Thymic carcinoma (TC) is a rare cancer with minimal evidence of survival with palliative-intent chemotherapy. Sunitinib and everolimus monotherapies have been proposed as active molecular-targeted approaches based on phase II (Ph II) trials, and S-1, an oral fluoropyrimidine, has been described in the NCCN guideline as an active cytotoxic agent for refractory TC based on a case series. Therefore, we conducted a Ph II trial to study the result of S-1 treatment in patients with refractory TC.
In this Ph II study performed at three cancer centers in Tokyo, we aimed to enroll 26 TC patients previously treated with platinum-based chemotherapy. The patients received S-1 orally twice daily at a dose of 40–60 mg/m2 for 4 weeks, followed by 2 weeks off until progressive disease or unacceptable toxicities. S-1 was used off-label. The primary end-point was determining the objective response rate, and secondary endpoints were progression-free survival (PFS), overall survival (OS), and toxicities.
Twenty-six patients (10 males) were recruited between November 2013 and May 2016. The median age was 63 (27–74) years. Among the 26 patients, 23 had squamous cell carcinoma histology and 10 had an ECOG performance status of 0. Additionally, one patient showed complete response and seven patients showed partial responses, resulting in a 30.8% response rate (95% confidence interval [CI], 16.5–50.0) and a 65.4% disease control rate (95% CI, 46.2–80.6). After a median follow-up of 13.4 months, the median PFS was 4.3 months (95% CI, 2.3–7.6 months) and median OS was 23.4 months (95% CI, 12.8–not reached). Treatment-related adverse events (AEs) of grade ≥3 included neutropenia (12%), skin rash (8%), elevated ALT, decreased WBC count, and fatigue (4%). No treatment-related death was observed. However, treatment was discontinued in three patients (12%) because of AEs.
S-1 as palliative-intent chemotherapy and a cytotoxic agent for refractory TC confirmed clinical activity with good tolerability.
Clinical trial identification
Legal entity responsible for the study
/National Cancer Center Hospital/The Cancer Institute Hospital of Japanese Foundation for Cancer Research/Tokyo Metropolitan Cancer and Infectious diseases Center Komagome Hospital
Y. Goto, S. Kanda, H. Horinouchi, H. Nokihara, N. Yamamoto, M. Nishio, Y. Ohe: Consulting or Advisory Role from Taiho Pharmaceutical All other authors have declared no conflicts of interest.