Sensorion announced preclinical data showing that the combination of its SENS-401 molecule with cochlear implants reduced loss of residual hearing at a frequency located beyond the electrode array. SENS-401 also showed a statistically significant electrode impedance reduction. The impedance is associated with electrode array insertion trauma and increased foreign body response around the electrode array. The study was designed to determine whether SENS-401 has the potential to improve preservation of residual acoustic hearing after cochlear implantation. Either SENS-401 or a placebo was delivered via an eluting electrode in an established pre-clinical model of cochlear implantation. The primary outcome of the study was functional hearing loss, assessed via Auditory Brainstem Response (ABR) thresholds. In this placebo-controlled preclinical study, more hearing was retained at 34 weeks (at a frequency located beyond the electrode array) where the cochlear implant was combined with SENS-401 than where the implant was combined with placebo. Hearing loss was a statistically significant 9.6 decibels lower in the SENS-401-treated group compared to placebo. There was a positive, but not statistically-significant trend at other frequencies in favor of the SENS-401 group. Encouragingly the SENS-401 treated group also showed a statistically significant 2.2kOhm reduction in electrode impedance, averaged across stimulation channels, compared to the placebo group. Sensorion and Cochlear are now assessing next steps, including options for clinical studies for SENS-401 in cochlear implant patients.