Group-Wide, Prospective Study of Ototoxicity Assessment in Children Receiving Cisplatin Chemotherapy (ACCL05C1): A Report From the Children's Oncology Group

Apoptosis, autophagy, ferroptosis, and pyroptosis in cisplatin-induced ototoxicity and protective agents

Cisplatin is widely used to treat various solid tumors. However, its toxicity to normal tissues limits its clinical application, particularly due to its ototoxic effects, which can result in hearing loss in patients undergoing chemotherapy. While significant progress has been made in preclinical studies to elucidate the cellular and molecular mechanisms underlying cisplatin-induced ototoxicity (CIO), the precise mechanisms remain unclear. Moreover, the optimal protective agent for preventing or mitigating cisplatin-induced ototoxicity has yet to be identified. This review summarizes the current understanding of the roles of apoptosis, autophagy, ferroptosis, pyroptosis, and protective agents in cisplatin-induced ototoxicity. A deeper understanding of these cell death mechanisms in the inner ear, along with the protective agents, could facilitate the translation of these agents into clinical therapeutics, help identify new therapeutic targets, and provide novel strategies for cisplatin-based cancer treatment.

Use of Sodium Thiosulfate as an Otoprotectant in Patients With Cancer Treated With Platinum Compounds: A Review of the Literature

PURPOSE

Hearing loss occurs in 50%-70% of children treated with cisplatin. Scientific efforts have led to the recent approval of a pediatric formula of intravenous sodium thiosulfate (STS) for otoprotection by the US Food and Drug Administration, the European Medicines Agency, and the Medicines and Health Regulatory Authority in the United Kingdom. To inform stakeholders regarding the clinical utility of STS, the current review summarizes available literature on the efficacy, pharmacokinetics (PK), and safety of systemic STS to minimize cisplatin-induced hearing loss (CIHL).

DESIGN

A comprehensive narrative review is presented.

RESULTS

Thirty-one articles were summarized. Overall, systemic STS effectively reduces CIHL in the preclinical and controlled clinical study settings, in both adults and children with cancer. The extent of CIHL reduction depends on the timing and dosing of STS in relation to cisplatin. Both preclinical and clinical data suggest that systemic STS may affect plasma platinum levels, but studies are inconclusive. Delayed systemic administration of STS, at 6 hours after the cisplatin infusion, does not affect cisplatin-induced inhibition of tumor growth or cellular cytotoxicity in the preclinical setting, nor affect cisplatin efficacy and survival in children with localized disease in the clinical setting.

CONCLUSION

Systemic administration of STS effectively reduces the development and degree of CIHL in both the preclinical and clinical settings. More studies are needed on the PK of STS and cisplatin drug combinations, the efficacy and safety of STS in patients with disseminated disease, and the ability of STS to prevent further deterioration of pre-established hearing loss.

Nuciferine Protects Cochlear Hair Cells from Ferroptosis through Inhibiting NCOA4-Mediated Ferritinophagy

Cisplatin is a widely used antineoplastic drug for treating various types of cancers. However, it can cause severe side effects, such as bilateral and irreversible hearing loss, which significantly impacts quality of life. Ferroptosis, an iron-dependent form of programmed cell death, has been implicated in the pathogenesis of cisplatin-induced ototoxicity. Here, we investigated the effects of nuciferine, a natural active ingredient isolated from lotus species, on the ferroptosis of cochlear hair cells. Firstly, our results demonstrated that nuciferine can protect hair cells against RSL3-induced and cisplatin-induced damage. Secondly, nuciferine treatment reduced ferrous iron (Fe2+) overload in cochlear hair cells via inhibiting NCOA4-mediated ferritinophagy. Inhibition of ferritinophagy by knocking down Ncoa4 alleviated cisplatin-induced ototoxicity. Importantly, nuciferine treatment mitigated cochlear hair cell loss and damage to ribbon synapse, and improved mouse hearing function in an acute cisplatin-induced hearing loss model. Our findings highlight the role of NCOA4-mediated ferritinophagy in the pathogenesis of cisplatin-induced ototoxicity and provide evidence for nuciferine as a promising protective agent for treating cisplatin-induced hearing loss.

Association of hearing loss with patient-reported functional outcomes in adult survivors of childhood cancer

BACKGROUND

Hearing loss is prevalent following ototoxic therapy for childhood cancer. Associations between hearing loss, self-perceived hearing handicap, and functional outcomes have not been examined in survivors.

METHODS

Adult survivors treated with platinum or head and neck radiotherapy with hearing loss were recruited. A total of 237 survivors (median age at survey = 37.0 years [range = 30.0-45.0 years]; median = 29.1 years [range = 22.4-35.0 years] since diagnosis; median = 4.0 years [range = 2.9-7.7 years] from last audiogram to survey) completed the Hearing Handicap Inventory for Adults and questionnaires on social and emotional functioning and hearing aid use. Hearing loss severity was defined according to Chang criteria. Multivariable logistic regression models estimated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between hearing loss, hearing handicap, functional outcomes, and hearing aid use with adjustment for sex, race, age at hearing loss diagnosis, and age at survey.

RESULTS

Two-thirds of survivors had severe hearing loss, which was associated with increased likelihood of hearing handicap (mild-moderate handicap: OR = 2.72, 95% CI = 1.35 to 5.47; severe handicap: OR = 5.99, 95% CI = 2.72 to 13.18). Survivors with severe hearing handicap had an increased likelihood of social isolation (OR = 8.76, 95% CI = 3.62 to 21.20), depression (OR = 9.11, 95% CI = 3.46 to 24.02), anxiety (OR = 17.57, 95% CI = 3.77 to 81.84), reduced personal income (OR = 2.82, 95% CI = 1.46 to 5.43), and less than full-time employment (OR = 2.47, 95% CI = 1.30 to 4.70). Survivors who did not use a recommended hearing aid were twice as likely to have less than full-time employment (OR = 2.26, 95% CI = 1.10 to 4.61) and reduced personal income (OR = 2.24, 95% CI = 1.08 to 4.63) compared with survivors who wore a hearing aid.

CONCLUSION

Self-perceived hearing handicap beyond measured hearing loss is associated with reduced functional outcomes. Assessment of hearing handicap may facilitate targeted interventions in adult survivors with hearing loss.

Cholesterol metabolism in tumor microenvironment: cancer hallmarks and therapeutic opportunities

Cholesterol is crucial for cell survival and growth, and dysregulation of cholesterol homeostasis has been linked to the development of cancer. The tumor microenvironment (TME) facilitates tumor cell survival and growth, and crosstalk between cholesterol metabolism and the TME contributes to tumorigenesis and tumor progression. Targeting cholesterol metabolism has demonstrated significant antitumor effects in preclinical and clinical studies. In this review, we discuss the regulatory mechanisms of cholesterol homeostasis and the impact of its dysregulation on the hallmarks of cancer. We also describe how cholesterol metabolism reprograms the TME across seven specialized microenvironments. Furthermore, we discuss the potential of targeting cholesterol metabolism as a therapeutic strategy for tumors. This approach not only exerts antitumor effects in monotherapy and combination therapy but also mitigates the adverse effects associated with conventional tumor therapy. Finally, we outline the unresolved questions and suggest potential avenues for future investigations on cholesterol metabolism in relation to cancer.

Assessing quality of life in childhood cancer survivors at risk for hearing loss: a comparison of HEAR-QL and PROMIS measures

Background

Childhood cancer survivors (CCS) exposed to platinum chemotherapy are at an increased risk of developing hearing loss and reporting decreased quality of life (QOL). This study compared two QOL measures; one developed for children with hearing loss, The Hearing Environments and Refection on Quality of Life (HEAR-QL), and one validated in CCS, the Patient-Reported Outcomes Measurement Information System (PROMIS), to assess their ability to evaluate QOL deficits in this population.

Methods

Subject eligibility were restricted to CCS exposed to platinum-based chemotherapy but who were free of known risk factors for cognitive impairment, (non-central nervous system tumor, no cranial radiation, or intrathecal chemotherapy). Participants had to be between 8-17 years, have completed anti-cancer therapy for at least 6 months, and have an audiogram within 1 year, Participants completed the HEAR-QL-26 (7-12 years) or the HEAR-QL-28 (13-18 years) and the PROMIS. Independent samples and/or one sample T-tests were utilized to compare participants with normal hearing and hearing loss, and to compare outcome measures to normative HEAR-QL and PROMIS data. Non-parametric correlations were utilized to evaluate the relationship between QOL and demographic and medical variables, and QOL and severity of hearing loss.

