Hear and Now: Ongoing Clinical Trials to Prevent Drug-Induced Hearing Loss.

Each year over half a million people experience permanent hearing loss caused by treatment with therapeutic drugs with ototoxic side effects. There is a major unmet clinical need for therapies that protect against this hearing loss without reducing the therapeutic efficacy of these lifesaving drugs. At least 17 clinical trials evaluating 10 therapeutics are currently underway for therapies aimed at preventing aminoglycoside- and/or cisplatin-induced ototoxicity. This review describes the preclinical and clinical development of each of these approaches, provides updates on the status of ongoing trials, and highlights the importance of appropriate outcome measures in trial design and the value of reporting criteria in the dissemination of results.

Phytosterols reverse antiretroviral-induced hearing loss, with potential implications for cochlear aging.

Cholesterol contributes to neuronal membrane integrity, supports membrane protein clustering and function, and facilitates proper signal transduction. Extensive evidence has shown that cholesterol imbalances in the central nervous system occur in aging and in the development of neurodegenerative diseases. In this work, we characterize cholesterol homeostasis in the inner ear of young and aged mice as a new unexplored possibility for the prevention and treatment of hearing loss. Our results show that cholesterol levels in the inner ear are reduced during aging, an effect that is associated with an increased expression of the cholesterol 24-hydroxylase (CYP46A1), the main enzyme responsible for cholesterol turnover in the brain. In addition, we show that pharmacological activation of CYP46A1 with the antiretroviral drug efavirenz reduces the cholesterol content in outer hair cells (OHCs), leading to a decrease in prestin immunolabeling and resulting in an increase in the distortion product otoacoustic emissions (DPOAEs) thresholds. Moreover, dietary supplementation with phytosterols, plant sterols with structure and function similar to cholesterol, was able to rescue the effect of efavirenz administration on the auditory function. Altogether, our findings point towards the importance of cholesterol homeostasis in the inner ear as an innovative therapeutic strategy in preventing and/or delaying hearing loss.

Leveraging large-scale datasets and single cell omics data to develop a polygenic score for cisplatin-induced ototoxicity.

BACKGROUND: Cisplatin-induced ototoxicity (CIO), characterized by irreversible and progressive bilateral hearing loss, is a prevalent adverse effect of cisplatin chemotherapy. Alongside clinical risk factors, genetic variants contribute to CIO and genome-wide association studies (GWAS) have highlighted the polygenicity of this adverse drug reaction. Polygenic scores (PGS), which integrate information from multiple genetic variants across the genome, offer a promising tool for the identification of individuals who are at higher risk for CIO. Integrating large-scale hearing loss GWAS data with single cell omics data holds potential to overcome limitations related to small sample sizes associated with CIO studies, enabling the creation of PGSs to predict CIO risk. RESULTS: We utilized a large-scale hearing loss GWAS and murine inner ear single nuclei RNA-sequencing (snRNA-seq) data to develop two polygenic scores: a hearing loss PGS (PGSHL) and a biologically informed PGS for CIO (PGSCIO). The PGSCIO included only variants which mapped to genes that were differentially expressed within cochlear cells that showed differential abundance in the murine snRNA-seq data post-cisplatin treatment. Evaluation of the association of these PGSs with CIO in our target CIO cohort revealed that PGSCIO demonstrated superior performance (P = 5.54 × 10- 5) relative to PGSHL (P = 2.93 × 10- 3). PGSCIO was also associated with CIO in our test cohort (P = 0.04), while the PGSHL did not show a significant association with CIO (P = 0.52). CONCLUSION: This study developed the first PGS for CIO using a large-scale hearing loss dataset and a biologically informed filter generated from cisplatin-treated murine inner ear snRNA-seq data. This innovative approach offers new avenues for developing PGSs for pharmacogenomic traits, which could contribute to the implementation of tailored therapeutic interventions. Further, our approach facilitated the identification of specific cochlear cells that may play critical roles in CIO. These novel insights will guide future research aimed at developing targeted therapeutic strategies to prevent CIO.

Inhibition of Gpx4-mediated ferroptosis alleviates cisplatin-induced hearing loss in C57BL/6 mice.

