CYP3A5 genotype and its impact on vincristine pharmacokinetics and development of neuropathy in Kenyan children with cancer

Vincristine exposure in Kenyan children with cancer: CHAPATI feasibility study

The low incidence of vincristine-induced peripheral neuropathy (VIPN) in Kenyan children may result from low vincristine exposure. We studied vincristine exposure in Kenyan children and dose-escalated in case of low vincristine exposure (NCT05844670). Average vincristine exposure was high. Individual vincristine exposure was assessed with a previously developed nomogram. A 20% dose increase was recommended for participants with low exposure and no VIPN, hyperbilirubinemia, or malnutrition. None of the 15 participants developed VIPN. Low vincristine exposure was seen in one participant: a dose increase was implemented without side effects. In conclusion, the participants did not develop VIPN despite having high vincristine exposure.

Pharmacogenetic Testing or Therapeutic Drug Monitoring: A Quantitative Framework

BACKGROUND

Pharmacogenetic profiling and therapeutic drug monitoring (TDM) have both been proposed to manage inter-individual variability (IIV) in drug exposure. However, determining the most effective approach for estimating exposure for a particular drug remains a challenge. This study aimed to quantitatively assess the circumstances in which pharmacogenetic profiling may outperform TDM in estimating drug exposure, under three sources of variability (IIV, inter-occasion variability [IOV], and residual unexplained variability [RUV]).

METHODS

Pharmacokinetic models were selected from the literature corresponding to drugs for which pharmacogenetic profiling and TDM are both clinically considered approaches for dose individualization. The models were used to simulate relevant drug exposures (trough concentration or area under the curve [AUC]) under varying degrees of IIV, IOV, and RUV.

RESULTS

Six drug cases were selected from the literature. Model-based simulations demonstrated that the percentage of patients for whom pharmacogenetic exposure prediction is superior to TDM differs for each drug case: tacrolimus (11.0%), tamoxifen (12.7%), efavirenz (49.2%), vincristine (49.6%), risperidone (48.1%), and 5-fluorouracil (5-FU) (100%). Generally, in the presence of higher unexplained IIV in combination with lower RUV and IOV, exposure was best estimated by TDM, whereas, under lower unexplained IIV in combination with higher IOV or RUV, pharmacogenetic profiling was preferred.

CONCLUSIONS

For the drugs with relatively low RUV and IOV (e.g., tamoxifen and tacrolimus), TDM estimated true exposure the best. Conversely, for drugs with similar or lower unexplained IIV (e.g., efavirenz or 5-FU, respectively) combined with relatively high RUV, pharmacogenetic profiling provided the most accurate estimate for most patients. However, genotype prevalence and the relative influence of genotypes on the PK, as well as the ability of TDM to accurately estimate AUC with a limited number of samples, had an impact. The results could be used to support clinical decision making when considering other factors, such as the probability for severe side effects.

Review of Personalized Medicine and Pharmacogenomics of Anti-Cancer Compounds and Natural Products

In recent years, the FDA has approved numerous anti-cancer drugs that are mutation-based for clinical use. These drugs have improved the precision of treatment and reduced adverse effects and side effects. Personalized therapy is a prominent and hot topic of current medicine and also represents the future direction of development. With the continuous advancements in gene sequencing and high-throughput screening, research and development strategies for personalized clinical drugs have developed rapidly. This review elaborates the recent personalized treatment strategies, which include artificial intelligence, multi-omics analysis, chemical proteomics, and computation-aided drug design. These technologies rely on the molecular classification of diseases, the global signaling network within organisms, and new models for all targets, which significantly support the development of personalized medicine. Meanwhile, we summarize chemical drugs, such as lorlatinib, osimertinib, and other natural products, that deliver personalized therapeutic effects based on genetic mutations. This review also highlights potential challenges in interpreting genetic mutations and combining drugs, while providing new ideas for the development of personalized medicine and pharmacogenomics in cancer study.

Characterization of CYP3A5 Selective Inhibitors for Reaction Phenotyping of Drug Candidates

CYP3A is one of the most important classes of enzymes and is involved in the metabolism of over 70% drugs. While several selective CYP3A4 inhibitors have been identified, the search for a selective CYP3A5 inhibitor has turned out to be rather challenging. Recently, several selective CYP3A5 inhibitors have been identified through high-throughput screening of ~ 11,000 compounds and hit expansion using human recombinant enzymes. We set forth to characterize the three most selective CYP3A5 inhibitors in a more physiologically relevant system of human liver microsomes to understand if these inhibitors can be used for reaction phenotyping studies in drug discovery settings. Gomisin A and T-5 were used as selective substrate reactions for CYP3A4 and CYP3A5 to determine IC50 values of the two enzymes. The results showed that clobetasol propionate and loteprednol etabonate were potent and selective CYP3A5 reversible inhibitors with selectivity of 24-fold against CYP3A4 and 39-fold or more against the other major CYPs. The selectivity of difluprednate in HLM is much weaker than that in the recombinant enzymes due to hydrolysis of the acetate group in HLM. Based on the selectivity data, loteprednol etabonate can be utilized as an orthogonal approach, when experimental fraction metabolized of CYP3A5 is greater than 0.5, to understand CYP3A5 contribution to drug metabolism and its clinical significance. Future endeavors to identify even more selective CYP3A5 inhibitors are warranted to enable accurate determination of CYP3A5 contribution to metabolism versus CYP3A4.

Model-Informed Precision Dosing to Reduce Vincristine-Induced Peripheral Neuropathy in Pediatric Patients: A Pharmacokinetic and Pharmacodynamic Modeling and Simulation Analysis

BACKGROUND

Vincristine-induced peripheral neuropathy (VIPN) is a common adverse effect of vincristine, a drug often used in pediatric oncology. Previous studies demonstrated large inter- and intrapatient variability in vincristine pharmacokinetics (PK). Model-informed precision dosing (MIPD) can be applied to calculate patient exposure and individualize dosing using therapeutic drug monitoring (TDM) measurements. This study set out to investigate the PK/pharmacodynamic (PKPD) relationship of VIPN and determine the utility of MIPD to support clinical decisions regarding dose selection and individualization.

METHODS

Data from 35 pediatric patients were utilized to quantify the relationship between vincristine dose, exposure and the development of VIPN. Measurements of vincristine exposure and VIPN (Common Terminology Criteria for Adverse Events [CTCAE]) were available at baseline and for each subsequent dosing occasions (1-5). A PK and PKPD analysis was performed to assess the inter- and intraindividual variability in vincristine exposure and VIPN over time. In silico trials were performed to portray the utility of vincristine MIPD in pediatric subpopulations with a certain age, weight and cytochrome P450 (CYP) 3A5 genotype distribution.

RESULTS

A two-compartmental model with linear PK provided a good description of the vincristine exposure data. Clearance and distribution parameters were related to bodyweight through allometric scaling. A proportional odds model with Markovian elements described the incidence of Grades 0, 1 and ≥ 2 VIPN overdosing occasions. Vincristine area under the curve (AUC) was the most significant exposure metric related to the development of VIPN, where an AUC of 50 ng⋅h/mL was estimated to be related to an average VIPN probability of 40% over five dosing occasions. The incidence of Grade ≥ 2 VIPN reduced from 62.1 to 53.9% for MIPD-based dosing compared with body surface area (BSA)-based dosing in patients. Dose decreases occurred in 81.4% of patients with MIPD (vs. 86.4% for standard dosing) and dose increments were performed in 33.4% of patients (no dose increments allowed for standard dosing).

