STYLE (NCT03449173) a phase II Trial of Sunitinib in patients with type B3 Thymoma or Thymic Carcinoma in second and further lines.

BACKGROUND: Thymic malignancies are rare tumors with few therapeutic options. The STYLE trial was aimed to evaluate activity and safety of sunitinib in advanced/recurrent type B3 thymoma (T) and thymic carcinoma (TC).

METHODS: In this multicenter Simon 2 stages phase II trial, patients with pretreated T/TC were enrolled in two cohorts and assessed separately. Sunitinib was administered 50mg daily for 4-weeks, followed by a 2-week rest period (schedule 4/2), until disease progression or unacceptable toxicity. The primary endpoint was objectives response rate (ORR). Progression free survival (PFS), overall survival (OS), disease control rate (DCR) and safety were secondary endpoints.

RESULTS: From 03/2017 to 01/2022, 12 T and 32 TC patients were enrolled. At stage 1 ORR was 0% (90%CI 0.0-22.1) in T and 16.7% (90%CI 3.1-43.8) in TC, so T cohort was closed. At stage 2, the primary endpoint was met for TC with ORR of 21.7% (90%CI 9.0%-40.4%). In the ITT analysis DCR was 91.7% (95%CI 61.5%-99.8%) in Ts and 89.3% (95%CI 71.8%-97.7%) in TCs. mPFS was 7.7 months (95%CI 2.4-45.5) in Ts, 8.8 (95%CI 5.3-11.1) in TCs; mOS was 47.9 months (95%CI 4.5-not reached) in Ts, and 27.8 (95%CI 13.2-53.2) in TCs. Adverse events (AEs) occurred in 91.7% T and 93.5% TCs. Grade ≥3 treatment-related AEs were reported in 25.0% T and 51.6% TC.

CONCLUSIONS: This trial confirms the activity of sunitinib in TC patients, supporting its use as second line treatment.