Cisplatin-induced hearing loss is a common side effect of cancer chemotherapy in clinics; however, the mechanism of cisplatin-induced ototoxicity is still not completely clarified. Cisplatin-induced ototoxicity is mainly associated with the production of reactive oxygen species, activation of apoptosis, and accumulation of intracellular lipid peroxidation, which also is involved in ferroptosis induction. In this study, the expression of TfR1, a ferroptosis biomarker, was upregulated in the outer hair cells of cisplatin-treated mice. Moreover, several key ferroptosis regulator genes were altered in cisplatin-damaged cochlear explants based on RNA sequencing, implying the induction of ferroptosis. Ferroptosis-related Gpx4 and Fsp1 knockout mice were established to investigate the specific mechanisms associated with ferroptosis in cochleae. Severe outer hair cell loss and progressive damage of synapses in inner hair cells were observed in Atoh1-Gpx4-/- mice. However, Fsp1-/- mice showed no significant hearing phenotype, demonstrating that Gpx4, but not Fsp1, may play an important role in the functional maintenance of HCs. Moreover, findings showed that FDA-approved luteolin could specifically inhibit ferroptosis and alleviate cisplatin-induced ototoxicity through decreased expression of transferrin and intracellular concentration of ferrous ions. This study indicated that ferroptosis inhibition through the reduction of intracellular ferrous ions might be a potential strategy to prevent cisplatin-induced hearing loss.

Repurposing AZD5438 and Dabrafenib for Cisplatin-Induced AKI.

SIGNIFICANCE STATEMENT: To combat both untoward effects of nephrotoxicity and ototoxicity in cisplatin-treated patients, two potential therapeutic oral anticancer drugs AZD5438 and dabrafenib, a phase-2 clinical trial protein kinase CDK2 inhibitor and an US Food and Drug Administration-approved drug BRAF inhibitor, respectively, were tested in an established mouse AKI model. Both drugs have previously been shown to protect significantly against cisplatin-induced hearing loss in mice. Each drug ameliorated cisplatin-induced increases in the serum biomarkers BUN, creatinine, and neutrophil gelatinase-associated lipocalin. Drugs also improved renal histopathology and inflammation, mitigated cell death by pyroptosis and necroptosis, and significantly enhanced overall survival of cisplatin-treated mice. BACKGROUND: Cisplatin is an effective chemotherapy agent for a wide variety of solid tumors, but its use is dose-limited by serious side effects, including AKI and hearing loss. There are no US Food and Drug Administration-approved drugs to treat both side effects. Recently, two anticancer oral drugs, AZD5438 and dabrafenib, were identified as protective against cisplatin-induced hearing loss in mice. We hypothesize that similar cell stress and death pathways are activated in kidney and inner ear cells when exposed to cisplatin and tested whether these drugs alleviate cisplatin-induced AKI. METHODS: The HK-2 cell line and adult FVB mice were used to measure the protection from cisplatin-induced cell death and AKI by these drugs. Serum markers of kidney injury, BUN, creatinine, and neutrophil gelatinase-associated lipocalin as well as histology of kidneys were analyzed. The levels of markers of kidney cell death, including necroptosis and pyroptosis, pERK, and proliferating cell nuclear antigen, were also examined by Western blotting and immunofluorescence. In addition, CDK2 knockout (KO) mice were used to confirm AZD5438 protective effect is through CDK2 inhibition. RESULTS: The drugs reduced cisplatin-induced cell death in the HK-2 cell line and attenuated cisplatin-induced AKI in mice. The drugs reduced serum kidney injury markers, inhibited cell death, and reduced the levels of pERK and proliferating cell nuclear antigen, all of which correlated with prolonged animal survival. CDK2 KO mice were resistant to cisplatin-induced AKI, and AZD5438 conferred no additional protection in the KO mice. CONCLUSIONS: Cisplatin-induced damage to the inner ear and kidneys shares similar cellular beneficial responses to AZD5438 and dabrafenib, highlighting the potential therapeutic use of these agents to treat both cisplatin-mediated kidney damage and hearing loss.

Sodium thiosulfate does not protect ovarian reserve from cisplatin-induced gonadotoxicity†.

