148P - Clinical significance of CD4+ T cell subsets in peripheral blood for anti-PD-1/PD-L1 therapy

Background

Although immune checkpoint inhibitor therapies are popular for various cancers, biomarkers using peripheral blood have not established yet. The CD62LlowCD4+ T cells are considered to enhance function of cytotoxic CD8+ cells. It is reported that the K-index (X2/Y; X = CD62LlowCD4+T cell %, Y = Treg % in peripheral blood CD4+ T cell population) could be augmented immune-reactive status and predict outcomes for anti-PD-1 therapy against non-small lung cancer. In this study, we examine the clinical significance of the CD4+ T cell subsets in peripheral blood for anti- PD-1/PD-L1 therapy against other cancers except lung cancer.

Methods

Peripheral blood mononuclear cells obtained from patients with urological cancers or hepatocellular carcinoma before anti-PD-1/PD-L1 therapy were served for flow cytometry analysis. Possible correlation of the subsets including K-index with therapy outcomes were investigated.

Results

Thirty-five patients with urological cancer (16 renal cell carcinoma, 8 ureteral cancer, 11 bladder cancer) and 28 patients with hepatocellular carcinoma (HCC) participated in the study. Regarding urological cancers, objective response rate (ORR) was significantly higher in patients with the high K-index (K-index ≧300, 75% vs. K-index <300, 30.4%; P=0.012). On the other hand, patients with immune-related adverse events (irAE) of ≧ had high K-index before treatment (P=0.017). In contrast, in HCC, no relevant relationship was seen between the K-index and treatment outcome. The ORR of patients with high Treg population (≧3% of CD4+ T cells) was significantly higher than that of low Treg patients (<3%) (63.6% vs. 17.6%, respectively; P=0.019). We found no relevant relationship between K-index and irAE of ≧grade 3.

Conclusions

The K-index could predict treatment outcomes and possibility of irAE in the urological cancers. It is considered as a valuable biomarker to select the anti-cancer regimens. Further study should be needed to find other cancers in which the K-marker is used as a predictive biomarker. In contrast, in the HCC, the Treg population could be a valuable marker different from lung cancer or urological cancers. It suggests that immune-oncological status is different in some cancers.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The author.

Funding

Has not received any funding.

Disclosure

The author has declared no conflicts of interest.