This 3 arm study will determine the dose of R1507 which will achieve a mean drug exposure in children and adolescents with advanced solid tumors equivalent to the exposure achieved in adults at the recommended dose of 9mg/kg/week. It will also determine the maximum tolerated dose (if appropriate) and the pharmacokinetic profile of R1507. Groups of patients will be sequentially enrolled in one of up to 3 dose levels (3,9mg/kg or a PK-derived dose, not to exceed 16 mg/kg) of R1507 administered weekly by intravenous infusion.An expanded cohort of patients will be enrolled at the optimal dose/MTD. The anticipated time on study treatment is until disease progression or dose limiting toxicity, and the target sample size is <100 individuals.

Inclusion Criteria:

• pediatric patients aged 2-17 years of age;
• histologically confirmed solid tumors;
• cancer which has relapsed after, or failed to respond to, curative therapy, or no other potentially curative treatment options available.

Exclusion Criteria:

• treatment with corticosteroids within past 2 weeks;
• current or past use of anti-IGF-1R antibodies;
• current treatment with immunosuppressive agents;
• patients with diabetes mellitus;
• known HIV or hepatitis B or C;
• hypersensitivity to any of the components of R1507 or to monoclonal antibodies.