Development and validation of a patient‐reported outcome measure to assess symptom burden after chimeric antigen receptor T‐cell therapy

Summary This cross‐sectional study aimed to develop and validate a patient‐reported outcomes (PROs) assessment tool to assess symptom burden and daily functioning in patients after chimeric antigen receptor (CAR) T‐cell therapy, the MD Anderson Symptom Inventory (MDASI‐CAR). The items were generated based on literature review, content elicitation interviews with patients, and clinician's review. The patients completed the MDASI core and module, single‐item quality‐of‐life (QoL) measure and Patient‐Reported Outcomes Measurement Information System‐29 (PROMIS‐29). The psychometric validation analysis was based on the acceptability after item reduction process. The final 10 MDASI‐CAR module items included tremors, fever/chills, headache, balance, dizziness, attention, difficulty speaking, coughing, sexual dysfunction, and diarrhoea with high internal consistency (Cronbach's alpha: MDASI Core, 0.865; MDASI Interference, 0.915; CAR‐T module, 0.746). The MDASI‐CAR has excellent known‐group validity that was demonstrated by differentiate patients based on patient's performance status (Cohen's d for MDASI core = −1.008, interference = −0.771, module = −0.835). Criterion validity was demonstrated by the significant correlations between the MDASI‐CAR composite score, the single QoL item and the relevant domains on PROMIS‐29 (all p