Pembrolizumab may be a safe and effective option for patients with advanced refractory or recurrent thymic carcinoma, according to a study published in The Lancet Oncology.1

Thymic carcinomas typically express high levels of PD-L1, leading researchers to predict a positive response to pembrolizumab.

For this single-arm phase 2 study (ClinicalTrials.gov Identifier: NCT02364076), researchers assigned 40 patients with thymic carcinoma who failed at least 1 previous line of chemotherapy to receive pembrolizumab 200 mg every 3 weeks. The median follow-up was 20 months.

Of the 40 patients, 1 (3%) and 8 (20%) had a complete response and partial response, respectively, leading to an overall response rate of 22.5% (95% CI, 10.8-38.5). Twenty-one (53%) patients had stable disease.

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Median time to response was 6 weeks. The median duration of response was 22.4 months (95% CI, 12.3-34.7) among the 9 patients with a complete or partial response. For patients with stable disease, the median duration of response was 6.8 months (95% CI, 1.8-11.7).

The median overall survival (OS) was 24.9 months (95% CI, 15.5-not evaluable); median progression-free survival (PFS) was 4.2 months (95% CI, 2.9-10.3). The 1-year OS and 1-year PFS rates were 71% and 29%, respectively.

The most frequently reported grade 3 to 4 adverse events included elevated levels of aspartate aminotransferase and alanine aminotransferase. Six (15%) patients developed 1 or more severe immune-related adverse events (irAEs) requiring steroid therapy; there were no irAE-related deaths and all patients recovered.

The authors concluded that “patients with thymic carcinoma have an increased risk of developing serious autoimmune toxicities after treatment with pembrolizumab and therefore close monitoring of patients is necessary.”

Reference

  1. Giaccone G, Kim C, Thompson J, et al. Pembrolizumab in patients with thymic carcinoma: a single-arm, single-centre, phase 2 study. Lancet Oncol. 2018 Jan 26. doi: 10.1016/S1470-2045(18)30062-7 [Epub ahead of print]