Acute Lymphoblastic Leukemia Maintenance Research Articles

Allopurinol adjuvant in acute lymphoblastic leukaemia maintenance: Benefits and potential risks

Allopurinol adjuvant in acute lymphoblastic leukaemia maintenance: Benefits and potential risks

Utilization of Thiopurine Metabolites and Allopurinol in Pediatric Acute Lymphoblastic Leukemia: Consideration for an Algorithmic Approach.

Persistently elevated absolute neutrophil counts during maintenance for acute lymphoblastic leukemia is a risk factor for relapse and may be related to wild-type thiopurine methyltransferase activity and overly efficient shunting of 6-mercaptopurine to hepatotoxic metabolites (6-methylmercaptopurine nucleotides), leading to low 6-thioguanine nucleotides. 6-mercaptopurine is also metabolized by xanthine oxidase, and therefore allopurinol, an inhibitor of xanthine oxidase, allows for increased 6-thioguanine nucleotides and decreased 6-methylmercaptopurine nucleotide. Here, we report our experience with allopurinol for persistently elevated absolute neutrophil count or hepatotoxicity and suggest an algorithmic approach for checking thiopurine metabolites and initiating allopurinol in acute lymphoblastic leukemia maintenance.

Functional SCD1 Is Critical for Acute Lymphoblastic Leukaemia Maintenance in the Central Nervous System

The largest advance in survival rates for childhood acute lymphoblastic leukaemia (ALL) came with the recognition that eradication of disease in the central nervous system (CNS) is needed to achieve long-term cure. All modern ALL protocols include large amounts of CNS-directed therapy, predominantly with methotrexate, which can result in significant acute and chronic neurotoxicity. In addition, CNS relapse remains a clinical challenge with a lack of effective drugs for recurrent disease. Despite this, little is known about the mechanisms by which leukaemic blasts enter the CNS and survive in this different microenvironment. Identifying specific mechanisms that support maintenance of ALL in the CNS should facilitate more effective targeted therapies.CNS ALL blasts reside in the leptomeninges, bathed in cerebrospinal fluid (CSF) which is low in glucose, protein, lipids and oxygen. Since blasts need building blocks and energy to survive and proliferate, and CSF nutrient supplies are scarce, we hypothesized that changes in their metabolism would occur. Such metabolic remodelling (flexible adaptation of metabolism according to tissue location and environmental conditions) is acknowledged as a hallmark of cancers. In a nutrient-deprived environment such as the CSF, metabolic adaptations are likely to be key to ALL survival.Thus, we investigated specific CNS-related metabolic signatures of ALL blasts. NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice were xenotransplanted with two human ALL cell lines: SEM (t(4;11), MLL-AF4) and REH (t(12;21), ETV6-RUNX1). After engraftment, cells were isolated from the CNS and spleen and RNA sequencing performed (Next Seq500). Transcript quantification was done against both human and mouse transcriptomes, in order to remove any possible mouse RNA contamination. Stearoyl-CoA Desaturase (SCD1) and Fatty Acid Synthase (FASN), key enzymes involved in fatty acid synthesis, were among the most upregulated genes in the CNS. Single sample gene set enrichment analysis confirmed that fatty acid and lipid synthesis showed a clear and significant upregulation in blasts from the CNS compared to the spleen for both cell lines, whereas the opposite result was observed for fatty acid and lipid oxidation. These results were replicated using a publicly available human dataset comparing bone marrow (BM) vs. CNS relapse samples from ALL patients (GEO dataset GSE60926).We went on to characterise the fatty acid profile of normal CSF and paired plasma from both non-leukaemic NSG mice and healthy human volunteers. Both murine and human CSF are about 1000-fold less rich in fatty acids than plasma. Immunostaining of SCD1 and FASN confirmed that both enzymes were strongly expressed on ALL blasts in the leptomeninges of post-mortem samples from patients with CNS-relapse and xenograft models. Murine BM showed equivalent levels of FASN expression but lower SCD1, and western blots confirmed that SCD1 was overexpressed at the protein level by about 2-fold in CNS compared to spleen or BM. We therefore chose to pursue SCD1 as a potential therapeutic target for CNS leukaemia.Two groups of NSG mice were xenografted with SEM cells and treated from day 15 post-transplant with either vehicle or 5mg/kg of the oral small-molecule SCD1 inhibitor MF-438 daily for 11 days. This dose strongly impaired SCD1 activity, since the ratios of oleate to stearate in plasma from vehicle- treated mice were 6 times higher than in plasma from MF-438 treated mice. We confirmed that the drug also reduced intra-cellular ratios of oleate:stearate by approximately 2-fold. Measurement of ALL burden in the leptomeninges showed an approximately 50% reduction in the area of leukaemic infiltrates in brain-skull sections. No difference in the burden of leukaemia in BM could be identified, supporting a specific vulnerability to SCD1 inhibition in the CNS microenvironment.In conclusion, we report a strong fatty acid and lipid signature in ALL blasts retrieved from the CNS environment, and identify the enzyme SCD1 as a critical target. We show a significant upregulation of the enzyme, from RNA levels to enzymatic activity, both in murine and human samples of CNS ALL. Using a small-molecule inhibitor in vivo, we show that inhibiting SCD1 activity reduces the amount of CNS leukaemia. Altogether, our data identify fatty acid metabolism as a novel therapeutic target for CNS leukaemia. DisclosuresHalsey:Jazz Pharmaceuticals: Consultancy, Other: Support to attend educational meetings.

