A thymidylate synthase polymorphism is associated with increased risk for bone toxicity among children treated for acute lymphoblastic leukemia

Development of osteonecrosis and improved survival in B-ALL: results of Children's Oncology Group Trial AALL0232

Osteonecrosis is a significant toxicity of acute lymphoblastic leukemia (ALL) therapy. In retrospective analyses, superior event-free survival was noted among affected adolescents in an earlier trial. We prospectively assessed osteonecrosis incidence, characteristics, and risk factors in patients 1-30 years with newly diagnosed high-risk B-ALL on COG AALL0232. Patients were randomized to induction dexamethasone vs prednisone, and interim maintenance high-dose methotrexate vs escalating-dose Capizzi methotrexate/pegaspargase. Event-free and overall survival were compared between patients with/without imaging-confirmed osteonecrosis. Osteonecrosis developed in 322/2730 eligible, evaluable patients. The 5-year cumulative incidence was 12.2%. Risk was greater in patients ≥10 years (hazard ratio [HR], 7.23; P < 0.0001), particularly females (HR, 1.37; P = 0.0057), but lower in those with asparaginase allergy (HR, 0.60; P = 0.0077). Among rapid early responders ≥10 years, risk was greater with dexamethasone (HR, 1.84; P = 0.0003) and with prednisone/Capizzi (HR, 1.45; P = 0.044), even though neither therapy was independently associated with improved survival. Patients with osteonecrosis had higher 5-year event-free (HR, 0.51; P < 0.0001) and overall survival (HR, 0.42; P < 0.0001), and this was directly attributable to reduced relapse rates (HR, 0.57; P = 0.0014). Osteonecrosis in high-risk B-ALL patients is associated with improved survival, suggesting an important role for host factors in mediating both toxicity and enhanced efficacy of specific therapies.

Folate, folic acid, and chemotherapy-induced toxicities: a systematic literature review

Folate metabolism is a target for various chemotherapeutic drugs. Folate and its synthetic variant folic acid are B-vitamins. To what extent these vitamins impact treatment tolerance in patients with cancer remains unclear. A systematic literature review was conducted on intake and status of folate and folic acid in relation to chemotherapy-induced toxicities in children and adults with cancer. A total of 6,231 publications were identified, of which 40 publications met the inclusion criteria. In 12 out of 22 studies focusing on antifolates, a deficient folate status and lower folate and folic acid intake were associated with a higher risk of toxicities. In 8 out of 14 studies focusing on fluoropyrimidine treatments, a higher folate status and intake were associated with a higher risk of toxicities. These findings might explain interindividual differences in treatment tolerance and highlight the importance of evaluating nutritional status in oncology care.

A GRIN3A polymorphism may be associated with glucocorticoid-induced symptomatic osteonecrosis in children with acute lymphoblastic leukemia

Aim: To evaluate the association between candidate genetic polymorphisms and glucocorticoid-induced osteonecrosis in Arab children treated for acute lymphoblastic leukemia. Methods: A total of 189 children treated for acute lymphoblastic leukemia were genotyped for four SNPs with allele discrimination assays. The incidence and timing of radiologically confirmed symptomatic grade 4 osteonecrosis were classified based on the Ponte di Legno toxicity working group consensus definition. Results: Thirteen children developed grade 4 osteonecrosis (6.8%), of whom 12 received the intermediate/high-risk treatment protocol. GRIN3A variant allele carriers had to stop dexamethasone therapy earlier resulting in significantly shorter duration of dexamethasone treatment (mean [95% CI]: 75.17 [64.28-86.06] vs 85.90 [81.22-90.58] weeks; p = 0.054) and lower cumulative dose (mean [95% CI]: 1118.11 [954.94-1281.29] vs 1341.14 [1264.17-1418.11] mg/m^2; p = 0.011). Conclusion: This is the first pharmacogenomics evaluation of the association between GRIN3A variants and glucocorticoid-induced osteonecrosis in Arab children.

