A comparative analysis exposes an amplification delay distinctive to SARS-CoV-2 Omicron variants of clinical and public health relevance.

ABSTRACTMutations in the SARS-CoV-2 genome may negatively impact a diagnostic test, have no effect, or turn into an opportunity for rapid molecular screening of variants. Using an in-house Emergency Use Authorized RT-qPCR-based COVID-19 diagnostic assay, we combined sequence surveillance of viral variants and computed PCR efficiencies for mismatched templates. We found no significant mismatches for the N, E, and S set of assay primers until the Omicron variant emerged in late November 2021. We found a single mismatch between the Omicron sequence and one of our assay's primers caused a > 4 cycle delay during amplification without impacting overall assay performance.Starting in December 2021, clinical specimens received for COVID-19 diagnostic testing that generated a Cq delay greater than 4 cycles were sequenced and confirmed as Omicron. Clinical samples without a Cq delay were largely confirmed as the Delta variant. The primer-template mismatch was then used as a rapid surrogate marker for Omicron. Primers that correctly identified Omicron were designed and tested, which prepared us for the emergence of future variants with novel mismatches to our diagnostic assay's primers. Our experience demonstrates the importance of monitoring sequences, the need for predicting the impact of mismatches, their value as a surrogate marker, and the relevance of adapting one's molecular diagnostic test for evolving pathogens.

Development and implementation of a scalable and versatile test for COVID-19 diagnostics in rural communities.

Rapid and widespread testing of severe acute respiratory coronavirus 2 (SARS-CoV-2) is essential for an effective public health response aimed at containing and mitigating the coronavirus disease 2019 (COVID-19) pandemic. Successful health policy implementation relies on early identification of infected individuals and extensive contact tracing. However, rural communities, where resources for testing are sparse or simply absent, face distinctive challenges to achieving this success. Accordingly, we report the development of an academic, public land grant University laboratory-based detection assay for the identification of SARS-CoV-2 in samples from various clinical specimens that can be readily deployed in areas where access to testing is limited. The test, which is a quantitative reverse transcription polymerase chain reaction (RT-qPCR)-based procedure, was validated on samples provided by the state laboratory and submitted for FDA Emergency Use Authorization. Our test exhibits comparable sensitivity and exceeds specificity and inclusivity values compared to other molecular assays. Additionally, this test can be re-configured to meet supply chain shortages, modified for scale up demands, and is amenable to several clinical specimens. Test development also involved 3D engineering critical supplies and formulating a stable collection media that allowed samples to be transported for hours over a dispersed rural region without the need for a cold-chain. These two elements that were critical when shortages impacted testing and when personnel needed to reach areas that were geographically isolated from the testing center. Overall, using a robust, easy-to-adapt methodology, we show that an academic laboratory can supplement COVID-19 testing needs and help local health departments assess and manage outbreaks. This additional testing capacity is particularly germane for smaller cities and rural regions that would otherwise be unable to meet the testing demand.

Model-Based Assessment of Alternative Study Designs in Pediatric Trials. Part II: Bayesian Approaches.

This study presents a pharmacokinetic-pharmacodynamic based clinical trial simulation framework for evaluating the performance of a fixed-sample Bayesian design (BD) and two alternative Bayesian sequential designs (BSDs) (i.e., a non-hierarchical (NON-H) and a semi-hierarchical (SEMI-H) one). Prior information was elicited from adult trials and weighted based on the expected similarity of response to treatment between the pediatric and adult populations. Study designs were evaluated in terms of: type I and II errors, sample size per arm (SS), trial duration (TD), and estimate precision. No substantial differences were observed between NON-H and SEMI-H. BSDs require, on average, smaller SS and TD compared to the BD, which, on the other hand, guarantees higher estimate precision. When large differences between children and adults are expected, BSDs can return very large SS. Bayesian approaches appear to outperform their frequentist counterparts in the design of pediatric trials even when little weight is given to prior information from adults.

Model-Based Assessment of Alternative Study Designs in Pediatric Trials. Part I: Frequentist Approaches.