Allopurinol use during pediatric acute lymphoblastic leukemia maintenance therapy safely corrects skewed 6-mercaptopurine metabolism, improving inadequate myelosuppression and reducing gastrointestinal toxicity.

Background:Inadequate myelosuppression during maintenance therapy for acute lymphoblastic leukemia (ALL) is associated with an increased risk of relapse. One mechanism is skewed metabolism of 6-mercaptopurine (6MP), a major component of maintenance therapy, which results in preferential formation of the hepatotoxic metabolite (6-methyl mercaptopurine [6MMP]) with low levels of the antileukemic metabolite, 6-thioguanine nucleotides (6TGN). Allopurinol can modify 6MP metabolism to favor 6TGN production and reduce 6MMP.Methods:Patients in maintenance were considered for allopurinol treatment who had the following features: (a) Grade ≥3 hepatotoxicity; (b) Grade ≥2 nonhepatic gastrointestinal (GI) toxicity; or (c) persistently elevated absolute neutrophil count (ANC) despite >150% protocol dosing of oral chemotherapy.Results:From 2013 to 2017, 13 ALL patients received allopurinol: nine for hepatotoxicity, five for inadequate myelosuppression, and three for nonhepatic GI toxicity (four met multiple criteria). Allopurinol was well tolerated, without significant adverse events. Allopurinol resulted in a significant decrease in the average 6MMP/6TGN ratio (mean reduction 89.1, P = .0001), with a significant increase in 6TGN (mean 550.4, P = .0008) and a significant decrease in 6MMP (mean 13 755, P = .0013). Patients with hepatotoxicity had a significant decrease in transaminase elevation after starting allopurinol (alanine transaminase [ALT] mean decrease 22.1%, P = .02), and all with nonhepatic GI toxicity had improved symptoms. Those with inadequate myelosuppression had a significant increase in the time with ANC in goal (mean increase 26.4%, P = .0004).Conclusions:Allopurinol during ALL maintenance chemotherapy is a safe, feasible, and effective intervention for those who have altered metabolism of 6MPcausing toxicity or inadequate myelosuppression.

Dosage of 6-Mercaptopurine in Relation to Genetic TPMT and ITPA Variants: Toward Individualized Pediatric Acute Lymphoblastic Leukemia Maintenance Treatment.

