Patient-Reported Outcomes with Chimeric Antigen Receptor-T Cell Therapy: Challenges and Opportunities

Patient-reported outcomes (PROs) are an important tool to assess the impact of a new therapy on symptom burden and health-related quality of life (HRQoL). Chimeric Antigen Receptor-T (CAR-T) cell therapies have been approved for use in relapsed or refractory leukemia and lymphoma based on promising efficacy in clinical trials. However, there is a lack of data on patient-reported toxicity and impact on HRQoL.

This review provides an overview of the incorporation of PROs in CAR-T cell therapy and the specific challenges in this context. The first step is to demonstrate feasibility of PRO monitoring in the acute phase after CAR-T cell infusion. Apart from core PRO domains like physical functioning, disease-related symptoms and symptomatic adverse effects, important measures to consider are cognitive functioning and financial toxicity. Since there are no validated PRO instruments in the setting of CAR-T cell therapy, universally validated measures like PROMIS (Patient-Reported Outcomes Measurement Information System) could be considered, which is also recommended in the setting of hematopoietic stem cell transplantation.

Given the timeline of toxicities with CAR-T cell therapy, PRO instruments should be administered at baseline and at least weekly in the first 30 days. Subsequently, frequent monitoring of PROs in the first year might be helpful in identifying short and intermediate-term toxicities, functional limitations and neuropsychiatric effects. The major potential challenge in acute phase would be missing data when patients develop severe cytokine release syndrome or neurotoxicity.

Designing a strategy for handling missing data is crucial. The long-term safety of CAR-T cell therapy is not well-characterized due to short follow-up in most studies reported thus far. PROs should be measured at least yearly after the 1st year to identify potential late effects like cognitive deficit or auto-immune manifestations. Collaboration between institutions performing cellular therapy and engagement with patients, clinicians and statisticians with expertise in PROs is crucial for setting a comprehensive agenda on integration of PROs with CAR-T cell therapy.