Results

Fifty-four CCS were evaluable. The mean age was 12.0 years. Twenty-eight participants (51.9%) received cisplatin, 30 (55.6%) carboplatin, and 4 (7.4%) received both. Twenty participants (37%) demonstrated hearing loss. Participants with hearing loss scored significantly lower on the HEAR-QL than those with normal hearing (mean: 70.3, SD: 21.7, vs mean: 88.0, SD: 9.3, p =.004 for the HEAR-QL-26; mean: 84.7, SD: 10.2 vs mean: 94.8, SD: 3.4, p =.040 for the HEAR-QL-28). Participants with normal hearing scored significantly lower on the HEAR-QL-26 than the normative mean (mean: 88, SD: 9.3, normative mean: 98, SD: 5, p =.000). The PROMIS failed to identify any differences in QOL between participants based on hearing status, or when compared to the normative mean.

Conclusion

The HEAR-QL was more sensitive than the PROMIS in identifying QOL deficits in CCS at risk for hearing loss. The HEAR-QL should be considered in studies seeking to improve the QOL of CCS with hearing loss.

Macrophage Depletion Protects Against Cisplatin-Induced Ototoxicity and Nephrotoxicity

Cisplatin is a widely used and highly effective anti-cancer drug with significant side effects including ototoxicity and nephrotoxicity. Macrophages, the major resident immune cells in the cochlea and kidney, are important drivers of both inflammatory and tissue repair responses. To investigate the roles of macrophages in cisplatin-induced ototoxicity and nephrotoxicity, we used PLX3397, an FDA-approved inhibitor of the colony-stimulating factor 1 receptor (CSF1R), to eliminate tissue-resident macrophages during the course of cisplatin administration. Mice treated with cisplatin alone (cisplatin/vehicle) had significant hearing loss (ototoxicity) as well as kidney injury (nephrotoxicity). Macrophage ablation using PLX3397 resulted in significantly reduced hearing loss measured by auditory brainstem responses (ABR) and distortion-product otoacoustic emissions (DPOAE). Sensory hair cells in the cochlea were protected against cisplatin-induced death in mice treated with PLX3397. Macrophage ablation also protected against cisplatin-induced nephrotoxicity, as evidenced by markedly reduced tubular injury and fibrosis as well as reduced plasma blood urea nitrogen (BUN) and neutrophil gelatinase-associated lipocalin (NGAL) levels. Mechanistically, our data suggest that the protective effect of macrophage ablation against cisplatin-induced ototoxicity and nephrotoxicity is mediated by reduced platinum accumulation in both the inner ear and the kidney. Together our data indicate that ablation of tissue-resident macrophages represents a novel strategy for mitigating cisplatin-induced ototoxicity and nephrotoxicity.

Treatment of High-Risk Neuroblastoma

High-risk neuroblastoma is a highly aggressive solid tumor that most commonly presents in early childhood. Advances in treatment through decades of clinical trials and research have led to improved outcomes. This review provides an overview of the current state of treatment for high-risk neuroblastoma.

Reevaluation of sodium thiosulfate otoprotection using the consensus International Society of Paediatric Oncology Ototoxicity Scale: A report from the Children's Oncology Group study ACCL0431

In two randomized trials (Children's Oncology Group ACCL0431 and International Childhood Liver Tumour Strategy Group SIOPEL-6), sodium thiosulfate (STS) demonstrated efficacy in preventing cisplatin-induced hearing loss (CIHL). However, the measures used in those trials have been superseded by the consensus International Society of Paediatric Oncology (SIOP) Ototoxicity Scale. To provide benchmark data for STS efficacy when using this contemporary scale, we reanalyzed ACCL0431 hearing outcomes with the SIOP scale and using multiple timepoints. Compared to the control arm, STS significantly reduced CIHL when assessed by the SIOP scale across these different approaches. These results provide critical data to inform treatment discussions and support future potential trial designs comparing otoprotectants.

Identification of IGF2 as Genomic Driver and Actionable Therapeutic Target in Hepatoblastoma

Management of hepatoblastoma (HB), the most frequent pediatric liver cancer, is based on surgical resection and perioperative chemotherapy regimens. In this study, we aimed to identify actionable targets in HB and assess the efficacy of molecular therapies in preclinical models of HB. Paired tumor and adjacent tissues from 31 HBs and a validation set of 50 HBs were analyzed using RNA-seq, SNP, and methylation arrays. IGF2 overexpression was identified as the top targetable HB driver, present in 71% of HBs (22/31). IGF2high tumors displayed progenitor cell features and shorter recurrence-free survival. IGF2 overexpression was associated in 91% of cases with fetal promoter hypomethylation, ICR1 deregulation, 11p15.5 loss of heterozygosity or miR483-5p overexpression. The antitumor effect of xentuzumab (a monoclonal antibody targeting IGF1/2) alone or in combination with the conventional therapeutic agent cisplatin was assessed in HB cell lines, in PDX-derived HB organoids and in a xenograft HB murine model. The combination of xentuzumab with cisplatin showed strong synergistic antitumor effects in organoids and in IGF2high cell lines. In mice (n = 55), the combination induced a significant decrease in tumor volume and improved survival compared with cisplatin alone. These results suggest that IGF2 is an HB actionable driver and that, in preclinical models of HB, the combination of IGF1/2 inhibition with cisplatin induces superior antitumor effects than cisplatin monotherapy. Overall, our study provides a rationale for testing IGF2 inhibitors in combination with cisplatin in HB patients with IGF2 overexpression.

miR-34a/DRP-1-mediated mitophagy participated in cisplatin-induced ototoxicity via increasing oxidative stress

PURPOSE

Cisplatin is a widely used and effective chemotherapeutic agent for most solid malignant tumors. However, cisplatin-induced ototoxicity is a common adverse effect that limits the therapeutic efficacy of tumors in the clinic. To date, the specific mechanism of ototoxicity has not been fully elucidated, and the management of cisplatin-induced ototoxicity is also an urgent challenge. Recently, some authors believed that miR34a and mitophagy played a role in age-related and drug-induced hearing loss. Our study aimed to explore the involvement of miR-34a/DRP-1-mediated mitophagy in cisplatin-induced ototoxicity.

METHODS

In this study, C57BL/6 mice and HEI-OC1 cells were treated with cisplatin. MiR-34a and DRP-1 levels were analyzed by qRT‒PCR and western blotting, and mitochondrial function was assessed via oxidative stress, JC-1 and ATP content. Subsequently, we detected DRP-1 levels and observed mitochondrial function by modulating miR-34a expression in HEI-OC1 cells to determine the effect of miR-34a on DRP-1-mediated mitophagy.

RESULTS

MiR-34a expression increased and DRP-1 levels decreased in C57BL/6 mice and HEI-OC1 cells treated with cisplatin, and mitochondrial dysfunction was involved in this process. Furthermore, the miR-34a mimic decreased DRP-1 expression, enhanced cisplatin-induced ototoxicity and aggravated mitochondrial dysfunction. We further verified that the miR-34a inhibitor increased DRP-1 expression, partially protected against cisplatin-induced ototoxicity and improved mitochondrial function.

CONCLUSION

MiR-34a/DRP-1-mediated mitophagy was related to cisplatin-induced ototoxicity and might be a novel target for investigating the treatment and protection of cisplatin-induced ototoxicity.

Special considerations in the design and implementation of pediatric otoprotection trials

PURPOSE

Cisplatin-induced hearing loss (CIHL) is a common late effect after childhood cancer treatment having profound, lifelong consequences that lower quality of life. The recent identification of intravenous sodium thiosulfate (STS) as an effective agent for preventing pediatric CIHL represents a paradigm shift that has created new opportunities for expanding STS usage and developing additional otoprotectants. The purpose of this paper is to discuss key considerations and recommendations for the design and implementation of future pediatric otoprotection trials.

METHODS

An approach synthesizing published data and collective experience was used.

RESULTS

Key issues were identified in the categories of translational research, trial designs for systemic and intratympanic agents, measurement of ototoxicity, and biostatistical challenges.

