Nivolumab for thymic epithelial tumors: Case series.

Abstract

e21115 Background: Metastatic and unresectable thymoma (T) or Thymic Carcinoma (TC) have limited treatment options, especially after first line. Methods: Patients with unresectable or recurrent thymic tumors who used minimum one dose of Nivolumab at any line of treatment were evaluated retrospectively. Even though standart dose of nivolumab is 3mg/kg dosage, due to financial concerns we used low dose regimen mostly. Results: 8 patients with TC (n = 3), T (n = 4) and mixt histology (n = 1) were included to study. Patients used nivolumab between April 2018 and August 2019, as median 3rd line of treatment. One patient used as first line treatment due to chemoresistant disease at neoadjuvant line. Three patients had previous myasthenia gravis that had to be controlled before treatment. Four patients showed moderate (n = 2) or severe (n = 2) adverse events with nivolumab treatment. Interestingly, two severe adverse events were occurred at first dose even with 40 mg nivolumab and required cessation of treatment permanently. Median follow-up time was 16.1 months (range: 12.7-165.4). The median number of nivolumab received was four (range: 1 – 18). Best response was partial response. Two patients progressed at the 3rd and 5th month of treatment. One of the patients with inoperable disease initially underwent surgery after nivolumab therapy. Duration of response for one patient with TC and one patient with T B2 were 9 and 14 months, respectively. Median survival time after nivolumab was 7.4 months (range: 2-22.1). Conclusions: Despite the small number of patients, nivolumab is an option for T and TC patients. Low dose nivolumab may also be very toxic for T, especially in patients with known myasthenia gravis history. [Table: see text]