CP-050 Adherence to protein tyrosine kinase inhibitors treatment in Chronic Myeloid Leukaemia and Gastrointestinal Stromal Tumours

Abstract

Background Tyrosine Kinase Inhibitors (TKI) are the standard treatment for Philadelphia chromosome positive chronic myeloid leukaemia (Ph + CML). Imatinib is also indicated for Kit- (CD117) positive metastatic malignant gastrointestinal stromal tumours. The high rates of survival obtained in recent years have turned these diseases into chronic conditions. Thus, adherence to treatment is hugely important. Many studies have shown that low adherence to treatment with imatinib (<85–90%) is related to a loss of cytogenetic response in Ph + CML. There is less evidence about adherence to the second line drugs dasatinib and nilotinib. Purpose To determine the degree of adherence to treatment with all TKI. Materials and methods One year prospective/retrospective study. All patients on treatment with TKI for at least a month coming to the Pharmacy to collect the medicine were included. The study was approved by a research ethics committee and all patients were required to give written informed consent. Adherence was assessed through two indirect methods: Structured interview: adherence was evaluated in a standardised way using the Morisky Medication Adherence Scale. Dispensing records: Patients taking less than 90% of the prescribed dose were considered non-adherent. Results Nineteen patients were prescribed these drugs and 15 agreed to enter the study (8 imatinib, 6 dasatinib and 1 nilotinib). Mean duration of treatment was 1,191 days. Mean Morisky score was 11.86 and only three patients were classified as non-adherent. According to the dispensing records, adherence was 96.82 (85.08–100%) and only one patient was non-adherent (85.08%). Only one patient showed non adherence with both methods. Conclusions Patients showed a high level of adherence similar to what has been reported with imatinib. High adherence was also seen with new TKI. This study allowed us to identify patients with suboptimal adherence and attempt to educate them. No conflict of interest.