Table 1.
Baseline patient and disease characteristics by baseline tumor size
| Factor | N (%†) | BTS below median, n/N (%) | BTS above median, n/N (%) | P |
|---|---|---|---|---|
| Total | 583 (100) | 292/583 (50) | 291/583 (50) | |
| Traditional factors | ||||
| ECOG PS | ||||
| 0 | 387 (66) | 224/387 (58) | 163/387 (42) | <0.001 |
| 1 | 195 (34) | 68/195 (35) | 127/195 (65) | |
| LDH level | ||||
| Normal | 333 (58) | 226/333 (68) | 107/333 (32) | <0.001 |
| Elevated | 238 (42) | 63/238 (27) | 175/238 (74) | |
| M stage | ||||
| M0, M1a, or M1b | 119 (20) | 96/119 (81) | 23/119 (19) | <0.001 |
| M1c | 464 (80) | 196/464 (42) | 268/464 (58) | |
| Age | ||||
| Below median (≤ 61 years) | 298 (51) | 134/298 (45) | 164/298 (55) | 0.012 |
| Above median (>61 years) | 285 (49) | 158/285 (55) | 127/285 (45) | |
| Sex | ||||
| Male | 365 (63) | 179/365 (49) | 186/365 (51) | 0.514 |
| Female | 218 (37) | 113/218 (52) | 105/218 (48) | |
| Other factors | ||||
| BRAFV600 mutation status | ||||
| Mutant | 133 (23) | 66/133 (50) | 67/133 (50) | 0.976 |
| Wild type | 444 (77) | 221/444 (50) | 223/444 (50) | |
| Prior brain metastases | ||||
| Yes | 50 (9) | 31/50 (62) | 19/50 (38) | 0.076 |
| No | 532 (91) | 260/532 (49) | 272/532 (51) | |
| Prior ipilimumab treatment | ||||
| Naive | 278 (48) | 155/278 (56) | 123/278 (44) | 0.009 |
| Exposed | 305 (52) | 137/305 (45) | 168/305 (55) | |
| Number of prior therapies | ||||
| 0 | 137 (23) | 77/137 (56) | 60/137 (44) | 0.102 |
| ≥ 1 | 446 (77) | 215/446 (48) | 231/446 (52) | |
| Pembrolizumab dose and schedule | ||||
| 10 mg/kg Q2W | 168 (29) | 92/168 (55) | 76/168 (45) | 0.329 |
| 10 mg/kg Q3W | 272 (47) | 133/272 (49) | 139/272 (51) | |
| 2 mg/kg Q3W | 143 (25) | 67/143 (47) | 76/143 (53) | |
| Tumor PD-L1 status | ||||
| Positive | 353 (77) | 175/353 (50) | 178/353 (50) | 0.925 |
| Negative | 106 (23) | 52/106 (49) | 54/106 (51) | |
| Site of metastasis | ||||
| Lung only | 84 (14) | 74/84 (88) | 10/84 (12) | <0.001 |
| Liver, with or without any other sites | 201 (34) | 62/201 (31) | 139/201 (69) | |
| Other | 298 (51) | 156/298 (52) | 142/298 (48) | |
Abbreviations: BTS, baseline tumor size; ECOG PS, Eastern Cooperative Oncology Group performance status; LDH, lactate dehydrogenase; PD-L1, programmed death ligand 1; Q2W, every 2 weeks; Q3W, every 3 weeks.
†
Percentages calculated by using the number of patients with available data for each baseline characteristic as the denominator (may be <583 patients for some characteristics).