Alternative designs can increase the feasibility of pediatric trials when compared to classical parallel designs (PaD). In this work we present a model-based approach based on clinical trial simulations for the comparison of PaD with the alternative sequential, crossover, and randomized withdrawal (RWD) designs. Study designs were evaluated in terms of: type I and II errors, sample size per arm (SS), trial duration (TD), treatment exposures, and parameter estimate precision (EP). The crossover requires the lowest SS and TD, although it implies higher placebo and no treatment exposures. RWD maximizes exposure to active treatment while minimizing that to placebo, but requires the largest SS. SS of sequential designs can sometimes be smaller than the crossover one, although with poorer EP. This pharmacometric framework allows a multiscale comparison of alternative study designs that can be used for design selection in future pediatric trials.

Successful private-public funding of paediatric medicines research: lessons from the EU programme to fund research into off-patent medicines.

UNLABELLED: The European Paediatric Regulation mandated the European Commission to fund research on off-patent medicines with demonstrated therapeutic interest for children. Responding to this mandate, five FP7 project calls were launched and 20 projects were granted. This paper aims to detail the funded projects and their preliminary results. Publicly available sources have been consulted and a descriptive analysis has been performed. Twenty Research Consortia including 246 partners in 29 European and non-European countries were created (involving 129 universities or public-funded research organisations, 51 private companies with 40 SMEs, 7 patient associations). The funded projects investigate 24 medicines, covering 10 therapeutic areas in all paediatric age groups. In response to the Paediatric Regulation and to apply for a Paediatric Use Marketing Authorisation, 15 Paediatric Investigation Plans have been granted by the EMA-Paediatric Committee, including 71 studies of whom 29 paediatric clinical trials, leading to a total of 7,300 children to be recruited in more than 380 investigational centres. CONCLUSION: Notwithstanding the EU contribution for each study is lower than similar publicly funded projects, and also considering the complexity of paediatric research, these projects are performing high-quality research and are progressing towards the increase of new paediatric medicines on the market. Private-public partnerships have been effectively implemented, providing a good example for future collaborative actions. Since these projects cover a limited number of off-patent drugs and many unmet therapeutic needs in paediatrics remain, it is crucial foreseeing new similar initiatives in forthcoming European funding programmes.

Impact of the new european paediatric regulatory framework on ethics committees: overview and perspectives.

AIM: To evaluate the impact of the new European paediatric regulatory framework on the activities of Ethics Committees operating in Europe and to assess their involvement and interest in paediatric research. METHODS: Task-force in Europe for Drug Development for the Young Network of Excellence and Relating Expectations and Needs to the Participation and Empowerment of Children in Clinical Trials project set up an inventory of Ethics Committees existing in Europe and conducted a survey on their approach to paediatric trials. RESULTS: Ethics Committees operating in 22 European Countries participated in this survey. Results showed a high lack of knowledge, understanding and awareness of the current European paediatric regulatory framework and a lack of involvement of Ethics Committees in paediatric research, especially in terms of training and education, demonstrated also by the decreasing number of Ethics Committees answering exhaustively to the whole questionnaire. The majority of participating Ethics Committees expressed interest in future initiatives related to paediatric research. CONCLUSIONS: Despite a limited knowledge and understanding of the current paediatric regulatory framework, a significant number of Ethics Committees operating in Europe show interest in initiatives related to paediatric research. Networking may be an essential tool to be used to enhance Ethics Committees role in supporting paediatric research. Any initiative should be undertaken at European level in collaboration with European Union Institutions.

In-label and off-label use of respiratory drugs in the Italian paediatric population.

AIM: To evaluate the prescription rate of respiratory drugs (ATC code R03) in an Italian community setting and to estimate the extent of off-label use by both age and indication. METHODS: A cohort study aimed at evaluating prescriptions of drugs with ATC code R03 was conducted for the period 2002-2006. Data source was the PEDIANET Database. RESULTS: Ninety percent of R03 prescriptions are covered by 11 active substances or combinations, corresponding to 67 medicinal products. Inhaled corticosteroids are the most prescribed anti-asthmatic agents, followed by short-acting beta2 mimetics. The mean off-label rate is 19 and 56%, by age and indication respectively. The majority of off-label uses is among children under the age of 2. Five active substances are used at dosages not supported by adequate dose-finding studies. CONCLUSION: In Italy, many respiratory drugs are approved for the treatment of paediatric respiratory diseases, but a remarkable percentage of their prescriptions is off-label. This pharmaco-utilization study demonstrates that there is a need to perform clinical studies aimed at increasing the current knowledge on marketed paediatric drugs, and to revise and re-label the existing regulatory documents to reduce their off-label uses.

Medicines for children licensed by the European Medicines Agency (EMEA): the balance after 10 years.