CONCLUSIONS

The PK and PKPD analysis supports the use of MIPD to guide clinical dose decisions and reduce the incidence of VIPN. The current work can be used to support decisions with respect to dose selection and dose individualization in children receiving vincristine.

Vincristine Disposition and Neurotoxicity Are Unchanged in Humanized CYP3A5 Mice

Previous studies have suggested that the incidence of vincristine-induced peripheral neuropathy (VIPN) is potentially linked with cytochrome P450 (CYP)3A5, a polymorphic enzyme that metabolizes vincristine in vitro, and with concurrent use of azole antifungals such as ketoconazole. The assumed mechanism for these interactions is through modulation of CYP3A-mediated metabolism, leading to decreased vincristine clearance and increased susceptibility to VIPN. Given the controversy surrounding the contribution of these mechanisms, we directly tested these hypotheses in genetically engineered mouse models with a deficiency of the entire murine Cyp3a locus [Cyp3a(-/-) mice] and in humanized transgenic animals with hepatic expression of functional and nonfunctional human CYP3A5 variants. Compared with wild-type mice, the systemic exposure to vincristine was increased by only 1.15-fold (95% confidence interval, 0.84-1.58) in Cyp3a(-/-) mice, suggesting that the clearance of vincristine in mice is largely independent of hepatic Cyp3a function. In line with these observations, we found that Cyp3a deficiency or pretreatment with the CYP3A inhibitors ketoconazole or nilotinib did not influence the severity and time course of VIPN and that exposure to vincristine was not substantially altered in humanized CYP3A5*3 mice or humanized CYP3A5*1 mice compared with Cyp3a(-/-) mice. Our study suggests that the contribution of CYP3A5-mediated metabolism to vincristine elimination and the associated drug-drug interaction potential is limited and that plasma levels of vincristine are unlikely to be strongly predictive of VIPN. SIGNIFICANCE STATEMENT: The current study suggests that CYP3A5 genotype status does not substantially influence vincristine disposition and neurotoxicity in translationally relevant murine models. These findings raise concerns about the causality of previously reported relationships between variant CYP3A5 genotypes or concomitant azole use with the incidence of vincristine neurotoxicity.

Influence of CYP3A5 and ABCB1 polymorphisms on the pharmacokinetics of vincristine in adult patients receiving CHOP therapy

PURPOSE

This study aims to clarify the impact of CYP3A5 and ABCB1 polymorphisms on the pharmacokinetics of vincristine (VCR) in adult patients receiving CHOP therapy.

METHODS

Plasma samples were collected immediately after the end of VCR administration and at 1.5, 2.5, 3.5, 5.5, 9.5, 13.5, and 25.5 h after the start of administration. Areas under the plasma concentration-time curves of VCR in the elimination phase (AUC1.5-25.5) were calculated using the linear trapezoidal rule. Half-lives of VCR during the early phase (1.5-5.5 h) and terminal phase (5.5-25.5 h; t1/2γ) were determined according to the log-linear regression of the concentration-time data for at least 3 sampling points.

RESULTS

A total of 41 adult patients were enrolled in this study. The median t1/2γ and AUC1.5-25.5 were significantly longer and higher in CYP3A5 non-expressers (CYP3A5*3/*3) than in CYP3A5 expressers (CYP3A5*1/*1 or *1/*3) (21.3 vs 13.8 h, P = 0.005 and 35.5 vs 30.0 ng･h/mL, P = 0.006, respectively). Conversely, there were no significant differences in pharmacokinetic parameters among the ABCB1 c.1236C>T, c.2677G>A/T, c.3435C>T genotype groups. A stepwise selection multiple linear regression analysis showed that the dose of VCR administered and CYP3A5 non-expresser status were independent factors influencing the AUC1.5-25.5 (partial R2 = 0.212, P = 0.002 and partial R2 = 0.143, P = 0.010, respectively).

CONCLUSION

The CYP3A5*3 polymorphism was found to be an indicator for predicting exposure to VCR in adult patients receiving CHOP therapy. This information may be useful for the individualization of VCR dosages.

Curcumin as a hepatoprotective agent against chemotherapy-induced liver injury

Despite significant advances in cancer therapeutics, chemotherapy remains the cornerstone of treatment for many tumors. Importantly, however, chemotherapy-induced toxicity, including hepatotoxicity, can lead to the interruption or discontinuation of potentially effective therapy. In recent years, special attention has been paid to the search for complementary therapies to mitigate chemotherapy-induced toxicity. Although there is currently a lack of specific interventions to mitigate or prevent hepatotoxicity in chemotherapy-treated patients, the polyphenol compound curcumin has emerged as a potential strategy to overcome this adverse effect. Here we review, firstly, the molecular and physiological mechanisms and major risk factors of chemotherapy-induced hepatotoxicity. We then present an overview of how curcumin has the potential to mitigate hepatotoxicity by targeting specific molecular mechanisms. Hepatotoxicity is a well-described side effect of cytotoxic drugs that can limit their clinical application. Inflammation and oxidative stress are the most common mechanisms involved in hepatotoxicity. Several studies have shown that curcumin could prevent and/or palliate chemotherapy-induced liver injury, mainly due to its anti-inflammatory, antioxidant, antifibrotic and hypolipidemic properties. Further clinical investigation using bioavailable curcumin formulations is warranted to demonstrate its efficacy as an hepatoprotective agent in cancer patients.

Targeting a xenobiotic transporter to ameliorate vincristine-induced sensory neuropathy

Vincristine is a widely used chemotherapeutic drug for the treatment of multiple malignant diseases that causes a dose-limiting peripheral neurotoxicity. There is no clinically effective preventative treatment for vincristine-induced sensory peripheral neurotoxicity (VIPN), and mechanistic details of this side effect remain poorly understood. We hypothesized that VIPN is dependent on transporter-mediated vincristine accumulation in dorsal root ganglion neurons. Using a xenobiotic transporter screen, we identified OATP1B3 as a neuronal transporter regulating the uptake of vincristine. In addition, genetic or pharmacological inhibition of the murine orthologue transporter OATP1B2 protected mice from various hallmarks of VIPN - including mechanical allodynia, thermal hyperalgesia, and changes in digital maximal action potential amplitudes and neuronal morphology - without negatively affecting plasma levels or antitumor effects of vincristine. Finally, we identified α-tocopherol from an untargeted metabolomics analysis as a circulating endogenous biomarker of neuronal OATP1B2 function, and it could serve as a companion diagnostic to guide dose selection of OATP1B-type transport modulators given in combination with vincristine to prevent VIPN. Collectively, our findings shed light on the fundamental basis of VIPN and provide a rationale for the clinical development of transporter inhibitors to prevent this debilitating side effect.

[A cohort study of vincristine-induced peripheral neuropathy in children]

OBJECTIVES

To study the characteristics of vincristine-induced peripheral neuropathy (VIPN) in children with acute lymphoblastic leukemia (ALL) and the factors influencing the development of VIPN.

