A Study of LY2880070 and Gemcitabine in People With Ewing Sarcoma,Ewing-Like Sarcoma, and Desmoplastic Small Round Cell Tumor

Inclusion Criteria: * Consent/Assent: all patients and/or their parents or legally authorized representatives must sign written informed consent; assent, when appropriate, will be obtained according to institutional guidelines * Weight/Age: patients must be ≥40 kg at the time of study enrollment, but may be of any age * Diagnosis: Patients must have histologically documented locally advanced or metastatic disease confirmed at MSK as follows: * Main cohort: Ewing sarcoma as molecularly defined by an EWSR1 fusion with an ETS-transcription factor family member including FLI1, ERG, ETV1, ETV4, and FEV * Pilot cohort: Ewing-like sarcomas including CIC-rearranged sarcoma, BCOR-rearranged sarcoma, and sarcomas with a rearrangement between EWSR1 and a non-ETS family gene or desmoplastic small round cell tumor as molecularly defined by an EWSR1-WT1 fusion Note: Any patient being enrolled into the pilot cohort that does not have a CIC, BCOR- rearranged sarcoma, or desmoplastic small round cell tumor will be reviewed with study pathologist, Dr. Cristina Antonescu, to ensure the categorization as Ewing-like sarcoma is appropriate * Patients must be able to swallow capsules * Therapeutic options: patient's current disease state must be one which has failed standard cytotoxic chemotherapy including cyclophosphamide/doxorubicin/vincristine and ifosfamide/etoposide * Disease Status: patients must have measurable disease based on RECIST 1.1 * Performance level: Karnofsky ≥70% for pati…