Protocol for the 2ND-STEP study, Japan Clinical Oncology Group study JCOG1802: a randomized phase II trial of second-line treatment for advanced soft tissue sarcoma comparing trabectedin, eribulin and pazopanib.

Background: Soft tissue sarcomas (STS) are a rare type of malignancy comprising a variety of histological diagnoses. Chemotherapy constitutes the standard treatment for advanced STS. Doxorubicin-based regimens, which include the administration of doxorubicin alone or in combination with ifosfamide or dacarbazine, are widely accepted as first-line chemotherapy for advanced STS. Trabectedin, eribulin, pazopanib, and gemcitabine plus docetaxel (GD), which is the empirical standard therapy in Japan, are major candidates for second-line chemotherapy for advanced STS, although clear evidence of the superiority of any one regimen is lacking. The Bone and Soft Tissue Tumor Study Group of the Japan Clinical Oncology Group (JCOG) conducts this trial to select the most promising regimen among trabectedin, eribulin, and pazopanib for comparison with GD as the test arm regimen in a future phase III trial of second-line treatment for patients with advanced STS.

Methods: The JCOG1802 study is a multicenter, selection design, randomized phase II trial comparing trabectedin (1.2 mg/m intravenously, every 3 weeks), eribulin (1.4 mg/m intravenously, days 1 and 8, every 3 weeks), and pazopanib (800 mg orally, every day) in patients with unresectable or metastatic STS refractory to doxorubicin-based first-line chemotherapy. The principal eligibility criteria are patients aged 16 years or above; unresectable and/or metastatic STS; exacerbation within 6 months prior to registration; histopathological diagnosis of STS other than Ewing sarcoma, embryonal/alveolar rhabdomyosarcoma, well-differentiated liposarcoma and myxoid liposarcoma; prior doxorubicin-based chemotherapy for STS, and Eastern Cooperative Oncology Group performance status 0 to 2. The primary endpoint is progression-free survival, and the secondary endpoints include overall survival, disease-control rate, response rate, and adverse events. The total planned sample size to correctly select the most promising regimen with a probability of > 80% is 120. Thirty-seven institutions in Japan will participate at the start of this trial.

Discussion: This is the first randomized trial to evaluate trabectedin, eribulin, and pazopanib as second-line therapies for advanced STS. We endeavor to perform a subsequent phase III trial comparing the best regimen selected by this study (JCOG1802) with GD.

Trial Registration: This study was registered with the Japan Registry of Clinical Trials ( jRCTs031190152 ) on December 5, 2019.