# Sodium thiosulfate (otoprotectant)

Source: https://onco.cc/drugs/sodium-thiosulfate/  
OnCo record `sodium-thiosulfate` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

An old antidote proven in two paediatric trials to halve permanent hearing loss from cisplatin, and approved in 2022 as the first drug to prevent a chemotherapy side effect in children.

## Summary

SIOPEL-6 (NEJM 2018, hepatoblastoma) and ACCL0431 (Lancet Oncol 2017) showed hearing loss reduced from ~63% to ~33% without compromising survival in localised disease (a survival signal in disseminated disease in ACCL0431 keeps use to localised tumours). Approved FDA September 2022 (ages ≥1 month), EMA 2023.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-08
- Tags: gap-fill; supportive
- Brand: Pedmark
- Modality: Small-molecule chemoprotectant
- Mechanism: Thiol that inactivates circulating cisplatin and scavenges reactive oxygen species in the cochlea when given 6 hours after cisplatin, after tumour exposure is complete.
- Approvals: US 2022: Reduce risk of ototoxicity from cisplatin in patients ≥1 month with localised, non-metastatic solid tumours; EU 2023: Same

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Sodium_thiosulfate_(medical_use)
- SIOPEL-6 (NEJM 2018): https://doi.org/10.1056/NEJMoa1801109
- Label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=Pedmark

## Connected records

- cancers: [Germ cell tumours of childhood and adolescence (extracranial and CNS)](https://onco.cc/cancers/paediatric-germ-cell-tumours/), [Hepatoblastoma](https://onco.cc/cancers/hepatoblastoma/), [Medulloblastoma](https://onco.cc/cancers/medulloblastoma/), [Neuroblastoma (paediatric)](https://onco.cc/cancers/neuroblastoma/), [Osteosarcoma](https://onco.cc/cancers/osteosarcoma/)
- technologies: [Hearing after platinum and cranial radiotherapy in a developing child](https://onco.cc/technologies/rejuv-paed-hearing/), [Hearing and tinnitus after platinum chemotherapy](https://onco.cc/technologies/hearing-after-platinum-chemotherapy/), [Platinum agents](https://onco.cc/technologies/platinum/), [Survivorship care and late-effects surveillance](https://onco.cc/technologies/survivorship-care-plan/)
- companies: [Fennec Pharmaceuticals](https://onco.cc/companies/fennec-pharmaceuticals/)
- trials: [A Study of Treatment for Medulloblastoma Using Sodium Thiosulfate to Reduce Hearing Loss](https://onco.cc/trials/nct05382338/), [Cisplatin With or Without Sodium Thiosulfate in Treating Young Patients With Stage I, II, or III Childhood Liver Cancer](https://onco.cc/trials/nct00652132/), [Sodium Thiosulfate in Preventing Hearing Loss in Young Patients Receiving Cisplatin for Newly Diagnosed Germ Cell Tumor, Hepatoblastoma, Medulloblastoma, Neuroblastoma, Osteosarcoma, or Other Malignancy](https://onco.cc/trials/nct00716976/)
- key papers: [Sodium Thiosulfate for Protection from Cisplatin-Induced Hearing Loss](https://onco.cc/key-papers/paper-brock-n-engl-j-med/)
- terms: [Peripheral neuropathy (chemotherapy-induced)](https://onco.cc/terms/peripheral-neuropathy/)
- roadmaps: [Chemotherapy roadmap: mustard gas → curative combinations → the warhead inside smarter drugs](https://onco.cc/roadmaps/chemotherapy-roadmap/), [Paediatric oncology roadmap: cooperative-group cures → engineered immunity → drugs developed for children first](https://onco.cc/roadmaps/paediatric-oncology-roadmap/), [Supportive care and survivorship roadmap: making treatment bearable → proving it extends life → caring for tens of millions afterwards](https://onco.cc/roadmaps/survivorship-roadmap/)

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