6-mercaptopurine (6-MP) is the mainstay in pediatric acute lymphoblastic leukemia (ALL) maintenance treatment. Variants in genes coding for thiopurine S-methyl transferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) are known to influence 6-MP metabolism. We determined TPMT and ITPA genotype and enzyme activity and the mean 6-MP doses during maintenance treatment in 40 children treated for ALL according to the Dutch Childhood Oncology Group (DCOG)-ALL11 protocol in the Radboudumc Amalia Children's Hospital, Nijmegen, The Netherlands. Patients with genetic variants in TPMT (N=3) had significantly lower TPMT enzyme activity (mean 0.46 vs. 0.72 µmol/mmol hemoglobin/h, P=0.005). Although the difference was not statistically significant, they were treated with lower mean 6-MP doses (28.1 mg/m [SD 25.5 mg/m] vs. 41.3 mg/m [SD 17.2 mg/m], P=0.375). In patients with genetic ITPA variants (N=21), ITPA enzyme activity was significantly lowered (mean 3.67 vs. 6.84 mmol/mmol hemoglobin/h, P<0.0005). The mean 6-MP doses did not differ between patients with and without variants in ITPA (40.0 mg/m [SD 20.3 mg/m] vs. 40.6 mg/m [SD 14.9 mg/m], P=0.663). The TPMT genotype, but not the ITPA genotype, should be considered as part of standard evaluation before starting ALL maintenance treatment.

Prediction of leukocyte counts during paediatric acute lymphoblastic leukaemia maintenance therapy

Maintenance chemotherapy with oral 6-mercaptopurine and methotrexate remains a cornerstone of modern therapy for acute lymphoblastic leukaemia. The dosage and intensity of therapy are based on surrogate markers such as peripheral blood leukocyte and neutrophil counts. Dosage based leukocyte count predictions could provide support for dosage decisions clinicians face trying to find and maintain an appropriate dosage for the individual patient. We present two Bayesian nonlinear state space models for predicting patient leukocyte counts during the maintenance therapy. The models simplify some aspects of previously proposed models but allow for some extra flexibility. Our second model is an extension which accounts for extra variation in the leukocyte count due to a treatment adversity, infections, using C-reactive protein as a surrogate. The predictive performances of our models are compared against a model from the literature using time series cross-validation with patient data. In our experiments, our simplified models appear more robust and deliver competitive results with the model from the literature.

Severely bothersome fatigue in children and adolescents with cancer and hematopoietic stem cell transplant recipients.

Objectives were to describe bothersome fatigue in children with cancer and hematopoietic stem cell (HSCT) recipients and to identify factors associated with severely bothersome fatigue. We included children ages 8-18years treated for cancer or HSCT recipients from three groups: [1] receiving active cancer treatment and admitted to hospital for at least 3days, [2] attending outpatient clinic for acute lymphoblastic leukemia maintenance therapy, and [3] attending outpatient clinic following treatment completion. Fatigue was measured using the Symptom Screening in Pediatrics Tool (SSPedi); severely bothersome fatigue was defined as a lot or extremely bothersome fatigue (score of 3-4 on 0-4 scale). Factors associated with severely bothersome fatigue were examined using univariate and multiple logistic regression. Of 502 children included, 414 (82.5%) reported some degree of bothersome fatigue (scores 1-4), and 123 (24.5%) reported severely bothersome fatigue (score 3 or 4). In multiple regression analysis, factors significantly associated with severely bothersome fatigue were child age 11-14 and 15-18years vs 8-10years (odds ratio (OR) 2.11, 95% confidence interval (CI) 1.21-3.77 and OR 2.96, 95% CI 1.66-5.44), and inpatients receiving cancer treatment vs outpatients who had completed therapy (OR 3.85, 95% CI 2.17-7.27). We found that 82.5% of children with cancer or HSCT recipients reported bothersome fatigue and 24.5% of children reported severely bothersome fatigue. Risk factors for severely bothersome fatigue were older age and inpatients receiving active cancer treatment. Future work should evaluate systematic symptom screening in clinical practice and apply interventions to reduce fatigue.

