EPT-15A PHASE1/2 CLINICAL TRIAL OF VELIPARIB (ABT-888) AND RADIATION FOLLOWED BY MAINTENANCE THERAPY WITH VELIPARIB AND TEMOZOLOMIDE (TMZ) IN PATIENTS WITH NEWLY DIAGNOSED DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG): A PEDIATRIC BRAIN TUMOR CONSORTIUM INTERIM REPORT OF PHASE II STUDY