museo Reina Sofía acogió ayer la entrega de las ayudas anuales de la AECC, dentro de los actos programados en el Día Mundial de la Investigación en Cáncer (WCRD en sus siglas en inglés), que se comemora cada año el 24 de septiembre. En total, la AECC ha entregado casi 21 millones de euros para financiar 171 proyectos que se suman a los 56M€ con los que hoy se están financiando 380 proyectos de investigación en desarrollo.

Asimismo, la asociación ha puesto de manifiesto la necesidad de elaborar un Plan Nacional de Investigación en Cáncer para alcanzar el 70% de supervivencia media a cinco años en el año 2030, en la actualidad se sitúa en un 53%.

Más información sobre el proyecto

La inmunoterapia antiPD1/PDL1 ha supuesto una revolución en el tratamiento del cáncer no-microcítico de pulmón, ya que ha mejorado los resultados de la quimioterapia, asociando además menor toxicidad. Por desgracia la proporción de pacientes que responden al tratamiento es reducida, son menos todavía los que mantienen la enfermedad controlada durante un periodo de tiempo prolongado, y no se dispone de biomarcadores predictivos que permitan identificar a estos pacientes con precisión.

El equipo del Dr. David Escors ha desarrollado un sistema de monitorización de poblaciones linfocitarias por citometría de flujo a partir de sangre periférica en pacientes en progresión a quimioterapia que permite predecir aquellos que van a responder a la inmunoterapia. Dada la reciente aprobación de la inmunoterapia en pacientes en primera línea, este proyecto pretende correlacionar los perfiles linfocitarios de los pacientes y su dinámica con la eficacia del tratamiento en este contexto, incorporando además el estudio de las citosinas proinmunogénicas en plasma y la posible influencia del daño genotóxico en las células inmunitarias producido por las diferentes terapias como causa de menor eficacia en segunda línea.

El proyecto del Dr. Hugo Arasanz se completará con estudios mecanísticos in vitro que permitan conocer los elementos que condicionan la respuesta al tratamiento y plantear combinaciones que puedan revertir la resistencia primaria a estas terapias.