Table 1. Patient Characteristics in the KEYNOTE-189 RCT Population and Emulation Inverse Probability Weighted, Post-Imputation EHR-Based Study Population.
| Characteristic | Patients, No. (%) | |||
|---|---|---|---|---|
| RCT | EHRa | |||
| Pembrolizumab + chemotherapy (n = 410) | Placebo + chemotherapy (n = 206) | Pembrolizumab + chemotherapy (n = 571)b | Chemotherapy only (n = 1274)b | |
| Age <65 y | 197 (48.0) | 115 (55.8) | 266 (46.7) | 672 (52.7) |
| Sex | ||||
| Female | 156 (38.0) | 97 (47.1) | 296 (51.2) | 618 (48.5) |
| Male | 254 (62.0) | 109 (52.9) | 275 (48.3) | 656 (51.5) |
| Region | ||||
| Europe | 243 (59.3) | 131 (63.6) | 0 | 0 |
| North America | 111 (27.1) | 46 (22.3) | 571 (100) | 1274 (100) |
| East Asia | 4 (1.0) | 6 (2.9) | 0 | 0 |
| Other region | 52 (12.7) | 23 (11.2) | 0 | 0 |
| Performance status | ||||
| 0 | 186 (45.4) | 80 (38.8) | 170 (29.8) | 342 (26.8) |
| 1 | 221 (53.9) | 125 (60.7) | 207 (36.3) | 466 (36.6) |
| 2 | 1 (0.2) | 0 (0.0) | 112 (19.5) | 270 (21.2) |
| 3 | 0 (0.0) | 0 (0.0) | 82 (14.4) | 196 (15.4) |
| Smoking status | ||||
| Current or former | 362 (88.3) | 181 (87.9) | 177 (31.0) | 433 (34.0) |
| Never or unknown | 48 (11.7) | 25 (12.1) | 394 (69.0) | 841 (66.0) |
| Histologic features | ||||
| Adenocarcinoma | 394 (96.1) | 198 (96.1) | 511 (89.5) | 1140 (89.5) |
| Other | 16 (3.9) | 8 (3.9) | 60 (10.5) | 134 (10.5) |
| Brain metastases | 73 (17.8) | 35 (17.0) | 15 (2.6) | 59 (4.6) |
| PD-L1 tumor proportion score, % | ||||
| <1 | 127 (31.0) | 63 (30.6) | 187 (32.7) | 409 (32.1) |
| ≥1 | 260 (63.4) | 128 (62.1) | 383 (67.1) | 865 (67.9) |
| 1-49 | 128 (31.2) | 58 (28.2) | 239 (41.9) | 533 (41.8) |
| ≥50 | 132 (32.2) | 70 (34.0) | 144 (25.3) | 332 (26.1) |
| Unavailable or missing | 23 (5.6) | 15 (7.3) | NA | NA |
| Previous therapy for nonmetastatic disease | ||||
| Thoracic radiotherapy | 28 (6.8) | 20 (9.7) | 163 (28.6) | 380 (29.8) |
| Neoadjuvant or adjuvant therapy | 30 (7.3) | 20 (9.7) | 2 (0.3) | 8 (0.7) |
| None | 352 (85.9) | 166 (80.6) | 406 (71.1) | 886 (69.5) |
| Racec | ||||
| African American or Black | NR | NR | 115 (20.2) | 249 (19.5) |
| White | NR | NR | 447 (78.4) | 998 (78.3) |
| Other | NR | NR | 8 (1.4) | 27 (2.2) |
Abbreviations: EHR, electronic health record; NA, not applicable; NR, not reported; PD-L1, programmed death ligand 1; RCT, randomized clinical trial.
a
Age, race, marital status, body mass index, performance status, PD-L1 tumor proportion score, and creatinine clearance were imputed. Results of imputation are shown; results were similar across other 9 imputed datasets.
b
Sample sizes shown are the sum of the inverse probability of treatment weights.
c
Race was not reported in KEYNOTE-189 but considered as a potential confounder for the emulation study and reported for transparency. In this study, other race included American Indian or Alaska Native, Asian, Native Hawaiian or Other Pacific Islander, and unknown.