1687PReal-world outcomes of patients with locally advanced or metastatic epithelioid sarcoma

Abstract Background Limited data are available on effectiveness and safety of systemic therapies for treatment of advanced (unresectable and/or metastatic) epithelioid sarcoma (ES). This natural history study collected real-world (rw) data on outcomes of ES patients (pts) receiving at least first-line (1L) or 2 or more lines (2L+) of systemic therapies. Methods Retrospective chart review was conducted in pts with advanced ES who initiated systemic therapy between 2000-2017 at 5 US cancer centers. Due to unavailability of RECIST assessment, rw overall response rate (rwORR) was assessed by review of radiology reports. rw disease control rate (rwDCR) was defined as percent of pts with response of any duration or stable disease ≥32 wks. Median rw duration of response (rwDOR), rw progression-free survival (rwPFS) and overall survival (OS) were estimated from start of therapy by Kaplan-Meier method. The index date for time-to-event endpoints was the start of first-line treatment. Adverse events (AEs) resulting in treatment modification, discontinuation, hospitalization, permanent sequelae or death, were abstracted. Results Of 74 eligible pts, 53 (71.6%) were male, and 63 (85.1%) had metastatic ES. INI1/BAF47 was not expressed in 90.2% of 41 tumors tested. Mean age at advanced ES diagnosis was 36.4 years. Anthracycline-based (54.1%) and gemcitabine-based (24.3%) regimens were most common in 1L. Median (range) number of lines of therapy received was 2 (1-7). 1L rwORR was 14.9%, rwDCR was 20.3%, rwDOR was 14.5 wks, and median OS was 66.3 wks. The table shows 1L and 2L+ results. Over 50% of pts had an AE; most frequently febrile neutropenia (13.5%), pain (9.5%), anemia, dyspnea, fever, thrombocytopenia and transaminitis (5.4% each). Conclusions Currently available systemic therapies are not specific for advanced ES, have a limited response durability and low tolerability. This is the largest US-based rw study that provides benchmarking treatment efficacy and safety data for development of standard of care therapies for ES. Table . 1687P Real-world outcomes by line of therapy 1L N = 74 2L+ N = 46 rwORR (95% CI), % 14.9 (7.7-25.0) 9.4 (4.4-17.1) Median rwDOR (95% CI), wks 14.5 (9.1-22.6) 19.6 (3.1-24.3) rwDCR (95% CI), % 20.3 (11.8-31.2) 19.8 (12.4-29.2) Median rwPFS (95% CI), wks 11.0 (7.3-29.9) 26.0 (13.9-32.0) Median OS (95% CI), wks 66.3 (49.6-94.1) 43.3 (33.6-78.3) Legal entity responsible for the study Epizyme, Inc. Funding Epizyme, Inc. Disclosure M.M. Gounder: Advisory / Consultancy, Travel / Accommodation / Expenses: Epizyme; Honoraria (self), Advisory / Consultancy: Karyopharm; Honoraria (self), Advisory / Consultancy: Daiichi; Honoraria (self): TRACON; Honoraria (self): Amgen. P. Merriam: Advisory / Consultancy: Lilly. S.R. Patel: Advisory / Consultancy, Research grant / Funding (self): Janssen; Advisory / Consultancy: PharmaMar; Advisory / Consultancy: MJ Hennessey/Onc Live; Advisory / Consultancy: Novartis; Advisory / Consultancy: Immune D; Research grant / Funding (self): Eisai; Research grant / Funding (self): Blueprint Medicines; Research grant / Funding (self): Bavarian Nordic. R. Chugh: Advisory / Consultancy: Epizyme, Janssen ,EMD Serono; Research grant / Funding (institution): AADi (Institution), Novartis (Institution), Lilly (Institution), Medivation (Institution), Advenchen (Institution), Epizyme (Institution), Plexiconn (Institution), Pfizer (Institution); Research grant / Funding (self): Portoia Pharmaceuticals. M. Thorton: Research grant / Funding (self): Epizyme; Advisory / Consultancy: Biologics Consulting Group; Shareholder / Stockholder / Stock options: Ziopharm, Novavax, Zogenix. B.A. Van Tine: Advisory / Consultancy, Research grant / Funding (institution): Epizyme. A.H. Abdelhamid: Research grant / Funding (institution): Dubai Harvard Foundation. P. Joshi: Full / Part-time employment: Epizyme. J. Whalen: Full / Part-time employment: Epizyme. J. Yang: Shareholder / Stockholder / Stock options, Full / Part-time employment: Epizyme. A. Rajarethinam: Shareholder / Stockholder / Stock options, Full / Part-time employment: Epizyme. M.S. Duh: Research grant / Funding (self): Epizyme, Novartis, GlaxoSmithKline, Janssen, Pfizer, Bayer, Taiho Pharmaceutical; Speaker Bureau / Expert testimony: AbbVie. P.J. Bobbili: Research grant / Funding (self): Epizyme, Novartis, AstraZeneca, GlaxoSmithKline. C.L. Cavanaugh: Research grant / Funding (institution): Epizyme, GlaxoSmithKline, NovoNordisk, Merck, Eisai, AstraZeneca. L. Huynh: Research grant / Funding (institution): Epizyme, Novartis, Pfizer, Taiho Pharmaceutical; Travel / Accommodation / Expenses: Novartis. T. Totev: Research grant / Funding (institution): Epizyme, Novartis, Takeda (formerly Shire). G. Demetri: Shareholder / Stockholder / Stock options: Blueprint Medicines, Merrimack G1 Therapeutics; Caris Life Sciences; Chapions Oncology; Besson Phramceuticals; Advisory / Consultancy: Novartis, Pfizer, EMD Serono, Jannsen, Ignyta, Loxo, Mirati Therapeutics, Epizyme, PharmaMar, Daiichi Sankyo, WIRB-copernicus group, Ziopharm Oncology, Polaris, Bluprint Medicines, Merrimack, G1 Therapeutics, Caris Life Sciences, Champions Oncology, Besso; Research grant / Funding (institution): Bayer, Novartis, Pfizer, Jannsen, Ignyta, Loxo, AbbVie, Epizyme, AdaptImmune.; Licensing / Royalties: Novartis. All other authors have declared no conflicts of interest.