Testing a New Combination of Anti-cancer Drugs in Patients Newly Diagnosed With Ewing Sarcoma Who Have Cancer That Has Spread to Other Parts of the Body

PRIMARY OBJECTIVE: I. To determine if the event-free survival (EFS) in patients with newly diagnosed metastatic Ewing sarcoma is improved when treated with vincristine-irinotecan-regorafenib (VIrR) after initial treatment with vincristine-doxorubicin-cyclophosphamide (VDC) and ifosfamide-etoposide (IE) compared to patients treated with 17 cycles of interval compressed VDC and IE chemotherapy. SECONDARY OBJECTIVES: I. To compare the overall survival (OS) of patients with newly diagnosed metastatic Ewing sarcoma treated with VDC/IE/VIrR versus VDC/IE. II. To compare the toxicity profile of VDC/IE/VIrR to VDC/IE in patients with newly diagnosed metastatic Ewing sarcoma, using both investigator-reported and patient-reported Common Terminology Criteria for Adverse Events (CTCAE). III. To describe the feasibility and toxicity of augmented dose radiotherapy with 64.8 Gy as local control for patients with newly diagnosed metastatic Ewing sarcoma with large primary tumors. IV. To prospectively validate that circulating tumor-derived DNA (ctDNA) levels greater than or equal to 5% at the time of diagnosis are associated with increased risk of EFS-event for patients with newly diagnosed metastatic Ewing sarcoma. V. To prospectively validate that elevated ctDNA levels greater than or equal to 0.5% burden following one cycle of chemotherapy are associated with increased risk of EFS-event for patients with newly diagnosed metastatic Ewing sarcoma. EXPLORATORY OBJECTIVES: I. To estimate 1- and 2-year EFS and response rate for patients with newly diagnosed, eligible metastatic round cell sarcomas other than Ewing sarcoma. II. To characterize the change in fludeoxyglucose F-18 (FDG)-positron emission tomography (PET) imaging response of primary disease site at the end of Induction chemotherapy and its association with EFS. III. To explore distinguishing histologic attributes of Ewing sarcoma and round cell sarcomas that mimic Ewing sarcoma. IV. To collect bone marrow and tissue samples to bank for future research. V. To explore other ctDNA predictor variables, time points, and potential association with EFS in patients with newly diagnosed metastatic Ewing sarcoma. VI. To estimate the frequency of selected toxicities by Patient Reported Outcomes (PRO)-CTCAE and symptom bother by Functional Assessment of Cancer Therapy General Questionnaire (FACT-G) and to evaluate if these findings are associated with duration of protocol therapy and treatment arm. OUTLINE: INDUCTION: Patients receive vincristine intravenously (IV) on days 1 and 8, doxorubicin IV over 3-15 minutes on days 1 and 2, and cyclophosphamide IV over 30-60 minutes on day 1 of cycles 1, 3 and 5. Patients also receive ifosfamide IV over 1 hour and etoposide IV over 1 hour on days 1-5 of cycles 2, 4 and 6. Cycles repeat every 14 days for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients then undergo surgery or radiation therapy per investigator choice. CONSOLIDATION I: Patients receive vincristine IV on days 1 and 8, doxorubicin IV over 3-15 minutes on days 1 and 2, and cyclophosphamide IV over 30-60 minutes on day 1 of cycles 1 and 2. Patients also receive ifosfamide IV over 1 hour and etoposide IV over 1 hour on days 1-5 of cycles 3 and 4. Cycles repeat every 14 days for up to 4 cycles in the absence of disease progression or unacceptable toxicity. CONSOLIDATION II: After 10 cycles of therapy, patients with Ewing Sarcoma are randomized to 1 of 2 regimens. Patients with a diagnosis of other eligible metastatic round cell sarcomas are assigned to Regimen A. REGIMEN A: Patients receive vincristine IV on days 1 and 8 and cyclophosphamide IV over 30-60 minutes on day 1 of cycles 1, 3, 5 and 7. Patients also receive ifosfamide IV over 1 hour and etoposide IV over 1 hour on days 1-5 of cycles 2, 4 and 6. Cycles repeat every 14 days for up to 7 cycles in the absence of disease progression or unacceptable toxicity. After systemic therapy completed, patients undergo metastatic site radiation therapy. REGIMEN B: Patients receive vincristine IV on days 1 and 8 and irinotecan IV over 90 minutes on days 1-5 of each cycle. Patients also receive regorafenib orally (PO) on days 8-14 or 15-21 of cycle 1, and then on days 8-21 of cycles thereafter. Cycles repeat every 21 days for up to 6 cycles in the absence of disease progression or unacceptable toxicity. After systemic therapy completed, patients undergo metastatic site radiation therapy. Additionally, patients undergo blood sample collection, echocardiography, magnetic resonance imaging (MRI), computed tomography (CT), chest CT, and/or FDG-PET throughout the study. Patients may also undergo optional collection of tumor tissue and/or bone marrow aspiration and biopsy on study. After completion of study treatment, patients are followed every 3 months for years 1 and 2, every 6 months for years 3 and 4 then every 12 months for years 5-10.