Early elevation of inflammatory cytokines, such as IL-6 or TNF-α, or CRP, which is a surrogate marker for IL-6, following commencement of PD-1/L1 inhibitors (PD1-I) may represent early activation of immune-cells. Serum IL-6 and TNF-α were measured in 10 non-small cell lung cancer patients who were evaluable within the 7 days before and after commencement of PD1-I. For CRP, medical records were reviewed and 34 patients with measured CRP within the 7 days before and after the treatment were evaluated. In the 10 patients analyzed for IL-6/TNF-α, the serum levels of IL-6/TNF-α were not significantly different between pre- and post-initial PD1-I [IL-6 20.3 (2.6-49.9) and 22.9 (3.6-96.1) pg/mL, p = 0.453; TNF-α 1.6 (0.7-6.3) and 3.3 (0.7-9.6) pg/mL, p = 0.329]; however, all four responses were observed among the 7 IL-6-elevated cases, resulting in a response rate of 57%. In the 34 patients analyzed for CRP, CRP was significantly increased after initial PD1-I [1.8 (0.1-17.8) mg/dL, 2.4 (0.0-27.8), p = 0.001]. Notably, in the 31 evaluable cases, all responses were again observed in either the IL-6 or CRP elevated groups and the response rate was 46% (11 of 24). The median overall survival time was not reached in the elevated group and was 112 days in the non-elevated group (p = 0.069). The early increase in inflammatory cytokines with PD1-I was indicated to be predictive for the efficacy in patients with non-small cell lung cancer.
Keywords: CRP; IL-6; Immune-checkpoint inhibitors; Non-small cell lung cancer; PD-1.