CONCLUSIONS

Future pediatric otoprotection trials should emphasize (1) deep integration of preclinical and early-phase studies; (2) an embedded or free-standing design for systemic agents based on mechanistic considerations; (3) use of suitable audiologic testing batteries for children, SIOP grading criteria, and submission of raw audiologic data for central review; and (4) novel endpoints and innovative study designs that maximize trial efficiency for limited sample sizes. Additional recommendations include routine collection of DNA specimens for assessing modifying effects of genetic susceptibility and meaningful inclusion of patient/family advocates for informing trial development.

IMPLICATIONS FOR CANCER SURVIVORS

Changing the historical paradigm from acceptance to prevention of pediatric CIHL through expanded research with existing and emerging otoprotectants will dramatically improve quality of life for future childhood cancer survivors exposed to cisplatin.

A review of effects of atorvastatin in cancer therapy

Cancer is one of the most challenging diseases to manage. A sizeable number of researches are done each year to find better diagnostic and therapeutic strategies. At the present time, a package of chemotherapy, targeted therapy, radiotherapy, and immunotherapy is available to cope with cancer cells. Regarding chemo-radiation therapy, low effectiveness and normal tissue toxicity are like barriers against optimal response. To remedy the situation, some agents have been proposed as adjuvants to improve tumor responses. Statins, the known substances for reducing lipid, have shown a considerable capability for cancer treatment. Among them, atorvastatin as a reductase (HMG-CoA) inhibitor might affect proliferation, migration, and survival of cancer cells. Since finding an appropriate adjutant is of great importance, numerous studies have been conducted to precisely unveil antitumor effects of atorvastatin and its associated pathways. In this review, we aim to comprehensively review the most highlighted studies which focus on the use of atorvastatin in cancer therapy.

Cisplatin exposure acutely disrupts mitochondrial bioenergetics in the zebrafish lateral-line organ

Cisplatin is a commonly used chemotherapeutic agent that causes debilitating high-frequency hearing loss. No targeted therapies currently exist to treat cisplatin ototoxicity, partly because the underlying mechanisms of cisplatin-induced hair cell damage are not completely defined. Zebrafish may offer key insights to cisplatin ototoxicity because their lateral-line organ contains hair cells that are remarkably similar to those within the cochlea but are optically accessible, permitting observation of cisplatin injury in live intact hair cells. In this study, we used a combination of genetically encoded biosensors in zebrafish larvae and fluorescent indicators to characterize changes in mitochondrial bioenergetics in response to cisplatin. Following exposure to cisplatin, confocal imaging of live intact neuromasts demonstrated increased mitochondrial activity. Staining with fixable fluorescent dyes that accumulate in active mitochondria similarly showed hyperpolarized mitochondrial membrane potential. Zebrafish expressing a calcium indicator within their hair cells revealed elevated levels of mitochondrial calcium immediately following completion of cisplatin treatment. A fluorescent ROS indicator demonstrated that these changes in mitochondrial function were associated with increased oxidative stress. After a period of recovery, cisplatin-exposed zebrafish demonstrated caspase-3-mediated apoptosis. Altogether, these findings suggest that cisplatin acutely disrupts mitochondrial bioenergetics and may play a key role in initiating cisplatin ototoxicity.

Severity of hearing loss after platinum chemotherapy in childhood cancer survivors

BACKGROUND

Hearing loss is a potential side effect from childhood cancer treatment. We described the severity of hearing loss assessed by audiometry in a representative national cohort of childhood cancer survivors (CCS) and identified clinical risk factors.

PROCEDURE

We included all CCS from the Swiss Childhood Cancer Registry who were diagnosed ≤18 age and treated with platinum-based chemotherapy between 1990 and 2014. We extracted audiograms, treatment-related information, and demographic data from medical records. Two reviewers independently assessed the severity of hearing loss at latest follow-up using the Münster Ototoxicity Scale. We used ordered logistic regression to identify clinical risk factors for severity of hearing loss.

RESULTS

We analyzed data from 270 CCS. Median time from cancer diagnosis to last audiogram was 5 years (interquartile range 2.5-8.1 years). We found 53 (20%) CCS with mild, 78 (29%) with moderate, and 75 (28%) with severe hearing loss. Higher severity grades were associated with (a) younger age at cancer diagnosis (odds ratio [OR] 5.4, 95% confidence interval [CI]: 2.5-12.0 for <5 years); (b) treatment in earlier years (OR 4.8, 95% CI: 2.1-11.0 for 1990-1995); (c) higher cumulative cisplatin doses (OR 13.5, 95% CI: 4.7-38.8 for >450 mg/m² ); (d) concomitant cranial radiation therapy (CRT) (OR 4.4, 95% CI: 2.5-7.8); and (e) hematopoietic stem cell transplantation (HSCT) (OR 2.7, 95% CI: 1.0-7.2).

CONCLUSION

Three of four CCS treated with platinum-based chemotherapy experienced some degree of hearing loss. We recommend closely monitoring patient's hearing function if treated at a young age with high cumulative cisplatin doses, and concomitant CRT as part of long-term care.

Advancements in the studies of novel nanomaterials for inner ear drug delivery

Hearing loss is currently one of the most prevalent sensory disorders worldwide. Because both the blood-labyrinth barrier and the limited blood circulation in the inner ear restrain the effective delivery of most drugs to the inner ear tissues, current treatments for hearing loss are limited to mainly medication, hearing devices and cochlear surgery for therapeutic purposes, whereas treatments lack a noninvasive targeted drug-delivery system. With the continuously rapid development of new nanomaterials, the nanodelivery systems are expected to provide a potentially effective method of clinical treatment for hearing loss. This paper reviews the advantages and disadvantages of the commonly used drug-delivery methods and novel nanomaterials for inner ears as well as advancements in the targeted treatment of hearing loss.

Ototoxicity in childhood: Recommendations of the CODEPEH (Commission for the Early Detection of Childhood Hearing Loss) for prevention and early diagnosis

Ototoxicity is defined as the damage, reversible or irreversible, produced in the inner ear by various substances that are called ototoxic and that can cause hearing loss and/or an alteration of the vestibular system. Permanent hearing loss significantly affects quality of life and is especially important in children. The lack or delay in its detection is frequent, since it often progresses in an inconspicuous manner until it affects communication and overall development. This impact can be minimized by following a strategy of audiological monitoring of ototoxicity, which allows for its early detection and treatment. This document recommends that children who are going to be treated with cisplatin or aminoglycosides be monitored. This CODEPEH review and recommendation document focuses on the early detection, prophylaxis, otoprotection, monitoring and treatment of ototoxicity caused by aminoglycosides and platinum-based antineoplastics in the paediatric population.

The audiogram: Detection of pure-tone stimuli in ototoxicity monitoring and assessments of investigational medicines for the inner ear

Pure-tone thresholds have long served as a gold standard for evaluating hearing sensitivity and documenting hearing changes related to medical treatments, toxic or otherwise hazardous exposures, ear disease, genetic disorders involving the ear, and deficits that develop during aging. Although the use of pure-tone audiometry is basic and standard, interpretation of thresholds obtained at multiple frequencies in both ears over multiple visits can be complex. Significant additional complexity is introduced when audiometric tests are performed within ototoxicity monitoring programs to determine if hearing loss occurs as an adverse reaction to an investigational medication and during the design and conduct of clinical trials for new otoprotective agents for noise and drug-induced hearing loss. Clinical trials using gene therapy or stem cell therapy approaches are emerging as well with audiometric outcome selection further complicated by safety issues associated with biological therapies. This review addresses factors that must be considered, including test-retest variability, significant threshold change definitions, use of ototoxicity grading scales, interpretation of early warning signals, measurement of notching in noise-induced hearing loss, and application of age-based normative data to interpretation of pure-tone thresholds. Specific guidance for clinical trial protocols that will assure rigorous methodological approaches and interpretable audiometric data are provided.

Nrf2 Knockout Affected the Ferroptosis Signaling Pathway against Cisplatin-Induced Hair Cell-Like HEI-OC1 Cell Death

Cisplatin is a well-known and widely used anticancer drug with high therapeutic efficacy in solid tumors; however, side effects are common with its use. Because cisplatin can be retained in the cochlea, ototoxicity leading to hearing loss limits its clinical applications. Here, we report that Nrf2 knockout (KO) strongly increased cisplatin resistance in HEI-OC1 cells, which are immortalized cells from the murine organ of Corti. The underlying mechanism of this phenomenon was uncovered, and an important novel therapeutic target for combating cisplatin-induced hearing loss was identified. Preliminary investigations determined that Nrf2 KO markedly decreased TfR1 protein levels and increased GPX4 protein levels. Thus, ferroptosis may protect organisms from cisplatin-induced cell death. Furthermore, Nrf2 KO cells were resistant to the classical ferroptosis inducers RSL3 and erastin, providing solid evidence that Nrf2 KO inhibits ferroptosis and that knocking out Nrf2 may be a new clinical strategy to prevent cisplatin-induced hearing loss.

