OBJECTIVES: To establish meaningful change thresholds at patient and group levels for the newly developed European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire 17-item chronic lymphocytic leukemia (CLL)–specific module (EORTC QLQ-CLL17) in patients with relapsed/refractory CLL or small lymphocytic lymphoma.

METHODS: EORTC QLQ-CLL17 data and selected anchor measures collected from the TRANSCEND CLL 004 study (NCT03331198) of the CD19-directed chimeric antigen receptor T cell therapy lisocabtagene maraleucel (liso-cel) were assessed at baseline (prelymphodepletion); pre-infusion on the day of liso-cel administration; and 1, 2, 3, 6, 9, 12, 15, 18, and 24 months after liso-cel administration. Postbaseline visits were pooled to support the analyses. Change thresholds for each of the EORTC QLQ-CLL17 domains were triangulated based on estimates derived from anchor- and distribution-based analyses, in accordance with published guidance. Included anchors were EORTC QLQ-C30 items (9 [pain], 12 [weakness], 22 [worry], and 29 [overall health]) with adequate longitudinal correlations with EORTC QLQ-CLL17 domain scores (Spearman correlation coefficient >0.3).

RESULTS: Analysis included 62 patients with 240 observations across visits. Estimated meaningful within-patient change thresholds for improvement (deterioration) were −11 points (11 points) for symptom burden score and −16 points (16 points) for physical condition/fatigue, worries/fears on health, and functioning scores. Estimated meaningful group-level change thresholds for improvement (deterioration) ranged from −9 to −5 points (5‒9 points) for symptom burden score, −11 to −6 points (6‒12 points) for physical condition/fatigue score, and −10 to −5 points (5‒9 points) for worries/fears on health and functioning scores.

CONCLUSIONS: To our knowledge, this is the first study to propose change thresholds for interpreting improvement and deterioration in EORTC QLQ-CLL17 domain scores at patient and group levels. These findings provide a foundation to better interpret treatment impact on health-related quality of life in future studies.