A Study of Intravenous EEDVsMit in Children With Recurrent / Refractory Solid or CNS Tumours Expressing EGFR

Inclusion Criteria: * Patients must be ≥ 2 years and ≤ 21 years old at the time of study enrolment. * Karnofsky ≥ 50% for patients \> 16 years of age and Lansky ≥ 50 for patients ≤ 16 years of age * Patients must have relapsed or refractory solid or CNS tumours or have a diagnosis of DIPG. Patients must have had histologic verification of malignancy at original diagnosis or relapse, or a diagnosis of DIPG by MRI imaging. * Patients must have either measurable or evaluable disease for Part B of the study only * Patient's current disease state must be one for which there is no known curative therapy or therapy proven to prolong survival with an acceptable quality of life. * Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study Exclusion Criteria: * Pregnant or breast-feeding women will not be entered on this study. * Any active uncontrolled infection * Patients who are known to be serologically positive for Hepatitis A, B or C, or have a history of liver disease, other forms of hepatitis or cirrhosis. * Known positive test for human immunodeficiency virus infection * Patients with disease of any major organ system that would compromise their ability to withstand therapy * Concurrent or prior (within 7 days of enrolment) anticoagulation therapy, except low molecular weight heparins or low dose aspirin * Patients receiving corticosteroids must be on a stable dose that has not been increased for at least 7 days prior to study enrolment. * Patients who are currently receiving another investigational drug are ineligible. * Patients who are currently receiving other antineoplastic agents are ineligible. * All herbal supplements, vitamins, and nutritional supplements taken within the last 30 days prior to dosing on Day 1 (and continued use, if appropriate), must be reviewed and approved by the Study Chair. * Patient will not be available for protocol-required study visits or procedures, to the best of the subject/parent/guardian's and investigator's knowledge. * Patient has any kind of disorder that, in the opinion of the investigator, may compromise the ability of the subject/parent/guardian to give written informed consent and/or to comply with all required study procedures. * History or evidence of any other clinically significant disorder, condition or disease (with the exception of those outlined above) that, in the opinion of the investigator would pose a risk to subject safety or interfere with the study evaluation, procedures or completion. * Patients will be screened for antibodies to S. typhimurium and will not be eligible until antibodies are non-detectable * Patients will be screened for IL6 and TNFa cytokines and will not be eligible until levels are less than 3x times the detectable limit of the assay.