Imatinib adherence associated clinical outcomes of chronic myeloid leukaemia treatment in Taiwan.
BACKGROUND
Since the launch of imatinib, chronic myeloid leukaemia has become a chronic condition requiring costly long-term treatment. Emerging evidence from several short-term studies has raised concerns on the detrimental clinical outcomes and waste of resources associated with poor adherence to imatinib.


OBJECTIVE
This study aims to evaluate the effects of long-term imatinib adherence on clinical treatment responses and mortality.


METHODS
This retrospective cohort study was conducted in a medical centre in southern Taiwan.


METHODS
Chronic myeloid leukaemia patients who were prescribed for more than 1 month of imatinib were identified and their medical charts were reviewed from the first date of imatinib prescription to the last date of medical record or upon patients' death. Patients' basic characteristics, imatinib prescriptions, results of laboratory tests, episodes of imatinib-related side effects and mortality rate were recorded.


METHODS
Participants' basic characteristics, medication possession ratio and their mortality rate; the association between the medication possession ratio and treatment responses.


RESULTS
Of the 119 included patients, the mean follow-up time was 3.9 ± 2.9 patient-years and the mean medication possession ratio was 89.7 %. At the 18th month of imatinib treatment, 67.2, 54.3 and 34.5 % patients achieved complete cytogenetic, major molecular and complete molecular responses, respectively. There was a significant difference in the 4-year survival rate between the adherence (n = 87) and non-adherence (n = 32) groups (91 vs. 72 %; p = 0.0076). Logistic regression analysis revealed that imatinib adherence was the only factor that significantly influenced the 18th month complete cytogenetic response [odds ratio (OR) 11.6; 95 % confidence interval (CI) 1.7, 114.7; p = 0.0131] and major molecular response (OR 5.1; 95 % CI 1.1, 26.8; p = 0.0351). Cox regression analysis demonstrated that a medication possession ratio greater than 90 % significantly reduced the mortality risk (hazard ratio 0.1; 95 % CI 0.01, 0.60; p = 0.0118).


CONCLUSIONS
Chronic myeloid leukaemia patients' long-term adherence to imatinib is significantly associated with the 18th month treatment responses including the cytogenetic response, molecular response and the long-term survival rate in clinical practice.
Graduate Institute of Clinical Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.
Teng-Chou
TC
Chen
Li-Chia
LC
Chen
Yaw-Bin
YB
Huang
Chao-Sung
CS
Chang
D000328:Adult; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001549:Benzamides / Q000009:adverse effects / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D000068877:Imatinib Mesylate; D053208:Kaplan-Meier Estimate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy* / Q000401:mortality / Q000523:psychology; D016015:Logistic Models; D008297:Male; D055118:Medication Adherence / Q000523:psychology; D008875:Middle Aged; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D011743:Pyrimidines / Q000009:adverse effects / Q000627:therapeutic use*; D012189:Retrospective Studies; D013624:Taiwan; D016896:Treatment Outcome; D016903:Drug Monitoring
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate