Pedmark Reduces Chemo-Induced Hearing Loss in Children With Cancer

Among pediatric as well as adolescent and young adult (AYA) patients with non-metastatic solid tumors in Japan, positive topline results from a phase 2/3 clinical trial have shown that Pedmark (sodium thiosulfate injection) is associated with a reduction in chemotherapy-induced ear damage.

The development was announced in a news release issued by Fennec Pharmaceuticals Inc., a specialty pharmaceutical company, which noted that Pedmark is the first and to date only therapy approved by the U.S. Food and Drug Administration (FDA) for the reduction of the risk of ototoxicity associated with cisplatin treatment in pediatric patients age 1 month and older with localized, non-metastatic, sold tumors.

The STS-J01 study enrolled 27 patients in its primary cohort, age 3 to 18 years, and six in exploratory cohorts. The study’s primary endpoint was met, with data showing that 24% and 16% of evaluable patients treated with Pedmark experienced hearing loss as assessed by the American Speech-Language-Hearing Association (ASHA) criteria and Brock grade scaling, respectively. In the cisplatin-only arms of Pedmark’s pivotal phase 3 trials, 56% of patients developed clinically significant hearing loss according to ASHA criteria and 63% developed hearing impairment under Brock grade scoring. According to the news release, the study also demonstrated that among the largest subgroup of patients, age 7 to 18 years, hearing loss only occurred in 19% and 14.3% according to the ASHA and Brock scores, respectively.

Analysis showing an overall tumor response rate of 95% confirmed that Pedmark did not interfere with cisplatin’s antitumor activity, the company stated.

“The STS‑J01 findings add compelling support to the global clinical evidence base for PEDMARK®,” said Pierre S. Sayad, chief medical officer of Fennec Pharmaceuticals, in a statement included in the news release. “Seeing such low rates of hearing loss in a real‑world, investigator‑initiated setting in Japan reinforces the consistency and magnitude of Pedmark’s protective effect, which has now been demonstrated across multiple continents, tumor types and clinical settings. Importantly, the high tumor response rate and the pharmacokinetic data show that Pedmark does not interfere with how cisplatin works; by six hours, the active platinum is already bound and inactive. This is a critical and highly reassuring finding for physicians, families and regulators alike.”

The news release additionally noted that in more than 200 treatment-emergent side effects, none were found to be attributable to Pedmark.

“For decades in Japan, we have witnessed the profound and lifelong burden of cisplatin‑induced hearing loss among the children and young adults,” said Dr. Eiso Hiyama, lead investigator and professor in the Department of Pediatric Surgery at Hiroshima University Hospital in Hiroshima, Japan. “These encouraging results from the first large-scale pediatric and adolescent and young adults trial in Japan demonstrate that Pedmark can protect hearing without compromising cisplatin’s efficacy or introducing any concerning side effects. As a clinician, and with the current unmet medical need of cancer patients in Japan, these findings give me confidence in the effectiveness and safety of Pedmark which may offer patients the chance for both survival and preserved quality of life.”

According to the news release, full results from the study will be shared in a future scientific presentation and submitted for publication in a peer-reviewed journal.

The study, according to the news release, enrolled patients across two cohorts, with 27 children age 3 to 18 years and six infants from age 1 month to less than 3 years, all with localized solid tumors, including neuroblastoma, hepatoblastoma, germ cell tumors, bone and soft tissue sarcomas, medulloblastoma and atypical teratoid rhabdoid tumors. Patients, the news release explained, received Pedmark intravenously six hours after cisplatin infusion, with dosing adjusted by body weight.

Reference

1. “Fennec Pharmaceuticals Announces Positive Topline Results From Investigator-Initiated Clinical Study of PEDMARK® in Japan to Reduce Cisplatin-Induced Hearing Loss,” news release; https://www.globenewswire.com/news-release/2025/12/02/3197763/0/en/Fennec-Pharmaceuticals-Announces-Positive-Topline-Results-From-Investigator-Initiated-Clinical-Study-of-PEDMARK-in-Japan-to-Reduce-Cisplatin-Induced-Hearing-Loss.html

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