METHODS

The children with ALL, aged 1-18 years, who were treated with CCCG-ALL2015 or CCCG-ALL2020 regimen in the Affiliated Hospital of Guizhou Medical University from January 2018 to February 2022 were enrolled as subjects. According to the influence of age on risk, the children were divided into 1-10 years group with 91 children and >10 years group with 29 children. VIPN was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (5th edition), and the incidence rate, severity, and type of VIPN were compared between different groups.

RESULTS

A total of 120 children were enrolled in this study, among whom 56 (46.7%) developed VIPN. The >10 years group had a significantly higher incidence rate of VIPN than the 1-10 years group (69% vs 40%, P<0.05). Among the 56 children with VIPN, 12 (21%) had grade 3 VIPN or above, and 44 (79%) had grade 2 VIPN. There were 77 cases of autonomic nerve symptoms (59.7%), 42 cases of peripheral nerve injury (32.5%), and 10 cases of cranial nerve injury (7.8%). There were no significant differences in the severity and type of VIPN between the groups with different ages, sexes, degrees of risk, or treatment regimens (P>0.05). The results of binary logistic regression analysis showed that age is the influencing factor for the occurrence of VIPN (P>0.05).

CONCLUSIONS

There is a relatively high incidence rate of VIPN in children with ALL, with the highest incidence rate of autonomic nervous symptoms. The incidence of VIP in children over 10 years old is relatively high.

Late Effects of Childhood Cancer Survivors in Africa: a Scoping Review

INTRODUCTION

The number of children surviving cancer in Africa is increasing. Knowledge about late effects of survivors is lacking. Our study maps literature regarding late effects of childhood cancer survivors in Africa.

METHODS

Scoping review was performed following JBI-guidelines. Systematic literature search was conducted in: Medline, Embase, African Index Medicus, Web of Science, Scopus, Psycinfo. Titles and abstracts were screened by two reviewers, followed by full-text analysis by the lead reviewer.

RESULTS

Sixty-eight studies were included for content analysis. Studies originated from 10 of 54 African countries. Most studies had retrospective study design, 2-5 years follow-up, solely chemotherapy as treatment modality, Egypt as country of origin. Fifty-three studies described physical, and seventeen studies described psychosocial late effects.

CONCLUSION

Literature concerning late effects is available from a limited number of African countries. Psychosocial domain lacks attention compared to the physical domain. More countries should report on this topic to prevent, identify and monitor late effects.

Development of a Therapeutic Drug Monitoring Strategy for the Optimization of Vincristine Treatment in Pediatric Oncology Populations in Africa

BACKGROUND

Recent studies have reported ethnic differences in vincristine exposure and outcomes such as toxicity. This resulted in the hypothesis of subtherapeutic dosing in African children. To optimize individual treatment, a strategy to identify subtherapeutic exposure using therapeutic drug monitoring is essential. The aim of the current study was to develop a strategy for therapeutic drug monitoring of vincristine in African children to meet the following criteria: (1) identify patients with low vincristine exposure with sufficient sensitivity (>70%), (2) determine vincristine exposure with a limited sampling strategy design of 3 samples, and (3) allow all samples to be collected within 4 hours after administration.

METHODS

An in silico simulation study was performed using a previously described population pharmacokinetic model and real-life demographic dataset of Kenyan and Malawian pediatric oncology patients. Two different therapeutic drug monitoring strategies were evaluated: (1) Bayesian approach and (2) pharmacometric nomogram. The sampling design was optimized using the constraints described above. Sensitivity analysis was performed to investigate the influence of missing samples, erroneous sampling times, and different boundaries on the nomogram weight bands.

RESULTS

With the Bayesian approach, 43.3% of the estimated individual exposure values had a prediction error of ≥20% owing to extremely high shrinkage. The Bayesian approach did not improve with alternative sampling designs within sampling constraints. However, the pharmacometric nomogram could identify patients with low vincristine exposure with a sensitivity, specificity, and accuracy of 75.1%, 76.4%, and 75.9%, respectively. The pharmacometric nomogram performed similarly for different weight bands.

CONCLUSIONS

The pharmacometric nomogram was able to identify patients with low vincristine exposure with high sensitivity, with 3 blood samples collected at 1, 1.5, and 4 hours after administration. Missing samples should be avoided, and the 3 scheduled samples should be collected within 15, 5, and 15 minutes of 1, 1.5, and 4 hours after administration, respectively.

A sensitive liquid chromatographic-mass spectrometry method for the quantification of vincristine in whole blood collected with volumetric absorptive microsampling

Vincristine is a well-established cytotoxic drug. In paediatric populations blood collection via venipuncture is not always feasible. Volumetric absorptive microsampling (VAMS) is a less invasive method for blood collection. Furthermore, VAMS lacks the haematocrit effect on the recovery known with dried blood spots. Therefore, a liquid chromatography tandem-mass spectrometry method was developed and validated for the quantification of vincristine in whole blood collected with VAMS devices. Sample preparation consisted of solid-liquid extraction with 0.2% formic acid in water and acetonitrile. The final extract was injected on a C18 column (2.0 ×50 mm, 5 µm). Gradient elution was used and quantification was accomplished with a triple quadruple mass spectrometer operating in the positive mode. The validated concentration range was from 1 to 50 ng/mL with an intra- and inter-accuracy and precision of ± 10.3% and ≤ 7.3%, respectively. This method was able to successfully quantify vincristine concentrations in whole blood collected with VAMS from paediatric oncology patients. Vincristine concentrations in whole blood were non-linearly associated with plasma concentrations, which could be described with a saturable binding equilibrium model.

Proactive therapeutic drug monitoring of vincristine in pediatric and adult cancer patients: current supporting evidence and future efforts

Vincristine (VCR), an effective antitumor drug, has been utilized in several polytherapy regimens for acute lymphoblastic leukemia, neuroblastoma and rhabdomyosarcoma. However, clinical evidence shows that the metabolism of VCR varies greatly among patients. The traditional based body surface area (BSA) administration method is prone to insufficient exposure to VCR or severe VCR-induced peripheral neurotoxicity (VIPN). Therefore, reliable strategies are urgently needed to improve efficacy and reduce VIPN. Due to the unpredictable pharmacokinetic changes of VCR, therapeutic drug monitoring (TDM) may help to ensure its efficacy and to manage VIPN. At present, there is a lot of supporting evidence for the suitability of applying TDM to VCR therapy. Based on the consensus guidelines drafted by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT), this review aimed to summarize various available data to evaluate the potential utility of VCR TDM for cancer patients. Of note, valuable evidence has accumulated on pharmacokinetics variability, pharmacodynamics, drug exposure-clinical response relationship, biomarkers for VIPN prediction, and assays for VCR monitoring. However, there are still many relevant clinical pharmacological questions that cannot yet be answered merely based on insufficient evidence. Currently, we cannot recommend a therapeutic exposure range and cannot yet provide a dose-adaptation strategy for clinicians and patients. In areas where the evidence is not yet sufficient, more research is needed in the future. The precision medicine of VCR cannot rely on TDM alone and needs to consider the clinical, environmental, genetic background and patient-specific factors as a whole.

