Oral D-methionine protects against cisplatin-induced hearing loss in humans: phase 2 randomized clinical trial in India.

This exploratory Phase 2 clinical trial is the first determining safety and efficacy of oral D-methionine (D-met) in reducing cisplatin-induced ototoxicity. Randomised parallel double-blind placebo-controlled exploratory Phase 2 study. Fifty adult cancer patients received oral D-met or placebo before each cisplatin dose.

Protection for medication-induced hearing loss: the state of the science.

Objective: This review will summarise the current state of development of pharmaceutical interventions (prevention or treatment) for medication-induced ototoxicity.

Design: Currently published literature was reviewed using PubMed and ClinicalTrials.gov to summarise the current state of the science.

D-methionine (D-met) significantly reduces kanamycin-induced ototoxicity in pigmented guinea pigs.

Objective: Test D-methionine (D-met) as an otoprotectant from kanamycin-induced ototoxicity and determine the lowest maximally protective D-met dose.

Design: Auditory brainstem responses (ABR) were measured at 4, 8, 14, and 20 kHz at baseline and two, four, and six weeks after kanamycin and D-met administration initiation. ABR threshold shifts assessed auditory function.

d-Methionine reduces tobramycin-induced ototoxicity without antimicrobial interference in animal models.

Background: Tobramycin is a critical cystic fibrosis treatment however it causes ototoxicity. This study tested d-methionine protection from tobramycin-induced ototoxicity and potential antimicrobial interference.

Methods: Auditory brainstem responses (ABRs) and outer hair cell (OHC) quantifications measured protection in guinea pigs treated with tobramycin and a range of d-methionine doses.

D-methionine pre-loading reduces both noise-induced permanent threshold shift and outer hair cell loss in the chinchilla.

Objective: This study tested multiple dosing epochs of pre-loaded D-methionine (D-met) for otoprotection from noise-induced hearing loss (NIHL).

Design: Auditory brainstem response (ABR) thresholds were measured at baseline, 1 day, and 21 days following a 6-hour 105 dB sound pressure level (SPL) octave band noise (OBN) exposure. Outer hair cell (OHC) counts were measured after day 21 sacrifice.

Digital music exposure reliably induces temporary threshold shift in normal-hearing human subjects.

Objectives: One of the challenges for evaluating new otoprotective agents for potential benefit in human populations is the availability of an established clinical paradigm with real-world relevance. These studies were explicitly designed to develop a real-world digital music exposure that reliably induces temporary threshold shift (TTS) in normal-hearing human subjects.

Design: Thirty-three subjects participated in studies that measured effects of digital music player use on hearing.

d-Methionine protects against cisplatin-induced neurotoxicity in cortical networks.

Cisplatin is a platinum-based chemotherapeutic agent widely used for the treatment of various types of cancer. Patients undergoing cisplatin treatment often suffer from a condition known as "chemobrain", ototoxicity, peripheral neuropathy, weight loss, nausea, vomiting, nephrotoxicity, seizures, hearing loss and tinnitus. d-Methionine (d-Met), a sulfur-containing nucleophilic antioxidant, has been shown to prevent cisplatin-induced side effects in animals without antitumor interference.

Dose-dependent protection on cisplatin-induced ototoxicity - an electrophysiological study on the effect of three antioxidants in the Sprague-Dawley rat animal model.

Background: Sprague-Dawley rats were used as an acute cisplatin ototoxicity model to compare the chemo-protective efficacy of 2 sulphur-containing antioxidants (D-methionine, N-L-acetylcysteine) and 1 seleno-organic compound (ebselen). Each putative chemo-protective agent was tested at 3 different dosages in order to assess the influence of dose on auditory preservation.

Material/methods: A total of 40 Sprague-Dawley albino male rats were used in the study.

Pharmacokinetic analysis and phase 1 study of MRX-1024 in patients treated with radiation therapy with or without cisplatinum for head and neck cancer.

Purpose: A previous study reported radiation protection from mucosal injury with D-methionine (D-met) in preclinical evaluation; therefore, the pharmacokinetics, safety, and utility of D-met were evaluated clinically.

Experimental Design: The pharmacokinetics of D-met following oral administration of a bioavailable formulation (MRX-1024) was evaluated in normal volunteers. Subsequently, 25 patients were enrolled on a phase 1 study of MRX-1024 concurrent with radiation therapy (RT) with or without weekly cisplatinum.

Evaluation of D-methionine as a novel oral radiation protector for prevention of mucositis.

Purpose: Oral mucositis is a common acute morbidity associated with radiation and/or chemotherapy treatment for cancer. D-Methionine (D-Met), the dextro-isomer of the common amino acid l-methionine, has been documented to protect normal tissues from a diverse array of oxidative insults.

Experimental Design: We evaluated if D-Met could selectively prevent radiation-induced oral mucositis using in vitro cell culture models as well as an in vivo model of radiation injury to the oral mucosa in C3H mice.