Methotrexate polyglutamate levels and co-distributions in childhood acute lymphoblastic leukemia maintenance therapy

Methotrexate polyglutamates (MTXpg) facilitate incorporation of thioguanine nucleotides into DNA (DNA-TG, the primary cytotoxic thiopurine metabolite and outcome determinant in MTX/6-mercaptopurine treatment of childhood ALL). We hypothesized that mapping erythrocyte levels of MTXpg with 1-6 glutamates and their associations with DNA-TG formation would facilitate future guidelines for maintenance therapy dosing. Summed MTX with 1-6 glutamates resolved by LCMS [median (interquartile): 5.47 (3.58-7.69) nmol/mmol hemoglobin] was in agreement with total MTX by radio ligand assay. In 16,389 blood samples from 1426 ALL maintenance therapy patients, MTXpg3 21.0 (15.2-27.4)% was the predominant metabolite, and MTXpg1 (the maternal drug) constituted 38.6 (27.2-50.2)% of MTXpg1-6. All subsets correlated; the strongest associations were between metabolites with similar polyglutamate lengths. Correlations of MTXpg1 with MTXpg2 and MTXpg3,4,5,6 were rs = 0.68 and rs = 0.25-0.42, respectively. Intercorrelations of MTXpg3,4,5,6 were all rs ≥ 0.51. MTXpg4 accounted for 29.8 (24.7-33.3)% of MTXpg3-6, yet explained 96% of the summed MTXpg3-6 variation. MTXpg1-4, MTXpg1-6, MTXpg2-6 and MTXpg3 were all associated with DNA-TG levels (p < 0.00001), but collinearity precluded identification of the most informative subset. Measuring erythrocyte MTXpg4 simplifies and can replace longer chain MTXpg monitoring. Resolving individual MTXpg identifies samples that are unsuitable for dose guidance due to high levels of MTXpg1 remaining in the plasma fraction because of recent MTX intake. All tested MTXpg subsets correlated with DNA-TG and may be used for ALL maintenance therapy dose adjustments, but the most informative subset remains to be identified.

Predictive Indicators to Identify High-Risk Paediatric Febrile Neutropenia in Paediatric Oncology Patients in a Middle-Income Country.

To validate a clinical risk prediction score (Ammann score) to predict adverse events (AEs) in paediatric febrile neutropenia (FN). Patients <16 years of age were enrolled. A risk prediction score (based on haemoglobin ≥ 9g/dl, white cell count (WCC) < 0.3G/l, platelet count <50G/l and chemotherapy more intensive than acute lymphoblastic leukaemia maintenance therapy) was calculated and AEs were documented. In total, 100 FN episodes occurred in 52 patients, male:female ratio was 1.8:1 and median age was 56 months. At reassessment, AEs occurred in 18 of 55 (45%) low-risk FN episodes (score < 9) and 21 of 42 (55%) high-risk episodes (score ≥9) (sensitivity 60%, specificity 65%, positive predictive value 53%, negative predictive value 71%). Total WCC and absolute monocyte count (AMC) were significantly associated with AEs. This study identified total WCC and AMC as significantly associated with AEs but failed to validate the risk prediction score.

The relationship between child and caregiver sleep in acute lymphoblastic leukemia maintenance.

The purposes of this study are to describe sleep quality and sleep disturbance among caregivers of children in the maintenance phase of acute lymphoblastic leukemia (ALL) and to examine the relationship between sleep quality, child sleep disturbance, and caregiver guilt and worry. Caregivers of 68 children with ALL, ages 3 to 12years old, completed measures of caregiver guilt and worry, caregiver sleep quality, and child's developmental history and sleep habits. Demographic and treatment correlates of poor caregiver sleep were examined, and caregiver guilt and worry was tested as a moderator between child and caregiver sleep. More than half of caregivers (55.9%) reported clinically significant poor sleep and less than 40% were obtaining adequate sleep durations. Caregiver sleep was significantly related to child age at diagnosis, child sleep, and caregiver guilt and worry. Caregiver guilt and worry did not moderate the relationship between child sleep and caregiver sleep. Poor sleep is common in caregivers of children with cancer. Further research on the timing of sleep interventions and the most effective intervention targets are needed to maximize caregiver functioning during a child's cancer treatment. Targeted interventions seeking to improve caregiver sleep should be directed towards caregivers of children diagnosed in early childhood, caregivers of children with poor sleep, and caregivers with high guilt and worry.

