Feasibility of and patients’ perspective on nilotinib dried blood spot self-sampling

PURPOSE To obtain insight into the feasibility of, and the patients' perspective on, dried blood spot (DBS) self-sampling by patients with chronic myeloid leukemia (CML) using nilotinib. METHODS Sixty-eight patients with CML using nilotinib participated in this multicenter observational study. Patients were asked to perform blood sampling by means of the DBS method at home just before drug intake (trough level) and to complete a questionnaire including demographics and five questions on their experience with DBS self-sampling. RESULTS Sixty-one patients (57.5 ± 15.0 years, 49% female) provided 178 DBS samples of which 137 (77%) proved useful in clinical practice. Twenty percent of the samples were rejected because the spot size was too small for analysis. A further 3% were taken at the wrong time. Unsuitable DBS samples were provided by 23 patients. Their educational level was significantly lower than that of patients whose samples were all suitable (p = 0.041). Patients considered DBS self-sampling easy and not painful, and three quarters of the patients performed DBS sampling without additional assistance. Patients' belief in the reliability of DBS self-sampling was moderate to high. It was preferred over venous sampling by 37% of the patients, whereas 39% had no preference. CONCLUSION DBS self-sampling by CML patients is feasible in clinical practice provided that patients, particularly those with a lower educational level, are adequately instructed about sample collection with emphasis on timing and volume of sample collection.