A multicenter phase II study of carboplatin and paclitaxel for advanced thymic carcinoma: WJOG4207L

Thymic carcinoma (TC) is an exceptionally rare tumor, which has a very poor prognosis differing from thymoma. Till date, there has been no report of any results of clinical trials focusing on TC. The role of non-anthracycline-based chemotherapy has not been elucidated since the previous studies included a relatively small number of TC patients. This single-arm study evaluated carboplatin and paclitaxel (CbP) in chemotherapy-naive patients with advanced TC.

The study treatment consisted of carboplatin (area under the curve 6) and paclitaxel (200 mg/m(2)) every 3 weeks for a maximum of six cycles. The primary end point was objective response rate (ORR) by independent review. The secondary end points included overall survival (OS), progression-free survival (PFS), and safety. Based on the SWOG 2-stage design, the planned sample size of 40 patients was determined to reject the ORR of 20% under the expectation of 40% with a power of 0.85 and a type I error of 0.05.

Forty patients from 21 centers were enrolled for this study from May 2008 to November 2010. Of the 39 patients evaluable for analysis, 36 were pathologically diagnosed by independent review, and 97% patients were eventually TC. There was 1/13 complete/partial responses with an ORR of 36% (95% confidence interval 21%-53%; P = 0.031). The median PFS was 7.5 (6.2-12.3) months, while OS did not reach the median value. Major adverse event was grade 3-4 neutropenia in 34 patients (87%). There was no treatment-related death.

In this largest trial with TC, CbP showed promising efficacy in advanced TC when compared with anthracycline-based chemotherapy, which is the current standard treatment of thymic neoplasm. Our results established that CbP, one of the standard treatments for non-small-cell lung cancer, might be an option as a chemotherapy regimen for TC.