Clinical characterization of colitis arising from anti-PD-1 based therapy

Area of Science:

• Oncology
• Immunology
• Gastroenterology

Background:

• Immune-related adverse events (irAEs) are common with immune checkpoint inhibitors.
• Colitis is a significant irAE associated with anti-programmed death-1 (PD-1) therapy.
• Clinical characteristics and management of anti-PD-1 associated colitis require further elucidation.

Purpose of the Study:

• To characterize the clinical features, timing, and management of colitis in patients receiving anti-PD-1 therapy.
• To compare colitis incidence and severity between anti-PD-1 monotherapy and combination therapy with ipilimumab.
• To identify factors influencing colitis presentation and treatment in advanced melanoma patients.

Main Methods:

• Retrospective review of 1261 advanced melanoma patients treated with anti-PD-1 based regimens at 8 academic centers.
• Identification of patients with clinically-relevant colitis requiring systemic steroids.
• Comparison of colitis incidence, symptom onset, treatment, and outcomes between monotherapy and combination therapy cohorts.

Main Results:

• Colitis occurred in 109/1261 patients (8.6%).
• Incidence was significantly higher in combination therapy (24.4%) versus monotherapy (3.2%).
• Combination therapy was associated with earlier symptom onset (7.2 vs 25.4 weeks), higher steroid doses, longer steroid tapers, and increased use of infliximab.

Conclusions:

• Anti-PD-1 associated colitis is more frequent and severe with combination therapy.
• Clinical presentation and management of colitis vary significantly, necessitating optimized treatment algorithms.
• While most patients achieve symptom resolution, colitis can have severe complications.