Table 1.

Clinical characteristics of the initial and validation cohorts

Initial cohort (n = 32)Validation cohort (n = 33)
VariableNumber (%)Number (%)P
Age (median, range)55 (33–80)62 (32–85)0.65
Sex
 Male21 (66)17 (52)0.25
 Female11 (34)16 (48)
Metastatic stage
 IV M1a3 (9)2 (6)0.79
 IV M1b5 (16)4 (12)
 IV M1c24 (75)27 (82)
Primary tumor site
 Cutaneous18 (56)26 (79)0.13
 Non-cutaneous10 (31)4 (12)
 Unknown4 (13)3 (9)
Treatment
 Nivolumab154<0.001
 Pembrolizumab1429
 Atezolizumab30
Prior therapy
 Lines of prior therapy (median, range)1 (0-4)1 (0-6)0.23
 Prior BRAF inhibitor3 (9)8 (24)0.11
 Prior ipilimumab14 (44)23 (70)0.03
 Prior chemotherapy5 (16)5 (15)0.96