Cisplatin, a platinum-containing alkylating agent, is used in the treatment of various tumors owing to its potent antitumor activity. However, it causes permanent and adverse effects, particularly hearing loss and depletion of ovarian reserve. Until recently, there were no clinically available protective agents to mitigate the adverse side effects of cisplatin-induced cytotoxicity. In 2022, sodium thiosulfate (STS) was approved by the Food and Drug Administration for mitigating hearing loss in children and adolescents undergoing cisplatin treatment. Consequently, our investigation aimed to determine if STS could protect ovarian reserve against cisplatin-induced gonadotoxicity. In an ex vivo culture, the cisplatin-only group exhibited a loss of primordial follicles, while post-STS administration after cisplatin exposure effectively protected primordial follicles. However, when post-STS was administrated either 6 or 4 h after cisplatin exposure, it did not confer protection against cisplatin-induced gonadotoxicity in postnatal day 7 or adolescent mouse models. Immunofluorescence assays using γH2AX and cPARP revealed that oocytes within primordial follicles exhibited DNA damage after cisplatin exposure, irrespective of post-STS administration. This underscores the rapid and heightened sensitivity of oocytes to gonadotoxicity. In addition, oocytes demonstrated an increased expression of pCHK2 rather than pERK, suggesting that the pathway leading to oocyte death differs from the pathway observed in the inner ear cell death following cisplatin exposure. These results imply that while the administration of STS after cisplatin is highly beneficial in preventing hearing loss, it does not confer a protective effect on the ovaries in mouse models.

Frequency and Patterns of Hearing Dysfunction in Patients Treated with Teprotumumab.

PURPOSE: To better characterize the frequency and patterns of hearing dysfunction in patients who have received teprotumumab to treat thyroid eye disease. DESIGN: Noncomparative case series. PARTICIPANTS: Patients who underwent audiology testing before and after completion of teprotumumab infusions. METHODS: A review of patients who underwent audiology testing before and after completion of teprotumumab infusions was carried out. Additional audiogram testing during treatment was included when available. Hearing function was analyzed using audiogram data measuring threshold hearing levels at specific frequencies. Basic demographic data as well as information regarding otologic symptoms also were obtained and analyzed. MAIN OUTCOME MEASURES: Hearing loss demonstrated by a significant change in decibel hearing thresholds or that meets criteria for ototoxicity. RESULTS: Twenty-two patients (44 ears) were included in the study, with baseline and most recent audiology testing after treatment ranging from 84 days before to 496 days after treatment. Fifteen patients (30 ears) also underwent testing during treatment starting after the second infusion up until the day of, but before, the eighth infusion. Hearing loss after treatment met criteria for ototoxicity in 17 of the 44 ears (38.6%), with 11 of the 22 patients (50.0%) meeting criteria in at least 1 ear. The pure-tone average decibel hearing levels (HLs) across all 44 ears demonstrated hearing loss after treatment (P = 0.0029), specifically at high (P = 0.0008) and middle frequencies (P = 0.0042), but not at low frequencies (P = 0.8344). Patients who were older also were more likely to experience hearing loss after treatment (P = 0.0048). CONCLUSIONS: Audiometric data demonstrate that teprotumumab influences hearing function, most significantly at higher frequencies and in older patients. Audiometric testing is critical for counseling patients regarding teprotumumab treatment. A protocol for monitoring hearing during treatment is needed to detect and manage hearing changes associated with teprotumumab use. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Occupational Lead Exposure Ototoxicity Evaluated With Distortion-Product Otoacoustic Emissions.

OBJECTIVES: To evaluate the extent of hearing loss among pottery workers in Mexico exposed to lead. DESIGN: The authors conducted a cross-sectional study including 315 adult pottery workers. Auditory function was evaluated by air conduction pure-tone audiometry (pure-tone average) and distortion-product otoacoustic emission (DPOAE) levels (amplitude and signal-to-noise ratio). Lead exposure was assessed with a single blood sample test and classified as low, medium, and high according to blood lead tertiles. Logistic regression models were calculated for the association between blood lead levels, pure-tone average, and DPOAE records. RESULTS: Median (25th-75th) blood lead levels were 14 µg/dL (7.5-22.6 µg/dL). The audiometric pattern and DPOAE records were similar across blood lead levels groups in all frequencies, and no statistically significant differences were found. Adjusted logistic regression models showed no increase in the odds for hearing thresholds >25 dB (HL) and DPOAE absence associated with blood lead levels, and no dose-response pattern was observed ( p > 0.05). CONCLUSIONS: Given the results from this cross-sectional study, no association was found between blood lead levels and hearing loss assessed with DPOAE. Future longitudinal work should consider chronic lead exposure estimates among underrepresented populations, which can potentially inform safer work practices to minimize the risk of ototoxicity.

