Safety Profile and Tumor Response of EGFR-TKIs in Clinical Practice: A Real-World Study in Thailand

<b>Background</b>: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the first-line treatment for patients with non-small cell lung cancer (NSCLC) harboring EGFR mutations. Although EGFR-TKIs can cause various adverse events (AEs), their profiles have not been fully elucidated in Thai patients. This study aimed to determine the incidence, characteristics, severity, and duration of the first AEs and to evaluate their association with tumor response in patients with NSCLC receiving EGFR-TKIs. <b>Method</b>: This retrospective cohort study was conducted at a super-tertiary care hospital in Thailand. Patients with NSCLC who received EGFR-TKIs between August 2021 and July 2024 were included. Descriptive statistics were used to summarize safety profiles and tumor response. The association between AEs and objective response was assessed using logistic regression. <b>Results</b>: A total of 187 patients were included in this study. Overall, 177 AEs were observed in patients receiving erlotinib, osimertinib, or gefitinib. The most common cutaneous AEs were rash (30.7%), xerosis (24.1%), and acneiform rash (19.3%), while diarrhea (20.3%) was the most frequent gastrointestinal toxicity. Most AEs were grade 1-2 and occurred within 1 month after treatment initiation. In multivariable logistic regression analysis, pruritus (OR 8.26, 95% CI: 1.00-67.75, <i>p</i> = 0.049) and treatment line (OR 0.27, 95% CI: 0.10-0.68, <i>p</i> = 0.006) were independently associated with objective response. <b>Conclusion</b>: Most of the AEs occurred early during EGFR-TKI therapy, with cutaneous reactions being the most common and generally mild to moderate. Pruritus and treatment line were independently associated with objective response, suggesting that pruritus may serve as a potential clinical indicator of treatment response and highlighting the importance of monitoring of the EGFR-TKI-related AEs during therapy.