Objective:

To evaluate the incidence, type, and timing of cutaneous adverse events (AEs) following CAR T-cell therapy in patients with relapsed or refractory hematologic malignancies, highlighting their clinical significance.

Key Findings:

• Cumulative incidence of cutaneous AEs was 11% by 36 months post-CAR-T, indicating a notable occurrence.
• Most common cutaneous AEs included maculopapular rash (39%) and pruritic macular rash (22%), which are significant for clinical monitoring.
• 57% of cutaneous AEs were early-onset, with 22% intermediate-onset and 22% late-onset, suggesting varying mechanisms.
• All cutaneous AEs were grade 1 (70%) or grade 2 (30%), indicating a generally low severity.
• An increasing number of prior lines of therapy was associated with a lower risk of cutaneous AEs, suggesting a potential area for further investigation.

Interpretation:

Cutaneous AEs following CAR-T therapy are not uncommon and primarily low-grade, with a notable occurrence of late-onset AEs suggesting chronic immune activation, which may have clinical implications for patient management.

Limitations:

• Small sample size for multiple myeloma patients (n = 18) may limit generalizability and warrant caution in interpretation.
• Retrospective design may introduce bias in data collection and interpretation, and potential confounding factors should be considered.

Conclusion:

Cutaneous AEs occur in approximately 1 in 10 patients following CAR-T therapy, predominantly early and low-grade, but with potential for late occurrences. Further studies are needed to explore the mechanisms behind these findings and their clinical implications.