November 2022: In children aged one month and older with localised, non-metastatic solid tumours, the Food and Drug Administration has approved sodium thiosulfate (Pedmark, Fennec Pharmaceuticals Inc.) to lower the risk of ototoxicity associated with cisplatin.
Two multicenter open-label, randomised controlled studies, SIOPEL 6 (NCT00652132) and COG ACCL0431, were conducted in children receiving cisplatin-based chemotherapy for cancer (NCT00716976).
114 patients with standard risk hepatoblastoma were enrolled in SIOPEL 6 and underwent 6 cycles of postoperative cisplatin-based chemotherapy. Depending on their actual body weight, patients were randomised (1:1) to receive cisplatin-based treatment with or without sodium thiosulfate at different doses of 10 g/m2, 15 g/m2, or 20 g/m2. The majority of patients having a Brock Grade 1 hearing loss, as determined by pure tone audiometry following therapy or at the age of at least 3.5 years, whichever came first, was the primary outcome. When cisplatin was combined with sodium thiosulfate, there was a decreased incidence of hearing loss (39% vs. 68%); the unadjusted relative risk was 0.58 (95% CI: 0.40, 0.83).
Children with solid tumours who were receiving chemotherapy that included cumulative cisplatin doses of 200 mg/m2 or more and individual cisplatin doses to be administered for a maximum of six hours were included in COG ACCL0431. The administration of chemotherapy based on cisplatin with or without sodium thiosulfate was randomly assigned (1:1) to patients. A group of 77 patients with locally contained, non-metastatic solid tumours had their efficacy assessed. The American Speech-Language-Hearing Association (ASHA) criteria for hearing loss were measured at baseline and four weeks following the final treatment of cisplatin. This was the main outcome. When cisplatin was combined with sodium thiosulfate, the incidence of hearing loss was decreased (44% vs. 58%); the unadjusted relative risk was 0.75 (95% CI: 0.48, 1.18).
Vomiting, nausea, a reduction in haemoglobin, hypernatremia, and hypokalemia were the most frequent adverse effects in the two studies (25% with a difference between arms of >5% compared to cisplatin alone).
The dosage of sodium thiosulfate that is advised is based on the surface area of the body as measured by real weight. Following intravenous infusions of cisplatin that last one to six hours, sodium thiosulfate is given over the course of 15 minutes.