OBJECTIVE: The 1995-2005 balance of EMEA activities in the field of paediatric medicines was evaluated, taking into account the number both of drugs authorised for children and paediatric studies supporting the Marketing Authorisation (MA). METHODS: Data on drugs authorised by EMEA were extracted from EPARs (European Public Assessment Reports). Active substance, year of approval, anatomical, therapeutic and chemical (ATC) code, indication, orphan status, ages, and registrative clinical studies characteristics were assessed. RESULTS: The percentage of authorised substances for paediatrics is 33.3%. This percentage decreased or increased when different subsets of medicines were considered [medicines for children under 2 years (23.4%), N-ATC code drugs (6%) and orphan drugs (46.4%)]. A total of 165 trials were included in the MA dossiers of 51 drugs at the time of approval, and additional 22 studies were added to the dossiers of 12 active substances submitted for paediatric variations. PK and Efficacy/Safety studies were performed for 32 (52%) active substances, while either one PK or one Efficacy/Safety study was carried out for 43 (69%) and 45 (73%) substances, respectively. CONCLUSIONS: This report demonstrates that the total number of paediatric medicines approved by EMEA is stable over the 10-year period, while an increase in drugs to treat serious or orphan diseases has been observed. In addition, under the Centralised Procedure, a valuable number of paediatric trials have been submitted to support drug approval.

Medicines for children licensed by the European Agency for the Evaluation of Medicinal Products.

OBJECTIVE: . The aim of this study was to evaluate the number and the characteristics of medicines approved for children in Europe by the European Agency for the Evaluation of Medicinal Products (EMEA) and whether the paediatric studies supporting the authorisation were in accordance with the Note for Guidance on the Clinical Investigation of Medicinal Products in children (CPMP/ICH/2711/99). We also considered any possible difference between the EMEA and the Food and Drug Administration (FDA) paediatric medicines evaluations. METHODS: . We examined the drugs authorised by the EMEA through the centralised procedure from January 1995 to September 2001 deriving information from the "European Medicines - Database" (EMD) set up in 1998 by the Italian Group for Pharmacoeconomic Studies (GISF) and sponsored by the Italian Ministry of Health. The analysis of paediatric data has been managed by experts belonging to the Clinical Pharmacology Working Group of the Italian Paediatric Society. The following parameters were assessed: active substance, year of approval, anatomical therapeutic and chemical (ATC) code, therapeutic indications, age for which the drug is authorised, interest to children and paediatric studies supporting a paediatric authorisation. European Public Assessment Reports (EPARs) were considered as reference sources. RESULTS: . The median percentage of drugs authorised for children from 1995 to 2001 (September) is 35% of the total of commercially available drugs; only 16 medicines have been approved for children under 2 years of age (11%), ten of these being vaccines. Medicines for children shared out 9 ATC classes, 24 belonging to the J- (anti-infective agents) -ATC class. Thirty-nine medicines were authorised on the basis of at least one clinical trial (27 phase III, 6 phase II, 6 phase I) while eight active substances have been licensed without any paediatric investigation. CONCLUSIONS: . Under the EMEA centralised procedure, several active substances have been licensed for children. Consequently serious and life-threatening diseases as AIDS and diabetes are now treatable, in a legal framework overcoming the orphan status of the past years. Despite the reported encouraging results, the number of drugs devoted to children remain low and important ATC classes, as L-(oncology) or N-(neurology), are still 'orphans' of innovative medicines. At the same time few medicinal products are specifically studied in children. Consequently, more efforts have to be made to increase the number of drugs assessed and licensed for the paediatric population, and manufacturers should be required to supply data on the effects of new drugs in children when the products are expected to offer a benefit over existing therapies.

A randomized trial of treatment for multisystem Langerhans' cell histiocytosis.

OBJECTIVE: To compare 2 active agents, vinblastine and etoposide, in the treatment of multisystem Langerhans' cell histiocytosis (LCH) in an international randomized study. STUDY DESIGN: One hundred forty-three untreated patients were randomly assigned to receive 24 weeks of vinblastine (6 mg/m(2), given intravenously every week) or etoposide (150 mg/m(2)/d, given intravenously for 3 days every 3 weeks), and a single initial dose of corticosteroids. RESULTS: Vinblastine and etoposide were equivalent (P > or = .2) in all respects: response at week 6 (57% and 49%); response at the last evaluation (58% and 69%); toxicity (47% and 58%); and probability of survival (76% and 83%) [corrected], of disease reactivation (61% and 55%), and of developing permanent consequences (39% and 51%) including diabetes insipidus (22% and 23%). LCH reactivations were usually mild, as was toxicity. All children > or = 2 years old without risk organ involvement (liver, lungs, hematopoietic system, or spleen) survived. With such involvement, lack of rapid (within 6 weeks) response was identified as a new prognostic indicator, predicting a high (66%) mortality rate. CONCLUSIONS: Vinblastine and etoposide, with one dose of corticosteroids, are equally effective treatments for multisystem LCH, but patients who do not respond within 6 weeks are at increased risk for treatment failure and may require different therapy.

