Inflammatory biomarkers in assessing severity and prognosis of immune checkpoint inhibitor-associated cardiotoxicity

Inflammatory biomarkers, including CRP, the neutrophil-to-lymphocyte ratio (NLR), and the neutrophil-to-eosinophil ratio (NER), may predict outcomes in cancer. However, their value in immune checkpoint inhibitor (ICI) therapy-associated cardiotoxicity remains elusive. We aimed to characterize the relationship of inflammatory markers with severity of ICI-related cardiotoxicities (iRCs) and prognosis among patients with iRCs.

Patients who were diagnosed with iRCs between January 2019 and December 2021 were retrospectively enrolled and were dichotomized based on iRC severity into low-grade (grade 1-2) vs. high-grade (grade 3-4) groups.

Forty-seven patients were included. The median time-to-event from first ICI infusion to onset of iRCs was 35 days (IQR: 19.0-65.5 days). When compared with respective baseline values, cardiac biomarkers and inflammatory markers were significantly elevated at onset of iRCs. Compared with low-grade iRCs, NER at iRC onset was significantly increased among patients with high-grade iRCs (Group × Time, P < 0.01). When grouped by the median NER (184.33) at iRC onset, NER ≥ 184.33 was associated with high-grade iRCs (OR: 10.77, P < 0.05) and had a 36.3% increased mortality compared to the lower NER group (HR: 2.67, P < 0.05).

In patients who develop iRCs, NER is significantly elevated at iRC onset, and higher NER correlates with greater iRC severity and higher mortality. Larger datasets are needed to validate these findings.