Baseline characteristics
| Overall | Microscopic colitis | Non-microscopic colitis | p-value | |
|---|---|---|---|---|
| Number of patients | 38 | 13 | 25 | 1.000 |
| Age in years | ||||
| Mean +/− SD | 62.3 +/− 8.9 | 62.4 +/− 8.6 | 62.2 +/− 9.2 | 0.952 |
| Median | 62.5 | 62.0 | 64.0 | |
| Sex (M:F) | 17:21 | 7:6 | 14:11 | 0.899 |
| CPI regimen | ||||
| α-CTLA-4 | 3/38 (7.9%) | 1/13 (7.7%) | 2/25 (8.0%) | 0.281 |
| α-PD-(L)1 | 27/38 (71.1%) | 11/13 (84.6%) | 16/25 (64.0%) | |
| Combination CPI | 8/38 (21.1%) | 1/13 (7.7%) | 7/25 (28.0%) | |
| Tumor type | ||||
| Melanoma | 21/38 (55.3%) | 6/13 (46.2%) | 15/25 (60.0%) | 0.415 |
| NSCLC | 7/38 (18.4%) | 3/13 (23.1%) | 4/25 (16.0%) | 0.672 |
| Other | 10/38 (26.3%) | 4/13 (30.8%) | 6/25 (24.0%) | 0.709 |
| Prior irAE | 14/38 (36.8%) | 5/13 (38.5%) | 11/25 (44.0%) | 0.743 |
| Prior medications | ||||
| Antibiotics within 3 months | 9/38 (23.7%) | 2/13 (15.4%) | 7/25 (28.0%) | 0.456 |
| PPI | 14/38 (36.8%) | 7/13 (53.9%) | 7/25 (28.0%) | 0.163 |
| SSRI/SNRI | 10/38 (26.3%) | 4/13 (30.8%) | 6/25 (24.0%) | 0.709 |
| Estrogen | 3/35 (7.9%) | 2/13 (15.4%) | 1/25 (4.0%) | 0.265 |
| Time from first CPI infusion to symptom onset (days) | ||||
| Mean +/− SD | 139.5 +/− 153.9 | 225.0 +/− 214.9 | 95.1 +/− 86.1 | 0.011* |
| Median | 72.5 | 150.0 | 68.0 | |
| CTCAE symptom grade: median (IQR) | 2 (1–3) | 2 (1–3) | 2 (1–3) | 1.000 |
The p-value was calculated by ANOVA for numerical covariates and chi-square test or Fisher’s exact for categorical covariates, where appropriate. Combination CPI: all patients received a PD-(L)1 inhibitor in combination with ipilimumab either as standard of care or on an investigational protocol. SD: standard deviation. CPI: immune checkpoint inhibitor. PD-(L)1: programmed cell death receptor (ligand)-1. NSCLC: non-small cell lung cancer. Other tumor types: breast cancer (n = 1); colorectal cancer (n = 1); cutaneous squamous cell cancer (n = 1); squamous cell cancer of the head and neck (n = 1); diffuse large B-cell lymphoma (n = 2); multiple myeloma (n = 1); ovarian adenocarcinoma (n = 2); renal cell cancer (n = 1). PPI: proton-pump inhibitor. SSRI/SNRI: selective serotonin reuptake inhibitor/serotonin and norepinephrine reuptake inhibitor. Prior medications were within one year of symptoms unless otherwise specified. CTCAE: Common Terminology Criteria for Adverse Events. IQR: interquartile range. *statistically significant at significance of 0.05
All of the boldfaced numbers should be statistically signficant