Immune checkpoint inhibitor resumption after discontinuation due to immune-related adverse events: a nomogram-based analysis of risk factors and outcomes.

Background: Immune checkpoint inhibitors (ICIs) elicit strong antitumour responses but may cause immune-related adverse events (irAEs) requiring treatment interruption. Resuming ICIs after irAEs remains a clinical challenge.

Methods: This single-center retrospective study included 97 patients with solid tumors treated with anti-PD-1 ± anti-CTLA-4 agents between January 2016 and September 2024. All patients developed irAEs that led to treatment interruption and subsequently resumed the same ICI regimen. Predictors of irAE recurrence were evaluated using LASSO regression followed by backward stepwise selection.

Results: The patient cohort had a median age of 60 years. 63.9% had received anti-PD-1 monotherapy and 36.1% had received combination therapy. Common first irAEs included colitis (37.1%) and hepatitis (24.7%), with 40.2% being grade ≥ 3. Upon resumption, 46.4% experienced recurrent irAEs. Overall survival did not differ significantly between patients with and without recurrence (84.3 vs. 74.6 months, p = 0.866). Younger age, high-grade irAE, colitis, elevated monocytes, and need for nonsteroidal immunosuppressants were independently associated with recurrence. A nomogram constructed using these factors demonstrated good discriminative ability (AUC = 0.818).

Conclusion: Resuming ICI therapy after an irAE is generally feasible, although nearly 50% of patients experience recurrent toxicity. The developed nomogram may support risk-based clinical decisions.