Severe Vincristine-Induced Neuropathic Pain: A Case Report with Pharmacogenetic Analysis and Literature Review

Vincristine-induced peripheral neuropathy (VIPN) is a common adverse effect of vincristine (VCR) for which there is no preventative or curative treatment. Here, we report a case of a patient suffering from severe VCR-related neurotoxicity. To explore the possible causes of severe VIPN in this patient, a set of genes involved in VCR metabolism, transport or are related to the cytoskeleton, microtubules, and inherited neurological diseases gene polymorphisms were examined via pharmacogenetic analyses. The genotyping results revealed the presence of a complex pattern of polymorphisms in CYP3A5, ABCC2, SYNE2, BAHD1, NPSR1, MTNR1B, CEP72, miR-4481 and miR-3117. A comprehensive understanding of all the pharmacogenetic risk factors for VIPN may explain the occurrence of severe neurotoxicity in our patient. This case brings to light the potential importance of pharmacogenetic testing in clinical practice. It also exemplifies the importance of developing early-detection strategies to optimize treatment regimens through prior risk stratification while reducing adverse drug reactions and personalizing therapy.

Genetic Polymorphisms Associated with Vincristine Pharmacokinetics and Vincristine-Induced Peripheral Neuropathy in Pediatric Oncology Patients

Simple Summary

Vincristine is a type of chemotherapy that is often used in the treatment of children with cancer. The main side effect of vincristine is nerve damage. Patients experience symptoms such as tingling, pain or muscle weakness. Some children are more sensitive to vincristine than others, which may depend on variations in genes and in the breakdown of vincristine by the body. In this study, we investigated the effect of variations in genes on nerve damage due to vincristine and breakdown of vincristine by the body. We found that nine variations in seven genes were associated with nerve damage due to vincristine, whereas three variations in three genes were associated with the breakdown of vincristine by the body. It is important that future studies try to replicate these findings. Our findings help us towards the goal of tailoring vincristine treatment to each child, with optimal therapeutic effect while limiting nerve damage.

Abstract

Vincristine (VCR) is an important component of curative chemotherapy for many childhood cancers. Its main side effect is VCR-induced peripheral neuropathy (VIPN), a dose limiting toxicity. Some children are more susceptible to VIPN, which is at least partially dependent on genetic factors and pharmacokinetics (PK). In this study, we identify and replicate genetic variants associated with VCR PK and VIPN. Patient samples from a randomized clinical trial studying the effect of administration duration of VCR on VIPN in 90 patients were used. PK sampling was conducted on between one and five occasions at multiple time points. A linear two-compartment model with first-order elimination was used, and targeted next-generation DNA sequencing was performed. Genotype–trait associations were analyzed using mixed-effect models or logistic regression analysis for repeated measures, or Poisson regression analysis in which the highest VIPN score per patient was included. Nine single-nucleotide polymorphisms (SNPs) in seven genes (NDRG1, GARS, FIG4, FGD4, SEPTIN9, CEP72, and ETAA1) were associated with VIPN. Furthermore, three SNPs in three genes (MTNR1B, RAB7A and SNU13) were associated with PK of VCR. In conclusion, PK of VCR and VIPN are influenced by SNPs; upfront identification of those that lead to an altered susceptibility to VIPN or VCR exposure could help individualize VCR treatment.

Modern developments in germline pharmacogenomics for oncology prescribing

The integration of genomic data into personalized treatment planning has revolutionized oncology care. Despite this, patients with cancer remain vulnerable to high rates of adverse drug events and medication inefficacy, affecting prognosis and quality of life. Pharmacogenomics is a field seeking to identify germline genetic variants that contribute to an individual's unique drug response. Although there is widespread integration of genomic information in oncology, somatic platforms, rather than germline biomarkers, have dominated the attention of cancer providers. Patients with cancer potentially stand to benefit from improved integration of both somatic and germline genomic information, especially because the latter may complement treatment planning by informing toxicity risk for drugs with treatment-limiting tolerabilities and narrow therapeutic indices. Although certain germline pharmacogenes, such as TPMT, UGT1A1, and DPYD, have been recognized for decades, recent attention has illuminated modern potential dosing implications for a whole new set of anticancer agents, including targeted therapies and antibody-drug conjugates, as well as the discovery of additional genetic variants and newly relevant pharmacogenes. Some of this information has risen to the level of directing clinical action, with US Food and Drug Administration label guidance and recommendations by international societies and governing bodies. This review is focused on key new pharmacogenomic evidence and oncology-specific dosing recommendations. Personalized oncology care through integrated pharmacogenomics represents a unique multidisciplinary collaboration between oncologists, laboratory science, bioinformatics, pharmacists, clinical pharmacologists, and genetic counselors, among others. The authors posit that expanded consideration of germline genetic information can further transform the safe and effective practice of oncology in 2022 and beyond.

Outcomes of Wilms tumor treatment in western Kenya

BACKGROUND/OBJECTIVES

Wilms tumor (WT) is a curable type of cancer with 5-year survival rates of over 90% in high-income countries, whereas this is less than 50% in low- and middle-income countries. We assessed treatment outcomes of children with WT treated at a large Kenyan teaching and referral hospital.

DESIGN/METHODS

We conducted a retrospective record review of children diagnosed with WT between 2013 and 2016. Treatment protocol consisted of 6 weeks of preoperative chemotherapy and surgery, and 4-18 weeks of postoperative chemotherapy depending on disease stage. Probability of event-free survival (pEFS) and overall survival (pOS) was assessed using Kaplan-Meier method with Cox regression analysis. Competing events were analyzed with cumulative incidences and Fine-Gray regression analysis.

RESULTS

Of the 92 diagnosed patients, 69% presented with high-stage disease. Two-year observed EFS and OS were, respectively, 43.5% and 67%. Twenty-seven percent of children died, 19% abandoned treatment, and 11% suffered from progressive or relapsed disease. Patients who were diagnosed in 2015-2016 compared to 2013-2014 showed higher pEFS. They less often had progressive or relapsed disease (p = .015) and borderline significant less often abandonment of treatment (p = .09). Twenty-nine children received radiotherapy, and 2-year pEFS in this group was 86%.

CONCLUSION

Outcome of children with WT improved over the years despite advanced stage at presentation. Survival probabilities of patients receiving comprehensive therapy including radiation are approaching those of patients in high-income countries. Additional improvement could be achieved by ensuring that patients receive all required treatment and working on earlier diagnosis strategies.

Pharmacogenomics of Vincristine-Induced Peripheral Neuropathy in Children with Cancer: A Systematic Review and Meta-Analysis

Simple Summary

Vincristine is a drug that is part of the treatment for many children with cancer. Its main side-effect is vincristine-induced peripheral neuropathy (VIPN), which often presents as tingling, pain, and lack of strength in the hands and feet. It is not yet possible to predict which children will suffer from VIPN. In this review, we report on all genetic variations that are associated with VIPN. We found that variations in genes related to vincristine transport, cell structure, hereditary nerve disease, and genes without a previously known connection to vincristine or VIPN are related to VIPN. Variations in genes involved in vincristine breakdown are not significantly associated with VIPN. In conclusion, genetic variations affect a child’s tendency to develop VIPN. In the future, this information might be used to predict the risk of VIPN and adapt treatment on this.

