Fennec Pharmaceuticals Reports Positive Results from Phase 2 Clinical Study of Pedmark® in Japan

Fennec Pharmaceuticals Inc. announced today the detailed results from a Phase 2 clinical study evaluating Pedmark® for reducing cisplatin-induced ototoxicity in pediatric and adolescent and young adult (AYA) patients with non-metastatic solid tumors in Japan. The study, known as STS-J01, was presented at the 58th Annual International Society of Pediatric Oncology (SIOP) Annual Meeting in San Antonio, TX.

The primary endpoint of the study was met, with ASHA-defined hearing loss occurring in only 24.0% of the 25 patients in the primary efficacy population, significantly lower than the prespecified historical benchmark of 56.4% (P=0.001). Nineteen of the 25 patients (76.0%) remained free of ASHA-defined hearing loss. By Brock criteria, 84.0% of patients had Grade 0 hearing loss, and no patient experienced Grade 3 or Grade 4 hearing loss.

The study also demonstrated objective tumor responses in 23 of the 24 evaluable patients (95.8%), providing clinical reassurance for the six-hour PEDMARK® administration interval following cisplatin. Prospective pharmacokinetic analyses further supported this administration strategy, showing that PEDMARK® acts on residual platinum after cisplatin has had time to distribute and initiate its antitumor activity.

Dr. Pierre S. Sayad, chief medical officer of Fennec Pharmaceuticals, commented, "The clinical and pharmacologic findings of STS-J01 are compelling. We observed a significant reduction in hearing loss, with no Grade 3 or Grade 4 hearing loss by Brock criteria, alongside a 95.8% objective response rate in evaluable patients. The prospective pharmacokinetic analyses further provide important mechanistic insight into why the six-hour interval matters."

The safety profile of PEDMARK® was consistent with its known tolerability profile and the expected toxicities of cisplatin-containing chemotherapy. No serious adverse events were attributed to PEDMARK®, and no Grade 4 PEDMARK®-related toxicity was observed.

Dr. Eiso Hiyama, the lead investigator and professor in the Department of Pediatric Surgery at Hiroshima University Hospital in Hiroshima, Japan, stated, "For patients navigating cancer in Japan, the ability to successfully treat their tumors while preserving hearing can have a profound impact on their lives long after treatment ends. The results from STS-J01 are encouraging because they demonstrate significant hearing protection and provide reassuring clinical context regarding antitumor activity with delayed PEDMARK® administration."

The STS-J01 study enrolled 33 patients across 11 institutions in Japan, including 27 patients in the primary cohort and six in exploratory cohorts. Patients received PEDMARK® intravenously six hours after cisplatin infusion, with dosing adjusted by body weight. The primary endpoint was the incidence of hearing impairment at the end of treatment in the 3- to 18-year-old cohort, assessed according to American Speech-Language-Hearing Association (ASHA) criteria. Secondary endpoints included safety, antitumor efficacy, pharmacokinetics, and incidence of hearing loss as measured by Brock grading. Exploratory measures included longitudinal audiometric follow-up and validation of surrogate hearing tests.

Fennec is pursuing registration in Japan and is currently exploring partnering or licensing opportunities for PEDMARK®. The company continues to build upon the positive results from the pivotal Children’s Oncology Group (COG) Protocol ACCL0431 and SIOPEL 6 studies, which also demonstrated that PEDMARK® showed no interference with cisplatin antitumor activity.

The findings from the STS-J01 study add an important independent body of evidence supporting the clinical rationale for delayed PEDMARK® administration. With approximately 500,000 patients in the U.S. diagnosed annually with cancers that could be treated with platinum-based chemotherapy, PEDMARK® offers a critical tool in reducing the risk of ototoxicity, thereby improving the quality of life for cancer patients.