Assessment of Quality of Life in the NCRI Spirit 2 Study Comparing Imatinib with Dasatinib in Patients with Newly-Diagnosed Chronic Phase Chronic Myeloid Leukaemia

Background: Imatinib and dasatinib are established drugs in the first-line treatment of chronic myeloid leukemia (CML). Several studies, including SPIRIT2 have shown that first-line dasatinib (100mg once daily) has a superior complete cytogenetic and major molecular response rate compared to imatinib (400mg once daily), but no significant differences in progression-free or overall survival have been shown in any study. To date, there has been no direct comparison of quality of life (QoL) using generic and cancer-specific instruments for first-line treatment of chronic-phase CML with imatinib and dasatinib. SPIRIT2 (STI571 Prospective International Randomised Trial 2) is the first randomized clinical trial to incorporates generic and cancer-specific QoL measurement for first-line therapy.

Methods: Quality of life is a secondary endpoint in the SPIRIT2 trial and has been assessed at baseline, and at 1, 2, 3, 6 and 12 months post trial entry and thereafter annually. The EQ-5D, FACT-G, FACT-BRM and the FACT-TOI have been used as QoL measures in this trial. The FACT-G covers cancer-specific QoL measure dimensions such as physical well-being, functional well-being, social and family well-being, emotional well-being and the FACT-BRM and the FACT-TOI different subsets of them. The QoL scores (EQ-5D, FACT-G, FACT-BRM, FACT-TOI) were calculated at different time points and comparison of the mean scores for both treatment groups was made.

Results: A comparison between imatinib and dasatinib shows no significant difference in QoL in generic instruments and also in cancer-specific instruments. EQ-5D was 0.77 and 0.79 at baseline and 0.80 and 0.82 at one year for dasatinib and imatinib, respectively (2-3 basis points increase over 1 year). Similar results were obtained for the FACT-G, FACT-BRM and the FACT-TOI. There was a slight increase for the FACT-G (4-5 basis points), FACT-TOI (3-4 basis points) and FACT-BRM (8-10 basis points) after 1 year for both treatments, but this difference was not significant. The effects on the well-being and the emotional dimensions have been analysed for both drugs and there was no change over time, demonstrating results similar to the imatinib arm of the IRIS trial.

Conclusions: Standard dose imatinib and dasatinib are both used as first-line treatments for CML and, despite different side effect profiles, there is no significant difference in QoL using the instruments described here between these two drugs over time. These data will allow the derivation of utility values to contribute to future health economic/technology appraisals. Additional analyses of how generic and cancer-specific measures of different QoL instruments change in CML patients over time in those patients that develop side effects, e.g. fluid retention with imatinib or pleural effusion with dasatinib will be presented.