Inclusion Criteria

Inclusion Criteria for Screening Phase:

Patient 1 to 70 years of age with neuroblastoma, rhabdomyosarcoma, or osteogenic sarcoma,
who have one or more of the following high risk features:

- Neuroblastoma:

- Stage IV disease

- Stage III disease with n-myc amplification

- Osteogenic sarcoma:

- Presence of metastases

- Elevated alkaline phosphatase or LDH at diagnosis

- Primary tumor affecting the axial skeleton

- Poor histopathological response after completion of pre-surgical
chemotherapy (≥10% viable tumor)

- Rhabdomyosarcoma:

- Stage IV disease

- Alveolar histology

- Positive tumor margins, with lymph node positivity

Inclusion Criteria for Vaccine Phase:

- Patient meets all screening criteria and tumor is positive for NY-ESO-1, MAGE- A1, or
MAGE-A3 by immunohistochemistry or RT-PCR.

- Patients who are between 3 months and 2 years following the completion of therapy,
and have achieved at least a very good partial response to primary therapy.

- No chemotherapy is planned for one month following the last vaccination.

- Bilirubin <2 mg/dL, and SGOT/SGPT <2.5 x normal

- Creatinine clearance > 50ml/min as estimated by patient's serum creatinine, weight,
and age

- Room air pulse oximetry >94%

- Patient is not pregnant

- Male and female sexually active patients of reproductive who wish to participate must
agree to use acceptable contraception

- Patient is not moribund and has a projected life expectancy >6 months

- Lansky performance scale > 70, ECOG < 2 (Appendix I)

- Potential subjects will be tested for HIV 1 and 2 antibodies, HTLV 1/2 antibodies,
and for HIV 1, hepatitis C and hepatitis B virus by NAT testing. - -Subjects testing
positive for any of these pathogens will be ineligible for vaccine.

- White blood cells ≥ 2.5 K/µL, Hemoglobin ≥ 8 g/dL, Hematocrit > 25%, and Platelets ≥
70 K/µL

- Patient does not have central nervous system involvement.

- Patient does not a have a history of autoimmune disease, specifically inflammatory
bowel disease, systemic lupus erythematosis, or rheumatoid arthritis

- Patient is not receiving concurrent systemic steroid therapy

- Patient does not have a known systemic hypersensitivity to imiquimod or any vaccine
component