Prevention of noise- and drug-induced hearing loss with D-methionine.

A number of otoprotective agents are currently being investigated. Various types of agents have been found in animal studies to protect against hearing loss induced by cisplatin, carboplatin, aminoglycosides, or noise exposure. For over a decade we have been investigating D-methionine (D-met) as an otoprotective agent.

Delivery of chemotherapy and antibodies across the blood-brain barrier and the role of chemoprotection, in primary and metastatic brain tumors: report of the Eleventh Annual Blood-Brain Barrier Consortium meeting.

Although knowledge of molecular biology and cellular physiology has advanced at a rapid pace, much remains to be learned about delivering chemotherapy and antibodies across the blood-brain barrier (BBB) for the diagnosis and treatment of central nervous system (CNS) disease. A meeting, partially funded by an NIH R13 grant, was convened to discuss the state of the science, current knowledge gaps, and future directions in the delivery of drugs and proteins to the CNS, for the treatment of primary and metastatic brain tumors. Meeting topics included CNS metastases and the BBB, and chemoprotection and chemoenhancement in CNS disorders.

Bromate-induced ototoxicity.

For decades, it has been known that ingested potassium bromate and sodium bromate can induce hearing loss. Hearing loss onset, following high-dose ingestion, is generally rapid occurring within 4-16 h and of a severe to profound degree. Unlike the sensorineural hearing loss which is generally irreversible, bromate-induced tinnitus, which is less well-studied, may reportedly be permanent or temporary.

Tolerability, pharmacokinetics, and serum bactericidal activity of intravenous dalbavancin in healthy volunteers.

Fifty-two healthy adult male and female volunteers were enrolled in this double-blind study to determine the maximum tolerated dose, characterize the pharmacokinetics, and obtain serum bactericidal activity (SBA) data for intravenous dalbavancin. Subjects were assigned to single- or multiple-dose groups and randomized to receive dalbavancin or placebo intravenously over 30 min. Doses started at 140 mg in the single-dose group and with a 300-mg loading dose (LD), followed by six daily 30-mg maintenance doses (MDs), in the multiple-dose cohort and escalated to a 1120-mg single dose and a 1000-mg LD and 100-mg MD regimen.

Audiologic monitoring for potential ototoxicity in a phase I clinical trial of a new glycopeptide antibiotic.

This study describes audiologic methodology and results for evaluating potential ototoxicity in a phase I clinical trial of a new glycopeptide. This study was conducted under good clinical practices, which are regulated by the US Food and Drug Administration (FDA) (21 Code of Federal Regulations), and input from the FDA was sought prior to study implementation. Healthy, normal volunteers underwent extensive medical and audiologic assessments as part of this phase I dose- escalation study of dalbavancin, a new glycopeptide, to assess potential side effects.

The effect of D-methionine on cochlear oxidative state with and without cisplatin administration: mechanisms of otoprotection.

D-methionine (D-met) protects against cisplatin (CDDP) ototoxicity, but the mechanisms are not well understood. This study investigated D-met protection of cochlear oxidative state as measured by superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), and malondiadehyde (MDA) levels. The design comprised four groups of five rats each: (1) a saline control group, (2) a CDDP-only-treated group, (3) a CDDP group pretreated with D-met, and (4) a group receiving only D-met.

Antioxidant enzyme levels inversely covary with hearing loss after amikacin treatment.

This study's purpose was to determine if a correlation exists between cochlear antioxidant activity changes and auditory function after induction of amino-glycoside (AG) ototoxicity. Two groups of five 250-350 g albino guinea pigs served as subjects. For 28 days, albino guinea pigs were administered either 200 mg/kg/day amikacin, or saline subcutaneously.

Glutathione ester but not glutathione protects against cisplatin-induced ototoxicity in a rat model.

Glutathione (GSH) provides an important antioxidant and detoxification pathway. We tested to determine if direct administration of GSH or GSH ester could reduce cisplatin- (CDDP) induced ototoxicity. We tested eight groups of five rats each: a control group, a group receiving 16 mg/kg ip CDDP infused over 30 minutes, and six groups receiving either GSH or GSH ester at 500, 1000, or 1500 mg/kg intraperitoneally 30 minutes prior to 16 mg/kg CDDP.

Candidate's thesis: enhancing intrinsic cochlear stress defenses to reduce noise-induced hearing loss.

Objectives/hypothesis: Oxidative stress plays a substantial role in the genesis of noise-induced cochlear injury that causes permanent hearing loss. We present the results of three different approaches to enhance intrinsic cochlear defense mechanisms against oxidative stress. This article explores, through the following set of hypotheses, some of the postulated causes of noise-induced cochlear oxidative stress (NICOS) and how noise-induced cochlear damage may be reduced pharmacologically.