Phase II study of sorafenib in children with recurrent or progressive low-grade astrocytomas

Neuro Oncol. 2014 Oct;16(10):1408-16. doi: 10.1093/neuonc/nou059. Epub 2014 May 6.

Abstract

Background: Activation of the RAS-RAF-MEK-ERK signaling pathway is thought to be the key driver of pediatric low-grade astrocytoma (PLGA) growth. Sorafenib is a multikinase inhibitor targeting BRAF, VEGFR, PDGFR, and c-kit. This multicenter phase II study was conducted to determine the response rate to sorafenib in patients with recurrent or progressive PLGA.

Methods: Key eligibility criteria included age ≥ 2 years, progressive PLGA evaluable on MRI, and at least one prior chemotherapy treatment. Sorafenib was administered twice daily at 200 mg/m(2)/dose (maximum of 400 mg/dose) in continuous 28-day cycles. MRI, including 3-dimensional volumetric tumor analysis, was performed every 12 weeks. BRAF molecular testing was performed on tumor tissue when available.

Results: Eleven patients, including 3 with neurofibromatosis type 1 (NF1), were evaluable for response; 5 tested positive for BRAF duplication. Nine patients (82%) came off trial due to radiological tumor progression after 2 or 3 cycles, including 3 patients with confirmed BRAF duplication. Median time to progression was 2.8 months (95% CI, 2.1-31.0 months). Enrollment was terminated early due to this rapid and unexpectedly high progression rate. Tumor tissue obtained from 4 patients after termination of the study showed viable pilocytic or pilomyxoid astrocytoma.

Conclusions: Sorafenib produced unexpected and unprecedented acceleration of tumor growth in children with PLGA, irrespective of NF1 or tumor BRAF status. In vitro studies with sorafenib indicate that this effect is likely related to paradoxical ERK activation. Close monitoring for early tumor progression should be included in trials of novel agents that modulate signal transduction.

Keywords: low-grade glioma; pediatric low-grade astrocytoma; phase II trial; sorafenib.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Animals
  • Antineoplastic Agents / therapeutic use*
  • Astrocytoma / drug therapy*
  • Astrocytoma / mortality
  • Astrocytoma / pathology
  • Brain Neoplasms / drug therapy*
  • Brain Neoplasms / mortality
  • Brain Neoplasms / pathology
  • Child, Preschool
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • MAP Kinase Signaling System / drug effects
  • Magnetic Resonance Imaging
  • Male
  • Mice
  • NIH 3T3 Cells
  • Niacinamide / administration & dosage
  • Niacinamide / analogs & derivatives*
  • Niacinamide / therapeutic use
  • Phenylurea Compounds / administration & dosage
  • Phenylurea Compounds / therapeutic use*
  • Protein Kinase Inhibitors / administration & dosage
  • Protein Kinase Inhibitors / therapeutic use
  • Sorafenib
  • Treatment Outcome

Substances

  • Antineoplastic Agents
  • Phenylurea Compounds
  • Protein Kinase Inhibitors
  • Niacinamide
  • Sorafenib