Abstract

Vincristine-induced peripheral neuropathy (VIPN) is a debilitating side-effect of vincristine. It remains a challenge to predict which patients will suffer from VIPN. Pharmacogenomics may explain an individuals’ susceptibility to side-effects. In this systematic review and meta-analysis, we describe the influence of pharmacogenomic parameters on the development of VIPN in children with cancer. PubMed, Embase and Web of Science were searched. In total, 1597 records were identified and 21 studies were included. A random-effects meta-analysis was performed for the influence of CYP3A5 expression on the development of VIPN. Single-nucleotide polymorphisms (SNPs) in transporter-, metabolism-, cytoskeleton-, and hereditary neuropathy-associated genes and SNPs in genes previously unrelated to vincristine or neuropathy were associated with VIPN. CYP3A5 expression status was not significantly associated with VIPN. The comparison and interpretation of the results of the included studies was limited due to heterogeneity in the study population, treatment protocol and assessment methods and definitions of VIPN. Independent replication is essential to validate the clinical significance of the reported associations. Future research should aim for prospective VIPN assessment in both a discovery and a replication cohort. Ultimately, the goal would be to screen patients upfront to determine optimal vincristine dosage with regards to efficacy and risk of VIPN.

Evaluation of genetic polymorphism of CYP3A5 in normal healthy participants from western India - A cross-sectional study

BACKGROUND

CYP3A5 enzymes belong to the phase I Group of drug-metabolizing enzymes, which are involved in the metabolism of 50% of the drugs. Participants with CYP3A5 genotype: CYP3A5 *1/*1 are fast metabolizers of drugs and hence will require higher dosing. Whereas those with CYP3A5 * 3/*3 are poor metabolizers of drugs and will require a lower dose to achieve target drug concentration in the blood and those with CYP3A5 * 1/*3 have intermediate drug metabolizing activity. Pharmacogenetic evaluation may improve disease outcomes by maximizing the efficacy and minimizing the toxicity of drugs in patients.

MATERIALS AND METHODS

This is a single-center cross-sectional study conducted in the year 2018-2019 to study the population prevalence of genetic polymorphisms of CYP3A5 in healthy participants from western India. Eligible participants willing to give written, informed consent were enrolled in the study. Subsequently, 2 ml venous blood was collected the deoxyribonucleic acid was extracted and then stored at ‒20°C. Genotyping was done by a polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

A total of 400 participants with a median age of 22 years (range: 18-58 years) were included. Among them, the genotype prevalence for CYP3A5 * 1/*1 was 17% (n = 67/400); CYP3A5 * 1/*3 was 37% (n = 149/400) and that of CYP3A5 * 3/*3 was 46% (184/400). Out of the total 400 healthy participants analyzed, the allele frequency for CYP3A5 * 1 was 35% (142/400) and that of CYP3A5*3 was 65% (259/400).

CONCLUSION

The genotype prevalence for CYP3A5 * 3*3 (46%) and the allele frequency for CYP3A5 * 3 (65%) respectively were the highest among the western Indian population.

Management of Side Effects in the Personalized Medicine Era: Chemotherapy-Induced Peripheral Neurotoxicity

Pharmacogenomics is a powerful tool to predict individual response to treatment, in order to personalize therapy, and it has been explored extensively in oncology practice. Not only efficacy on the malignant disease has been investigated but also the possibility to predict adverse effects due to drug administration. Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of those. This potentially severe and long-lasting/permanent side effect of commonly administered anticancer drugs can severely impair quality of life (QoL) in a large cohort of long survival patients. So far, a pharmacogenomics-based approach in CIPN regard has been quite delusive, making a methodological improvement warranted in this field of interest: even the most refined genetic analysis cannot be effective if not applied correctly. Here we try to devise why it is so, suggesting how THE "bench-side" (pharmacogenomics) might benefit from and should cooperate with THE "bed-side" (clinimetrics), in order to make genetic profiling effective if applied to CIPN.

Mechanistic insights into the pathogenesis of microtubule-targeting agent-induced peripheral neuropathy from pharmacogenetic and functional studies

Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting toxicity that affects 30%-40% of patients undergoing cancer treatment. Although multiple mechanisms of chemotherapy-induced neurotoxicity have been described in preclinical models, these have not been translated into widely effective strategies for the prevention or treatment of CIPN. Predictive biomarkers to inform therapeutic approaches are also lacking. Recent studies have examined genetic risk factors associated with CIPN susceptibility. This review provides an overview of the clinical and pathologic features of CIPN and summarizes efforts to identify target pathways through genetic and functional studies. Structurally and mechanistically diverse chemotherapeutics are associated with CIPN; however, the current review is focused on microtubule-targeting agents since these are the focus of most pharmacogenetic association and functional studies of CIPN. Genome-wide pharmacogenetic association studies are useful tools to identify not only causative genes and genetic variants but also genetic networks implicated in drug response or toxicity and have been increasingly applied to investigations of CIPN. Induced pluripotent stem cell-derived models of human sensory neurons are especially useful to understand the mechanistic significance of genomic findings. Combined genetic and functional genomic efforts to understand CIPN hold great promise for developing therapeutic approaches for its prevention and treatment.

Vincristine-Induced Peripheral Neuropathy in Childhood Acute Lymphoblastic Leukemia: Genetic Variation as a Potential Risk Factor

Vincristine (VCR) is the first-line chemotherapeutic medication often co-administered with other drugs to treat childhood acute lymphoblastic leukemia. Dose-dependent neurotoxicity is the main factor restricting VCR’s clinical application. VCR-induced peripheral neuropathy (VIPN) sometimes results in dose reduction or omission, leading to clinical complications or affecting the patient’s quality of life. With regard to the genetic basis of drug responses, preemptive pharmacogenomic testing and simultaneous blood level monitoring could be helpful for the transformation of various findings into individualized therapies. In this review, we discussed the potential associations between genetic variants in genes contributing to the pharmacokinetics/pharmacodynamics of VCR and VIPN incidence and severity in patients with acute lymphoblastic leukemia. Of note, genetic variants in the CEP72 gene have great potential to be translated into clinical practice. Such a genetic biomarker may help clinicians diagnose VIPN earlier. Besides, genetic variants in other genes, such as CYP3A5, ABCB1, ABCC1, ABCC2, TTPA, ACTG1, CAPG, SYNE2, SLC5A7, COCH, and MRPL47, have been reported to be associated with the VIPN, but more evidence is needed to validate the findings in the future. In fact, a variety of complex factors jointly determine the VIPN. In implementing precision medicine, the combination of genetic, environmental, and personal variables, along with therapeutic drug monitoring, will allow for a better understanding of the mechanisms of VIPN, improving the effectiveness of VCR treatment, reducing adverse reactions, and improving patients’ quality of life.

Long-Term Effects of Pediatric Acute Lymphoblastic Leukemia Chemotherapy: Can Recent Findings Inform Old Strategies?

