Patient characteristics
| Variables | Total cohort, n (%) | Early CRP kinetics | P value | |||
| CRP flare-responder, n (%) | CRP responder, n (%) | Non-CRP responder, n (%) | ||||
| No. of patients | 42 | 11 (26) | 15 (36) | 16 (38) | ||
| Age (years) | Median (IQR) | 67 (60–73) | 71 (59–74) | 63 (56–68) | 69 (66–73) | 0.192 |
| Sex | Male | 34 (81) | 9 (82) | 12 (80) | 13 (81) | 0.993 |
| Female | 8 (19) | 2 (18) | 3 (20) | 3 (19) | ||
| ECOG PS | 0 | 19 (45) | 6 (55) | 7 (47) | 6 (37) | 0.306 |
| 1 | 12 (29) | 4 (36) | 5 (33) | 3 (19) | ||
| ≥2 | 11 (26) | 1 (9) | 3 (20) | 7 (44) | ||
| IMDC risk | Favorable | 9 (21) | 4 (36) | 2 (12) | 3 (19) | 0.497 |
| Intermediate | 23 (55) | 6 (55) | 8 (53) | 9 (56) | ||
| Poor | 10 (24) | 1 (9) | 5 (33) | 4 (25) | ||
| Histology | Clear cell | 38 (90) | 10 (90) | 14 (93) | 14 (87) | 0.856 |
| Non-clear cell | 4 (10) | 1 (10) | 1 (7) | 2 (13) | ||
| Sites of metastases | Lung | 33 (79) | 10 (91) | 12 (80) | 11 (69) | 0.358 |
| Liver | 7 (17) | 2 (18) | 3 (20) | 2 (13) | 0.841 | |
| Bone | 16 (38) | 3 (27) | 6 (40) | 7 (44) | 0.667 | |
| Brain | 4 (10) | 0 (0) | 2 (13) | 2 (13) | 0.275 | |
| Lymph node | 19 (45) | 5 (45) | 6 (40) | 8 (50) | 0.855 | |
| Retroperitoneal | 10 (24) | 3 (27) | 5 (33) | 2 (13) | 0.357 | |
| Previous nephrectomy | Presence | 37 (88) | 11 (100) | 13 (87) | 13 (81) | 0.179 |
| Absence | 5 (12) | 0 (0) | 2 (13) | 3 (19) | ||
| No. of previous systemic therapies | 1 | 14 (33) | 3 (27) | 5 (33) | 6 (38) | 0.938 |
| 2 | 19 (45) | 6 (55) | 6 (40) | 7 (44) | ||
| ≥3 | 9 (21) | 2 (18) | 4 (27) | 3 (18) | ||
| Baseline LDH (IU/L) | Median (IQR) | 192 (163–251) | 198 (170–214) | 190 (144–348) | 183 (162–232) | 0.685 |
| Baseline NLR | Median (IQR) | 3.24 (2.20–4.58) | 2.48 (1.71–4.96) | 3.31 (2.31–4.44) | 3.66 (1.80–6.09) | 0.611 |
| Baseline CRP level (mg/L) | Median (IQR) | 23 (2.0–64) | 6.1 (0.4–34) | 39 (9.0–82) | 17 (2.0–69) | 0.195 |
CRP, C-reactive protein; ECOG PS, Eastern Cooperative Oncology Group performance status; IMDC, International Metastatic Renal Cell Carcinoma Database Consortium; No., number; LDH, lactate dehydrogenase; NLR, neutrophil-to-lymphocyte ratio.