The invention relates to one or more inhibitors, in particular siRNAs, which down-regulate the expression of human pro-apoptotic genes. The invention also relates to a pharmaceutical composition comprising the compound, or a vector capable of expressing the compound, and a pharmaceutically acceptable carrier. The present invention also contemplates a method of treating or preventing the incidence or severity of hearing impairment (or balance impairment), particularly hearing impairment associated with cell death of the inner ear hair cells or outer ear hair cells, comprising administering to the patient the pharmaceutical composition in a therapeutically effective dose so as to thereby treat the patient.