434MO - Increased eosinophil is a universal biomarker for immune-related adverse events induced by immune checkpoint inhibitors in various cancer patients: A retrospective multidisciplinary study

Background

Immune checkpoint inhibitors (ICIs) cause severe and lethal immune-related adverse events (irAEs). However, there are no reports of practical and cross-sectional biomarkers for irAEs common to different types of ICIs and primary tumors. This study examined whether eosinophils proportion could be a universal biomarker for irAEs.

Methods

614 patients with various cancers (esophageal, gastric, head and neck, lung, melanoma, renal cell, urothelial, other cancer) received with anti-PD-1 monotherapy, anti-PD-L1 monotherapy, or anti-CTLA-4 plus anti-PD-1 combination therapy. We divided into two groups depending on whether patients had experienced an irAEs (irAE group) or not (non-irAE group). Eosinophils proportion were examined before 2-course of treatment.

Results

Patients in the irAE group who had received anti-PD-1 monotherapy (mean, 4.1% vs. 2.4%) and anti-CTLA-4 plus anti-PD-1 combination therapy (mean, 5.2% vs. 3.4%) showed higher eosinophils proportion before 2-course of treatment than those in the non-irAE group (P<0.05). Eosinophils proportion in anti-PD-L1 monotherapy tended to increase in irAE group (mean, 4.3% vs. 2.7%; P=0.05). Furthermore, eosinophils proportion in gastric cancer (mean, 4.5% vs. 2.1%), head and neck cancer (mean, 3.2% vs. 1.9%), lung cancer (mean, 4.5% vs. 2.4%), melanoma (mean, 4.8% vs. 2.5%), renal cell carcinoma (mean, 4.6% vs. 2.7%), and urothelial carcinoma (mean, 5.0% vs. 3.0%) was significantly increased in irAE group than in non-irAE group (P<0.05). The optimal cut-off value for eosinophils proportion against irAEs was 3.0% (area under the curve=0.668). In multivariate analyses, eosinophils of ≥3.0% were an independent factor for irAEs (odds ratio 2.57, 95% confidence interval 1.79–3.67).

Conclusions

An increased eosinophils proportion before 2-course treatment might be a universal biomarker for irAEs in various cancer patients received with different ICI types.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

NITTO foundation.

Disclosure

All authors have declared no conflicts of interest.