OTHR-03. Oxaliplatin as a hearing-sparing alternative to carboplatin in tandem autologous stem cell transplants in pediatric CNS malignancy

Abstract BACKGROUND: Intensive chemotherapy with tandem autologous stem cell transplants (autoSCT) is shown to improve survival for children with CNS malignancy. Platinum-based chemotherapeutic agents in these regimens, mainly cisplatin and carboplatin, have resulted in significant sensorineural hearing loss. Oxaliplatin, a newer platinum-based agent, is considered less ototoxic. Empiric substitution of oxaliplatin for carboplatin in preparative regimens for autoSCT have been tried. However, the survival and ototoxicity outcomes have not been studied. OBJECTIVE: To compare the overall survival and ototoxicity of oxaliplatin versus carboplatin preparatory chemotherapy regimens in children who received tandem autoSCT for treatment of CNS malignancy. METHODS: We performed a retrospective chart review of all pediatric patients with primary CNS tumors who received tandem autoSCT from 2011 to 2018 at Children’s Hospital Colorado. Demographics, clinical outcomes, and medication administration records were extracted from electronic medical records. Hearing evaluations, performed at pre-transplant, after each transplant episode, and at follow-up visits, were reviewed and graded by an audiologist. Comparisons were performed using Fisher’s exact tests and log rank test statistics. RESULTS: 32 pediatric patients with CNS tumors met inclusion criteria. Seven patients received oxaliplatin in place of carboplatin in one or more preparatory regimens. There was no statistically significant difference in overall survival between the two groups (p=0.99). A total of 85 follow-up audiograms were available for assessment, including long-term follow up. Of the 13 audiograms that showed hearing loss, one (8%) had prior oxaliplatin exposure, compared to 18/72 (25%) audiograms without hearing loss had prior oxaliplatin exposure (p=0.28). CONCLUSIONS: Oxaliplatin is effective and well-tolerated when used in lieu of carboplatin in preparatory regimen for autoSCT for pediatric CNS malignancy. This study is limited by its small size. A larger, multi-center study is warranted to confirm oxaliplatin’s safety and effect on survival and ototoxicity in pediatric autoHSCT.