Efficacy Of Dasatinib Therapy In Patients With Imatinib-Resistant Or -Intolerant Chronic Myeloid Leukemia From Physician’s and Patient’s Perspective: “Real World” Data

There is limited published data about the efficacy and safety of the second-line therapy with dasatinib in patients in chronic phase chronic myeloid leukemia (CML-CP) in a “real world” patients setting outside clinical trials. In addition, comprehensive evaluation of benefits and risks of the treatment is worthwhile to better define treatment outcomes in this patients’ population. We aimed to study clinical and patient-reported outcomes as well as safety of dasatinib treatment in a “real world” setting within the context of its approved indication through the analysis of prospectively collected data in patients with imatinib resistance or intolerance receiving dasatinib as the second-line therapy.

75 CML-CP patients resistant or -intolerant to imatinib were enrolled in the prospective, multicenter, non-interventional study (mean age 51.3 years old, SD 15.4; range 22–83 years; male/female – 37/38). The median of disease duration was 5.0 years (0.75–17 years). 63 patients had resistance to imatinib; 12 patients were intolerant to imatinib; the median duration of imatinib treatment 40 months (3–121 months). All the patients received dasatinib as the second-line therapy (100 mg daily). Median follow-up was 12 months. For quality of life (QoL) and symptom assessment patients filled out the SF-36 and Comprehensive Symptom Profile in Chronic Myeloid Leukemia Patients (CSP Leuk-CML), respectively, at base-line, in 1, 3, 6 months after treatment start and every 6 months thereafter. Comparison of QoL and symptom scores was conducted using t-test. QoL scores were analyzed using t-test, adjusting for sociodemographic and disease status. Mean symptom severity and percentage of patients with moderate-to-severe (ratings ³ 5) symptoms was evaluated.

After 12 months of treatment 83% patients achieved or maintained complete hematologic response and 35 % – complete cytogenetic response. The twenty four-month progression free survival rate was 93% (95% CI; 84–97%). Four cases of pleural effusion events were registered: they were easily managed in 3 cases; one patient died at 1 month after treatment start due to accompanied infection complication. No severe hematological adverse effects were observed except two cases of grade III-IV neutropenia. Two patients were resistant to dasatinib. Two patients died of disease progression at 6 months of follow-up. At 12 months of dasatinib treatment QoL parameters were stable for 5 out of 8 scales; vitality, social functioning and mental health significantly improved as compared with base-line (p< 0.01). At 24 months of dasatinib treatment improvement of physical functioning, vitality, social functioning and mental health as compared with base-line was registered (p< 0.01); no worsening was observed for other QoL scales. Before treatment 75% of patients experienced at least one moderate-to-severe symptom; more than 40% had more than 7 moderate-to-severe symptoms. The majority of patients (96%) experienced fatigue; half of them suffered from moderate-to-severe fatigue. While treatment the number of patients with moderate-to-severe symptoms decreased. After 12 months of therapy only 25% of patients experienced moderate-to-severe fatigue. Before treatment 36% of patients exhibited critical or severe QoL impairment. Remarkably, in the subgroup of patients (44%) with critical or severe QoL impairment at base-line dramatic QoL improvement was observed: QoL index increased 3.4 fold (p<0.01).

Thus, our study on “real world” patient data confirms that dasatinib as second-line therapy in CML-CP patients is effective both in terms of clinical outcomes and patient-reported outcomes, as well as exhibits good tolerability. Comprehensive evaluation of the outcomes of the second-line treatment of CML-CP allows to assess the benefits and risks of therapy both from physician’s and patient’s perspective.