A pooled subgroup analysis of glucarpidase treatment in 86 pediatric, adolescent, and young adult patients receiving high-dose methotrexate therapy in open-label trials.

BACKGROUND: Delayed methotrexate elimination can occur in patients undergoing high-dose methotrexate cancer treatment. Effectiveness of glucarpidase for rapidly reducing methotrexate concentrations was shown in compassionate-use trials in patients aged 0-84 years. METHODS: We performed post hoc analyses of infants (≥28 days to <2 years), children (≥2 to <12 years), adolescents (≥12 to <15 years), and young adults (≥15 to <25 years) from four multicenter, open-label, single-arm, glucarpidase compassionate-use trials. Patients had toxic methotrexate levels due to delayed methotrexate elimination and/or renal dysfunction, and received glucarpidase (50 U/kg). The primary endpoint was clinically important reduction (CIR) in plasma methotrexate (methotrexate ≤1 µmol/L at all post-glucarpidase measurements) based on high-performance liquid chromatography. RESULTS: Among 86 patients included in efficacy analyses, CIR was achieved by zero of one infant (0.0%), five of 16 children (31.3%), seven of 24 adolescents (29.2%), and 26/45 young adults (57.8%). Median methotrexate reduction was 98.7% or higher in each group 15 minutes post-glucarpidase. Patients with pre-glucarpidase methotrexate less than 50 µmol/L (35/42, 83.3%) were more likely to achieve CIR than those with methotrexate 50 µmol/L or higher (1/37, 2.7%). The most common treatment-related adverse event was paresthesia, occurring in three adolescents (4.5%) and six young adults (5.2%). No other treatment-related adverse event occurred in 5% or higher of any age group. CONCLUSION: After accounting for pre-glucarpidase methotrexate levels, glucarpidase efficacy at inducing CIR in pediatric/young adult patients was consistent, with efficacy observed in the overall study population (i.e., patients aged 0-84), and no unexpected safety findings were observed. These findings demonstrate glucarpidase (50 U/kg) is an effective and well-tolerated dose for pediatric, adolescent, and young adult patients.

Incidence and management of patients with methotrexate delayed elimination in the clinical practice: A Delphi study.

INTRODUCTION: High-dose methotrexate (HDMTX) is administered for the treatment of some cancers. HDMTX is usually safe but may crystallize in renal tubules causing acute kidney injury (AKI). Consequently, MTX elimination is delayed, resulting in a severe and life-threatening condition. No studies have been published about the impact of MTX toxicity in Spain. This study aims to estimate the incidence and management of MTX delayed elimination and toxicity. METHODS: A two-round Delphi study was performed to reach consensus between 10 medical experts on haemato-oncology and paediatric oncology with experience in the management of HDMTX treated patients from leading Spanish hospitals. An online questionnaire was developed based on national and international guidelines and previous evidence regarding HDMTX-related toxicity. Consensus was established at 80% agreement. Median and interquartile ranges were calculated, and incidence data were extrapolated to the Spanish general population. RESULTS: Out of 1.475 patients estimated to receive HDMTX treatment annually in Spain, 27.5% present MTX delayed elimination and 11.6% develop HDMTX-induced AKI (35.4% with severe systemic toxicities (>grade 3) and 18.8% develop chronic renal disease). Mortality is estimated in 4.2%. Immuno-enzymatic assay is used in most of the hospitals (90%) for MTX serum level monitoring. All experts use increased supportive care and high leucovorin as first-line treatment. Available treatments in experts' hospitals in case toxicity persists are haemodialysis (90% of hospitals), glucarpidase (60%) and hemofiltration (50%). Most prevalent non-renal systemic toxicities are haematologic and mucositis (21-40% of patients). Patients with HDMTX-induced AKI require from intensive care (5% of patients), more than 3 sessions and 4 days of dialysis, and about 8.5 days of hospitalization (non-ICU patients) and 12 days in case of patients requiring ICU. CONCLUSIONS: These results are the first evidence regarding HDMTX-induced AKI in Spain. Incidence and mortality results are in line with previous studies. Clinical management is based on preventive measures and the treatment depend on the availability in the hospital. The need for effective, safe and rapid treatment for the reduction of MTX toxic levels and the improvement of monitoring methods were noted by experts as urgent needs. Further observational studies to validate these results would be needed.

Adverse Reactions to Drugs of Special Interest in a Pediatric Oncohematology Service.

