Irinotecan, Temozolomide and Bevacizumab in Combination With Existing High Dose Alkylator Based Chemotherapy for Treatment of Newly Diagnosed Patients With Desmoplastic Small Round Cell Tumor

Inclusion Criteria: * Age greater than or equal to 1 year, less than 30 years * Newly diagnosed, previously untreated patients with histologically or molecularly confirmed DSRCT * Adequate hematologic function: * Absolute neutrophil count ≥ 1,000/mm3 * Platelet count ≥ 100,000/mytm3 * Adequate renal function: * Normal creatinine for age OR * Creatinine clearance or radioisotope GFR ≥ 70ml/min/1.73 m2 * Adequate hepatic function: * Total bilirubin ≤ 1.5 x the ULN for age * AST ≤ 2.5 x the ULN for age \[in the absence of hepatic involvement of tumor\] * Normal cardiac function * Shortening fraction greater than or equal to 28% by echocardiogram OR * Left ventricular ejection fraction (LVEF) greater than or equal to 50% on technetium-99m pertechnetate radionuclide cineangiography (MUGA) or echocardiogram * Hypertension must be well controlled on stable doses of medication for at least two weeks prior to enrollment. * Patients must consent to an indwelling central venous catheter. * Sexually active patients of reproductive potential must be willing to use an effective method of contraception. Exclusion Criteria: * Prior chemotherapy or radiotherapy * Pregnant or breastfeeding females * Patients with documented chronic non-healing wound, ulcer or bone fracture. * Incomplete healing from previous oncologic or other major surgery. * Surgical procedures: Patients who have undergone major surgery (including open biopsy, thoracotomy, organ resection, exploratory laparotomy, arteriovenous grafts) \<28 days prior to enrollment will have bevacizumab dosing delayed as outlined in section 9.1 * Patients must be at least 48 hours from placement of central catheter before receiving first dose of bevacizumab * Minor surgical procedures (needle/laparoscopic core biopsies) for limited purposes of tissue retrieval will be allowed. Patients should not receive the first planned dose of bevacizumab until the wound is healed and 7 days have elapsed since the procedure. * Evidence of bleeding diathesis or significant coagulopathy (in the absence of therapeutic anticoagulation). * Thrombosis: * Patients must not have had a deep venous or arterial thrombosis (non-central venous catheter related) within the last three months prior to study entry. * Patients with cerebrovascular accident or transient ischemic attack within 6 months of therapy are excluded * History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within 6 months prior to study entry. * CNS status: Patients must not have known CNS metastases or leptomeningeal disease. Screening with brain imaging is not required for asymptomatic patients. Proteinuria: Urine protein: creatinine ratio greater than or equal to 1.0 * Uncontrolled hypertension (defined as SBP and/or DBP \> 95th percentile for age) * Prior history of hypertensive crisis or hypertensive encephalopathy * NYHA Grade II or greater congestive heart failure * History of myocardial infarction or unstable angina within 12 months prior to Day 1 * History of stroke or transient ischemic attack * Significant vascular (e.g., aortic aneurysm, requiring surgical repair or recent peripheral arterial thrombosis) within 6 months prior to Day 1 * History of hemoptysis (greater than or equal to 1/2 teaspoon of bright red blood per episode) within 1 month prior to Day 1 * Known hypersensitivity to any component of bevacizumab