Extracorporeal photopheresis vs. systemic immunosuppression for immune-related adverse events: Interim analysis of a prospective two-arm study.

BACKGROUND

Checkpoint inhibitor-induced steroid-refractory (sr) and steroid-dependent (sd) immune-related adverse events (irAE) account for about 11 % of irAE. Although these patients face worse outcomes due to irAE mortality and/or sustained immunosuppression, which impairs anti-tumor response, there is no established second-line treatment based on prospective trial data.

METHODS

This prospective comparative study investigates outcomes of extracorporeal photopheresis (ECP), an immunomodulating therapy, versus second-line immunosuppressants (SLI) in sr/sd-irAE. The primary endpoint was longitudinal change in immunophenotype; secondary endpoints were outcome of irAE and tumor response. Patient demographics, quality of life (EORTC QLQ-C30; global health status (GHS/QoL)) and longitudinal blood samples were analyzed at baseline; in weeks 1, 4, 8, and 12.

RESULTS

At interim analysis, 21 patients (11 ECP, 10 SLI) with 7 different sr/sd-irAE were included. Compared with the SLI group, the ECP group demonstrated a higher clinical response rate of irAE (93 % vs. 80 %; 95 % CI 0.83-1.92; P = 0.54) and a better GHS/QoL score throughout all follow-up visits. ECP patients showed a numerically higher overall survival (23 vs. 12 months; 95 % CI 0.02-3.02; P = 0.27) and lower cancer progression rates (33 % vs. 67 %; 95 % CI 0.09-1.60; P = 0.52). Immunophenotyping revealed changes in immune cell populations and the regulation of immune checkpoints. There were no significant safety issues in either treatment group.

CONCLUSION

This prospective comparative study supports the clinical efficacy of ECP in the treatment of sr/sd-irAE in comparison to the SLI cohort. Thus, ECP represents a potential treatment option for this indication, given its good safety profile while maintaining anti-tumor response.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT05700565, https://classic.

CLINICALTRIALS: gov/ct2/show/NCT05700565.