OBJECTIVES: MySIm-Q is a validated disease-specific PRO instrument that measures symptoms and impacts experienced by patients with active MM. We describe psychometric properties of the MySIm-Q Symptom score using data from the CARTITUDE-2 study.

METHODS: CARTITUDE-2 is evaluating ciltacabtagene autoleucel (cilta-cel) in patients with MM in different disease settings. Pooled data from cohorts A (lenalidomide-refractory MM and 1–3 prior treatments), B (early relapse after initial treatment), and C (relapsed/refractory MM and prior proteasome inhibitor, immunomodulatory drug, anti-CD38 monoclonal antibody, and noncellular BCMA-directed treatment) were examined. MySIm-Q, EORTC QLQ-C30, PGIS, and PGIC assessments were administered at screening, enrollment/apheresis, 1 week, and every 3–4 weeks post cilta-cel. As per recommended FDA clinical trial evaluation framework for PRO measurement properties, internal consistency, test-retest reliability, concurrent validity, known-groups validity, and meaningful within-patient change (MWPC) in MySIm-Q Symptom score analyses were conducted.

RESULTS: 82 patients completed MySIm-Q assessments (cohorts A/B/C, n=43/19/20). The internal consistency estimate for the MySIm-Q symptom score was acceptable (Cronbach’s α-coefficient, 0.89), with results exceeding the predefined threshold (≥0.70). Adequate test-retest reliability was supported (2-way random intraclass correlation coefficient [ICC(2,1)]), 0.81), based on achieving the minimally acceptable ICC(2,1) of 0.70. MySIm-Q Symptom score demonstrated acceptable concurrent validity with existing symptom and impact measures from the EORTC QLQ-C30, with a high proportion of correlations exceeding │0.60│. Known-groups validity for MySIm-Q Symptom score was secured, reflected by discrimination across disease severity groups based on PGIS and EORTC QLQ-C30 GHS/QoL domain items. The PGIC anchor-based MWPC deterioration threshold and the average distribution-based clinical significance threshold triangulated well.

CONCLUSIONS: This preliminary analysis provides evidence that the MySIm-Q yields reliable and valid scores and detects changes in MM symptoms, supporting use as a fit-for-purpose PRO instrument in MM trials. Analysis of psychometric properties using data from the phase 3 CARTITUDE-4 study are forthcoming.