Enoblituzumab (MGA271) in Children With B7-H3-expressing Solid Tumors

This study is a Phase 1, open-label, dose escalation and cohort expansion trial designed to characterize the safety, tolerability, PK, PD, immunogenicity and preliminary antitumor activity of enoblituzumab administered IV on a weekly schedule for up to 96 doses (approximately 2 years) in children and young adults with B7-H3-expressing relapsed or refractory malignant solid tumors. The study consists of a Dose Escalation Phase to determine the MTD (or MAD) of enoblituzumab followed by a Cohort Expansion Phase to further define the safety and initial antitumor activity of enoblituzumab. In the cohort expansion phase, 5 cohorts of 10 patients each will be enrolled to further evaluate the safety and potential efficacy of enoblituzumab administered at the MTD/MAD in patients with:1) neuroblastoma - measurable disease, 2) neuroblastoma - non-measurable disease, 3) rhabdomyosarcoma, 4) osteosarcoma, and 5) Ewing's sarcoma, Wilms' tumor, desmoplastic small round cell tumors, or malignant solid tumors of any other histology that test positive for B7-H3. All tumor evaluations will be carried out by both Response Evaluation Criteria in Solid Tumors (RECIST) and immune-related response criteria (irRC). Disease assessment in patients with neuroblastoma will use neuroblastoma overall response criteria.