Creatine as nutritional supplementation and medicinal product.

Because of assumed ergogenic effects, the creatine administration has become popular practice among subjects participating in different sports. Appropriate creatine monohydrate dosage may be considered a medicinal product since, in accordance with the Council Directive 65/65/EEC, any substance which may be administered with a view to restoring, correcting or modifying physiological functions in humans beings is considered a medicinal product. Thus, quality, efficacy and safety must characterise the substance. In addition, the European Court of Justice has held that a product which is recommended or described as having preventive or curative properties is a medicinal product even if it is generally considered as a foodstuff and even if it has no known therapeutic effect in the present state of scientific knowledge. In biochemical terms, creatine administration increases creatine and phosphocreatine muscle concentration, allowing for an accelerated rate of ATP synthesis. In thermodynamics terms, creatine stimulates the creatine-creatine kinase-phosphocreatine circuit, which is related to the mitochondrial function as a highly organised system for the control of the subcellular adenylate pool. In pharmacokinetics terms, creatine entry into skeletal muscle is initially dependent on the extracellular concentration, but the creatine transport is subsequently downregulated. In pharmacodynamics terms, the creatine enhances the possibility to maintain power output during brief periods of high-intensity exercises. In spite of uncontrolled daily dosage and long-term administration, no researches on creatine monohydrate safety in humans were set up by standardised protocols of clinical pharmacology and toxicology, as currently occurs in phases I and II for products for human use. More or less documented side effects induced by creatine monohydrate are weight gain; influence on insulin production; feedback inhibition of endogenous creatine synthesis; long-term damages on renal function. A major point that related to the quality of creatine monohydrate products is the amount of creatine ingested in relation to the amount of contaminants present. During the industrial production of creatine monohydrate from sarcosine and cyanamide, variable amounts of contaminants (dicyandiamide, dihydrotriazines, creatinine, ions) are generated and, thus, their tolerable concentrations (ppm) must be defined and made consumers known. Furthermore, because sarcosine could originate from bovine tissues, the risk of contamination with prion of bovine spongiform encephalopathy (BSE or mad-cow disease) can t be excluded. Thus, French authorities forbade the sale of products containing creatine. Creatine, as other nutritional factors, can be used either at supplementary or therapeutic levels as a function of the dose. Supplementary doses of nutritional factors usually are of the order of the daily turnover, while therapeutic ones are three or more times higher. In a subject of 70 kg with a total creatine pool of 120 g, the daily turnover is approximately of 2 g. Thus, in healthy subjects nourished with fat-rich, carbohydrate, protein-poor diet and participating in a daily recreational sport, the oral creatine monohydrate supplementation should be of the order of the daily turnover, i.e., less than 2.5-3 g per day, bringing the gastrointestinal absorption to account. In healthy athletes submitted daily to high-intensity strength or sprint training, the maximal oral creatine monohydrate supplementation should be of the order of two times the daily turnover, i.e., less than 5-6 g per day for less than two weeks, and the creatine monohydrate supplementation should be taken under appropriate medical supervision. The oral administration of more that 6 g per day of creatine monohydrate should be considered as a therapeutic intervention and should be prescribed by physicians only in the cases of suspected or proven deficiency, or in conditions of severe stress and/or injury. The incorporation of creatine into the medicinal product class is supported also by the use in pathological conditions, e.g., some mitochondrial cytopathies, the guanidinoacetate methyltransferase deficiency, etc.

Detection of anti-erythropoietin antibodies in haemodialysis patients treated with recombinant human-erythropoietin.

