Patient demographic, clinical, and treatment characteristics*
| Characteristic | All patients (N=124) | Non-progressors (N=14) | Resistant (N=110) |
| Age | |||
| Mean (SD) | 59.5 (12.4) | 58.2 (12.7) | 59.7 (12.4) |
| Gender (binary) | |||
| Female | 57 (46.0) | 5 (35.7) | 52 (47.3) |
| Male | 67 (54.0) | 9 (64.3) | 58 (52.7) |
| Histology | |||
| Acral | 76 (61.3) | 10 (71.4) | 66 (60.0) |
| Mucosal | 44 (35.5) | 4 (28.6) | 40 (36.4) |
| Unknown primary† | 4 (3.2) | 0 (0.0) | 4 (3.6) |
| BRAF status | |||
| Patients with data | 122 | 14 | 108 |
| V600 | 15 (12.3) | 4 (28.6) | 11 (10.2) |
| WT | 105 (86.1) | 10 (71.4) | 95 (88.0) |
| Other | 2 (1.6) | 0 (0.0) | 2 (1.9) |
| M stage at baseline biopsy‡ | |||
| M0 | 6 (4.8) | 3 (21.4) | 3 (2.7) |
| M1a | 44 (35.5) | 2 (14.3) | 42 (38.2) |
| M1b | 9 (7.3) | 1 (7.1) | 8 (7.3) |
| M1c | 65 (52.4) | 8 (57.1) | 57 (51.8) |
| ECOG performance status | |||
| 1 | 123 (99.2) | 14 (100) | 109 (99.1) |
| 2 | 1 (0.8) | 0 (0.0) | 1 (0.9) |
| Rounds of previous systemic therapies | |||
| 0 | 108 (87.1) | 14 (100) | 94 (85.5) |
| 1 | 15 (12.1) | 0 (0.0) | 15 (13.6) |
| 2 | 1 (0.8) | 0 (0.0) | 1 (0.9) |
| Type of anti-PD-1 treatment | |||
| Nivolumab | 20 (16.1) | 4 (28.6) | 16 (14.5) |
| Pembrolizumab | 104 (83.9) | 10 (71.4) | 94 (85.5) |
| Number of cycles received | |||
| Median (range) | 10 (2–67) | 33 (14–67) | 8 (2–64) |
| Duration of anti-PD-1 treatment (months) | |||
| Median (range) | 6.3 (1.3–45.0) | 23.2 (9.4–38.4)‡ | 5.4 (1.3–45.0) |
*All values given as N (%) unless otherwise stated.
†Only those unknown primary tumors with the clinical appearance of mucosal melanoma were included in the study.
‡M0, no distant metastases; M1a, non-visceral metastases to skin, soft tissue including muscles, and/or non-regional lymph nodes; M1b, distant metastases to the lung; M1c, all other visceral metastases and any distant metastases with elevated lactase dehydrogenase levels.
§Nine non-progressors were still on anti-PD-1 therapy at the time of data cut-off and were not included.
BRAF, B-raf proto-oncogene serine/threonine kinase; ECOG, Eastern Cooperative Oncology Group; PD-1, programmed cell death-1; WT, wild type.