E. Anders Kolb

Initial Testing of the Aurora Kinase A Inhibitor MLN8237 by the Pediatric Preclinical Testing Program (PPTP)

MLN8237 is a small molecule inhibitor of Aurora Kinase A (AURKA) that is currently in early phase clinical testing. AURKA plays a pivotal role in centrosome maturation and spindle formation during mitosis.

Initial testing (stage 1) of a monoclonal antibody (SCH 717454) against the IGF-1 receptor by the pediatric preclinical testing program

SCH 717454 (19D12) is a fully human antibody directed against the insulin‐like growth factor 1 receptor (IGF‐1R), which is implicated in the growth and metastatic phenotype of a broad range of malignancies. The activity of SCH 717454 was evaluated against the in vitro and in vivo panels of the Pediatric Preclinical Testing Program (PPTP).

Initial testing (stage 1) of the mTOR inhibitor rapamycin by the pediatric preclinical testing program

Rapamycin is a highly specific inhibitor of mTOR, a serine/threonine kinase that controls cap‐dependent translation. Here we report the activity of rapamycin against the in vitro and in vivo panels of the Pediatric Preclinical Testing Program (PPTP).

Initial testing of the VEGFR inhibitor AZD2171 by the pediatric preclinical testing program

Inhibition of vascular endothelial growth factor mediated signaling shows promise as an antiangiogenic strategy for solid tumors. AZD2171 is a potent and relatively selective inhibitor of the vascular endothelial growth factor (VEGF) receptor family that is orally bioavailable. This study was designed to screen for antitumor activity of AZD2171 against the in vitro and in vivo childhood cancer preclinical models of the Pediatric Preclinical Testing Program (PPTP).

Initial testing (stage 1) of the proteasome inhibitor bortezomib by the pediatric preclinical testing program

Bortezomib is a proteasome inhibitor that has been approved by FDA for the treatment of multiple myeloma and that has completed phase 1 testing in children. The purpose of the current study was to evaluate the antitumor activity of bortezomib against the in vitro and in vivo childhood cancer preclinical models of the Pediatric Preclinical Testing Program (PPTP).

Initial testing (stage 1) of the BH3 mimetic ABT-263 by the pediatric preclinical testing program.

ABT‐263 is a potent (Ki < 1 nM) small‐molecule BH3 mimetic that inhibits the antiapoptotic proteins Bcl‐2, Bcl‐xL and Bcl‐w. The structurally related Bcl‐2 inhibitor ABT‐737 exhibits single‐agent preclinical activity against lymphoma, small‐cell lung carcinoma, and chronic lymphocytic leukemia and displays synergistic cytotoxicity with chemotherapeutics and radiation.

Parallel randomized trials of risk-based therapy for fetal alloimmune thrombocytopenia.

OBJECTIVE: Antenatal therapy with intravenous immunoglobulin (IVIG) and prednisone has been shown to improve fetal thrombocytopenia and reduce the incidence of intracranial hemorrhage in neonatal alloimmune thrombocytopenia. Optimization of this therapy for individual patients, however, has yet to be achieved. METHODS: In these parallel, randomized, multicenter studies, 78 patients in 79 pregnancies were stratified to 2 different treatment arms based on the presence of a peripartum intracranial hemorrhage in a previously affected sibling and/or the initial fetal platelet count. Patients with a history of an antenatal intracranial hemorrhage in a prior pregnancy were excluded. RESULTS: Forty women whose children from a previous birth had a peripartum intracranial hemorrhage or whose current fetus had an initial platelet count less than 20,000/mL3 were randomly assigned to receive IVIG plus prednisone or IVIG alone. The mean increase in fetal platelet counts in the following 3 to 8 weeks was 67,100/mL3 and 17,300/mL3, respectively (P < .001). Thirty-nine patients whose prior affected child did not have an intracranial hemorrhage and whose initial platelet count was more than 20,000/mL3 were randomly assigned to receive IVIG alone or prednisone alone. There were no significant differences, and 33 (85%) had birth platelet counts more than 50,000/mL3. There were 11 (6%) significant complications after a total of 175 fetal blood sampling procedures, 2 of which led to fetal or neonatal deaths. CONCLUSION: The spectrum of disease severity of alloimmune thrombocytopenia is reflected in the initial fetal platelet count and response to therapy. Fetal blood sampling may be associated with significant fetal/neonatal morbidity and mortality. Empiric therapy sufficient to treat the most severely affected fetuses will overtreat others and is likely to be associated with additional maternal morbidity.

Initial testing of a monoclonal antibody (IMC-A12) against IGF-1R by the pediatric preclinical testing program†

Many childhood malignancies including sarcomas, neuroblastoma, and Wilms tumor show the presence of both, active, type‐1‐insulin‐like growth factor receptor (IGF‐1R), and the autocrine production of its ligands IGF‐1/IGF‐2. IMC‐A12 is a fully human IgG1 antibody that prevents ligand binding to the IGF‐1R.

Stage 2 combination testing of rapamycin with cytotoxic agents by the pediatric preclinical testing program

Rapamycin demonstrated broad-spectrum tumor growth inhibition activity against the in vivo panels of childhood tumors used in the Pediatric Preclinical Testing Program (PPTP). Here we have evaluated rapamycin combined with agents used frequently in the treatment of childhood malignancies. Rapamycin was tested in vitro against 23 cell lines alone or in combination with melphalan, cisplatin, vincristine, or dexamethasone (leukemic models only). In vivo, the impact of combining rapamycin with a cytotoxic agent was evaluated using two measures: 1) the therapeutic enhancement measure, and 2) a linear regression model for time-to-event to formally evaluate for sub- and supraadditivity for the combination compared to the agents used alone. Combining rapamycin with cytotoxic agents in vitro gave predominantly subadditive or additive effects, except for dexamethasone in leukemia models for which supra-additive activity was observed. In vivo testing demonstrated that therapeutic enhancement was common for rapamycin in combination with cyclophosphamide and occurred for 4 of 11 evaluable xenografts for the rapamycin and vincristine combination. The combinations of rapamycin with either cyclophosphamide or vincristine were significantly more effective than the respective standard agents used alone at their maximum tolerated doses (MTD) for most evaluable xenografts. The combination of rapamycin and cisplatin produced excessive toxicity requiring cisplatin dose reductions, and therapeutic enhancement was not observed for this combination. Addition of rapamycin to either cyclophosphamide or vincristine at their respective MTDs appears promising, as these combinations are relatively well tolerated and as many of the pediatric preclinical models evaluated demonstrated therapeutic enhancement for these combinations. Mol Cancer Ther; 9(1); 101–12

Initial testing (stage 1) of sunitinib by the pediatric preclinical testing program

Sunitinib is an orally bioavailable, multi‐targeted tyrosine kinase inhibitor with selectivity for PDGF receptors, VEGF receptors, FLT3, and KIT.