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

Children with non-central nervous system tumors treated with platinum-based chemotherapy are at risk for hearing loss and cognitive impairments

Background

Childhood cancer survivors (CCS) with chemotherapy induced sensorineural hearing loss (SNHL) are at risk for neurocognitive impairments. The purpose of this study was to determine the relationship between SNHL and cognitive function among CCS.

Procedure

Inclusion: non-CNS solid tumor diagnosis; history of platinum chemotherapy (cisplatin and/or carboplatin); 8-17 years of age; off anti-cancer treatment for ≥6 months; and English speaking. Exclusion: history of intrathecal chemotherapy, cranial radiation, or baseline neurocognitive disorder. Participants completed the NIH Toolbox Cognition Battery at enrollment. T-tests were used to compare participants with normal hearing to those with hearing loss and the total sample with established Toolbox normative data (mean: 50; SD: 10).

Results

Fifty-seven individuals enrolled; 52 completed full cognitive testing. Participants were on average 12.2 years of age and 7.0 years since treatment completion. Twenty-one participants (40%) received cisplatin, 27 (52%) carboplatin, and 4 (8%) received both. Fifteen participants (29%) demonstrated SNHL based on the better ear. CCS, regardless of the presence or absence of SNHL, demonstrated significantly lower mean cognitive skills compared to the normative sample in attention, executive function, language- vocabulary and oral reading, processing speed, and fluid, crystallized and total composite scores (all p < 0.01). Participants with SNHL had significantly lower crystallized composite (vocabulary, oral reading) than those with normal hearing (41.9 vs. 47.2, p < 0.05, Cohen's d = 0.62).

Conclusions

CCS at risk for platinum induced hearing loss but without cranial radiation or intrathecal chemotherapy exposure demonstrate impaired cognitive skills and those with SNHL demonstrate lower crystallized composite scores.

Prevention of cisplatin-induced hearing loss in children: achievements and challenges for evidence-based implementation of sodium Thiosulfate

Ototoxicity is a devastating direct, irreversible side effect of platinum use in children with cancer, with its consequent effect on speech, language and social development, quality of life and adult productivity. Cisplatin, an essential chemotherapeutic agent for the treatment of solid tumors in children, is a DNA cross-linking agent. Which causes hearing loss in 50-70% of cisplatin treated children. Fortunately, to prevent hearing loss, sodium thiosulfate (STS), which binds to cisplatin, and reduces the superoxides in both tumor and outer hair cells of the cochlea has now been discovered to be an effective and safe otoprotectant if administered correctly. The aim of this perspective paper is to explore the key safety issues and challenges important for pediatric oncologists and pharmacists when considering the clinical use of STS as an otoprotectant for children and adolescents receiving cisplatin. These include: the choice of the formulation; the timing, both that of the STS in relation to cisplatin as well as the timing of the cisplatin infusion itself; the dosing; the challenge left by the definition of localized versus disseminated disease and the difference in indication for STS, between cisplatin treated patients and those receiving another platinum chemotherapeutic agent, carboplatin.

Clinical and Therapeutic Considerations for Older Adults with Head and Neck Cancer

Approximately 30% of patients with head and neck squamous cell carcinoma (HNSCC) are at least 70 years of age, and this percentage is expected to increase as the population increases and lives longer. Elderly patients are underrepresented in head and neck oncology clinical trials, and there is minimal evidence on the management of HNSCC for this population. Subsequently, despite their best intentions, physicians may unknowingly recommend an ill-suited course of therapy, which may result in suboptimal oncological or functional outcomes or adverse events. Surgical approaches have the potential to carry a higher risk of morbidity and mortality in older adults, especially in patients with multiple comorbidities. Definitive radiation therapy treatment in patients with HNSCC frequently involves 7 weeks of daily radiation, sometimes with concurrent chemotherapy, and this demanding treatment can be difficult for older adult patients, which may lead to treatment interruptions, potential removal of concurrent systemic therapy, compromised outcomes, and diminished quality of life. There are clinical trials currently underway investigating altered fractionation regimens and novel, less toxic systemic treatments in this population. This review provides an overview of how best to approach an older adult with HNSCC, from initial work-up to treatment selection.

Systematic Review and Meta-Analysis of the Influence of Genetic Variation on Ototoxicity in Platinum-Based Chemotherapy

OBJECTIVE

The objective of this meta-analysis is to evaluate the impact of genetic polymorphisms on platinum-based chemotherapy (PBC)-induced ototoxicity.

DATA SOURCES

Systematic searches of PubMed, Embase, Cochrane, and Web of Science were conducted from the inception of the databases to May 31, 2022. Abstracts and presentations from conferences were also reviewed.

REVIEW METHODS

Four investigators independently extracted data in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Differences in the prevalence of PBC-induced ototoxicity between reference and variant (i) genotypes and (ii) alleles were analyzed. The overall effect size was presented using the random-effects model as an odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

From 32 included articles, 59 single nucleotide polymorphisms on 28 genes were identified, with 4406 total unique participants. For allele frequency analysis, the A allele in ACYP2 rs1872328 was positively associated with ototoxicity (OR: 2.61; 95% CI: 1.06-6.43; n = 2518). Upon limiting to cisplatin use only, the T allele of COMT rs4646316 and COMT rs9332377 revealed significant results. For genotype frequency analysis, the CT/TT genotype in ERCC2 rs1799793 demonstrated an otoprotective effect (OR: 0.50; 95% CI: 0.27-0.94; n = 176). Excluding studies using carboplatin or concomitant radiotherapy revealed significant effects with COMT rs4646316, GSTP1 rs1965, and XPC rs2228001. Major sources of variations between studies include differences in patient demographics, ototoxicity grading systems, and treatment protocols.