Surgical resection of pediatric PRETEXT III and IV hepatoblastoma: A retrospective study investigating the need for preoperative chemotherapy

OBJECTIVE

This study analyzed the feasibility of upfront surgical resection for pediatric PRETEXT III and IV hepatoblastoma (HB).

SUMMARY BACKGROUND DATA

Neoadjuvant chemotherapy is recommended for patients with PRETEXT III and IV HB to obtain a chance of curative surgery. However, chemotherapy can cause toxic side effects and adverse outcomes, and the PRETEXT staging system may overstage the patients. Therefore, whether preoperative chemotherapy is necessary for HB patients remains unclear.

METHODS

The clinical data of 37 children who underwent surgical resection for PRETEXT III and IV HB at our hospital were obtained retrospectively. Patients were divided into the neoadjuvant chemotherapy group (NCG; n = 19) and the routine surgery group (RSG; n = 18). Clinicopathologic characteristics, treatment regimens, and outcomes were compared between the groups.

RESULTS

The RSG had a lower incidence of portal vein involvement than the NCG (p < 0.002). The estimated 3-year event-free survival rates were similar (RSG: 89 ± 0.7% and NCG: 79 ± 0.9%, p = 0.3923). The RSG underwent fewer courses of chemotherapy than the NCG (five vs. six; p < 0.001). Furthermore, the RSG had lower incidences of febrile neutropenia, myelosuppression, and gastrointestinal reactions (all p < 0.05). The severity of surgery-related complications did not differ significantly.

CONCLUSION

Upfront surgical resection in children with PRETEXT III and IV HB is safe and feasible, and reduces the total number of courses and side effects of chemotherapy. The degree of vascular involvement is the most important consideration when evaluating resectability during diagnosis.

AZD5438-PROTAC: A selective CDK2 degrader that protects against cisplatin- and noise-induced hearing loss

Cyclin-dependent kinase 2 (CDK2) is a potential therapeutic target for the treatment of hearing loss and cancer. Previously, we identified AZD5438 and AT7519-7 as potent inhibitors of CDK2, however, they also targeted additional kinases, leading to unwanted toxicities. Proteolysis Targeting Chimeras (PROTACs) are a new promising class of small molecules that can effectively direct specific proteins to proteasomal degradation. Herein we report the design, synthesis, and characterization of PROTACs of AT7519-7 and AZD5438 and the identification of PROTAC-8, an AZD5438-PROTAC, that exhibits selective, partial CDK2 degradation. Furthermore, PROTAC-8 protects against cisplatin ototoxicity and kainic acid excitotoxicity in zebrafish. Molecular dynamics simulations reveal the structural requirements for CDK2 degradation. Together, PROTAC-8 is among the first-in-class PROTACs with in vivo therapeutic activities and represents a new lead compound that can be further developed for better efficacy and selectivity for CDK2 degradation against hearing loss and cancer.

Investigational Medicinal Products for the Inner Ear: Review of Clinical Trial Characteristics in ClinicalTrials.gov

BACKGROUND

The previous 30 years have provided information on the mechanisms of cell death in the inner ear after noise exposure, ototoxic drug injury, and during aging, and clinical trials have emerged for all of these acquired forms of hearing loss. Sudden hearing loss is less well understood, but restoration of hearing after sudden hearing loss is also a long-standing drug target, typically using steroids as an intervention but with other agents of interest as well.

PURPOSE

The purpose of this review was to describe the state of the science regarding clinical testing of investigational medicinal products for the inner ear with respect to treatment or prevention of acquired hearing loss.

DATA COLLECTION AND ANALYSIS

Comprehensive search and summary of clinical trials listed in the National Library of Medicine (www.

CLINICALTRIALS

gov) database identified 61 clinical trials.

RESULTS

Study phase, status, intervention, and primary, secondary, and other outcomes are summarized for studies assessing prevention of noise-induced hearing loss, prevention of drug-induced hearing loss, treatment of stable sensorineural hearing loss, and treatment of sudden sensorineural hearing loss.

CONCLUSION

This review provides a comprehensive summary of the state of the science with respect to investigational medicinal products for the inner ear evaluated in human clinical trials, and the current challenges for the field.

Ototoxicity in cancer survivors: Experience and proposal of a surveillance protocol

INTRODUCTION

Ototoxicity occurs in different percentages in patients after treatment with platinum-based chemotherapy or cranial radiation therapy. The aim of this study was to present our experience in ototoxicity monitoring.

MATERIAL AND METHODS

A review was made of the registry of paediatric cancer patients referred to the Children's Hearing Loss Unit from 1999 to 2019.

RESULTS

Of the 46 patients referred to this unit, 41 had received platinum as part of their treatment, 17 patients underwent neurosurgery, and 18 patients received cranial radiation therapy. An anamnesis and otoscopy were performed on all of them, and the monitoring was carried out with tone-verbal audiometry and/or distortion products. Hearing loss was observed in eight patients (21.05% of patients referred for audiological follow-up) as a consequence of the treatment. It was impossible to determine the audiological situation in eight patients at the end of treatment. Hearing aid adaption was necessary in two patients. In coordination with Paediatric Oncology, a change from cisplatin to carboplatin due to bilateral grade two ototoxicity was considered appropriate during treatment in one patient.

CONCLUSION

Adequate coordination with Paediatric Oncology is essential to carry out active surveillance for ototoxicity and to modify, if possible, the dosage or type of chemotherapy in case hearing is affected. In our experience, and following current recommendations, a pre-treatment assessment is usually performed, as well as monitoring during treatment, at the end of treatment, and annually thereafter due to the risk of a later development of hearing loss.

New insights into cisplatin ototoxicity

LAY SUMMARY

Platinum-containing chemotherapy is often used to treat children with cancer. Although it is a very effective medication, unfortunately, it causes permanent hearing loss in more than one-half of the children who receive it. In this issue of Cancer, an article by Meijer and colleagues shows that very young children are affected early on in their treatment and suggests that the younger the child the more frequently their hearing should be tested during treatment. This proposal is a real challenge for oncology centers and families practically, emotionally, and socioeconomically. The findings are provocative but equally stimulating and encouraging; hopefully, they will lead to a new standard of multidisciplinary care for children receiving platinum chemotherapy.

Atorvastatin is associated with reduced cisplatin-induced hearing loss

BACKGROUNDCisplatin is widely used to treat adult and pediatric cancers. It is the most ototoxic drug in clinical use, resulting in permanent hearing loss in approximately 50% of treated patients. There is a major need for therapies that prevent cisplatin-induced hearing loss. Studies in mice suggest that concurrent use of statins reduces cisplatin-induced hearing loss.METHODSWe examined hearing thresholds from 277 adults treated with cisplatin for head and neck cancer. Pretreatment and posttreatment audiograms were collected within 90 days of initiation and completion of cisplatin therapy. The primary outcome measure was a change in hearing as defined by the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE).RESULTSAmong patients on concurrent atorvastatin, 9.7% experienced a CTCAE grade 2 or higher cisplatin-induced hearing loss compared with 29.4% in nonstatin users (P < 0.0001). A mixed-effect model analysis showed that atorvastatin use was significantly associated with reduced cisplatin-induced hearing loss (P ≤ 0.01). An adjusted odds ratio (OR) analysis indicated that an atorvastatin user is 53% less likely to acquire a cisplatin-induced hearing loss than a nonstatin user (OR = 0.47; 95% CI, 0.30-0.78). Three-year survival rates were not different between atorvastatin users and nonstatin users (P > 0.05).CONCLUSIONSOur data indicate that atorvastatin use is associated with reduced incidence and severity of cisplatin-induced hearing loss in adults being treated for head and neck cancer.TRIAL REGISTRATIONClinicalTrials.gov identifier NCT03225157.FUNDINGFunding was provided by the Division of Intramural Research at the National Institute on Deafness and Other Communication Disorders (1 ZIA DC000079, ZIA DC000090).