During the last few decades, pediatric acute lymphoblastic leukemia (ALL) cure rates have improved significantly with rates exceeding 90%. Parallel to this remarkable improvement, there has been mounting interest in the long-term health of the survivors. Consequently, modified treatment protocols have been developed and resulted in the reduction of many adverse long-term consequences. Nevertheless, these are still substantial concerns that warrant further mitigation efforts. In the current review, pediatric-ALL survivors’ late adverse events, including secondary malignant neoplasms (SMNs), cardiac toxicity, neurotoxicity, bone toxicity, hepatic dysfunction, visual changes, obesity, impact on fertility, and neurocognitive effects have been evaluated. Throughout this review, we attempted to answer a fundamental question: can the recent molecular findings mitigate pediatric-ALL chemotherapy’s long-term sequelae on adult survivors? For SMNs, few genetic predisposition factors have been identified including TP53 and POT1 variants. Other treatment-related risk factors have been identified such as anthracyclines’ possible association with breast cancer in female survivors. Cardiotoxicity is another significant and common adverse event with some germline variants been found, albeit with conflicting evidence, to increase the risk of cardiac toxicity. For peripheral neurotoxicity, vincristine is the primary neurotoxic agent in ALL regimens. Some germline genetic variants were found to be associated with the vincristine neurotoxic effect’s vulnerability. However, these were mainly detected with acute neuropathy. Moreover, the high steroid doses and prolonged use increase bone toxicity and obesity risk with some pharmacogenetic biomarkers were associated with increased steroid sensitivity. Therefore, the role of these biomarkers in tailoring steroid choice and dose is a promising research area. Future directions in pediatric ALL treatment should consider the various opportunities provided by genomic medicine. Understanding the molecular bases underlying toxicities will classify patients into risk groups and implement a closer follow-up to those at higher risk. Pharmacogenetic-guided dosing and selecting between alternative agents have proven their efficacy in the short-term management of childhood ALL. It is the right time to think about a similar approach for the life-long consequences on survivors.

Personalized medicine of non-gene-specific chemotherapies for non-small cell lung cancer

Non-small cell lung cancer is recognized as the deadliest cancer across the globe. In some areas, it is more common in women than even breast and cervical cancer. Its rise, vaulted by smoking habits and increasing air pollution, has garnered much attention and resource in the medical field. The first lung cancer treatments were developed more than half a century ago. Unfortunately, many of the earlier chemotherapies often did more harm than good, especially when they were used to treat genetically unsuitable patients. With the introduction of personalized medicine, physicians are increasingly aware of when, how, and in whom, to use certain anti-cancer agents. Drugs such as tyrosine kinase inhibitors, anaplastic lymphoma kinase inhibitors, and monoclonal antibodies possess limited utility because they target specific oncogenic mutations, but other drugs that target mechanisms universal to all cancers do not. In this review, we discuss many of these non-oncogene-targeting anti-cancer agents including DNA replication inhibitors (i.e., alkylating agents and topoisomerase inhibitors) and cytoskeletal function inhibitors to highlight their application in the setting of personalized medicine as well as their limitations and resistance factors.

Characteristics and patterns of pediatric chemotherapy-induced peripheral neuropathy: A systematic review

This systematic review provides a high-quality synthesis of the empirical evidence regarding chemotherapy-induced peripheral neuropathy (CIPN) characteristics and patterns described in studies of children who received neurotoxic chemotherapy to treat cancer. PubMed, CINAHL, PsycINFO, and Embase were searched for articles published 2009 - 2019, yielding 861. Forty-two papers met the eligibility criteria, including 31 that described characteristics and patterns of vincristine-induced CIPN. Fifty-seven percent of articles were of low to moderate quality; measurement flaws were the most common limitations. The reported CIPN incidence varies widely (2.8%-100%) depending on risk factors (e.g., race) and the measurement approach. Incidence rates of sensory, motor, autonomic CIPN, and pain were 12-28%, 50-72%, 0.8-83% and 5.7-44%, respectively. The evidence suggests that sensory and motor neuropathy, pain, and functional deficits are common and can persist into adulthood. Caucasian race is a risk factor and, contrary to prior thinking, cumulative chemotherapy dosage alone does not predict CIPN severity. The influence of other risk factors is less clear, and studies to date have not explored potential interactions among race, genetics, age, sex, drug metabolism, and nutritional status, among other factors.

Mechanistic physiology-based pharmacokinetic modeling to elucidate vincristine-induced peripheral neuropathy following treatment with novel kinase inhibitors

Purpose

Limited information is available regarding the drug–drug interaction (DDI) potential of molecular targeted agents and rituximab plus cyclophosphamide, doxorubicin (hydroxydaunorubicin), vincristine (Oncovin), and prednisone (R-CHOP) therapy. The addition of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib to R-CHOP therapy results in increased toxicity versus R-CHOP alone, including higher incidence of peripheral neuropathy. Vincristine is a substrate of P-glycoprotein (P-gp, ABCB1); drugs that inhibit P-gp could potentially cause increased toxicity when co-administered with vincristine through DDI. While the combination of the BTK inhibitor acalabrutinib and R-CHOP is being explored clinically, the DDI potential between these therapies is unknown.

Methods

A human mechanistic physiology-based pharmacokinetic (PBPK) model of vincristine following intravenous dosing was developed to predict potential DDI interactions with combination therapy. In vitro absorption, distribution, metabolism, and excretion and in vivo clinical PK parameters informed PBPK model development, which was verified by comparing simulated vincristine concentrations with observed clinical data.

Results

While simulations suggested no DDI between vincristine and ibrutinib or acalabrutinib in plasma, simulated vincristine exposure in muscle tissue was increased in the presence of ibrutinib but not acalabrutinib. Extrapolation of the vincristine mechanistic PBPK model to other P-gp substrates further suggested DDI risk when ibrutinib (area under the concentration–time curve [AUC] ratio: 1.8), but not acalabrutinib (AUC ratio: 0.92), was given orally with venetoclax or digoxin.

Conclusion

Overall, these data suggest low DDI risk between acalabrutinib and P-gp substrates with negligible increase in the potential risk of vincristine-induced peripheral neuropathy when acalabrutinib is added to R-CHOP therapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-021-04302-5.

Vincristine-Induced Peripheral Neuropathy (VIPN) in Pediatric Tumors: Mechanisms, Risk Factors, Strategies of Prevention and Treatment

Vincristine-induced peripheral neurotoxicity (VIPN) is a very common side effect of vincristine chemotherapy among pediatric patients with cancer. Neuropathy may be sensory, motor and/or autonomic, with consequent reduction, delay or discontinuation of vincristine-chemotherapy, but also pain, disability, reduced quality of life of patients and an increase in medical costs. Vincristine acts out its antineoplastic function by altering the normal assembly and disassembly of microtubules, with their consequent mitosis block and death. Vincristine leads to VIPN through a complex mechanism of damage, which occurs not only on the microtubules, but also on the endothelium and the mitochondria of nerve cells. Furthermore, both patient-related risk factors (age, race, ethnicity and genetic polymorphisms) and treatment-related risk factors (dose, time of infusion and drug–drug interactions) are involved in the pathogenesis of VIPN. There is a lack of consensus about the prophylaxis and treatment of VIPN among pediatric oncologic patients, despite several molecules (such as gabapentin, pyridoxine and pyridostigmine, glutamic acid and glutamine) having been already investigated in clinical trials. This review describes the molecular mechanisms of VIPN and analyzes the risk factors and the principal drugs adopted for the prophylaxis and treatment of VIPN in pediatric patients with cancer.