Shorter versus longer duration of antibiotic treatment in children with bacterial meningitis: a systematic review and meta-analysis.

The optimal duration of antibiotic treatment for the most common bacterial meningitis etiologies in the pediatric population, namely Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis, is not well-established in the literature. Therefore, we aimed to perform an updated meta-analysis comparing shorter versus longer antibiotic treatment in children with meningitis. PubMed, EMBASE, and Cochrane databases were searched for randomized controlled trials (RCTs) that compared shorter (up to 7 days) versus longer (10 days or double the days of the equivalent short course) duration of antibiotic treatment in children with meningitis and reported the outcomes of treatment failure, death, neurologic sequelae, non-neurologic complications, hearing impairment, nosocomial infection, and relapse. Heterogeneity was examined with I2 statistics. RevMan 5.4.1 was used for statistical analysis and RoB-2 (Cochrane) for risk of bias assessment. Of 684 search results, 6 RCTs were included, with a cohort of 1333 children ages 3 weeks to 15.5 years, of whom 49.51% underwent a short antibiotic course. All RCTs included monotherapy with ceftriaxone, except one, which added vancomycin as well. No differences were found comparing the short and long duration of therapy concerning treatment failure, relapse, mortality, and neurologic complications at discharge and at follow-up.  Conclusion: Because no statistically significant differences were found between groups for the analyzed outcomes, the results of this meta-analysis support shorter therapy. However, generalizing these results to complicated meningitis and infections caused by other pathogens should be made with caution. (PROSPERO identifier: CRD42022369843). What is Known: • Current recommendations on the duration of antibiotic therapy for bacterial meningitis are mostly based on clinical practice. • Defining an optimal duration of antibiotic therapy is essential for antimicrobial stewardship achievement, improving patient outcomes, and minimizing adverse effects. What is New: • There are no differences between shorter versus longer antibiotic treatment duration in regard to treatment failure, relapse, mortality, neurologic complications, and hearing impairment at discharge and at follow-up.

Calcium channel inhibitor and extracellular calcium improve aminoglycoside-induced hair cell loss in zebrafish.

Aminoglycosides are commonly used antibiotics for treatment of gram-negative bacterial infections, however, they might act on inner ear, leading to hair-cell death and hearing loss. Currently, there is no targeted therapy for aminoglycoside ototoxicity, since the underlying mechanisms of aminoglycoside-induced hearing impairments are not fully defined. This study aimed to investigate whether the calcium channel blocker verapamil and changes in intracellular & extracellular calcium could ameliorate aminoglycoside-induced ototoxicity in zebrafish. The present findings showed that a significant decreased number of neuromasts in the lateral lines of zebrafish larvae at 5 days' post fertilization after neomycin (20 µM) and gentamicin (20 mg/mL) exposure, which was prevented by verapamil. Moreover, verapamil (10-100 µM) attenuated aminoglycoside-induced toxic response in different external calcium concentrations (33-3300 µM). The increasing extracellular calcium reduced hair cell loss from aminoglycoside exposure, while lower calcium facilitated hair cell death. In contrast, calcium channel activator Bay K8644 (20 µM) enhanced aminoglycoside-induced ototoxicity and reversed the protective action of higher external calcium on hair cell loss. However, neomycin-elicited hair cell death was not altered by caffeine, ryanodine receptor (RyR) agonist, and RyR antagonists, including thapsigargin, ryanodine, and ruthenium red. The uptake of neomycin into hair cells was attenuated by verapamil and under high external calcium concentration. Consistently, the production of reactive oxygen species (ROS) in neuromasts exposed to neomycin was also reduced by verapamil and high external calcium. Significantly, zebrafish larvae when exposed to neomycin exhibited decreased swimming distances in reaction to droplet stimulus when compared to the control group. Verapamil and elevated external calcium effectively protected the impaired swimming ability of zebrafish larvae induced by neomycin. These data imply that prevention of hair cell damage correlated with swimming behavior against aminoglycoside ototoxicity by verapamil and higher external calcium might be associated with inhibition of excessive ROS production and aminoglycoside uptake through cation channels. These findings indicate that calcium channel blocker and higher external calcium could be applied to protect aminoglycoside-induced listening impairments.

Association between blood volatile organic aromatic compound concentrations and hearing loss in US adults.

