Phase I and pharmacokinetic trial of PTC299 in pediatric patients with refractory or recurrent central nervous system tumors: a PBTC study.

Abstract

PTC299 is a novel, orally-bioavailable small molecule that selectively inhibits vascular endothelial growth factor receptor protein synthesis at the post-transcriptional level. Based on promising preclinical results, we conducted a pediatric phase I study to estimate the maximum tolerated dose, describe dose-limiting toxicities (DLT) and characterize the pharmacokinetic profile of PTC299 in children with recurrent CNS tumors. PTC299 was administered orally twice or three times daily, depending on the regimen. Four regimens were evaluated using the rolling 6 design, starting with 1.2 mg/kg/dose twice daily and escalating to 2 mg/kg/dose three times daily. Pharmacokinetic studies were performed during the first two courses. Twenty-seven children (14 male, median age 11.2, range 5.5-21 years) with recurrent brain tumors were treated; 21 were fully evaluable for toxicity assessment. Therapy was well-tolerated, and the only DLT was grade 3 hyponatremia. Grade three and grade four toxicities were uncommon in subsequent cycles. Median AUC0-Tlast values at the 2 mg/kg were similar to those observed in adults. The study was terminated while patients were being treated at the highest planned dose, due to hepatotoxicity encountered in the ongoing adult phase I studies. No complete or partial responses were observed. Two patients with low-grade gliomas were noted to have minor responses, and at the time of the study's closure, 5 children with low-grade gliomas had been on therapy for 8 or more courses (range 8-16). PTC299 was well-tolerated at the highest dose level tested (2 mg/kg/dose TID) in children with recurrent brain tumors and prolonged disease stabilization was seen in children with low-grade gliomas.

• Authors: Roger J Packer, Brian R Rood, David C Turner, Clinton F Stewart, Michael Fisher, Christopher Smith, Tina Young-Pouissant, Stewart Goldman, Rishi Lulla, Anu Banerjee, Ian Pollack, Larry Kun, Arzu Onar-Thomas, Shengjie Wu, James M Boyett, Maryam Fouladi
• Journal: Journal of neuro-oncology (J Neurooncol) Vol. 121 Issue 1 Pg. 217-24 (Jan 2015) ISSN: 1573-7373 [Electronic] United States
• PMID: 25407389 (Publication Type: Clinical Trial, Phase I, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Imidazoles
• Thiazoles
• 6-(4-fluorophenyl)-2,3-dihydro-5-(4-pyridinyl)imidazo(2,1-b)thiazole

Topics

• Adolescent
• Antineoplastic Agents (administration & dosage, adverse effects, pharmacokinetics)
• Central Nervous System Neoplasms (drug therapy)
• Child
• Child, Preschool
• Female
• Humans
• Hyponatremia (chemically induced)
• Imidazoles (administration & dosage, adverse effects, pharmacokinetics)
• Male
• Neoplasm Recurrence, Local (drug therapy)
• Thiazoles (administration & dosage, adverse effects, pharmacokinetics)
• Treatment Outcome
• Young Adult