The cumulative incidence of cisplatin-induced hearing loss in young children is higher and develops at an early stage during therapy compared with older children based on 2052 audiological assessments

BACKGROUND

Ototoxicity is a common adverse event of cisplatin treatment. The authors investigated the development of cisplatin-induced hearing loss (CIHL) over time in children with cancer by age and examined the influence of other clinical characteristics on the course of CIHL.

METHODS

Data from Canadian patients with childhood cancer were retrospectively reviewed. Hearing loss was graded according to International Society of Pediatric Oncology criteria. The Kaplan-Meier method was applied to estimate the cumulative incidence of CIHL for the total cohort and according to age. Cox regression models were used to explore the effects of independent variables on CIHL development up to 3 years after the start of therapy.

RESULTS

In total, 368 patients with 2052 audiological assessments were included. Three years after initiating therapy, the cumulative incidence of CIHL was highest in patients aged ≤5 years (75%; 95% confidence interval [CI], 66%-84%), with a rapid increase observed to 27% (95% CI, 21%-35%) at 3 months and to 61% (95% CI, 53%-69%) at 1 year, compared with patients aged >5 years (48%; 95% CI, 37%-62%; P < .001). The total cumulative dose of cisplatin at 3 months (per 100 mg/m² increase: hazard ratio [HR], 1.20; 95% CI, 1.01-1.41) vincristine (HR, 2.87; 95% CI, 1.89-4.36) and the total duration of concomitantly administered antibiotics (>30 days: HR, 1.85; 95% CI, 1.17-2.95) further influenced CIHL development over time.

CONCLUSIONS

In young children, the cumulative incidence of CIHL is higher compared with that in older children and develops early during therapy. The course of CIHL is further influenced by the total cumulative dose of cisplatin and other ototoxic (co-)medication. These results highlight the need for audiological monitoring at each cisplatin cycle.

Recommendations for Age-Appropriate Testing, Timing, and Frequency of Audiologic Monitoring During Childhood Cancer Treatment: An International Society of Paediatric Oncology Supportive Care Consensus Report

Importance

Ototoxicity is an irreversible direct and late effect of certain childhood cancer treatments. Audiologic surveillance during therapy as part of the supportive care pathway enables early detection of hearing loss, decision-making about ongoing cancer treatment, and, when applicable, the timely use of audiologic interventions. Pediatric oncologic clinical practice and treatment trials have tended to be driven by tumor type and tumor-specific working groups. Internationally accepted standardized recommendations for monitoring hearing during treatment have not previously been agreed on.

Objective

To provide standard recommendations on hearing loss monitoring during childhood cancer therapy for clinical practice.

Methods

An Ototoxicity Task Force was formed under the umbrella of the International Society of Paediatric Oncology, consisting of international audiologists, otolaryngologists, and leaders in the field of relevant pediatric oncology tumor groups. Consensus meetings conducted by experts were organized, aimed at providing standardized recommendations on age-directed testing, timing, and frequency of monitoring during cancer treatment based on literature and consensus. Consensus statements were prepared by the core group, adapted following several videoconferences, and finally agreed on by the expert panel.

Findings

The consensus reached was that children who receive ototoxic cancer treatment (platinum agents, cranial irradiation, and/or brain surgery) require a baseline case history, monitoring of their middle ear and inner ear function, and assessment of tinnitus at each audiologic follow-up. As a minimum, age-appropriate testing should be performed before and at the end of treatment. Ideally, audiometry with counseling before each cisplatin cycle should be considered in the context of the individual patient, specific disease, feasibility, and available resources.

Conclusions and Relevance

This is an international multidisciplinary consensus report providing standardized supportive care recommendations on hearing monitoring in children undergoing potentially ototoxic cancer treatment. The recommendations are intended to improve the care of children with cancer and facilitate comparative research on the timing and development of hearing loss caused by different cancer treatment regimens.

Statins: a repurposed drug to fight cancer

As competitive HMG-CoA reductase (HMGCR) inhibitors, statins not only reduce cholesterol and improve cardiovascular risk, but also exhibit pleiotropic effects that are independent of their lipid-lowering effects. Among them, the anti-cancer properties of statins have attracted much attention and indicated the potential of statins as repurposed drugs for the treatment of cancer. A large number of clinical and epidemiological studies have described the anticancer properties of statins, but the evidence for anticancer effectiveness of statins is inconsistent. It may be that certain molecular subtypes of cancer are more vulnerable to statin therapy than others. Whether statins have clinical anticancer effects is still an active area of research. Statins appear to enhance the efficacy and address the shortcomings associated with conventional cancer treatments, suggesting that statins should be considered in the context of combined therapies for cancer. Here, we present a comprehensive review of the potential of statins in anti-cancer treatments. We discuss the current understanding of the mechanisms underlying the anti-cancer properties of statins and their effects on different malignancies. We also provide recommendations for the design of future well-designed clinical trials of the anti-cancer efficacy of statins.

Effect of cisplatin chemotherapy on the inner ear function and serum prestin concentration

PURPOSE

One of the main side effects of chemotherapy with cisplatin is irreversible sensorineural hearing loss. This study was conducted to assess the correlation between the serum prestin concentration as a potential cochlear biomarker and audiologic findings in patients after cisplatin chemotherapy.

METHODS

A total of 52 patients aged 18-75 years were included in this prospective study. All the subjects were recruited from the radiotherapy and oncology center of a tertiary hospital in Rasht, Iran. Audiologic parameters evaluations and serum prestin concentrations were measured at baseline and after 1-3 weeks of chemotherapy. The inner ear function was evaluated by pure-tone audiometry (PTA) and distortion product of otoacoustic emission (DPOAE). A repeated-measure analysis of variance was performed to evaluate the relationship between the PTA, DPOAE, serum prestin concentration and cumulative cisplatin dose.

RESULTS

Fifty-two patients (36 females) participated in this study. The PTA results showed that ototoxicity was more frequent among the patients with a high cumulative dose of cisplatin (χ2 trend = 15.25; P < 0.001). DPOAE responses revealed that 38.5% of the patients had ototoxicity change after 40-80 mg of cisplatin administration. After receiving 40-80 mg of cisplatin, serum prestin concentration increased from 130 to 230 pg/ml. There is a significant positive correlation between prestin concentration after receiving more than 80 mg of cisplatin and the ototoxic changes in the DPOAE response.

CONCLUSION

The present study showed correlations between prestin concentrations and ototoxicity diagnosis by DPOAE findings. An early rise in prestin concentration is particularly important and an early sign of hearing loss. Future studies are recommended to investigate the effect of varying doses of cisplatin on prestin concentration and any association between ototoxicity and clinicopathological features.

Cisplatin Ototoxicity: Examination of the Impact of Dosing, Infusion Times, and Schedules In Pediatric Cancer Patients

Background

Sensorineural hearing loss is a well-known side effect of cisplatin (CDDP). There is limited research on the effect of dosing, infusion times, and schedules of cisplatin administration and their impact on hearing loss.

Methods

A retrospective review of 993 pediatric patients' medical and audiological charts from August 1990 to March 2015 was conducted using stringent inclusion criteria to characterize patients with hearing loss. 248 of these patients received CDDP. Of these, 216 patients had sufficient CDDP infusion data to assess for sensorineural hearing loss attributable to CDDP and its associated risk factors. Chart reviews were performed to extract clinical data including CDDP dosing information. Demographic and clinical characteristics were summarized by descriptive statistics, and univariate and multivariate logistic regressions were performed to examine the relationship between hearing loss and specific parameters of cisplatin administration (amount infused per dose, prescribed infusion time, total number of doses, number of doses per cycle, number of cycles, cumulative cisplatin exposure). Stepwise variable selection procedure was performed in the multivariate model building to extract the best subset of risk factors for the prediction of hearing loss and worsening ototoxicity grade using an established ototoxicity grading scale from the International Society of Pediatric Oncology (SIOP).

Results

A total of 153 patients with complete medical and audiologic data were evaluable for analysis. Hearing loss was identified in 72.6% of the patients. Multivariate analysis revealed that age [OR=0.90 (0.84-0.97), p-value=0.0086], radiation to any part of the body, [OR=3.20 (1.29-7.93), p-value=0.012], amount infused per dose (mg/m²) [OR=1.018 (1.002-1.033), p-value=0.029], and cumulative cisplatin exposure (mg/m ²) [OR=1.004 (1-1.008), p-value=0.027] were associated with hearing loss. Similar associations were also found between these risk factors and worsening SIOP grade.

