1695PPrior exposure to pazopanib (PAZ) did not minor efficacy of regorafenib (REG) in non-adipocytic soft tissue sarcoma patients (pts)

Abstract Background REG is an active drug in non-adipocytic soft tissue sarcoma previously treated with doxorubicin (Mir et al. Lancet Oncol 2016). Efficacy of REG in PAZ pretreated pts is unknown. REGOSARC is a multi-cohort double-blind placebo (PLAC)-controlled phase II trial assessing the activity of REG in soft-tissue sarcoma previously treated with doxorubicin. Cross-over after centrally confirmed disease progression was allowed. Methods In the present subgroup analyses of the pooled study (cohorts B,C,D and E), we analyzed the magnitude of REG activity in pts with prior exposure to PAZ. Results The total study population consisted of 176 pts (101 women, 57%), with a median age of 59 (20-81). with the following histologies (n/%): leiomyosarcoma (80/45), synovial sarcoma (28/16) or other sarcoma (68/39). Most pts had PS = 0 (N = 83, 47%) or PS = 1 (N = 92, 52%). Median time from initial diagnosis to study enrollment was 30 months (range, 5.6-498). Median follow-up was 59.6 months. 88 pts each were allocated to the REG and placebo (PLAC) arms, including 21 (24%) and 22 (25%) pts with previous PAZ exposure. Overall, the significant benefit of REG compared to PLAC in terms of PFS with a median PFS of 3.8 (REG) vs 1.0 months (PLAC); HR(REG/PLAC)=0.43 [95%CI: 0.32-0.59], p