OBJECTIVE: Benzene, ethylbenzene, meta/para-xylene, and ortho-xylene, collectively referred to as benzene, ethylbenzene, and xylene (BEX), constitute the main components of volatile organic aromatic compounds (VOACs) and can have adverse effects on human health. The relationship between exposure to BEX and hearing loss (HL) in the adult U.S. population was aimed to be assessed. METHODS: Cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) for the years 2003-2004, 2011-2012, and 2015-2016 were analyzed. This dataset included complete demographic characteristics, pure-tone audiometry measurements, and volatile organic compound detection data from the NHANES database. A weighted multivariate logistic regression model was employed to investigate the associations between blood BEX concentrations HL, low-frequency hearing loss (SFHL), and high-frequency hearing loss (HFHL). RESULTS: 2174 participants were included, with weighted prevalence rates of HL, SFHL, and HFHL being 46.81%, 25.23%, and 45.86%, respectively. Exposure to benzene, ethylbenzene, meta/para-xylene, and ortho-xylene, and cumulative BEX concentrations increased the risk of hearing loss (odds ratios [ORs] were 1.36, 1.22, 1.42, 1.23, and 1.31, respectively; all P < 0.05). In the analysis with SFHL as the outcome, ethylbenzene, m-/p-xylene, o-xylene, benzene, and overall BEX increased the risk (OR 1.26, 1.21, 1.28, 1.20, and 1.25, respectively; all P < 0.05). For HFHL, exposure to ethylbenzene, m-/p-xylene, o-xylene, benzene, and overall BEX increased the risk (OR 1.36, 1.22, 1.42, 1.22, and 1.31, respectively; all P < 0.05). CONCLUSION: Our study indicated that a positive correlation between individual or cumulative exposure to benzene, ethylbenzene, meta/para-xylene, and ortho-xylene and the risk of HL, SFHL, and HFHL. Further research is imperative to acquire a more comprehensive understanding of the mechanisms by which organic compounds, notably BEX, in causing hearing loss and to validate these findings in longitudinal environmental studies.

The effect of cisplatin-based chemotherapy on hearing loss (the frequency of >8 kHz) in children with cancer.

INTRODUCTION: In this study we investigated the effect of cisplatin-based chemotherapy on hearing loss in children with cancer. MATERIAL AND METHOD: In this retrospective study, 20 children aged 6 to 17 years with cancer who were treated with cisplatin and had normal results on initial audiometry test were included. The demographic, clinical, and medical information of all children was extracted and recorded. The hearing thresholds were determined for the frequency of >8 kHz by an audiometrist two weeks after receiving the last course of cisplatin. Finally, all data was analyzed. RESULTS: In this study, 20 children with cancer were included of who 9 were girls (45 %) and 11 were boys (55 %). The patients' mean age at the time of diagnosis was 6.65 years. Results showed that children who received cisplatin ≥70 mg/m2 (P.value = 0.09) and ≥ 7 courses of cisplatin (P.value = 0.01), and a cumulative dose higher than 400 mg/m2 (P.value = 0.02) had higher chance of hearing loss. CONCLUSION: According to the results it can be concluded that since higher doses caused higher risk of hearing loss and also since lower doses were effective for treatment of the cancer in children therefore to preventing the hearing loss, lower doses of cisplatin are recommended for cancer treatment in children.

Teprotumumab-Related Hearing Loss: A Large-Scale Analysis and Review of Voluntarily Reported Patient Complaints to the Food and Drug Administration (FDA).

PURPOSE: Accumulating case reports and series have suggested that teprotumumab may significantly increase the risk of hearing impairment that, in some cases, does not resolve. This study investigates the association between hearing impairment and teprotumumab use. METHODS: A disproportionality analysis was conducted using the United States Food and Drug Administration Adverse Event Reporting System, a publicly accessible database used for postmarketing surveillance and research. All adverse event reports containing the terms "teprotumumab" or "Tepezza" and a similar comparison group from all patients with the same indications for teprotumumab use (e.g., autoimmune thyroiditis, endocrine ophthalmopathy, and hyperthyroidism) but who had not received the drug were selected. Hearing impairment events were identified using the hearing impairment Standardized MedDRA Query. RESULTS: A total of 940 teprotumumab-associated adverse events were identified, including 84 hearing-related adverse events, with the first reported to the Food and Drug Administration in April 2020. A comparison group of 32,794 nonteprotumumab adverse events was identified with 127 hearing-related adverse events reported. Use of teprotumumab in patients with thyroid conditions was associated with a nearly 24-fold (proportional reporting ratio [PRR] 23.6, 95% confidence interval [CI]: 18.1-30.8) increased likelihood of any hearing disorder ( p value <0.0001). The association was specifically elevated for a variety of deafness conditions (e.g., bilateral deafness [PRR: 41.9; 95% CI: 12.8-136.9]), Eustachian tube disorders (PRR: 34.9; 95% CI: 4.9-247.4), hypoacusis (PRR: 10.1; 95% CI: 7.6-13.3), and tinnitus (PRR: 8.7; 95% CI: 6.2-12.1). CONCLUSIONS: Patients treated with teprotumumab should receive warnings regarding the increased risk of hearing-related impairments and receive audiometry before, during, and after treatment.