Conclusion

In one of the largest studies examining the influence of CDDP dosing and schedules on hearing loss, we found the amount of CDDP infused per dose is a significant risk factor. Considerations in designing regimens that reduce the amount of CDDP infused per dose may reduce the risk of hearing loss. Randomized prospective trials are needed.

Advances in the conventional clinical treatment for hepatoblastoma and therapeutic innovation

Background

Hepatoblastoma (HB) is a rare malignancy usually occurring in children under 3 years old. With advancements in surgical techniques and molecular biology, new treatments have been developed.

Data resources

The recent literatures on new treatments, molecular mechanisms and clinical trials for HB were searched and reviewed.

Results

Surgical resection remains the main option for treatment of HB. Although complete resection is recommended, a resection with microscopical positive margins (R1) may have similar 5-year overall survival and 5-year event-free survival (EFS) rates after cisplatin chemotherapy and the control of metastasis, as only once described so far. Indocyanine green-guided surgery can help achieve precise resection. Additionally, associating liver partition and portal vein ligation for staged hepatectomy can rapidly increase future liver remnant volume compared with portal vein ligation or embolization. Cisplatin-containing chemotherapies slightly differ among the guidelines from the International Childhood Liver Tumors Strategy Group (SIOPEL), Children’s Oncology Group (COG) and Chinese Anti-Cancer Association Pediatric Committee (CCCG), and the 3-year EFS rate of patients in SIOPEL and CCCG studies was recently shown to be higher than that in COG studies. Liver transplantation is an option for patients with unresectable HB, and successful cases of autologous liver transplantation have been reported. In addition, effective inhibitors of important targets, such as the mTOR (mammalian target of rapamycin) inhibitor rapamycin, β-catenin inhibitor celecoxib and EpCAM (epithelial cell adhesion molecule) inhibitor catumaxomab, have been demonstrated to reduce the activity of HB cells and to control metastasis in experimental research and clinical trials.

Conclusion

These advances in surgical and medical treatment provide better outcomes for children with HB, and identifying novel targets may lead to the development of future targeted therapies and immunotherapies.

Prevalence and risk factors for cisplatin-induced hearing loss in children, adolescents, and young adults: a multi-institutional North American cohort study

BACKGROUND

Cisplatin is used to treat a wide range of childhood cancers and cisplatin-induced hearing loss (CIHL) is a common and debilitating toxicity. We aimed to address persistent knowledge gaps in CIHL by establishing benchmarks for the prevalence of and risk factors for CIHL.

METHODS

In this multi-institutional cohort study, children (age 0-14 years), adolescents, and young adults (age 15-39 years) diagnosed with a cisplatin-treated tumour from paediatric cancer centres, who had available cisplatin dosing information, and primary audiology data for central review from consortia located in Canada and the USA were eligible for inclusion. Audiology was centrally reviewed and CIHL graded using the consensus International Society of Pediatric Oncology (SIOP) Boston Ototoxicity Scale. We assessed the prevalence of moderate or severe CIHL (SIOP grade ≥2) at latest follow-up and end of therapy, in each demographic, diagnosis, and treatment group and their relative contributions to risk for CIHL. Secondary endpoints explored associations of cisplatin dose reductions and CIHL with survival. We also examined whether cisplatin dose reductions and CIHL were associated with survival outcomes.

FINDINGS

We included 1481 patients who received cisplatin. Of the 1414 (95·5%) participants who had audiometry at latest follow-up (mean 3·9 years [SD 4·2] since diagnosis), 620 (43·8%) patients developed moderate or severe CIHL. The highest prevalence of CIHL was seen in the youngest patients (aged <5 years; 360 [59·4%] of 606 patients) and those with a CNS tumour (221 [50·9%] of 434 patients), hepatoblastoma (110 [65·9%] of 167 patients), or neuroblastoma (154 [62·1%] of 248 patients). After accounting for cumulative cisplatin dose, higher fractionated doses were associated with risk for CIHL (for each 10mg/m2 increase per day, adjusted odds ratio [aOR] 1·15 [95% CI 1·07-1·25]; for each 50 mg/m2 increase per cycle aOR 2·16 [1·37-3·51]). Vincristine exposure was newly identified as a risk factor for CIHL (aOR 3·55 [2·19-5·84]). Dose reductions and moderate or severe CIHL were not significantly associated with survival differences.

INTERPRETATION

Using this large, multicentre cohort, benchmarks were established for the prevalence of CIHL in patients treated with cisplatin. Variations in cisplatin dosing confer additive risk for developing CIHL and warrant investigation as a potential approach to decrease the burden of therapy.

FUNDING

US National Institutes of Health and National Institute on Deafness and Other Communication Disorders, US National Institutes of Health and National Cancer institute, St Baldrick's Foundation, Genome Canada, Genome British Columbia, Canadian Institutes of Health Research, the Canada Foundation for Innovation, University of British Columbia, British Columbia Children's Hospital Research Institute, British Columbia Provincial Health Services Authority, Health Canada, and C17 Research Network.

Characterization of quinoxaline derivatives for protection against iatrogenically induced hearing loss

Hair cell loss is the leading cause of hearing and balance disorders in humans. It can be caused by many factors, including noise, aging, and therapeutic agents. Previous studies have shown the therapeutic potential of quinoxaline against drug-induced ototoxicity. Here, we screened a library of 68 quinoxaline derivatives for protection against aminoglycoside-induced damage of hair cells from the zebrafish lateral line. We identified quinoxaline-5-carboxylic acid (Qx28) as the best quinoxaline derivative that provides robust protection against both aminoglycosides and cisplatin in zebrafish and mouse cochlear explants. FM1-43 and aminoglycoside uptake, as well as antibiotic efficacy studies, revealed that Qx28 is neither blocking the mechanotransduction channels nor interfering with aminoglycoside antibacterial activity, suggesting that it may be protecting the hair cells by directly counteracting the ototoxin’s mechanism of action. Only when animals were incubated with higher doses of Qx28 did we observe a partial blockage of the mechanotransduction channels. Finally, we assessed the regulation of the NF-κB pathway in vitro in mouse embryonic fibroblasts and in vivo in zebrafish larvae. Those studies showed that Qx28 protects hair cells by blocking NF-κB canonical pathway activation. Thus, Qx28 is a promising and versatile otoprotectant that can act across different species and toxins.

Ototoxicity-induced hearing loss and quality of life in survivors of paediatric cancer

INTRODUCTION

Hearing loss is a permanent and debilitating side-effect of a range of interventions commonly used in the treatment of childhood cancers, primarily ototoxic medications such as cisplatin. The purpose of this study was to examine the impact of hearing loss, in a population already at risk of reduced quality of life due to the cancer and treatment-related factors.

METHODS

This study used a questionnaire specifically designed to tap issues relevant to children with hearing loss, the Paediatric Audiology Quality of Life questionnaire (PAQL). Parents of 78 children treated for a wide range of solid tumours and leukaemias completed the PAQL, 41 of whom had sensorineural hearing loss as a result of the cancer treatment.

RESULTS

Significant differences between those children with hearing loss and those whose hearing remained normal were found on all four scales of the questionnaire. Children affected by ototoxicity were rated as having poorer quality of life in terms of their ability to communicate with family and peers, their independence, interactions with peers and emotional well-being.

CONCLUSION

These results highlight the impact of acquired hearing loss and reinforce the importance of assessing quality of life with a measure capable of tapping the issues of consequence to the population under investigation. They also have implications for the clinical management of children during and following treatment for a wide range of cancers: medically, audiologically, psychologically and educationally.

[Ototoxicity in cancer survivors: experience and proposal of a surveillance protocol]

INTRODUCTION

Ototoxicity occurs in different percentages in patients after treatment with platinum-based chemotherapy or cranial radiation therapy. The aim of this study was to present experience in ototoxicity monitoring.

MATERIAL AND METHODS

A review was made of the registry of paediatric cancer patients referred to the Children's Hearing Loss Unit from 1999 to 2019.

