Analysis and evaluation of factors contributing to the occurrence of immune-related adverse events with immune checkpoint inhibitors.

In recent years, there has been a growing trend in the use of immune checkpoint inhibitors (ICIs) for treating a larger patient population. However, it is important to note that immune-related adverse events (irAEs) frequently arise as a result. Therefore, precise patient monitoring becomes essential. We present the findings of a retrospective study conducted at the International University of Health and Welfare Narita Hospital (referred to as "our hospital") that aimed to identify risk factors linked to the occurrence of irAEs. The study focused on analyzing various factors, including therapeutic and lifestyle backgrounds, as well as laboratory values of patients who received ICI treatment and were subsequently diagnosed with irAE. The study included patients who met the eligibility criteria for ICIs (both single agent and combination therapy) as well as ICI in combination with anticancer drugs. The inclusion period for the study encompassed April 2020 to May 2022 at our hospital. The fifty patients were divided into two groups based on the severity of irAEs: the first group consisted of patients with irAE Grade 2 or lower (referred to as irAE Grade under 2), while the second group included patients with irAE Grade 3 or higher (referred to as irAE Grade over 3). Statistical analysis revealed significant differences in age (p=0.027) and CRP (C-reactive protein) levels (p=0.008) among the background factors when comparing the two groups. Additionally, statistically significant differences were observed among different ICI treatment groups in the occurrence of irAEs (p=0.035). however, it was indicated to be a relatively weak correlation. Moving forward, we shifted our focus to examine the frequency of irAEs in relation to exposure. However, we did not observe any significant correlation between exposure and irAE grade. Additionally, even when exposure was doubled through the use of ipilimumab in combination with ICIs (referred to as "Mod exposure"), no correlation was found. Exposure was further categorized into three groups: the PD-1 group, PD-L1 group, and PD-1 + CTLA-4 group. However, no significant correlation was observed between exposure in any of these groups and the grade of irAEs. Similarly, no significant correlation was observed between the dosage of ICI in the fixed-dose group and the weight-based dosage group with exposure and irAE Grade. Based on our study findings, there is a suggestive relationship between age and CRP levels and the occurrence of irAEs of Grade 3 or higher. These factors may play a role in contributing to the development of more severe irAEs.