The miR-182-5p/GPX4 Pathway Contributes to Sevoflurane-Induced Ototoxicity via Ferroptosis.

Our study aimed to investigate the role of ferroptosis in sevoflurane-induced hearing impairment and explore the mechanism of the microRNA-182-5p (miR-182-5p)/Glutathione Peroxidase 4 (GPX4) pathway in sevoflurane-induced ototoxicity. Immunofluorescence staining was performed using myosin 7a and CtBP2. Cell viability was assessed using the CCK-8 kit. Fe2+ concentration was measured using FerroOrange and Mi-to-FerroGreen fluorescent probes. The lipid peroxide level was assessed using BODIPY 581/591 C11 and MitoSOX fluorescent probes. The auditory brainstem response (ABR) test was conducted to evaluate the hearing status. Bioinformatics tools and dual luciferase gene reporter analysis were used to confirm the direct targeting of miR-182-5p on GPX4 mRNA. GPX4 and miR-182-5p expression in cells was assessed by qRT-PCR and Western blot. Ferrostatin-1 (Fer-1) pretreatment significantly improved hearing impairment and damage to ribbon synapses in mice caused by sevoflurane exposure. Immunofluorescence staining revealed that Fer-1 pretreatment reduced intracellular and mitochondrial iron overload, as well as lipid peroxide accumulation. Our findings indicated that miR-182-5p was upregulated in sevoflurane-exposed HEI-OC1 cells, and miR-182-5p regulated GPX4 expression by binding to the 3'UTR of GPX4 mRNA. The inhibition of miR-182-5p attenuated sevoflurane-induced iron overload and lipid peroxide accumulation. Our study elucidated that the miR-182-5p/GPX4 pathway was implicated in sevoflurane-induced ototoxicity by promoting ferroptosis.

Prevention and treatment of cisplatin-induced ototoxicity in adults: A systematic review.

OBJECTIVES: Ototoxicity is a common disabling side effect of platinum-based chemotherapy. This study aimed to assess the evidence on the management of platinum-induced ototoxicity in adult cancer patients. METHODS: Four databases were searched up to 1 November 2022. Original studies were included if they reported on a pharmacologic or non-pharmacologic intervention to prevent or treat platinum ototoxicity in adults. The articles' quality was assessed via two grading scales. RESULTS: Nineteen randomised controlled trials and five quasi-experimental studies with 1673 patients were analysed. Eleven interventions were identified, nine pharmacological and two non-pharmacological. Six of the interventions (sodium thiosulphate, corticoids, sertraline, statins, multivitamins and D-methionine) showed mild benefits in preventing cisplatin-induced ototoxicity. Only one trial assessed corticoids as a potential treatment. Overall, only six trials were deemed with a low risk of bias. The majority of studies inadequately documented intervention-related adverse effects, thereby limiting safety conclusions. CONCLUSIONS: Current interventions have mild benefits in preventing cisplatin-induced ototoxicity in adult cancer patients. Sodium thiosulphate is the most promising intervention as a preventive strategy. Rigorous, high-quality research is warranted, encompassing an evaluation of all potential symptoms and innovative treatment modalities.

Ototoxicity associated with high-dose carboplatin for patients with previously treated germ cell tumors.

