Enzastaurin in Treating Young Patients With Refractory Primary CNS Tumors

OBJECTIVES: Primary * To estimate the maximum tolerated dose (MTD) and/or recommend a phase II dose of enzastaurin hydrochloride in children with recurrent or refractory CNS tumors who are not receiving enzyme-inducing anticonvulsants. * To further characterize the pharmacokinetics and toxicity of the recommended phase II dose of enzastaurin hydrochloride given twice daily in these patients. Secondary * To characterize the pharmacokinetics of enzastaurin hydrochloride at the recommended phase II dose given once a day or twice a day in children. * To document and describe toxicities associated with enzastaurin hydrochloride. * To document antitumor activity in children with recurrent or refractory CNS tumors. * To explore changes in MR perfusion scans obtained within 15 ± 2 days after initiation of enzastaurin hydrochloride therapy as compared to baseline and to correlate these changes with clinical outcome. * To evaluate a panel of biological surrogate markers in this patient population at baseline and following enzastaurin hydrochloride administration. OUTLINE: This is a multicenter study. Patients receive oral enzastaurin hydrochloride once daily until the maximum tolerated dose (MTD) is determined. Patients then receive enzastaurin hydrochloride at the MTD twice daily on days 1-28. Treatment repeats every 28 days for 13 courses in the absence of disease progression or unacceptable toxicity. Patients may receive 13 additional courses (for a total of 26 courses) of oral enzastaurin hydrochloride if the patient is benefitting from the treatment and the investigator and subject agree to continue treatment. Patients undergo blood sample collection periodically for pharmacokinetic studies. After completion of study treatment, patients are followed periodically.