Cho J, et al. - In this phase 2 study, efficacy and safety of pembrolizumab were tested in patients with thymic epithelial tumor (TET). In those with advanced TET, encouraging antitumor activity was seen by pembrolizumab. High incidence of autoimmunity was also reported.

Methods

• This study included patients with histologically confirmed TET whose disease progressed after at least one line of platinum-based chemotherapy, and excluded those that had an active autoimmune disease requiring systemic treatment within the past year or documented history of clinically severe autoimmune disease.
• Until tumor progression or unacceptable toxicity, patients were administered 200 mg of pembrolizumab intravenously every 3 weeks.
• Every 9 weeks, investigators evaluated the primary objective of response rate.

Results

• Thymic carcinoma and thymoma was detected in 26 and seven, respectively, out of a total of 33 patients enrolled.
• Partial response and stable disease was observed in two (28.6%; 95% CI, 8.2% to 64.1%) and five (71.6%) of overall seven thymoma, respectively.
• They noted that out of 26 thymic carcinomas, five (19.2%; 95% CI, 8.5% to 37.9%) had partial response and 14 (53.8%) had stable disease.
• For both groups, the observed median progression-free survival was 6.1 months.
• Dyspnea (11; 33.3%), chest wall pain (10; 30.3%), anorexia (seven; 21.2%), and fatigue (seven; 21.2%) were documented as the most common adverse events of any grade.
• Grade ≥ 3 immune-related adverse events, including hepatitis (four; 12.1%), myocarditis (three; 9.1%), myasthenia gravis (two; 6.1%), thyroiditis (one; 3.0%), antineutrophil cytoplasmic antibody–associated rapidly progressive glomerulonephritis (one; 3.0%), colitis (one; 3.0%), and subacute myoclonus (one; 3.0%) were experienced by five (71.4%) of seven patients with thymoma and four (15.4%) of 26 patients with thymic carcinoma.