RESULTS

Of the 46 patients referred to this unit, 41 had received platinum as part of their treatment, 17 patients underwent neurosurgery, and 18 patients received cranial radiation therapy. An anamnesis and otoscopy were performed on all of them, and the monitoring was carried out with tone-verbal audiometry and/or distortion products. Hearing loss was observed in eight patients (21.05% of patients referred for audiological follow-up) as a consequence of the treatment. It was impossible to determine the audiological situation in eight patients at the end of treatment. Hearing aid adaption was necessary in two patients. In coordination with Paediatric Oncology, a change from cisplatin to carboplatin due to bilateral grade two ototoxicity was considered appropriate during treatment in one patient.

CONCLUSION

Adequate coordination with Paediatric Oncology is essential to carry out active surveillance for ototoxicity and to modify, if possible, the dosage or type of chemotherapy in case hearing is affected. In our experience, and following current recommendations, a pre-treatment assessment is usually performed, as well as monitoring during treatment, at the end of treatment, and annually thereafter due to the risk of a later development of hearing loss.

Current Strategies to Combat Cisplatin-Induced Ototoxicity

Cisplatin is widely used for the treatment of a number of solid malignant tumors. However, ototoxicity induced by cisplatin is an obstacle to effective treatment of tumors. The basis for this toxicity has not been fully elucidated. It is generally accepted that hearing loss is due to excessive production of reactive oxygen species by cells of the cochlea. In addition, recent data suggest that inflammation may trigger inner ear cell death through endoplasmic reticulum stress, autophagy, and necroptosis, which induce apoptosis. Strategies have been extensively explored by which to prevent, alleviate, and treat cisplatin-induced ototoxicity, which minimize interference with antitumor activity. Of these strategies, none have been approved by the Federal Drug Administration, although several preclinical studies have been promising. This review highlights recent strategies that reduce cisplatin-induced ototoxicity. The focus of this review is to identify candidate agents as novel molecular targets, drug administration routes, delivery systems, and dosage schedules. Animal models of cisplatin ototoxicity are described that have been used to evaluate drug efficacy and side effect prevention. Finally, clinical reports of otoprotection in patients treated with cisplatin are highlighted. For the future, high-quality studies are required to provide reliable data regarding the safety and effectiveness of pharmacological interventions that reduce cisplatin-induced ototoxicity.

Generation of inner ear hair cells by direct lineage conversion of primary somatic cells

The mechanoreceptive sensory hair cells in the inner ear are selectively vulnerable to numerous genetic and environmental insults. In mammals, hair cells lack regenerative capacity, and their death leads to permanent hearing loss and vestibular dysfunction. Their paucity and inaccessibility has limited the search for otoprotective and regenerative strategies. Growing hair cells in vitro would provide a route to overcome this experimental bottleneck. We report a combination of four transcription factors (Six1, Atoh1, Pou4f3, and Gfi1) that can convert mouse embryonic fibroblasts, adult tail-tip fibroblasts and postnatal supporting cells into induced hair cell-like cells (iHCs). iHCs exhibit hair cell-like morphology, transcriptomic and epigenetic profiles, electrophysiological properties, mechanosensory channel expression, and vulnerability to ototoxin in a high-content phenotypic screening system. Thus, direct reprogramming provides a platform to identify causes and treatments for hair cell loss, and may help identify future gene therapy approaches for restoring hearing.

GSTM1 null and GSTT1 null: predictors of cisplatin-caused acute ototoxicity measured by DPOAEs

Preventing the ototoxicity caused by cisplatin is a major issue yet to be overcome. Useful preventive treatments will soon be available. Consequently, the next step is to filter out those patients who are more prone to develop ototoxicity. The aim of this study was to prospectively evaluate potential predictive markers of acute ototoxicity as determined by measures of distortion product otoacoustic emissions (DPOAEs). A total of 118 patients from our previous DPOAE analysis were put under evaluation. Ototoxic cases were divided according to unilateral (n = 45) or bilateral (n = 23) involvement. The clinicopathological characteristics, hearing test results, germline GSTT1, GSTM1, and GSTP1 polymorphisms, and common laboratory parameters were included in the new analysis. Univariate and multivariate statistical tests were applied. According to multivariate logistic regression, the only independent predictor of unilateral ototoxicity (vs. non-affected) was a GSTM1 null genotype (OR = 4.52; 95%CI = 1.3-16.3), while for bilateral damage, the GSTT1 null genotype (OR = 4.76; 1.4-16) was a predictor. The higher starting serum urea level was characteristic of bilateral ototoxicity; however, the only independent marker of bilateral (vs. unilateral) ototoxicity was the presence of GSTT1 null genotype (OR = 2.44; 1.23-4.85). Different processes, involving the GSTM1 and GSTT1 genotypes, respectively, govern the development of acute unilateral and bilateral ototoxicities. Further research is needed to clarify these processes. Based on the above findings, patients whom are at risk may be selected for otoprotective therapies. KEY MESSAGES: The acute ototoxicity was determined by DPOAE in 118 testicular cancer patients. GSTM1 null was the only marker of unilateral ototoxicity (vs. non-affected). The only marker of bilateral hearing loss (vs. non-affected) was the GSTT1 null. GSTT1 null was also the marker of bilateral vs. unilateral ototoxicity. A high-risk group may be selected for new, individualized otoprotective treatment.

Assessment and Management of Platinum-Related Ototoxicity in Children Treated for Cancer

Platinum compounds are a group of chemotherapeutic agents included in many pediatric and adult oncologic treatment protocols. The main platinum compounds are cisplatin, carboplatin, and oxaliplatin. Their use in clinical practice has greatly improved long-term survival of pediatric patients, but they also cause some toxic effects: ototoxicity, myelosuppression, nephrotoxicity, and neurotoxicity. Hearing damage is one of the main toxic effects of platinum compounds, and it derives from the degeneration of hair cells of the ear, which, not having self-renewal capacity, cannot reconstitute themselves. Hearing loss from platinum exposure is typically bilateral, sensorineural, and permanent, and it is caused by the same mechanisms with which platinum acts on neoplastic cells. According to available data from the literature, the optimal timing for the audiological test during and after treatment with platinum compounds is not well defined. Moreover, no substances capable of preventing the onset of hearing loss have been identified.

Clinical trials evaluating transtympanic otoprotectants for cisplatin-induced ototoxicity: what do we know so far?

BACKGROUND

Cisplatin (CDDP) chemotherapy can cause serious side effects including irreversible and progressive hearing loss. Studies have aimed to assess potential protective strategies; however, systemic treatments have presented variable results, and potential interactions with CDDP have limited clinical trials.

METHODS

A review of the literature was performed in order to evaluate clinical trials that have studied a transtympanic approach as an otoprotectant strategy.

RESULTS

Six clinical trials were included. While a transtympanic approach can limit side effects and avoid interactions with CDDP, recurrent issues have been expressed including which otoprotectant to test, time delays between CDDP treatment and transtympanic injections, side effects such as pain and dizziness, concentrations, and number of injections. Clinical trials have used sodium thiosulfate, N-acetylcysteine and dexamethasone.

CONCLUSIONS

While a transtympanic approach seems like an attractive strategy, further research is needed to clarify which is the optimal otoprotectant, its dosage, and the number of injections.

Toxicity, risk factors and management of cisplatin-induced toxicity: A prospective study

Background and propose

Cisplatin is a cytotoxic drug that triggers several toxicities. However, nephrotoxicity and ototoxicity remain major clinical limitations. The aim of our study was to evaluate the incidence of chemotherapy toxicity induced by cisplatin and to analyze the influence of risk factors in the Tunisian population.

Methods

We performed a prospective descriptive study in a period of four months. Patients were eligible if they had pathologically confirmed malignancies and treated with cisplatin-regimen chemotherapy. Nephrotoxicity and digestive toxicity were graded according to the World Health Organization toxicity scale and ototoxicity was scored clinically according to the Common Terminology Criteria for Adverse Events (CTCAE). Multivariate logistic regression analysis was performed to evaluate the influence of clinical variables on cisplatin-induced toxicity.

Results

A total of 150 patients were included. Forty-four percent of patients developed cisplatin-regimen toxicity: 15% developed cisplatin-induced nephrotoxicity, 9% cisplatin-induced ototoxicity and 27% digestive toxicity. In the multivariate analysis, age >65 years (OR= 6.129, p = 0.010), metastatic cancer (OR = 0.171, p = 0.007) and cumulative dose (OR= 1.004 mg/m2; p = 0.042) were strong predisposing factors for CDDP-induced nephrotoxicity. The cumulative dose was an independent prognostic indicator for digestive toxicity (OR = 0.997, p = 0.002).

