FDA Approves Fennec Hearing Loss Treatment for Pediatric Cancer Patients Treated with Cisplatin

Fennec Pharmaceuticals Inc (NASDAQ:FENC), a specialty pharmaceutical company, has received approval from the U.S. Food and Drug Administration (FDA) for the company’s unique formulation of sodium thiosulfate (STS) called Pedmark for the prevention of platinum-induced ototoxicity in pediatric patients one month to <18 years of age with localized, non-metastatic, solid tumors. Pedmark had previously received both Breakthrough Therapy and Fast Track Designation by the FDA in March 2018.

According to Fennec, cisplatin and other platinum compounds are essential chemotherapeutic agents for many pediatric malignancies.  Unfortunately, platinum-based therapies cause ototoxicity, or hearing loss, which is permanent, irreversible and particularly harmful to the survivors of pediatric cancer.

In the U.S. and Europe, it is estimated that, annually, over 10,000 children may receive platinum-based chemotherapy.  The incidence of ototoxicity depends upon the dose and duration of chemotherapy, and many of these children require lifelong hearing aids.

There is currently no established preventive agent for this hearing loss and only expensive, technically difficult and sub-optimal cochlear (inner ear) implants have been shown to provide some benefit. Infants and young children that suffer ototoxicity at critical stages of development lack speech language development and literacy, and older children and adolescents lack social-emotional development and educational achievement.

Pedmark has been studied by cooperative groups in two Phase 3 clinical studies of survival and reduction of ototoxicity, The Clinical Oncology Group Protocol ACCL0431 and SIOPEL 6. Both studies have been completed. The COG ACCL0431 protocol enrolled childhood cancers typically treated with intensive cisplatin therapy for localized and disseminated disease, including newly diagnosed hepatoblastoma, germ cell tumor, osteosarcoma, neuroblastoma, and medulloblastoma.  SIOPEL 6 enrolled only hepatoblastoma patients with localized tumors.

According to the FDA, efficacy was evaluated in two multicenter open-label, randomized controlled trials in pediatric patients undergoing treatment with cisplatin-based chemotherapy for cancer. Combining the data, the incidence of hearing loss was 39-44% with the sodium thiosulfate and cisplatin versus the cisplatin treatment (58-68%). The most common adverse reactions in the two trials (≥25% with difference between arms of >5% compared to cisplatin alone) were vomiting, nausea, decreased hemoglobin, hypernatremia, and hypokalemia. Sodium thiosulfate is administered as an intravenous infusion over 15 minutes following cisplatin infusions that are 1 to 6 hours in duration.