Rapid quantification of vincristine in mouse plasma using ESI-LC-MS/MS: Application to pharmacokinetic studies

A simple, rapid, and sensitive LC-MS/MS method for determining concentrations of the anticancer alkaloid vincristine in micro volumes of mouse plasma was developed and validated in positive ion mode. Separation of vincristine and the internal standard [²H₃]-vincristine was achieved on an Accucore aQ column with a gradient mobile phase delivered at a flow rate of 0.4 mL/min and a run time of 2.2 min. Calibration curves were linear (r² > 0.99, n = 8) up to 250 ng/mL, with a lower limit of quantitation of 2.5 ng/mL. The matrix effect and extraction recovery for vincristine were ranging 108-110% and 88.4-107%, respectively. The intra-day and inter-day precision of quality controls tested at 3 different concentrations were always less than 15%, and accuracy ranged from 91.7 to 107%. The method was successfully applied to evaluate the pharmacokinetic profile of vincristine in wild-type and CYP3A-deficient mice in support of a project to provide mechanistic insight into drug-drug interactions and to identify sources of inter-individual pharmacokinetic variability associated with vincristine-induced peripheral neuropathy.

Evaluation for pharmacokinetic exposure of cytotoxic anticancer drugs in elderly patients receiving (R-)CHOP therapy

(R-)miniCHOP therapy, which delivers approximately half-doses of the (R-)CHOP regimen, has shown efficacy and safety in patients who are more than 80 years old. This study aimed to compare the area under the plasma concentration–time curves (AUCs) of vincristine (VCR), doxorubicin (DXR), and cyclophosphamide (CPA) between (R-)CHOP and (R-)miniCHOP regimens. The AUCs were compared between patients aged 65–79 years receiving (R-)CHOP therapy and those aged 80 years and older receiving (R-)miniCHOP therapy. Age was not an independent variable for predicting the dose-adjusted AUCs (AUC/Ds) of cytotoxic anticancer drugs. The median AUCs of DXR and CPA were significantly smaller in the (R-)miniCHOP group than in the (R-)CHOP group (168.7 vs. 257.9 ng h/mL, P = 0.003, and 219.9 vs. 301.7 µg h/mL, P = 0.020, respectively). The median AUCs of VCR showed the same trend but the difference was not significant (24.83 vs. 34.85 ng h/mL, P = 0.135). It is possible that the AUCs of VCR, DXR, and CPA in patients aged 80 years and older receiving (R-)miniCHOP therapy may be lower than those in patients 65–79 years old receiving (R-)CHOP therapy.

microRNA-222-Mediated VHL Downregulation Facilitates Retinoblastoma Chemoresistance by Increasing HIF1α Expression

Purpose

Retinoblastoma (RB) is the most common primary intraocular tumor in children. Chemoresistance is the major obstacle for treatment of these tumors. This study aims to determine whether or not downregulating microRNA-222 (miR-222) could serve as a potential therapeutic target for preventing chemoresistance in RB treatment.

Methods

Differentially expressed miR-222 in RB samples and its downstream target genes were predicted using bioinformatics methods. The expression of miR-222 was altered by mimic or inhibitor to examine its role in RB cell in response to the chemotherapeutic agent vincristine (VCR). Further bioinformatic analysis predicted involvement of the stability of hypoxia-inducible factor 1α (HIF1α) protein in regulation of the von Hippel–Lindau (VHL) tumor suppressor, followed by characterization of the effect of VHL on the ubiquitin–proteasome degradation of HIF1α. Next, VHL or HIF1α was overexpressed to determine their effects on RB cell activities after VCR treatment. In vivo assays were performed on nude mice to further verify the in vitro results.

Results

miR-222 is highly expressed in RB tissues and cells and was found to facilitate resistance of RB cells to VCR. Of note, miR-222 specifically bound to and negatively regulated VHL. VHL could inhibit the stability of HIF1α and promote the degradation of ubiquitin–proteasome, thus reducing HIF1α expression to attenuate VCR resistance in RB cells. Moreover, inhibition of miR-222 in combination with VCR suppressed tumor formation in nude mice.

Conclusions

miR-222 promotes the expression of HIF1α by targeting VHL, thus accelerating the resistance of RB cells to the chemotherapeutic agent VCR.

Genetic factors influencing the development of vincristine-induced neurotoxicity

Introduction: One of the most common side effects during vincristine (VCR) use is the establishment of VCR-induced peripheral neuropathy (VIPN). Among several risk factors that can influence the development of VIPN, such as cumulative dose and patient's age, sex, ethnicity, and genetic variants, this review is focused on the genetic variability. Areas covered: A literature research was performed firstly using the following PubMed search string ((((CIPN OR (vincristine AND neurotoxicity OR (vincristine AND neuropathy))) AND (polymorphisms OR (genetic variants OR (genetic factors OR (genetic profile OR (pharmacogenetics OR (genome-wide OR (genetic risk OR (expression genotype))))))))))) but also other relevant papers cited by the selected articles were included. Based on the obtained results, we identified two main categories of genes: genes involved in pharmacokinetics (genes related to metabolism and transport) or pharmacodynamics (genes related to mechanism of action) of VCR. Expert opinion: Despite several clinical retrospective studies investigating the possible correlations between patient genotype and VIPN onset, contrasting and inconsistent results are reported. In conclusion, given the clinical relevance of VIPN, further and more focused research would be fundamental in order to identify genetic variants able to predict its development and to allow a safer management of treated patients.

Pharmacogenomics in Pediatric Oncology: Mitigating Adverse Drug Reactions While Preserving Efficacy

Cancer is the leading cause of death in American children older than 1 year of age. Major developments in drugs such as thiopurines and optimization in clinical trial protocols for treating cancer in children have led to a remarkable improvement in survival, from approximately 30% in the 1960s to more than 80% today. Short-term and long-term adverse effects of chemotherapy still affect most survivors of childhood cancer. Pharmacogenetics plays a major role in predicting the safety of cancer chemotherapy and, in the future, its effectiveness. Treatment failure in childhood cancer-due to either serious adverse effects that limit therapy or the failure of conventional dosing to induce remission-warrants development of new strategies for treatment. Here, we summarize the current knowledge of the pharmacogenomics of cancer drug treatment in children and of statistically and clinically relevant drug-gene associations and the mechanistic understandings that underscore their therapeutic value in the treatment of childhood cancer.

