Children's bone health

The thesis can be divided in two main parts. In the first part (Chapter 2 to 5) bone mineral density, bone metabolism and body composition in healthy children and young adults have been evaluated, while in the second part (Chapter 6 to 10) these issues were studied in children with various diseases. Healthy children were studied to gain references for parameters of bone turnover, and to extend our reference data for bone density and body composition. Furthermore, the effect of polymorphisms in two candidate genes, e.g. polymorphisms in the vitamin D receptor gene and the coll

Asparaginase-Associated toxicity in children with acute lymphoblastic leukemia

Asparaginase is an integral component of multiagent chemotherapy regimens for the treatment of children with acute lymphoblastic leukemia. Positive outcomes are seen in patients who are able to complete their entire prescribed course of asparaginase therapy. Toxicities associated with asparaginase use include hypersensitivity (clinical and subclinical), pancreatitis, thrombosis, encephalopathy, and liver dysfunction. Depending on the nature and severity of the toxicity, aspara

Allergic-like reactions to asparaginase: Atypical allergies without asparaginase inactivation

Background: Asparaginase is an important component of pediatric acute lymphoblastic leukemia (ALL) therapy. Unfortunately, this treatment is hampered by hypersensitivity reactions. In general, allergies – regardless of severity – cause complete inactivation of the drug. However, we report atypical allergic reactions without inactivation of asparaginase, here called allergic-like reactions. Procedure: Patients with an allergic-like reaction, who were treated according to the Dutch Childhood Oncology Group ALL-11 or the CoALL 08–09 protocol, were described. The reactions were identified by continual measurement of asparaginase activity levels. Characteristics, including timing of occurrence, symptoms, grade, and the presence of antiasparaginase antibodies, were compared to those of real allergies. Results: Fourteen allergic-like reactions occurred in nine patients. Five reactions were to PEGasparaginase and nine to Erwinia asparaginase. Allergic-like reactions occurred relatively late after the start of infusion compared to real allergies. Antibodies were absent in all but one patient with an allergic-like reaction, while they were detected in all patients with a real allergy. Symptoms and grade did not differ between the groups. Asparaginase was continued with the same formulation in six patients of whom four finished treatment with adequate activity levels. Conclusions: In conclusion, allergic-like reactions occur relatively late after the start of infusion and without antibodies. Despite these clinical differences, allergic-like reactions can only be distinguished from real allergies by continually measuring asparaginase activity levels. If clinically tolerated, formulations should not be switched in case of allergic-like reactions. Moreover, failure to recognize these reactions may lead to a less favorable prognosis if asparaginase therapy is terminated unnecessarily

Longitudinal follow-up of bone density and body composition in children with precocious or early puberty before, during and after cessation of GnRH agonist therapy

We studied bone mineral density (BMD), bone metabolism, and body composition in 47 children with central precocious puberty (n = 36) or early puberty (n = 11) before, during, and after cessation of GnRH agonist. Bone density and body composition were measured with dual energy x-ray absorptiometry and expressed as SD scores. Bone age and biochemical parameters of bone turnover were assessed. Measurements were performed at baseline, after 6 months, and on a year

Acute lymphoblastic leukaemia patients treated with PEGasparaginase develop antibodies to PEG and the succinate linker

Polyethylene glycol (PEG) conjugated asparaginase (PEGasparaginase) is essential for treatment of paediatric acute lymphoblastic leukaemia. We developed an assay identifying antibodies against the PEG-moiety, the linker and the drug itself in patients experiencing hypersensitivity reactions to PEGasparaginase. Eighteen patients treated according to the DCOG ALL-11 protocol, with a neutralizing hypersensitivity reaction to PEGasparaginase to the first PEGasparaginase doses in induction (12 patients) or during intensification after interruption of several months (6 patients) were included. ELISA was used to measure antibodies, coating with the succinimidyl succinate linker conjugated to BSA, PEGfilgrastim and Escherichia coli asparaginase, and using hydrolysed PEGasparaginase and mPEG5,000 for competition. Anti-PEG antibodies were detected in all patients (IgG 100%; IgM 67%) of whom 39% had anti-PEG antibodies exclusively. Pre-existing anti-PEG antibodies were also detected in patients who not previously received a PEGylated therapeutic (58% IgG; 21% IgM). Antibodies against the SS-linker were predominantly detected during induction (50% IgG; 42% IgM). Anti-asparaginase antibodies were detected in only 11% during induction but 94% during intensification. In conclusion, anti-PEG and anti-SS-linker antibodies predominantly play a role in the immunogenic response to PEGasparaginase during induction. Thus, switching to native E. coli asparaginase would be an option for adequate asparaginase treatment

Parental Sleep, Distress, and Quality of Life in Childhood Acute Lymphoblastic Leukemia:A Longitudinal Report from Diagnosis up to Three Years Later

