Enrollment progresses in study for cisplatin-induced hearing loss in testicular cancer

The 50% enrollment goal has been met in the phase 2a PROHEAR study (NCT06521190), evaluating the safety and efficacy of the Kv7.4 channel activator,ACOU085 (bimokalner), in preventing cisplatin-induced hearing loss in patients with testicular cancer who are undergoing high-dose chemotherapy, Acousia Therapeutics GmbH announced in a news release.¹

In total, the PROHEAR study plans to enroll 40 male patients with testicular cancer.

ACOU85 is an investigational “first-in-class, small-molecule, etiology-agnostic otoprotective drug-candidate delivered using standard transtympanic administration of a proprietary, slow-release gel formulation,” according to the company. In preclinical studies, the agent showed potential to reduce cisplatin-induced hearing loss and preserve outer hair cells, the sensory cells in the inner ear, from ototoxicity.

Acousia also noted that up to 80% of patients who receive cisplatin may experience clinically-relevant hearing loss.

"This marks a significant milestone on Acousia's journey to offer a treatment for the prevention of permanent hearing loss caused by cisplatin," said Professor Hubert Löwenheim, chair of the department of otolaryngology - head & neck surgery at Tuebingen University, Germany, in the news release.¹ "Preventing this often-overlooked [adverse event] is critical for [patients with] cancer. Notably, all PROHEAR participants who have received ≥300 mg/m² of cisplatin to date have developed ototoxicity. This is higher than reported in most, if not all, previous studies."

In total, the split-body PROHEAR study plans to enroll 40 male patients across 13 clinical trial sites in Germany.² Patients are eligible for enrollment in the study if they are aged between 18 and 45 years and are at risk for sensorineural hearing loss due to cisplatin-based chemotherapy. Participants must also have normal hearing in both ears per WHO criteria for air-conduction 4PTA as well as per ASHA criteria with a hearing threshold at any frequency.

Those enrolled in the study will be undergoing high-dose cisplatin-based chemotherapy regimens, defined as those dosed at least 300 mg/m² or higher.ACOU085 will be administered in each patient in 1 ear, with a matching placebo injection in the respective contralateral middle ear. The dosing regimen includes 3 transtympanic injections corresponding with 3 planned 3-week chemotherapeutic cycles.

The primary end point for the study is the proportion of patients showing a 10 dB or greater difference between the ears in at least 2 frequencies for air conduction in PTA, as assessed at 9 weeks. Secondary outcome measure include distortion product otoacoustic emissions, PTA bone, the Oldenburger test (speech understanding), and the Freiburger test, which will be measured at 150 days.

The company reported that completed enrollment in the trial is expected in the second half of 2025.

REFERENCES

1. Acousia Therapeutics reaches 50% patient enrollment milestone in phase 2 PROHEAR study. News release. April 29, 2025. Accessed May 14, 2025. https://www.prnewswire.com/news-releases/acousia-therapeutics-reaches-50-patient-enrollment-milestone-in-phase-2-prohear-study-302440113.html

2. ACOU085 for hearing loss prevention in testicular cancer patients receiving cisplatin (PROHEAR). ClinicalTrials.gov. Last updated September 19, 2024. Accessed May 14, 2025. https://clinicaltrials.gov/study/NCT06521190