An enzyme-immunoassay was developed to evaluate the presence of anti-erythropoietin antibodies in plasma samples obtained from renal failure patients treated with recombinant human erythropoietin (rh-EPO). The assay was specific and reproducible. Normal donors had no antibodies to EPO, while 67% of treated patients were positive to the assay. While the specificity of anti-EPO IgG antibodies was high, their affinity for the antigen was low. This finding can be explained by the very small differences in the structure of rh-EPO compared to that of natural EPO. The assay described could be useful in evaluating the long-term effects of rh-EPO treatment on the control of anaemia in renal failure patients.

Ear involvement in childhood Langerhans' cell histiocytosis.

BACKGROUND: Ear involvement (EI) in Langerhans' cell histiocytosis (LCH) occurs quite often. We reviewed the Italian pediatric population of 251 children with LCH diagnosed between 1982 and 1995, focusing on EI, to highlight the prevalence, the clinical presentation, the outcome during follow-up, and the prognostic impact of otologic LCH. METHODS: EI was defined by chronic otorrhea and/or mastoid infiltration, external auditory meatus lesions, and middle/internal EI. The age at diagnosis, sex, system involved, organ dysfunction, treatment, disease control, and outcome were recorded. RESULTS: EI was noted at presentation in 34 children (13. 5%). They had a younger age at diagnosis (p=.0013) and near totality of multisystem disease (93.8% of patients with EI). Among patients with multisystem disease, children with EI seemed to have a higher risk of poor response and a higher percentage of second line treatment (p=.003). CONCLUSIONS: EI seems to identify patients with a particular disease behavior, which requires a more accurate evaluation at diagnosis, staging and treatment, and a strict follow-up, considering the possibility of an unfavorable outcome.

Cyclosporine A therapy for multisystem langerhans cell histiocytosis.

BACKGROUND: Treatment of multisystem Langerhans cell histiocytosis (LCH) remains difficult. Various regimens of single and multiagent chemotherapy have been used, but a significant proportion of patients fail to respond to treatment. PROCEDURE: We have evaluated the use of cyclosporine A (CSA) in a controlled group of patients, who had received a systematic primary therapy (LCH-I). Patients received CSA either as a single agent (10 patients) or in combination with vinblastine, etoposide, prednisolone, and/or antithymocyte globulin (16 patients). RESULTS: Among the total of 26 patients treated, a single patient developed a complete response and three a partial response, whereas 85% (22 patients) had no response to CSA. CONCLUSIONS: CSA is at best of limited value in the treatment of patients with multisystem LCH, particularly those who had progressive disease while receiving chemotherapy.

Effect of antipsychotic drugs and selective dopaminergic antagonists on dopamine-induced facilitatory activity in prelimbic cortical pyramidal neurons. An in vitro study.

Intracellular recordings were obtained from 119 pyramidal neurons localized in prelimbic cortex, five in the dorsal cingulate cortex, one in the infralimbic cortex, one in the border of prelimbic and cingulate cortex and two in the border of prelimbic and infralimbic cortex. The passive membrane properties of these pyramidal neurons (i.e. resting membrane potential, input membrane resistance, shape of the tetrodotoxin-sensitive action potentials, spike frequency adaptation with a prominent postspike afterhyperpolarization, tetrodotoxin-sensitive inward rectification in the depolarizing direction and the absence of bursting) suggested that they resembled regular spiking or intrinsically bursting pyramidal neurons. Bath application of dopamine (EC50 of 1.8 microM) produced a reversible facilitatory effect on all 119 pyramidal neurons localized in the middle layer of the prelimbic cortex. No consistent change in membrane potential was detected during the application of dopamine. No effect of dopamine was noted on the nine pyramidal neurons that were not localized in the prelimbic cortex. The facilitatory effect of dopamine in prelimbic cortex was concentration dependently antagonized by haloperidol, risperidone, quetiapine, clozapine and by the selective D4 dopaminergic receptor antagonist L-745,870, but not by the selective D2/D3 dopaminergic receptor antagonist (-)-sulpiride. (+)-SCH 23390, which is a selective D1/D5 dopamine receptor antagonist, produced, similarly to dopamine, a facilitatory effect per se, and an additive effect when co-administered with dopamine. These results provide evidence that dopamine has a facilitatory effect specifically on pyramidal neurons localized in the middle layer of prelimbic cortex. Antipsychotic drugs and L-745,870 block this effect of dopamine.

BIIR 561 CL: a novel combined antagonist of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and voltage-dependent sodium channels with anticonvulsive and neuroprotective properties.