This study assessed sleep, distress and quality of life (QoL) in parents of children with acute lymphoblastic leukemia (ALL) from diagnosis to three years after, and the impact of sleep and distress on QoL. Additionally, this study explored determinants of sleep and distress. Parents completed the MOS Sleep, Distress Thermometer for Parents and SF-12 at four-five months (T0), one year (T1), two years (T2), and three years (T3) after diagnosis. The course of outcomes and longitudinal impact of clinically relevant sleep problems (>1SD above reference’s mean) and clinical distress (score ≥ 4) on QoL Z-scores were assessed with linear mixed-models. Determinants of sleep and distress were assessed with multinomial mixed-models. Parents (81% mothers) of 139 patients (60% males; 76% medium-risk (MR)) participated. Distress and QoL gradually restored from T0 to T3. Sleep problems improved, but were still elevated at T3: 33% reported clinically relevant sleep problems, of which 48% in concurrence with distress. Over time, presence of sleep problems or distress led to lower mental QoL Z-scores (SD-score −0.2 and −0.5, respectively). Presence of both led to a cumulatively lower Z-score (SD-score −1.3). Parents in the latter group were more likely to report insufficient social support, parenting problems, a chronic illness, pain for their child, having a child with MR-ALL, and being closer to diagnosis. In conclusion, parental well-being improves over time, yet sleep problems persist. In combination with ongoing distress, they cumulatively affect QoL. Special attention should be given to parents who are vulnerable to worse outcomes

Cost-analysis of treatment of childhood acute lymphoblastic leukemia with asparaginase preparations: The impact of expensive chemotherapy

__Abstract__ Asparaginase is an expensive drug, but important in childhood acute lymphoblastic leukemia. In order to compare costs of PEGasparaginase, Erwinia asparaginase and native E. coli asparaginase, we performed a cost-analysis in the Dutch Childhood Oncology Group ALL-10 medium-risk group intensification protocol. Treatment costs were calculated based on patient level data of 84 subjects, and were related to the occurrence of allergy to PEGasparaginase. Simultaneously, decision tree and sensitivity analyses were conducted. The total costs of the intensification course of 30 weeks were $57,893 in patients without PEGasparaginase allergy (n=64). The costs were significantly higher ($113,558) in case of allergy (n=20) necessitating a switch to Erwinia asparaginase. Simulated scenarios (decision tree analysis) using native E. coli asparaginase in intensification showed that the costs of PEGasparaginase were equal to those of native E. coli asparaginase. Also after sensitivity analyses, the costs for PEGasparaginase were equal to those of na

The effect of asparaginase therapy on methotrexate toxicity and efficacy in children with acute lymphoblastic leukemia

ABSTRACT Asparaginase and methotrexate (MTX), both essential for pediatric acute lymphoblastic leukemia therapy, are often used concomitantly. Depending on the sequence, in vitro, asparaginase inhibits MTX-polyglutamate (MTXPG) formation, and side effects overlap. MTX toxicity and efficacy, reflected by intracellular erythrocyte MTXPG’s, were compared between children treated with and without asparaginase during high dose MTX (HD-MTX) courses of the DCOG ALL-11 protocol (NL50250.078.14). Seventy-three patients, of whom 23 received asparaginase during the HDMTX courses, were included. Grade 3–4 leukopenia and neutropenia occurred more often (59% and 86% vs. 30% and 62%). The number of infections, grade 3–4 hepatotoxicity, nephrotoxicity, and neurotoxicity did not differ. Patients with asparaginase had lower MTXPG levels, although to a lesser extent than in vitro studies. Although patients with asparaginase during HD-MTX courses showed more myelosuppression, this had no (serious) clinical consequences. Regarding the MTX efficacy, the schedule-related antagonism seen in in vitro seems less important in vivo

Consensus definitions of 14 severe acute toxic effects for childhood lymphoblastic leukaemia treatment: a Delphi consensus

Although there are high survival rates for children with acute lymphoblastic leukaemia, their outcome is often counterbalanced by the burden of toxic effects. This is because reported frequencies vary widely across studies, partly because of diverse definitions of toxic effects. Using the Delphi method, 15 international childhood acute lymphoblastic leukaemia study groups assessed acute lymphoblastic leukaemia protocols to address toxic effects that were to be considered by the Ponte di Legno working group. 14 acute toxic effects (hypersensitivity to asparaginase, hyperlipidaemia, osteonecrosis, asparaginase-associated pancreatitis, arterial hypertension, posterior reversible encephalopathy syndrome, seizures, depressed level of consciousness, methotrexate-related stroke-like syndrome, peripheral neuropathy, high-dose methotrexate-related nephrotoxicity, sinusoidal obstructive syndrome, thromboembolism, and Pneumocystis jirovecii pneumonia) that are serious but too rare to be addressed comprehensively within any single group, or are deemed to need consensus definitions for reliable incidence comparisons, were selected for assessment. Our results showed that none of the protocols addressed all 14 toxic effects, that no two protocols shared identical definitions of all toxic effects, and that no toxic effect definition was shared by all protocols. Using the Delphi method over three face-to-face plenary meetings, consensus definitions were obtained for all 14 toxic effects. In the overall assessment of outcome of acute lymphoblastic leukaemia treatment, these expert opinion-based definitions will allow reliable comparisons of frequencies and severities of acute toxic effects across treatment protocols, and facilitate international research on cause, guidelines for treatment adaptation, preventive strategies, and development of consensus algorithms for reporting on acute lymphoblastic leukaemia treatment