BACKGROUND: High-dose carboplatin is an essential part of curative high-dose chemotherapy (HDCT) for patients with previously treated germ cell tumors (GCTs). Although hearing loss (HL) is a known side effect of HDCT, data on its severity and characteristics are limited. METHODS: Eligible patients received HDCT for GCTs from 1993 to 2017 and had audiograms before and after HDCT. HL severity was classified by American Speech-Language-Hearing Association criteria, and mean change in hearing threshold at each frequency (0.25-8 kHz) was estimated from pre- to post-HDCT and between HDCT cycles. RESULTS: Of 115 patients (median age, 32 years), 102 (89%) received three cycles of HDCT. Of 106 patients with normal hearing to mild HL in the speech frequencies (0.5-4 kHz) before HDCT, 70 (66%) developed moderate to profound HL in the speech frequencies after HDCT. Twenty-five patients (22%) were recommended for hearing aids after HDCT. Patients with moderate to profound HL isolated to the higher frequencies (6-8 kHz) before HDCT were more likely to develop moderate to profound HL in the speech frequencies after HDCT (94% vs. 61%; p = .01) and to be recommended for hearing aids (39% vs. 18%; p = .05). CONCLUSIONS: HL was frequent after HDCT for GCTs, with most patients developing at least moderate HL in the speech frequencies and approximately one in five recommended for hearing aids. Moderate to profound HL isolated to high frequencies at baseline was predictive of more clinically significant hearing impairment after HDCT. PLAIN LANGUAGE SUMMARY: Some patients with germ cell tumors, the most common malignancy in adolescent and young adult men, are not cured with standard-dose chemotherapy and require high-dose chemotherapy (HDCT). Using detailed hearing assessments of patients receiving HDCT, we found that most patients developed significant hearing loss and that one in five needed hearing aids. Thus, strategies to reduce this side effect are urgently needed, and all patients receiving HDCT should have a hearing test after therapy.

Clinical and genome-wide association analysis of chemoradiation-induced hearing loss in nasopharyngeal carcinoma.

Chemoradiation-induced hearing loss (CRIHL) is one of the most devasting side effects for nasopharyngeal carcinoma (NPC) patients, which seriously affects survivors' long-term quality of life. However, few studies have comprehensively characterized the risk factors for CRIHL. In this study, we found that age at diagnosis, tumor stage, and concurrent cisplatin dose were positively associated with chemoradiation-induced hearing loss. We performed a genome-wide association study (GWAS) in 777 NPC patients and identified rs1050851 (within the exon 2 of NFKBIA), a variant with a high deleteriousness score, to be significantly associated with hearing loss risk (HR = 5.46, 95% CI 2.93-10.18, P = 9.51 × 10-08). The risk genotype of rs1050851 was associated with higher NFKBIA expression, which was correlated with lower cellular tolerance to cisplatin. According to permutation-based enrichment analysis, the variants mapping to 149 hereditary deafness genes were significantly enriched among GWAS top signals, which indicated the genetic similarity between hereditary deafness and CRIHL. Pathway analysis suggested that synaptic signaling was involved in the development of CRIHL. Additionally, the risk score integrating genetic and clinical factors can predict the risk of hearing loss with a relatively good performance in the test set. Collectively, this study shed new light on the etiology of chemoradiation-induced hearing loss, which facilitates high-risk individuals' identification for personalized prevention and treatment.

Role of Cisplatin Dose Intensity and TPMT Variation in the Development of Hearing Loss in Children.

BACKGROUND: Cisplatin, widely used in the treatment of solid tumors, causes permanent hearing loss in more than 60% of treated children. Previous studies have implicated several clinical factors in the development of ototoxicity, including cumulative cisplatin dose. However, the role of cisplatin dose intensity in the development of hearing loss in children remains unclear. Pharmacogenetic studies have also identified genetic variants in TPMT that increase the risk of cisplatin-induced hearing loss. This study aims to determine whether cisplatin dose intensity contributes to the risk of hearing loss in children and whether genetic variations in TPMT further modifies the risk of cisplatin-induced hearing loss. METHODS: The authors genotyped 371 cisplatin-treated children for the presence of any 3 TPMT -risk variants. Patients were categorized into high-, moderate-, and low-intensity cisplatin dosing groups according to the cisplatin dose administered per unit time. Kaplan-Meier curves were plotted to compare the cumulative incidence of hearing loss between the genotype and dose intensity groups. RESULTS: Patients receiving cisplatin at high dose intensity experienced significantly higher incidences of ototoxicity than those receiving cisplatin at low dose intensity ( P = 9 × 10 -7 ). Further stratification by TPMT genotype revealed that carriers of ≥1 TPMT variants receiving high-intensity cisplatin developed ototoxicity sooner and more often than their wild-type counterparts (93.8% vs. 56.6% at 12 months; P = 5 × 10 -5 ) and noncarriers receiving low-intensity cisplatin (21.2% at 12 months). CONCLUSIONS: Cisplatin dose intensity is strongly associated with ototoxicity development in children, and this risk is further increased by the presence of TPMT -risk alleles.

