The prognosis of pts who have failed multiple chemotherapy (CT) regimens is quite dismal. PD-L1 is frequently expressed by immunohistochemistry (IHC) in GCT. D is a monoclonal antibody (mAb) that inhibits the binding of PD-L1. T, an anti-CTLA4 mAb, is an immunomodulatory therapy. Combination immunotherapy has shown improved activity compared to monotherapy. We aimed to investigate the activity of D, alone or in combination with T, in chemorefractory GCT.
This is an open-label, randomized, 3-stage, phase 2 study. Pts who have failed ≥2 prior CT regimens (including high-dose CT) will be randomized to receive one of the following: D, 1.5 g via IV infusion q4w, for up to a total of 12 months (13 doses/cycles) alone or with T, 75 mg IV q4w, starting on week 0, for up to 4 months (4 doses/cycles). Serum tumor markers, computed tomography and FDG-PET scans will be repeated q8 weeks. The primary endpoint is the objective response-rate (ORR = complete response or partial response with normal markers). H0: ORR rate ≤10%, H1: ORR ≥25%, type I and II error rates at 10%. In stage 1, 11 pts will be allocated in each arm. According to Gehan's rule, the trial will be terminated whenever no response will be observed. 29 additional pts will be added to each arm fulfilling stage 1 criteria. ORR in ≥7 pts will be required. In stage 3, pts from stage 1-2 of both arms will be retrospectively evaluated for PDL-1 IHC. The Ventana PD-L1 IHC assay will be used. In case of negative findings at the end of stage 2, if the target benefit is likely to occur only in PD-L1+ pts, further study prosecution in accordance with an enrichment strategy will be undertaken. In particular, predictive power (PP) will be calculated assuming expansion of PD-L1+ cohorts up to a maximum of 60 pts. Each arm will be categorized as not-promising (PP
Clinical trial identification
Legal entity responsible for the study
Fondazione IRCCS Istituto Nazionale dei Tumori
All authors have declared no conflicts of interest.