CONCLUSION

Our meta-analysis presents polymorphisms that exert ototoxic or otoprotective effects in patients undergoing PBC. Importantly, several of these alleles are observed at high frequencies globally, highlighting the potential for polygenic screening and cumulative risk evaluation for personalized care.

Emerging and established therapies for chemotherapy-induced ototoxicity

PURPOSE

Ototoxicity is considered a dose-limiting side effect of some chemotherapies. Hearing loss, in particular, can have significant implications for the quality of life for cancer survivors. Here, we review therapeutic approaches to mitigating ototoxicity related to chemotherapy.

METHODS

Literature review.

CONCLUSIONS

Numerous otoprotection strategies are undergoing active investigation. However, numerous challenges exist to confer adequate protection while retaining the anti-cancer efficacy of the chemotherapy.

IMPLICATIONS FOR CANCER SURVIVORS

Ototoxicity can have significant implications for cancer survivors, notably those receiving cisplatin. Clinical translation of multiple otoprotection approaches will aid in limiting these consequences.

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.

Putative COVID-19 therapies imatinib, lopinavir, ritonavir, and ivermectin cause hair cell damage: A targeted screen in the zebrafish lateral line

The biomedical community is rapidly developing COVID-19 drugs to bring much-need therapies to market, with over 900 drugs and drug combinations currently in clinical trials. While this pace of drug development is necessary, the risk of producing therapies with significant side-effects is also increased. One likely side-effect of some COVID-19 drugs is hearing loss, yet hearing is not assessed during preclinical development or clinical trials. We used the zebrafish lateral line, an established model for drug-induced sensory hair cell damage, to assess the ototoxic potential of seven drugs in clinical trials for treatment of COVID-19. We found that ivermectin, lopinavir, imatinib, and ritonavir were significantly toxic to lateral line hair cells. By contrast, the approved COVID-19 therapies dexamethasone and remdesivir did not cause damage. We also did not observe damage from the antibiotic azithromycin. Neither lopinavir nor ritonavir altered the number of pre-synaptic ribbons per surviving hair cell, while there was an increase in ribbons following imatinib or ivermectin exposure. Damage from lopinavir, imatinib, and ivermectin was specific to hair cells, with no overall cytotoxicity noted following TUNEL labeling. Ritonavir may be generally cytotoxic, as determined by an increase in the number of TUNEL-positive non-hair cells following ritonavir exposure. Pharmacological inhibition of the mechanotransduction (MET) channel attenuated damage caused by lopinavir and ritonavir but did not alter imatinib or ivermectin toxicity. These results suggest that lopinavir and ritonavir may enter hair cells through the MET channel, similar to known ototoxins such as aminoglycoside antibiotics. Finally, we asked if ivermectin was ototoxic to rats in vivo. While ivermectin is not recommended by the FDA for treating COVID-19, many people have chosen to take ivermectin without a doctor's guidance, often with serious side-effects. Rats received daily subcutaneous injections for 10 days with a clinically relevant ivermectin dose (0.2 mg/kg). In contrast to our zebrafish assays, ivermectin did not cause ototoxicity in rats. Our research suggests that some drugs in clinical trials for COVID-19 may be ototoxic. This work can help identify drugs with the fewest side-effects and determine which therapies warrant audiometric monitoring.

Perspectives and Expertise in Establishing a Therapeutic Drug Monitoring Programme for Challenging Childhood Cancer Patient Populations

The utility of Therapeutic Drug Monitoring (TDM) in the setting of childhood cancer is a largely underused tool, despite the common use of cytotoxic chemotherapeutics. While it is encouraging that modern advances in chemotherapy have transformed outcomes for children diagnosed with cancer, this has come at the cost of an elevated risk of life-changing long-term morbidity and late effects. This concern can limit the intensity at which these drugs are used. Widely used chemotherapeutics exhibit marked inter-patient variability in drug exposures following standard dosing, with fine margins between exposures resulting in toxicity and those resulting in potentially suboptimal efficacy, thereby fulfilling criteria widely accepted as fundamental for TDM approaches. Over the past decade in the UK, the paediatric oncology community has increasingly embraced the potential benefits of utilising TDM for particularly challenging patient groups, including infants, anephric patients and those receiving high dose chemotherapy. This has been driven by a desire from paediatric oncologists to have access to clinical pharmacology information to support dosing decisions being made. This provides the potential to modify doses between treatment cycles based on a comprehensive set of clinical information, with individual patient drug exposures being used alongside clinical response and tolerability data to inform dosing for subsequent cycles. The current article provides an overview of recent experiences of conducting TDM in a childhood cancer setting, from the perspectives of the clinicians, scientists and pharmacists implementing TDM-based dosing recommendations. The ongoing programme of work has facilitated investigations into the validity of current approaches to dosing for some of the most challenging childhood cancer patient groups, with TDM approaches now being expanded from well-established cytotoxic drugs through to newer targeted treatments.