Conclusion

In our study, age >65 years and metastatic cancer were risk factors for cisplatin-induced nephrotoxicities. We also found the correlation between cumulative dose and nephrotoxicity or digestive toxicity.

Prevention of cisplatin-induced ototoxicity in children and adolescents with cancer: a clinical practice guideline

Despite ototoxicity being a prevalent consequence of cisplatin chemotherapy, little guidance exists on interventions to prevent this permanent and progressive adverse event. To develop a clinical practice guideline for the prevention of cisplatin-induced ototoxicity in children and adolescents with cancer, we convened an international, multidisciplinary panel of experts and patient advocates to update a systematic review of randomised trials for the prevention of cisplatin-induced ototoxicity. The systematic review identified 27 eligible adult and paediatric trials that evaluated amifostine, sodium diethyldithiocarbamate or disulfiram, systemic sodium thiosulfate, intratympanic therapies, and cisplatin infusion duration. Regarding systemic sodium thiosulfate, the panel made a strong recommendation for administration in non-metastatic hepatoblastoma, a weak recommendation for administration in other non-metastatic cancers, and a weak recommendation against its routine use in metastatic cancers. Amifostine, sodium diethyldithiocarbamate, and intratympanic therapy should not be routinely used. Cisplatin infusion duration should not be altered as a means to reduce ototoxicity. Further research to determine the safety of sodium thiosulfate in patients with metastatic cancer is encouraged.

Overview of cisplatin-induced neurotoxicity and ototoxicity, and the protective agents

Cisplatin has dramatically improved the survival rate of cancer patients, but it has also increased the prevalence of hearing and neurological deficits in this population. Cisplatin induces ototoxicity, peripheral (most prevalent) and central (rare) neurotoxicity. This review addresses the ototoxicity and the neurotoxicity associated with cisplatin-based chemotherapy, providing an integrated view of the potential protective agents that have been evaluated in vitro, in vivo and in clinical trials, their targets and mechanisms of protection and their effects on the antitumor activity of cisplatin. So far, the findings are insufficient to support the use of any oto- or neuroprotective agent before, during or after cisplatin chemotherapy. Despite their promising effects in vitro and in animal studies, many agents have not been evaluated in clinical trials. Additionally, the clinical trials have limitations concerning the sample size, controls, measurement, heterogeneous groups, several arms of treatment, short follow-up or no blinding. Besides that, for most agents, the effects on the antitumor activity of cisplatin have not been evaluated in tumor-bearing animals, which discourages clinical trials. Further well-designed randomized controlled clinical trials are necessary to definitely demonstrate the effectiveness of the oto- or neuroprotective agents proposed by animal and in vitro studies.

Effect of sensorineural hearing loss on neurocognitive and adaptive functioning in survivors of pediatric embryonal brain tumor

PURPOSE

Survivors of pediatric embryonal brain tumors (BT) are at high risk for sensorineural hearing loss (SNHL) associated with neurocognitive decline. However, previous studies have not assessed the relationship between SNHL and adaptive functioning. We examined neurocognitive and adaptive functioning in patients with and without SNHL.

METHODS

Participants included 36 patients treated for an embryonal BT with craniospinal irradiation (CSI) and cisplatin chemotherapy who were assessed 6.7 years post-treatment on average. The impact of SNHL on neurocognitive performance and parent-rated adaptive functioning was assessed in univariate and multivariate analyses.

RESULTS

There were 17 cases with SNHL (mean age at evaluation = 14.4) and 19 cases with NH (mean age at evaluation = 13.8). After accounting for age at diagnosis and additional covariates in multivariable analyses, SNHL was associated with worse overall intellectual functioning (p = 0.027) and perceptual reasoning (p = 0.016) performance. There was no effect of SNHL on adaptive functioning in multivariable models. Age at diagnosis and sex were associated with performance on neurocognitive measures.

CONCLUSIONS

SNHL in pediatric embryonal BT is associated with increased risk for neurocognitive deficits in conjunction with other demographic and treatment-related factors.

Clinical and Genome-Wide Analysis of Serum Platinum Levels after Cisplatin-Based Chemotherapy

PURPOSE

Serum platinum is measurable for years after completion of cisplatin-based chemotherapy (CBC). We report the largest investigation of serum platinum levels to date of 1,010 testicular cancer survivors (TCS) assessed 1-35 years after CBC and evaluate genetic contributions to these levels.

EXPERIMENTAL DESIGN

Eligible TCS given 300 or 400 (±15) mg/m2 cisplatin underwent extensive audiometric testing, clinical examination, completed questionnaires, and had crude serum platinum levels measured. Associations between serum platinum and various risk factors and toxicities were assessed after fitting a biexponential model adjusted for follow-up time and cumulative cisplatin dose. A genome-wide association study (GWAS) was performed using the serum platinum residuals of the dose and time-adjusted model.

RESULTS

Serum platinum levels exceeded the reference range for approximately 31 years, with a strong inverse relationship with creatinine clearance at follow-up (age-adjusted P = 2.13 × 10-3). We observed a significant, positive association between residual platinum values and luteinizing hormone (age-adjusted P = 6.58 × 10-3). Patients with high residual platinum levels experienced greater Raynaud phenomenon than those with medium or low levels (age-adjusted ORhigh/low = 1.46; P = 0.04), as well as a higher likelihood of developing tinnitus (age-adjusted ORhigh/low = 1.68, P = 0.07). GWAS identified one single-nucleotide polymorphism (SNP) meeting genome-wide significance, rs1377817 (P = 4.6 × 10-8, a SNP intronic to MYH14).

CONCLUSIONS

This study indicates that residual platinum values are correlated with several cisplatin-related toxicities. One genetic variant is associated with these levels.

Prevalence of Ototoxicity Following Hematopoietic Stem Cell Transplantation in Pediatric Patients

The use of hematopoietic stem cell transplantation (HSCT) is increasing for a variety of diseases. Ototoxicity from this procedure has not been extensively studied. A retrospective chart review examined 275 patients from this institution who underwent HSCT between January 1, 2007, and April 30, 2017. Data extracted included therapy before HSCT and the subsequent course of transplantation. Evaluable patients had complete medical records and interpretable audiograms available. Ototoxicity constituted significant threshold changes from baseline or changes in International Society of Pediatric Oncology/Boston Ototoxicity Grading Scale (SIOP) grade comparing audiogram results just before HSCT with those following the transplantation procedure. A total of 147 patients were evaluable. Ototoxicity was observed in 10.2% of the patients. Higher SIOP grade before HSCT was significantly associated with a higher risk of post-transplantation ototoxicity (P < .01). Previous cisplatin treatment (P < .0001), but not carboplatin or radiation treatment, was also associated with ototoxicity. Patients with a solid tumor or brain tumor (P < .0001) and those who received an autologous transplant (P = .0002) were also at increased risk. No post-transplantation event was significantly associated with ototoxicity. Ototoxicity affects a significant percentage of patients undergoing HSCT, and careful monitoring is needed to identify patients impacted by this procedure.

Interventions for cisplatin-induced hearing loss in children and adolescents with cancer

The identification of preventive interventions that are safe and effective for cisplatin-induced ototoxicity is important, especially in children because hearing loss can impair speech-language acquisition development. Previous randomised trials assessed systemic drugs such as amifostine, sodium diethyldithiocarbamate or disulfiram, and sodium thiosulfate. Amifostine, sodium diethyldithiocarbamate, and disulfiram did not show hearing preservation. Paediatric trials assessing sodium thiosulfate showed efficacy in terms of hearing protection. The SIOPEL 6 trial consisted solely of patients with localised hepatoblastoma and no effects on survival were shown. In the ACCL0431 trial, which included heterogeneous patients, a post-hoc analysis showed significantly worse overall survival among patients who had disseminated disease receiving sodium thiosulfate than among controls, but not among those with localised disease. Intratympanically administered drugs have mainly been assessed in adults and include N-acetylcysteine and dexamethasone. Inconsistent effects of these drugs were identified but these studies were limited by design, small sample size, and statistical approach. Future studies of systemic drugs will need to consider the measurement of disease outcomes through study design and sample size, and ototoxicity endpoints should be harmonised to enhance comparability between trials.