Phase 3 Clinical Trial: D-methionine to Reduce Noise-Induced Hearing Loss (NIHL)
Condition: Noise-induced Hearing Loss
MeSH terms: Hearing Loss; Deafness; Hearing Loss, Noise-Induced
Intervention: D-methionine; Placebo
Intervention description: D-methionine, oral liquid suspension; Placebo contains sorbitol, orange flavor and purified water; is flavor and color matched to D-Met.
Phase: Phase 3
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 351.0
Sex: All
Minimum age: 21 Years
Maximum age: 45 Years
Healthy volunteers: Accepts Healthy Volunteers

Summary:

      This prospective study is a randomized, double-blind, placebo-controlled Phase 3 clinical
      trial of oral D-methionine (D-met) to reduce noise-induced hearing loss (NIHL) and tinnitus.
      The goal of the study is to develop a safe, oral pharmacological agent to augment physical
      hearing protectors for noise exposures that exceed the protective capabilities of ear plugs
      and/or muffs. The study population is a cohort of Drill Sergeant (DS) instructor trainees
      during and 22 days after their 11 day weapons training. The primary objective of this study
      is to determine the efficacy of D-met in preventing NIHL or reducing tinnitus secondary to a
      minimum of 500 rounds of M-16 weapons training occurring over an 11 day period.
    

Eligibility criteria:

        Inclusion criteria:

        Male or female 21 to 45 years of age Negative pregnancy test at enrollment and prior to
        taking study drug Willing to use an effective method of birth control during the study
        (Both male and female participants should avoid pregnancy during study) Pure tone air
        conduction threshold average at 0.5, 1 and 2 kHz of no greater than 40 dB HL bilaterally
        with no air bone gaps greater than 10 dB and normal otoscopy and tympanometry screens
        Willing to refrain from using supplements containing or derived from protein while
        participating in this study Ability to comply with all study requirements

        Exclusion criteria:

        History of allergic or idiosyncratic reaction to methionine, amino acid mixtures,
        nutritional supplements, egg white, or other proteins or food additives Vegetarian
        (Individual excludes meat and fish from their diet) History of chronic balance disorders
        Abnormal otoscopic findings, otologic surgery, autoimmune inner ear disease, significant
        air-bone gaps, abnormal tympanograms or other indication of middle-ear abnormality, history
        of fluctuant hearing or asymmetric hearing worse than 25 dB at any frequency in either ear,
        perilymphatic fistula, tumor of the auditory system, or other CNS disorder that is likely
        to affect hearing Treatment with intravenous (IV) antibiotics within the past 6 months Any
        surgical or medical condition which might significantly alter the absorption, distribution,
        metabolism, or excretion of any drug Treatment for alcohol or substance abuse within past 6
        months Women of childbearing age who are not using effective contraceptive methods and who
        may become pregnant during the course of the study Women who are pregnant or breastfeeding.
        National Guardsmen History of psychotic schizophrenia Exposure within the previous 6 months
        to systemic ototoxic substances including aminoglycosides or vancomycin Body weight
        exceeding 225 pounds Renal impairment measured as eGFR < 50 on screening creatinine
        clearance blood draw.