Outcomes of immunotherapy in thymoma: A systematic review and meta-analysis.

Abstract

e20142 Background: Immunotherapy has emerged as a promising treatment for Thymoma patients, particularly where traditional therapies fail. Thymoma, a tumor originating from epithelial cells of the thymus, is often associated with autoimmune conditions, especially myasthenia gravis, which complicates its management. Clinical trials demonstrating its efficacy explore the application of immunotherapy. This meta-analysis aims to assess the efficacy and safety of immunotherapy in Thymoma patients. Methods: Comprehensive literature search was performed on PubMed, Cochrane, and Clinicaltrials.gov. After screening 36 articles, 6 studies reporting outcomes of immunotherapy in Thymoma patients were included. The combined effect sizes were weighted by the inverse of their variance, assigning greater weight to studies with larger sample sizes. To address the variability between studies, the Der Simonian-Laird random-effects model was applied to estimate the overall pooled rates and their 95% confidence intervals. All analyses were conducted using the STATA software, version 16. Results: A total of 97 patients from 6 studies (2018–2023) were included in the analysis. The median age of the patients was 55.25 years (range: 22–76), and the majority were male (57.78%, n=52/90). Among the included studies, 3 (50%) were phase II trials, 2 (33.33%) were retrospective studies, and 1 (16.67%) was a phase I trial. Regarding disease staging, Stage IV was present in 42.86% (12/28) of patients, with Stage IVA in 17.86% (5/28) and Stage IVB in 39.29% (11/28). All patients received PD-1 inhibitors, with Pembrolizumab administered in 33.33% (2/6) of cases, Nivolumab in 33.33% (2/6), Avelumab in 16.67% (1/6), and atezolizumab in 16.67% (1/6). The median follow-up duration was 14.1 months (range: 6.2–20.7). The pooled overall survival (OS) rates at 6, 12, 18, and 24 months were 76.4% (95% CI: 62.1–94.0), 59.7% (95% CI: 46.1–77.2), 56.5% (95% CI: 41.9–76.2); 45.9% (95% CI: 31.8–66.3). Corresponding progression-free survival (PFS) rates were 50.0% (95% CI: 37.6–66.4), 32.7% (95% CI: 19.2–55.8), 15.8% (95% CI: 13.2–40.6), and 12.4% (95% CI: 4.4–35.3). The pooled rate of overall response, partial response, stable disease and progressive disease was 19% (95% CI: 9%-30%; I²: 33.01%, P = 0.19), 22% (95% CI: 12%-32%; I²: 15.42%, P = 0.31), 52% (95% CI: 41%-63%; I²: 7.59%, P = 0.37), and 16% (95% CI: 9%-23%; I²: 0.00%, P = 0.42). The total adverse event rate was 89% (95% CI: 77%-100%; I²: 76.33%, P < 0.0001). The rate of grade III adverse events was 35% (95% CI: 22%-48%; I²: 34.58%, P = 0.18) and the mortality rate was 16% (95% CI: 0%-33%; I²: 78.46%, P = 0.01). Conclusions: The analysis demonstrates favorable efficacy with an acceptable safety profile with immunotherapy in thymoma patients. These results highlight immunotherapy as a potential treatment option for Thymoma patients, suggesting the need for more research to confirm these results.