Antagonists of glutamate receptors of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtype, as well as of voltage-gated sodium channels, exhibit anticonvulsive and neuroprotective properties in vivo. One can postulate that a compound that combines both principles might be useful for the treatment of disorders of the central nervous system, like focal or global ischemia. Here, we present data on the effects of dimethyl-(2-[2-(3-phenyl-[1,2, 4]oxadiazol-5-yl)-phenoxy]ethyl)-amine hydrochloride (BIIR 561 CL) on neuronal AMPA receptors and voltage-dependent sodium channels. BIIR 561 CL inhibited AMPA receptor-mediated membrane currents in cultured cortical neurons with an IC50 value of 8.5 microM. The inhibition was noncompetitive. In a cortical wedge preparation, BIIR 561 CL reduced AMPA-induced depolarizations with an IC50 value of 10.8 microM. In addition to the effects on the glutamatergic system, BIIR 561 CL inhibited binding of radiolabeled batrachotoxin to rat brain synaptosomal membranes with a Ki value of 1.2 microM. The compound reduced sodium currents in voltage-clamped cortical neurons with an IC50 value of 5.2 microM and inhibited the veratridine-induced release of glutamate from rat brain slices with an IC50 value of 2.3 microM. Thus, BIIR 561 CL inhibited AMPA receptors and voltage-gated sodium channels in a variety of preparations. BIIR 561 CL suppressed tonic seizures in a maximum electroshock model in mice with an ED50 value of 2.8 mg/kg after s.c. administration. In a model of focal ischemia in mice, i.p. administration of 6 or 60 mg/kg BIIR 561 CL reduced the area of the infarcted cortical surface. These data show that BIIR 561 CL is a combined antagonist of AMPA receptors and voltage-gated sodium channels with promising anticonvulsive and neuroprotective properties.

The 'drug value' in the European pharmaceutical system.

European regulatory authorities (EMEA, European Commission) and/or national pharmacological and medical decision-makers can utilise the drug value to help themselves to decide which drugs to define as really innovative instead of new, which regulations to implement, which drugs to include on formularies, or which restrictions to enforce. As economic research becomes widely accepted for pharmaceutical evaluation, it needs to utilise prospective rather than retrospective study design. Analyses conducted at the time of therapy have better access to patients and can obtain both more accurate information on consumption of resources and the impact of pharmacotherapy on non-monetary quality of life for patients, survival, comparative clinical effectiveness and economic outcomes within social health service or in wider economy.

ALL R-87 protocol in the treatment of children with acute lymphoblastic leukaemia in early bone marrow relapse.

Seventy-three children with acute lymphoblastic leukaemia (ALL) in first bone marrow (BM) relapse, occurring within 30 months from complete remission (CR), were enrolled in an Italian cooperative study (ALL R-87 protocol). This treatment programme consisted of an induction phase with intermediate-dose cytarabine (IDARA-C) plus idarubicin (IDA) and prednisone (PDN), followed by a multidrug consolidation therapy and bone marrow transplant (BMT). 55/73 children achieved CR (75.3%); 15 (20.5%) failed to respond and three (4.2%) died during induction. The response rate was significantly higher for children with a first CR duration > or = 12 months (P=0.0005) and for those with a white blood cell (WBC) count at relapse < 20 x 10(9)/l (P=0.004). The estimated disease-free survival (DFS +/- SE) at 82 months was 0.18 +/- 0.05 for all responders, and 0.70 +/- 0.14 for allotransplanted patients versus 0.05 +/- 0.05 for those autografted (P=0.001). The estimated probabilities of survival +/- SE and event-free survival (EFS +/- SE) at 83 months were 0.16 +/- 0.07 and 0.13 +/- 0.04, respectively. for all enrolled children. Univariate analysis showed that age < 10 years at initial diagnosis and B-lineage immunophenotype favourably influenced both DFS (P=0.001) and EFS probabilities (P=0.0014 and P=0.012, respectively), whereas a first CR duration > or = 12 months and a WBC count at relapse < 20 x 10(9)/l were associated only with a better EFS rate (P=0.026 and P=0.004, respectively). Our results show the efficacy of the IDA plus IDARA-C schedule used in the ALL R-87 protocol in high-risk relapsed ALL children. Allogeneic BMT proved effective for patients with an HLA sibling donor. In a multivariate analysis, age > or = 10 years at initial diagnosis (P=0.016) and WBC count at relapse > or = 20 x 10(9)/l (P=0.048) were independently associated with a worse disease outcome.