The circadian schedule for childhood acute lymphoblastic leukemia maintenance therapy does not influence event‐free survival in the NOPHO ALL92 protocol

The event-free survival of childhood acute lymphoblastic leukemia (ALL) has been reported to be superior when oral methotrexate (MTX) and 6-mercaptopurine (6MP) maintenance therapy (MT) is administered in the evening compared to the morning. In the ALL92 MT study we prospectively registered the intake of MTX/6MP. The registration was done when blood samples for erythrocyte MTX/6MP metabolite measurements were collected, and referred to the time of intake in the period since last registration. Nine thousand one hundred ninety-five registrations in total. The administration of MTX/6MP was scored as morning, midday, or evening. Of 532 patients, 296 took their medication consistently in the evening, 129 in the evening 50.0-99.9% of the time, and 101 in the evening <50% of the time, six did not have any registrations. The circadian schedule did not differ significantly by age, sex, MTX/6MP doses, and average absolute neutrophil counts. The circadian schedule groups did differ on risk groups (P = 0.003) with fewer HR patients in the 50-99.9% group, and there was a negative correlation between percentage of time on evening schedule and average WBC (Spearman's rho -0.15; P = 0.0004). Average WBC was not associated with relapse on ALL92. In a Cox multivariate model the circadian schedule of MTX/6MP was not of prognostic significance for the risk of relapse, and the 10-year cumulative relapse risk was below 20% in all groups. An evening schedule may still be recommended based on the previous publications, but in this study morning administration of MTX and 6MP does not seem to impact EFS.

Immunogenicity of Pandemic (H1N1) 2009 Vaccine in Children with Cancer in the United Kingdom

Children with cancer have an increased susceptibility to influenza infection. The objective of this study was to assess the immunogenicity of pandemic (H1N1) 2009 vaccine in children with cancer. Children were recruited from the Royal Marsden Hospital, England, during November 2009. The vaccination schedule consisted of 2 doses of an AS03(B)-adjuvanted vaccine given at days 0 and 21. Serological analysis was performed on blood samples obtained at day 0 and day 42. The primary immunological end point was the seroconversion rate, which was defined as the proportion of subjects with an individual 4-fold increase in hemagglutination inhibition titer and a postvaccination hemagglutination inhibition titer ≥1:32. Fifty-four children with a median age of 6.3 years (range, 1.4-16.6 years) were vaccinated and had samples taken for serological analysis. Twenty-four (44.4%) of 54 children demonstrated seroconversion. Seroconversion rates were 33.3% (9 of 27) among children with acute lymphoblastic leukemia, 36.4% (4 of 11) among those with lymphoma or other leukemias, 66.7% (6 of 9) among those with brain tumors, and 71.4% (5 of 7) among those with other solid tumors. Seroconversion occurred in 4 (28.6%) of 14 children receiving acute lymphoblastic leukemia maintenance therapy. Univariate analysis showed significantly higher responses among children with solid tumors, compared with those with hematological malignancies (11 [68.8%] of 16 vs 13 [34.2%] of 38; P = .03), and among those not receiving treatment, compared with those receiving treatment (7 [87.5%] of 8 vs 17 [37.0%] of 46; P = .02). Multivariable analysis showed that age, cancer type, and lymphopenia did not influence seroconversion rates. These data suggest that this AS03(B)-adjuvanted pandemic (H1N1) 2009 vaccine can induce limited but useful protective immune responses in children with cancer.