Association of expression and genotypes of thymidylate synthase in non-small cell lung cancer patients with different clinicopathological characteristics

Objective

To explore the expression and genotypes of thymidylate synthase (TS) in patients of non-small cell lung cancer (NSCLC) with different clinicopathological characteristics.

Methods

The expression profiles of TS were examined by immunohistochemical staining and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) in 160 patients with NSCLC. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect TS-5′UTR tandem repeats, G/C nucleotide polymorphisms, and 3′UTR 6 bp deletion/insertion polymorphisms. The relationships between clinicopathological characteristics and TS expression or genotypes were investigated through χ 2 test. Kaplan–Meier survival analysis was used to analyze the association between TS expression and overall survival (OS) and disease-free survival (DFS) of NSCLC patients.

Results

The expression levels of TS protein and TS gene in NSCLC tissues were significantly higher than that in paracancerous tissues (P < 0.05). Furthermore, high expression of TS protein and 5′UTR polymorphism of TS gene showed significant correlation with differentiation, TNM stage, and lymph node metastases. The frequency of −6 bp/−6 bp genotypes in patients with NSCLC was 43.13% (69/160), which was higher than others. In addition, the rate of TS protein overexpression in NSCLC patients with 3R/3R was 79.79%, which was higher than others. Interestingly, high expression of TS protein predicted shorter DFS and OS and lower 3-year DFS rate and 3-year OS rate.

Conclusions

The expression levels of TS in NSCLC were significantly increased and may help to predict the prognosis of NSCLC, and high expression of TS protein and 5′UTR polymorphism of TS gene were significantly related to differentiation, TNM stage, and lymph node metastases.

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.

Clinical Implications of Methotrexate Pharmacogenetics in Childhood Acute Lymphoblastic Leukaemia

Background:

In the past two decades, a great body of research has been published regarding the effects of genetic polymorphisms on methotrexate (MTX)-induced toxicity and efficacy. Of particular interest is the role of this compound in childhood acute lymphoblastic leukaemia (ALL), where it is a pivotal drug in the different treatment protocols, both at low and high doses. MTX acts on a variety of target enzymes in the folates cycle, as well as being transported out and into of the cell by several transmembrane proteins.

Methods:

We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question.

Results:

This review has intended to summarize the current knowledge concerning the clinical impact of polymorphisms in enzymes and transporters involved in MTX disposition and mechanism of action on paediatric patients with ALL.

Conclusion:

In this work, we describe why, in spite of the significant research efforts, pharmacogenetics findings in this setting have not yet found their way into routine clinical practice.

Pharmacogenomic and Pharmacotranscriptomic Profiling of Childhood Acute Lymphoblastic Leukemia: Paving the Way to Personalized Treatment

Personalized medicine is focused on research disciplines which contribute to the individualization of therapy, like pharmacogenomics and pharmacotranscriptomics. Acute lymphoblastic leukemia (ALL) is the most common malignancy of childhood. It is one of the pediatric malignancies with the highest cure rate, but still a lethal outcome due to therapy accounts for 1%⁻3% of deaths. Further improvement of treatment protocols is needed through the implementation of pharmacogenomics and pharmacotranscriptomics. Emerging high-throughput technologies, including microarrays and next-generation sequencing, have provided an enormous amount of molecular data with the potential to be implemented in childhood ALL treatment protocols. In the current review, we summarized the contribution of these novel technologies to the pharmacogenomics and pharmacotranscriptomics of childhood ALL. We have presented data on molecular markers responsible for the efficacy, side effects, and toxicity of the drugs commonly used for childhood ALL treatment, i.e., glucocorticoids, vincristine, asparaginase, anthracyclines, thiopurines, and methotrexate. Big data was generated using high-throughput technologies, but their implementation in clinical practice is poor. Research efforts should be focused on data analysis and designing prediction models using machine learning algorithms. Bioinformatics tools and the implementation of artificial i Lack of association of the CEP72 rs924607 TT genotype with intelligence are expected to open the door wide for personalized medicine in the clinical practice of childhood ALL.

