Table 1. . General patient characteristics.
| Variables | Cohort A (metformin) N = 21 (42%) | Cohort B (no metformin) N = 29 (58%) | |
|---|---|---|---|
| Mean age at diagnosis (years) | 70.1 ± 10.3 | 66.7 ± 10.3 | p = 0.2 |
| Sex – Male – Female |
12 (57.1%) 09 (42.9%) |
16 (55.2%) 13 (44.8%) |
p = 0.8 |
| ECOG performance status – 0 – 1 – 2 – 3 |
4 (19%) 10 (47.6%) 6 (28.6%) 1 (4.8%) |
4 (13.8%) 13 (44.8%) 6 (20.7%) 6 (20.7%) |
p = 0.4 |
| Smoking history | 19 (90.5%) | 29 (100%) | p = 0.09 |
| KRAS mutations | 4/16† (25%) | 10/24† (41.6%) | p = 0.2 |
| PD-L1 status known | 12 (57.1%) | 17 (58.6%) | |
| PD-L1 status (only patients with known status) – <1 % – 1–50% – >50% |
6 (50%) 2 (16.7%) 4 (33.3%) |
7 (41.1%) 3 (17.6%) 7 (41.1%) |
p = 0.8 |
| History of diabetes/hyperglycemia | 21 (100%) | 0 (0%) | p < 0.001‡ |
| Median metformin dose | 500 mg BID (range: 500 mg daily–1000 mg BID) | ||
| Median duration of metformin therapy (months) | 18.8 (1–110.3) | ||
| Median duration of concurrent metformin and ICI (months) | 2.3 (0.4–18.3) | ||
| History of concurrent chemoradiation therapy | 7 (33.3%) | 7 (24.1%) | p = 0.4 |
| ICIs as second- or third-line therapy | 12 (57.1%) | 17 (58.6%) | p = 0.9 |
| Surgery | 2 (9.5%) | 3 (10.3%) | p = 0.5 |
| History of malignancy | 3 (14.3%) | 4 (13.8%) | p = 0.9 |
| ICIs – Anti-PD-1 (pembrolizumab, nivolumab) – Anti-PD-L1 (atezolizumab) |
18 (85.7%) 3 (14.3%) |
24 (82.8%) 5 (17.2%) |
p = 0.7 |
| Mean number of cycles | 6.6 ± 5.9 | 5.8 ± 5 | p = 0.6 |
| ICI+ chemotherapy | 3 (14.2%) | 6 (20.7%) | p = 0.5 |
| Progression | 13 (61.9%) | 19 (65.5%) | p = 0.7 |
| Mean number of metastatic sites involved before starting therapy | 3 ± 0.8 | 2.9 ± 1 | p = 0.7 |
†Of the patients in which KRAS mutation was checked.
‡Signifies statistical significance.
BID: Twice daily; ECOG: Eastern Cooperative Oncology Group; ICI: Immune checkpoint inhibitor; KRAS: v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog.