Abstract 425P
Background
TETs are rare malignancies originating in the anterior mediastinum, with type B3 thymoma (T) and thymic carcinoma (TC) being the most aggressive subtypes. A phase II study demonstrated a median progression-free survival (PFS) of 10.1 months (16.6 months for T and 5.6 months for TC) with everolimus (E). Real-world data on E benefit are limited.
Methods
We retrospectively selected patients (pts) with refractory TETs who received everolimus as a second-line or later treatment from 7 centers in France (part of the nationwide RYTHMIC network) and 1 US center. Clinical and pathological characteristics were collected. Toxicity and efficacy were evaluated locally, with adverse events graded according to the Common Terminology Criteria for Adverse Events v5. PFS and overall survival (OS) were calculated using the initiation date of E.
Results
From Mar 2022 to Dec 2024, 37 pts were analyzed. The median age at diagnosis was 48 years (range: 22 to 75); 22 pts (59.5%) were male. Autoimmune diseases were reported in 7 pts (18.9%). Among the 28 T cases, 11 (39.3%) were classified as B2 and 5 (17.9%) as B3. Among the 9 TC cases, 8 (88.9%) were squamous cell carcinomas, and 1 (11.1%) was an adenocarcinoma. E was used as a second-line treatment in 12 pts (32.4%), all of whom started at a daily dose of 10 mg. Out of 37 pts, 34 were eligible for response evaluation; 5 achieved a partial response, resulting in an objective response rate of 13.5%. 20 pts experienced stable disease. The disease control rate was 67.6%. The median follow-up was 56 months (95% CI: 41.562–70.438). The median PFS for pts was 5.5 months (95% CI: 0.9–10.1). The median OS for pts was 34.0 months (95% CI: 16.1–51.9). The PFS and OS for the pts with TC was 3.22 (95% CI: 0.00–6.58) and 9.00 months (95% CI: 0.235–17.765) respectively. The PFS and OS for the pts with T was 8.5 (95% CI: 3.3–13.8) and 38 months (95% CI: 29.61–46.39), respectively. The most common toxicities were mucositis, asthenia, neutropenia, and pneumonitis, occurring in 9 (24.3%), 8 (21.6%), 7 (18.9%), and 4 pts (10.8%), respectively. Dose reduction was required in 9 pts (24.3%).
Conclusions
We confirm the activity of everolimus in pts with advanced T. Pulmonary toxicity remains a critical adverse event that requires close monitoring during everolimus treatment.
Legal entity responsible for the study
Institut Gustave Roussy.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.