LAUSR

11063 Background: Few effective US FDA approved therapies exist for refractory, metastatic sarcomas. Many of these patients therefore enroll onto phase 1 clinical trials. Because tumor-specific outcomes are not always reported in less common cancers such as sarcomas, outcomes of sarcoma patients treated with novel immunotherapy and targeted therapy approaches remains unknown. Methods: We analyzed clinical and next generation sequencing data from all sarcoma patients treated on phase 1 trials at MD Anderson Cancer Center (MDACC) and performed logistic and Cox proportional hazards regression analyses to evaluate response rate (RR), median time to progression (mTTP), clinical benefit rate (CBR; defined as CR, PR, or SD > 6 months), and median overall survival (OS). Results: Among the 406 patients with advanced sarcomas (321 soft tissue sarcoma, 85 bone sarcomas) treated on phase 1 trials at MDACC from May 2006 to May 2018, median age was 53 (range 11-84), 48% were female, with a median 3 prior lines of therapy (range 0-9). The most commonly treated soft tissue sarcoma subtypes included leiomyosarcoma (n = 66; 16%), liposarcoma (n = 52; 13%), GIST (n = 44; 11%), UPS (n = 14; 3%), and synovial sarcoma (n = 11; 3%) and most commonly treated bone sarcomas included osteosarcoma (n = 34; 8%), chondrosarcoma (n = 28; 7%), and Ewing’s sarcoma (n = 25; 6%). RR was 7% (95% CI 5, 10), mTTP was 2.9 months (95%CI 2.6, 3.1), CBR was 24% (95% CI 20, 29), mOS was 17.2 months (95% CI 13.8, 20.8). 2 patients had a CR as best response, 1 chondrosarcoma patient treated with an anti-APO2L/Trail agent and 1 Ewing’s sarcoma patient treated with the combination of an IGF1R inhibitor plus mTOR inhibitor. 26 patients (6%) had a PR as best response using novel immunotherapies targeting PD1, PDL1 plus CCR4, CTLA4 plus KIT, and TLR7/8 and novel targeted therapies against TRK, LRRC15, cMET, mTOR, VEGF, MDM2, KIT/PDGFRA, and FGFR. Responses were seen across sarcoma subtypes - ASPS, UPS, myxoid sarcoma, liposarcoma, GIST, carcinosarcoma, clear cell sarcoma, embryonal rhabdomyosarcoma, epitheliod sarcoma, fibrious histiosarcoma, and Ewing’s sarcoma. Conclusions: Our analysis identifies a reasonable survival in heavily pretreated, metastatic refractory sarcoma patients with responses seen with novel targeted therapies and immunotherapies that are not yet US-FDA approved. Biomarker analysis is ongoing to help identify the subset of responders in our cohort. Advanced sarcoma patients should be considered for molecular profiling and early phase clinical trials.