Introduction: Drugs used in oncological diseases are frequently related to adverse drug reactions (ADR). Few studies have analyzed the toxicity of cancer treatments in children in real practice. Methods: An observational, longitudinal and prospective study has been carried out in an Oncohematology Service of a tertiary hospital. During 2017, patients exposed to one or more drugs of a previously agreed list were identified and followed-up for at least 6 months each. Characteristics of ADR, incidence, causality and possible preventability, have been evaluated. Results: 72 patients have been treated with at least one study drug, and 159 ADR episodes involving at least one of these drugs have been identified, with a total of 293 ADR. Most episodes required hospital admission (35.2%) or happened during the hospital stay (33%), and 91.2% were severe. Blood disorders were the most frequent ADR (96; 32.8%), related to thioguanine (42) and pegaspargase (39) mainly, followed by infections (86; 29.4%) related to thioguanine (32), pegaspargase (27), Erwinia asparaginase (14) and rituximab (13). Two ADR were unknown. Most ADR were dose-dependent or expectable (>90%). The global incidence of ADR was 3.1/100 days at risk (95% CI 2.7-3.5), with 3.5 ADR/100 days at risk with pegaspargase (95% CI 2.9-4.2), 1.2/100 days at risk with rituximab (95% CI 0.8-1.8) and 11.6/100 days at risk with thioguanine (95% CI 9.4-14.2). Controversial additional measures of prevention, other than those already used, were identified. Conclusion: ADR are frequent in pediatric oncohematological patients, mainly blood disorders and infectious diseases. Findings regarding incidence and preventability may be useful to compare data between different centers and to evaluate new possibilities for action or prevention.

Circulating tumour DNA from the cerebrospinal fluid allows the characterisation and monitoring of medulloblastoma.

The molecular characterisation of medulloblastoma, the most common paediatric brain tumour, is crucial for the correct management and treatment of this heterogenous disease. However, insufficient tissue sample, the presence of tumour heterogeneity, or disseminated disease can challenge its diagnosis and monitoring. Here, we report that the cerebrospinal fluid (CSF) circulating tumour DNA (ctDNA) recapitulates the genomic alterations of the tumour and facilitates subgrouping and risk stratification, providing valuable information about diagnosis and prognosis. CSF ctDNA also characterises the intra-tumour genomic heterogeneity identifying small subclones. ctDNA is abundant in the CSF but barely present in plasma and longitudinal analysis of CSF ctDNA allows the study of minimal residual disease, genomic evolution and the characterisation of tumours at recurrence. Ultimately, CSF ctDNA analysis could facilitate the clinical management of medulloblastoma patients and help the design of tailored therapeutic strategies, increasing treatment efficacy while reducing excessive treatment to prevent long-term secondary effects.

Targeting of epigenetic regulators in neuroblastoma.

Approximately 15,000 new cases of pediatric cancer are diagnosed yearly in Europe, with 8-10% corresponding to neuroblastoma, a rare disease with an incidence of 8-9 cases per million children <15 years of age. Although the survival rate for low-risk and intermediate-risk patients is excellent, half of children with high-risk, refractory, or relapsed tumors will be cured, and two-thirds of the other half will suffer major side effects and life-long disabilities. Epigenetic therapies aimed at reversing the oncogenic alterations in chromatin structure and function are an emerging alternative against aggressive tumors that are or will become resistant to conventional treatments. This approach proposes targeting epigenetic regulators, which are proteins that are involved in the creation, detection, and interpretation of epigenetic signals, such as methylation or histone post-translational modifications. In this review, we focused on the most promising epigenetic regulators for targeting and current drugs that have already reached clinical trials.

Detection of bone marrow micrometastasis and microcirculating disease in rhabdomyosarcoma by a real-time RT-PCR assay.

PURPOSE: To assess if molecular detection of minimal disseminated disease by real-time reverse transcription and polymerase chain reaction (RT-PCR) could contribute to a better treatment stratification in patients with rhabdomyosarcoma (RMS). METHODS: Relative quantification of the tumor-mRNA present in serial samples of bone marrow (BM) and peripheral blood (PB) from 16 patients with RMS (7 alveolar and 9 embryonal) was performed by a real-time RT-PCR assay. Expression of MyoD1 and acetylcholine receptor (AChR) was analyzed in all samples, along with PAX3/7-FKHR in samples from alveolar tumors. RESULTS: A good correlation was found between the expression of PAX3/7-FKHR and AChR, while MyoD1 was more sensitive but less specific. In this study, patients with positive PB at the end of treatment showed a poorer prognosis than patients with negative PB. Moreover, in this patient cohort, metastatic relapses were preceded by the detection of microcirculating disease in all cases. CONCLUSION: The detection of minimal circulating and micrometastatic disease by real-time RT-PCR, based on the expression of multiple genes, yields highly reproducible results. Patients with positive PB after treatment show poorer survival than patients without microcirculating disease.