Pharmacogenomics as a Tool to Limit Acute and Long-Term Adverse Effects of Chemotherapeutics: An Update in Pediatric Oncology

In the past decades, new cancer treatments have been introduced in pediatric oncology leading to improvement in clinical outcomes and survival rates. However, due to inter-individual differences, some children experience severe chemotherapy-induced toxicities or a poor clinical outcome. An explanation for the diversity in response to chemotherapy is genetic variation, leading to differences in expression and activity of metabolizing and transport enzymes as well as drug targets. Pharmacogenetic testing has emerged as a promising tool to predict and limit acute and long-term adverse effects in patients. However, in pediatric oncology, limited number of patients and a considerable diversity in study results complicate the interpretation of test results and its clinical relevance. With this review, we provide an overview of new developments over the past four years regarding relevant polymorphisms related to toxicity in pediatric oncology. The following chemotherapeutics and associated toxicities are discussed: alkylating agents, anthracyclines, asparaginase, methotrexate, platinum compounds, steroids, thiopurines, topoisomerase inhibitors, and vinca alkaloids. Our review identifies several questions regarding the role of genetic variants in chemotherapy-induced toxicities. Ambiguities in the literature stem from small population sizes, differences in (statistical) interpretation and variations in sequencing technologies as well as different clinical outcome definitions. Standardization of clinical outcome data and toxicity definitions within electronic health records combined with the increased availability of genomic sequence techniques in clinical practice will help to validate these models in upcoming years.

Approaches to measure paediatric chemotherapy-induced peripheral neurotoxicity: a systematic review

In children who receive neurotoxic chemotherapy, peripheral neurotoxicity occurs frequently, necessitates dose reduction or treatment cessation, and affects function and long-term quality of life. No treatments exist for peripheral neurotoxicity and few assessment measures are specific to children. We did a systematic review to analyse the published literature concerning the evaluation of assessment measures for paediatric chemotherapy-induced peripheral neurotoxicity. We searched PubMed, CINAHL, PsycINFO, and Embase on Nov 7-8, 2018; of 1409 articles, seven met the inclusion criteria. A total of 335 children (excluding ten healthy controls) were enrolled in the seven studies and the sample sizes ranged from 17 to 86 individuals. 276 (82%) of the 335 children were actively undergoing chemotherapy treatment. Most studies did not comprehensively evaluate the psychometric properties of assessment measures for chemotherapy-induced peripheral neurotoxicity. By use of a narrative analysis that combined approaches from the Joanna Briggs Institute (Adelaide, SA, Australia) and the quality of diagnostic accuracy studies assessment method (known as QUADAS), only one study was deemed high quality. We identified two variants of the Total Neuropathy Score, two grading scales, two semi-objective tests, one patient-reported outcome, and several mobility measures. The National Cancer Institute Common Terminology Criteria for Adverse Events and the Balis grading scales showed lower sensitivity and specificity than the items of the Total Neuropathy Score. Although there is insufficient evidence to support the use of most approaches to assess chemotherapy-induced peripheral neurotoxicity in children, two variants of the Total Neuropathy Score, the pediatric-modified Total Neuropathy Score and the Total Neuropathy Score-pediatric vincristine, are promising but require further testing. Other approaches are less sensitive or less feasible. A patient-reported outcome measure for chemotherapy-induced peripheral neurotoxicity in children is needed.

Measuring vincristine-induced peripheral neuropathy in children with cancer: validation of the Dutch pediatric-modified Total Neuropathy Score

Purpose

The aims were to evaluate the construct validity and reliability of the Dutch version of the pediatric-modified Total Neuropathy Score (ped-mTNS) for assessing vincristine-induced peripheral neuropathy (VIPN) in Dutch pediatric oncology patients aged 5–18 years.

Methods

Construct validity (primary aim) of the ped-mTNS was determined by testing hypotheses about expected correlation between scores of the ped-mTNS (range: 0–32) and the Common Terminology Criteria for Adverse Events (CTCAE) (range: 0–18) for patients and healthy controls and by comparing patients and controls regarding their total ped-mTNS scores and the proportion of children identified with VIPN. Inter-rater and intra-rater reliability and measurement error (secondary aims) were assessed in a subgroup of study participants.

Results

Among the 112 children (56 patients and 56 age- and gender-matched healthy controls) evaluated, correlation between CTCAE and ped-mTNS scores was as expected (moderate (r = 0.60)). Moreover, as expected, patients had significantly higher ped-mTNS scores and more frequent symptoms of VIPN compared with controls (both p < .001). Reliability as measured within the intra-rater group (n = 10) (intra-class correlation coefficient (ICC_agreement) = 0.64, standard error of measurement (SEM_agreement) = 2.92, and smallest detectable change (SDC_agreement) = 8.1) and within the inter-rater subgroup (n = 10) (ICC_agreement = 0.63, SEM_agreement = 3.7, and SDC_agreement = 10.26) indicates insufficient reliability.

Conclusion

The Dutch version of the ped-mTNS appears to have good construct validity for assessing VIPN in a Dutch pediatric oncology population, whereas reliability appears to be insufficient and measurement error high. To improve standardization of VIPN assessment in children, future research aimed at evaluating and further optimizing the psychometric characteristics of the ped-mTNS is needed.

Electronic supplementary material

The online version of this article (10.1007/s00520-019-05106-3) contains supplementary material, which is available to authorized users.

Biological predictors of chemotherapy-induced peripheral neuropathy (CIPN): MASCC neurological complications working group overview

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating condition associated with a number of chemotherapeutic agents. Drugs commonly implicated in the development of CIPN include platinum agents, taxanes, vinca alkaloids, bortezomib, and thalidomide analogues. As a drug response can vary between individuals, it is hypothesized that an individual's specific genetic variants could impact the regulation of genes involved in drug pharmacokinetics, ion channel functioning, neurotoxicity, and DNA repair, which in turn affect CIPN development and severity. Variations of other molecular markers may also affect the incidence and severity of CIPN. Hence, the objective of this review was to summarize the known biological (molecular and genomic) predictors of CIPN and discuss the means to facilitate progress in this field.

Aspects of vincristine-induced neuropathy in hematologic malignancies: a systematic review

PURPOSE

Vincristine is widely used as anticancer therapy for a variety of hematological malignancies. The treatment is limited by progressive vincristine-induced neuropathy, possibly including both peripheral sensory and motor nerves, autonomic nervous functions, and the central nervous system. This dose-limiting side-effect can diminish quality of life and, furthermore, cause discontinuation of vincristine treatment. The present review elucidates the current knowledge regarding vincristine-induced neuropathy in hematologic malignancies, focusing on neuropathy assessment, clinical and molecular predictive markers, drug-drug interference, prevention, and treatment.

METHODS

This review is conducted by a systematic search strategy for the identification of relevant literature in the PubMed and Embase databases.

RESULTS

No clinical parameters displayed convincing potential as predictors of vincristine-induced neuropathy; however, preexisting neuropathy was consistently reported to be associated with an increased risk of neurotoxicity. In contrast, molecular markers, including polymorphisms in genes involved in the pharmacodynamics and pharmacokinetics of vincristine, displayed great potential as predictive markers of neuropathy incidence and severity. Furthermore, antifungal drugs, such as itraconazole and voriconazole, decrease the metabolism of vincristine and consequently lead to severe neuropathy when co-administered with vincristine, underscoring why fluconazole should be the antifungal drug of choice.

CONCLUSION

Reports from the 71 included studies clearly emphasize the lack of consistency in neuropathy assessment, grading systems, and reporting, making it difficult to interpret results between studies. Thus, truer clinical and molecular markers could emerge if the consistency of neuropathy detection and reporting increases by the use of conventional standardized neuropathy assessment tools and grading scales.