FDA OKs Sodium Thiosulfate Injection to Reduce Ototoxicity Risk in Kids With Cancer

Patricia McKnight

September 21, 2022

The US Food and Drug Administration (FDA) has approved sodium thiosulfate (Pedmark, Fennec Pharmaceuticals) injection to reduce the risk for ototoxicity associated with cisplatin in pediatric patients 1 month of age or older with localized, nonmetastatic solid tumors.

This approval makes sodium thiosulfate the first and only treatment FDA-approved in this area.

"Historically, there have been no approved treatments for preventing cisplatin-induced hearing loss," said David R. Freyer, DO, of Children's Hospital Los Angeles in California and primary investigator of one of the two trials, COG ACCL0431. The FDA's approval "addresses an enormous unmet need and for many children and young adults."

The approval was based on safety and efficacy data from two multicenter open-label, randomized controlled phase 3 trials — SIOPEL 6 and COG ACCL0431 — comparing sodium thiosulfate plus a cisplatin-based regimen to a cisplatin-based regimen alone in pediatric patients. SIOPEL 6 included patients with standard risk hepatoblastoma, and COG ACCL0431 included pediatric patients with solid tumors.

In both studies, the incidence of hearing loss was significantly lower in the sodium thiosulfate group compared with the cisplatin-only group. In SIOPEL 6, hearing loss of grade 1 or higher occurred in 33% of children (18 of 55) in the cisplatin–sodium thiosulfate group and 63% (29 of 46) in the cisplatin-only group, indicating a 48% lower incidence of hearing loss for those receiving sodium thiosulfate. In COG ACCL0431, hearing loss was identified in 28.6% of patients (14 of 49) receiving sodium thiosulfate compared with 56.4% (31 of 55) in the control group, indicating a 69% lower risk for hearing loss in the sodium thiosulfate group.

The FDA reported the same overall trend but highlighted slightly different figures. In SIOPEL 6, hearing loss incidence occurred in 39% of patients (24 of 61) in the sodium thiosulfate arm vs 68% (36 of 53) in the control group; in COG ACCL0431, hearing loss incidence occurred among 44% of patients (17 of 39) in the sodium thiosulfate group vs 58% (22 of 38) in the control group.

The recommended dose is based on surface area according to body weight. Sodium thiosulfate is administered as an intravenous infusion over 15 minutes following cisplatin infusions that are 1 to 6 hours in duration.

Serious adverse reactions occurred in 40% of patients who received cisplatin–sodium thiosulfate in SIOPEL 6 and 36% of these patients in COG ACCL0431. The most common adverse reactions in the trials included vomiting, infection, nausea, decreased hemoglobin, hypernatremia, and hypokalemia.

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