Applications of the Grading Scales for the Detection of Ototoxicity in Children after Treatment of Neuroblastoma and Extracranial Germinal Tumor.

INTRODUCTION: Advances in treatment have resulted in a significant increase in survival rates for patients cured of malignant diseases such as neuroblastoma (NBL) and extracranial germ cell tumor (GCT). NBL is one of the pediatric cancers during which potentially ototoxic cytostatic drugs (cisplatin and carboplatin) are used for treatment. Other cancers include germinal tumors, hepatoblastoma, sarcomas, and brain tumors. Often, this very aggressive treatment has a high risk of causing long-term side effects, including hearing loss. Hence, the present study aimed to evaluate the usefulness of the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), Brock, Chang, and International Society of Pediatric Oncology (SIOP) Boston scales in terms of detecting the high-frequency nature of hearing loss induced by ototoxic drugs and monitoring hearing status in children after completion of oncological treatment. Additionally, the frequency of hearing loss in children treated for NBL and extracranial GCT was assessed, and the principles of monitoring hearing in these patients were indicated. METHODS: The study group consisted of 78 patients diagnosed with NBL (n = 47) and GCT (n = 31). There were 23 boys and 24 girls in the NBL group, aged 0-16 years, and 21 boys and 10 girls in the GCT group, aged 0-18 years. The control group consisted of 54 patients who had never received oncological treatment, were not taking potentially ototoxic drugs, and appeared socially efficient in the subjective audiological assessment. Audiometric examinations and DP-acoustic otoemission measurements were performed. Additionally, impedance audiometry tests were done to exclude a possible conductive component of the hearing loss. RESULTS: The analysis shows that ototoxicity-induced hearing loss was observed in 13.8-65.5% of children. 75.9% of patients showed hearing loss in the 16 kHz frequency range, and at least 56.8% of patients showed hearing loss in the frequency range above 12.5 kHz. Hearing impairment, relevant to speech understanding, was displayed by more than 40% of children treated for NBL and GCT. CONCLUSIONS: The confirmation of hearing loss in nearly 65% of cases in both patients indicates the necessity to monitor the long-term side effects of anticancer treatment. Acoustic otoemission measurements, the adoption of articulatory indices based on an audiogram, or the use of arbitrary ototoxicity assessment scales such as Brock, Chang, or SIOP Boston are fully justified techniques for studying ototoxicity induced by cytostatic drugs. However, they all require continuous improvement to increase their sensitivity and specificity, especially in the pediatric group.

Immune checkpoint inhibitor-related hearing loss: a systematic review and analysis of individual patient data.

PURPOSE: Immune checkpoint inhibitors (ICIs) are related to various immune-related adverse events (irAEs). However, the knowledge is limited with rare irAEs like hearing loss. Therefore, we evaluated the characteristics, presentation, and treatment of ICI-related hearing loss by reviewing the individual patient data from the previous studies. METHODS: We conducted a systematic search of the Web of Science, PubMed, and Embase databases for studies published until 17 November 2022. The selected MeSH search terms were "hearing loss" OR "hearing impairment" OR "ototoxicity" OR "vestibular toxicity" OR "audiovestibular toxicity" AND "immune checkpoint inhibitor" OR "immunotherapy." RESULTS: A total of 38 patients were included. Melanoma was the most frequent diagnosis (73.7%). The median time from ICI initiation to hearing loss development was 3 months. The hearing impairment was secondary to bilateral sensorineural hearing loss (SNHL) in 24 (68.6%) patients, and at least one other irAE accompanied the hearing loss in 24 patients. Hearing loss significantly improved in 45.7% of the patients. The overall response rate and disease control rate were 67.6% and 85.3%, respectively. CONCLUSION: We observed that most cases of ICI-related hearing loss were reversible, observed in patients with melanoma, accompanied by other irAEs, and associated with a high response rate to ICIs. With the expanded use of ICIs in the earlier treatment lines and adjuvant settings, the number of survivors with ICI-related hearing loss is expected to increase. Further research is needed to define the true prevalence of ICI-related hearing loss, optimal diagnosis, and management.