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Browsing by Subject "tyrosine kinase inhibitor"

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  • Ylinen, Varpu (2016)
    Chronic myeloid leukemia (CML) is a malignant hematologic disorder, which is fatal without a treatment. Oral tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of CML and transformed the disease to a chronic condition that can be treated at patient's home. The common problem in the treatment of CML is patient's poor adherence to TKIs. The regular, consistent use of TKIs is crucial to keep disease under control. For this reason and to obtain an optimal treatment outcome, adherence to TKIs is extremely important. The aim of the study was to assess reasons for poor adherence to TKI-medications in Finnish CMLpatients, including patient characteristics, treatment related factors, comorbidities and concomitant medications. In addition, patients' experiences, beliefs, knowledge and perception about CML and its treatment were explored and how these could contribute to nonadherent behaviour. This study is part of the larger study, assessing adherence to TKI treatment among Finnish CML population. The data was obtained by using patient questionnaires and semi-structured theme-interview during patient meetings in 2012. Study population consisted of Finnish adult CML patients who had been on TKI -medication (imatinib, nilotinib or dasatinib) for more than six months prior to the study baseline. Patients' adherence was measured using Morisky Medication Adherence 8-Item Scale (MMAS-8) and based on their score, patients were divided into three groups: high, medium and low adherence. Both quantitative and qualitative methods were used in data analysis. Study findings show that 21% (n=18) of the patients were low adherent and 23% (n=20) were high adherent to their treatment. Patient sociodemographic characteristics or experienced adverse drug reactions (ADRs) did not predict adherence, while more concomitant medications and comorbidities were associated with high adherence. However, ADRs had negative effect on the quality of life of several nonadherent patients. All nonadherent patients reported unintentional nonadherence and the most common reason was forgetting. Two-thirds of the patients (n=12) reported intentional nonadherence, which often was a result of experienced ADRs. The knowledge of CML and its treatment was poor among all patients while over half of the nonadherent patients (n=11) thought that they received enough information received. Overall, patients were very satisfied with care provided by the hospitals, physicians and other healthcare professionals. Managing TKI-treatment regimen is challenging for many patients and ADRs can have a negative impact on the quality of life. Healthcare professionals should regularly assess patient adherence and provide information and support for the patients to help them to succeed in medication management. Reasons for poor adherence are complex and have to be identified from each individual patient so that adherence can be improved.
  • Björkstén, Sofie (2011)
    Angiogenesis, the formation of new blood vessels from preexisting vascular network, is an essential process during tumor development. Growing tumors secrete different growth factors that induce angiogenesis, of which vascular endothelial growth factor (VEGF) is predominant. Angiogenesis inhibitors act either by blocking the extracellular bindning of growth factor to its receptor by monoclonal antibodies or by blocking the intracellular signalling pathway by small-molecule agents. The small-molecule agent sunitinib is a multitargeted tyrosine kinase inhibitor that has antiangiogenic and antitumor activities due to the selective inhibition of several tyrosine kinase receptors. Sunitinib is approved for treatment of gastrointestinal stromal tumors, renal cell carcinoma and pancreatic neuroendocrine tumors. Known side effects are hypertension, cardiotoxicity and renal damage. These toxic effects are due to sunitinibs "off-target" toxicity, which occurs when a tyrosine kinase inhibitor causes adverse effects via inhibiton of a kinase not intended to be a target of the drug. For example inhibition by sunitinib of AMPK, a kinase that plays key roles in maintaining metabolic homeostasis in the heart, accounts in part for the toxicity seen in cardiomyocytes exposed to sunitinib. By achieving a better understandning of what causes the side effects it could be possible to develop treatments that reduce off-target effects. Caloric restriction is one nonpharmacological approach that has been shown to have beneficial effects on the heart partly by activating sirtuins. Sirtuins regulate a diverse array of cellular functions, including metabolism, gene transcription, cell division and cellular stress response. The aim for this study was to investigate whether caloric restriction improves sunitinib-induced cardiovascular toxicity and renal damage in rats, and to study activated cellular pathways. In this study 40 spontaneously hypertensive rats (SHR) and 10 normotensive Wistar-Kyoto (WKY) rats were used. They were divided into groups depending on treatment; I WKY control, II SHR control, III SHR + caloric restriction 70 %, IV SHR + sunitinib 3 mg/kg and V SHR sunitinib 3 mg/kg + caloric restriction 70 %. The follow-up period was eigth weeks. Blood pressure was messured weekly, metabolic cages were used week 4 and week 8 for urine samples, echocardiography was performed the last week and vascular response was studied at the end. The proteins Sirt1 and AMPK in heart were investigated by Western blot and the amount of the marker of macrofage ED1 in kidney by immunohistochemistry. Based on this study it was observed that the dose 3 mg/kg sunitinib was well tolerated in rats because it did not cause more extensive hypertension, worse hypertrophy or renal damage compared to untreated SHR groups. This study also showed that short-term caloric restriction has beneficial cardiovascular effects.