Characteristics of immune checkpoint inhibitor (ICI)-exposed myositis cases
| Characteristics | ICI-exposed myositis cases (n=345) |
| Age (years), median (P25–P75) (n=265) | 71 (63–76) |
| Sex, n (%) | |
| Male | 228 (69.7) |
| Female | 99 (30.3) |
| Unknown | 18 |
| Reporter type, n (%) | |
| Health professional | 293 (86.2) |
| Other | 47 (13.8) |
| Unknown | 5 |
| Reporting year, n (%) | |
| 2019 | 4 (1.2) |
| 2018 | 184 (53.3) |
| 2017 | 90 (26.1) |
| 2016 | 47 (13.6) |
| 2008–2015 | 20 (5.8) |
| Cancer type, n (%) | |
| Lung cancer | 111 (34.8) |
| Skin cancer | 109 (34.2) |
| Melanoma | 102 (32.0) |
| Other cancers | 32 (31%) |
| Exposure to ICIs | |
| Monotherapy, n (%) | 294 (85.2) |
| Anti-PD-1 | 252 (73.0) |
| Nivolumab | 154 (44.6) |
| Pembrolizumab | 97 (28.1) |
| Nivolumab or pembrolizumab | 1 (0.3) |
| Anti-PD-L1 | 15 (4.3) |
| Atezolizumab | 7 (2.0) |
| Avelumab | 3 (0.9) |
| Durvalumab | 5 (1.4) |
| Anti-CTLA-4 | 27 (7.8) |
| Ipilimumab | 27 (7.8) |
| Tremelimumab | 0 (0.0) |
| Combination therapy | 51 (14.8) |
| Nivolumab/ipilimumab | 49 (14.2) |
| Pembrolizumab/ipilimumab | 1 (0.3) |
| Durvalumab/tremelimumab | 1 (0.3) |
| Time to onset (days) (n=97) | |
| Median (P25–P75) | 33 (19–57) |
| Min–Max | 1–606 |
| Reported myositis term | |
| Myositis | 276 (80.0) |
| Dermatomyositis | 25 (7.2) |
| Polymyositis | 20 (5.8) |
| Immune-mediated necrotising myopathy | 13 (3.8) |
| Orbital myositis | 8 (2.3) |
| Inclusion body myositis | 2 (0.6) |
| Antisynthetase syndrome | 1 (0.3) |
| Specific co-reported irAEs | |
| Myocarditis | 39 (11.3%) |
| Myasthenia | 41 (11.9%) |
| Death, n (%) | 77 (22.3) |
Anti-CTLA-4, Anti-Cytotoxic-T-Lymphocyte-Associated Protein (CTLA)-4; Anti-PD-1, Anti-Programmed-Death-1; anti-PD-L1, anti-Programmed-Death-Ligand-1; ICI, immune checkpoint inhibitor; irAEs, immune-related-adverse events.