Prognostic impact of the detection of microcirculating tumor cells by a real-time RT-PCR assay of tyrosine hydroxylase in patients with advanced neuroblastoma.

Molecular detection of microcirculating or microdisseminated disease (MDD) with a sensitive methodology could contribute to a better treatment for children with neuroblastoma. To detect circulating neuroblastoma cells, we developed a quantitative assay for the analysis of tyrosine hydroxylase (TH) gene expression. We analyzed 155 samples of peripheral blood (PB) from 25 patients with neuroblastoma in advanced stages (8 stage III and 17 stage IV). TH mRNA was analyzed by RT-PCR assay using TaqMan technology. PB samples (n=25) from donors were used for normalizing TH, and values <7 were considered negative. With a median follow-up of 40 months (range 15-73 months), 9 patients relapsed and 8 patients died of progressive disease. TH expression was detected in the PB of 16 patients (64%) at diagnosis. During treatment, 10 patients had positive samples and 9 patients were still positive for circulating tumor cells at the end of treatment. Actuarial 3-year event-free survival of patients with PB positive for TH mRNA after induction therapy (40%) (p=0.018) and at the completion of treatment (33%) (p=0.003) were significantly worse than the survival of TH-negative patients (86 and 87%, respectively). In multivariate analysis, MYCN status and TH expression in PB at the end of treatment remained significant prognostic factors. Our results show that patients with advanced neuroblastoma who have PB positive for TH at the end of treatment seem to have a worse prognosis compared with patients with undetectable TH. These results suggest the usefulness of MDD monitoring in neuroblastoma.

The role of leptin in diencephalic syndrome.

Diencephalic syndrome is a rare condition associated with central nervous system tumors. The most common presentation is secondary failure to thrive with proper caloric intake and no statural impairment. Despite the importance of this syndrome, little is known of its pathophysiology. Some reports have documented changes in human growth hormone and insulin levels at the onset, whereas others have described endocrine disorders of hypothalamic insufficiency resulting from surgery of the tumor. It has been suggested that the hormonal changes described, such as increased human growth hormone and ghrelin or decreased insulin and leptin levels, are related to a patient's BMI. These findings support the role of these 4 hormones as indicators of the patient's nutritional status but not as mediators or potential therapeutic targets of the disease. We report the case of an infant who initially presented with tumor progression and, after chemotherapy, progressive weight gain and reduced tumor size. Because he presented no hormonal deficiencies or obesity after therapy, we were able to analyze his hormonal status uninfluenced by effects of metabolic treatment or excess weight. Although ghrelin and leptin levels have been related to nutritional status, our patient's leptin levels fell when tumor size decreased and weight increased: an extraordinary finding because leptin concentration is expected to increase with weight gain. This paradoxical response suggests that leptin may be dysregulated in diencephalic syndrome or that the diencephalic astrocytoma may have had an effect on leptin secretion.

Long-term results of the Spanish Protocol SO-95 for the treatment of non-metastatic high-grade osteosarcoma of the extremities in children.

INTRODUCTION: The long-term results of the Spanish Study Protocol SEOP-SO-95 for treatment of localised osteosarcoma of the extremities in children were evaluated. PATIENTS AND METHODS: One hundred consecutive patients under 18 years of age from 22 institutions were enrolled from January 1995 to December 2000. Immunohistochemical expression of p53, HER/erbB-2 and P-glycoprotein were retrospectively studied in 27 patients. Treatment consisted of: preoperative chemotherapy with doxorubicin, cisplatin, high-dose methotrexate with leucovorin rescue and ifosfamide for 14 weeks; surgery of primary tumour in week 16; postoperative chemotherapy with the above-mentioned drugs for 25 weeks. RESULTS: With a median follow-up of 124 months (range 84-158 months), 69 patients (69%) were continuously event-free survivors; the 10-year probability of event-free survival (EFS) was 62%. Conservative surgery was performed in 85% of patients. Twenty-six patients had local recurrence or distant relapse. The median time to recurrence/ relapse was 27 months (range 17-93 months). The local recurrence rate was 7% (7 of the 100 patients); 4 had wide surgical margins, 2 marginal and 1 intralesional. Four patients died as a result of chemotherapy-related toxicity and 1 developed a second neoplasia (acute myeloid leukaemia). p53 expression and HER2/erbB-2 expression showed no effect on survival or EFS. CONCLUSIONS: This therapeutic protocol achieved good oncologic and orthopaedic results. We observed a significant treatment-related toxicity.