Systematic review of pharmacogenomics and adverse drug reactions in paediatric oncology patients

Many paediatric patients with cancer experience significant chemotherapy side effects. Predisposition to drug reactions is governed by single nucleotide polymorphisms (SNPs). We performed a systematic review of the literature from 2006 through 2016. Outcomes of interest included patient characteristics, cancer type drug of interest, genes investigated, toxicity identified and genetic polymorphisms implicated. The primary toxicities studied were neurotoxicity cardiotoxicity, osteonecrosis, and thromboembolism and hypersensitivity reactions. The retrieved studies were grouped according to toxicity reported and SNP associations. This review highlights the discoveries to date in pharmacogenomics and paediatric oncology along with highlighting some of the important limitations in the area.

An investigation of toxicities and survival in Hispanic children and adolescents with ALL: Results from the Dana-Farber Cancer Institute ALL Consortium protocol 05-001

PURPOSE

This study compared the relative incidence of treatment-related toxicities and the event-free and overall survival between Hispanic and non-Hispanic children undergoing therapy for acute lymphoblastic leukemia (ALL) on Dana-Farber Cancer Institute ALL Consortium protocol 05-001.

PATIENTS AND METHODS

Secondary analysis of prospectively collected data from a phase III multicenter study in children and adolescents of 1-18 years with previously untreated ALL.

RESULTS

Between 2005 and 2011, 794 eligible patients enrolled on DFCI 05-001, 730 of whom were included in this analysis (19% [N = 150] Hispanic, 73% [N = 580] non-Hispanic). Hispanic patients were more likely to be ≥10 years of age (32% vs. 24%, P = 0.045) at diagnosis. Toxicity analyses revealed that Hispanic patients had significantly lower cumulative incidence of bone fracture (P < 0.001) and osteonecrosis (ON; P = 0.047). In multivariable risk regression, the risk of ON was significantly lower in Hispanic patients ≥10 years (HR 0.23; P = 0.006). Hispanic patients had significantly lower 5-year event-free survival (EFS) (79.4%; 95% CI: 71.6-85.2) and overall survival (OS) (89.2%; 95% CI: 82.7-93.4) than non-Hispanic patients (EFS: 87.5%; 95% CI: 84.5-90.0, P = 0.004; OS: 92.7%; 95% CI: 90.2-94.6, P = 0.006). Exploratory analyses revealed differences between Hispanic and non-Hispanic patients in the frequency of common variants in genes related to toxicity or ALL outcome.

CONCLUSION

Hispanic children treated for ALL on DFCI 05-001 had fewer bone-related toxicities and inferior survival than non-Hispanic patients. While disease biology is one explanatory variable for outcome disparities, these findings suggest that biologic and non-biologic mechanisms affecting drug delivery and exposure in this population may be important contributing factors as well.

Non-infectious chemotherapy-associated acute toxicities during childhood acute lymphoblastic leukemia therapy

During chemotherapy for childhood acute lymphoblastic leukemia, all organs can be affected by severe acute side effects, the most common being opportunistic infections, mucositis, central or peripheral neuropathy (or both), bone toxicities (including osteonecrosis), thromboembolism, sinusoidal obstruction syndrome, endocrinopathies (especially steroid-induced adrenal insufficiency and hyperglycemia), high-dose methotrexate-induced nephrotoxicity, asparaginase-associated hypersensitivity, pancreatitis, and hyperlipidemia. Few of the non-infectious acute toxicities are associated with clinically useful risk factors, and across study groups there has been wide diversity in toxicity definitions, capture strategies, and reporting, thus hampering meaningful comparisons of toxicity incidences for different leukemia protocols. Since treatment of acute lymphoblastic leukemia now yields 5-year overall survival rates above 90%, there is a need for strategies for assessing the burden of toxicities in the overall evaluation of anti-leukemic therapy programs.