Predicting Adverse Events in Children With Fever and Chemotherapy-Induced Neutropenia: The Prospective Multicenter SPOG 2003 FN Study

PURPOSE To develop a score predicting the risk of adverse events (AEs) in pediatric patients with cancer who experience fever and neutropenia (FN) and to evaluate its performance. PATIENTS AND METHODS Pediatric patients with cancer presenting with FN induced by nonmyeloablative chemotherapy were observed in a prospective multicenter study. A score predicting the risk of future AEs (ie, serious medical complication, microbiologically defined infection, radiologically confirmed pneumonia) was developed from a multivariate mixed logistic regression model. Its cross-validated predictive performance was compared with that of published risk prediction rules. Results An AE was reported in 122 (29%) of 423 FN episodes. In 57 episodes (13%), the first AE was known only after reassessment after 8 to 24 hours of inpatient management. Predicting AE at reassessment was better than prediction at presentation with FN. A differential leukocyte count did not increase the predictive performance. The score predicting future AE in 358 episodes without known AE at reassessment used the following four variables: preceding chemotherapy more intensive than acute lymphoblastic leukemia maintenance (weight = 4), hemoglobin > or = 90 g/L (weight = 5), leukocyte count less than 0.3 G/L (weight = 3), and platelet count less than 50 G/L (weight = 3). A score (sum of weights) > or = 9 predicted future AEs. The cross-validated performance of this score exceeded the performance of published risk prediction rules. At an overall sensitivity of 92%, 35% of the episodes were classified as low risk, with a specificity of 45% and a negative predictive value of 93%. CONCLUSION This score, based on four routinely accessible characteristics, accurately identifies pediatric patients with cancer with FN at risk for AEs after reassessment.

Oral chemotherapy in paediatric oncology in the UK: problems, perceptions and information needs of parents

To identify problems, perceptions and information needs of parents and carers regarding oral chemotherapy. Two Paediatric Oncology Centres in the UK. A semi-structured questionnaire was developed in consultation with professionals working within paediatric oncology. Questionnaires were administered in face-to-face interviews with parents of patients attending clinic appointments. Responses to questions were coded and entered into a database for descriptive and inferential analyses. Responses to open questions were coded using simple thematic analysis whereby codes and themes emerged from the data and were compared and contrasted between respondents. Findings were further validated by quotes from interviewees to open questions. Awareness and knowledge of medicines, information needs and handling procedures. Fifty-five interviews were conducted. Most interviewees viewed oral and intravenous chemotherapy as equally important and potent. Three-quarters of parents were aware of the adverse effects chemotherapy could have on them, worryingly three-quarters of the same group of parents did not use all the handling precaution methods advised by health care professionals. Knowledge of acute lymphoblastic leukaemia maintenance treatment was assessed in 47 interviewees; 31 parents were able to explain the reasons for maintenance chemotherapy. Interviewees felt well informed by the hospital and found it easy to access information they needed. The data suggest the majority of parents had a great interest in understanding the disease and treatment, with 91% using the internet to access further information. Three-quarters of parents faced some kind of difficulty when dealing with oral chemotherapy, including problems with the patient not taking the drug, technical and supply problems and problems following the drug regimen. Self-reported compliance in this study was high with 69.1% of interviewees stating they never forgot a single dose. 72.2% of interviewees used a reminder method, of which 81.6% were written reminders. This study highlights that although the support systems offered by the paediatric oncology centres were good, certain areas need improvement, specifically the manner in which parents/carers are educated and informed.

Comparison of Chemotherapy With Immunotherapy for Maintenance of Acute Lymphoblastic Leukemia in Children and Adults

Abstract Two hundred and seventeen patients, 1–50 yr old, with acute lymphoblastic leukemia in complete remission were randomized to receive a 1-yr consolidation chemotherapy of either type P, comprising 7 different drugs, or type M, consisting of methotrexate interspersed with prednisone and vincristine. Thereafter, they were randomized a second time to receive a 4-yr maintenance of either chemotherapy or immunotherapy, comprised of allogeneic blasts and bacillus Calmette- Guerin (BCG). Consolidation P caused more toxicity than consolidation M. However, comparison between the consolidation therapies P and M showed no significant difference, neither for disease-free interval nor for duration of survival. Chemotherapy showed more lethal toxicity in adults than in children. Comparison between chemotherapy (C) and immunotherapy (I) as maintenance treatment showed a significant (p = 0.016) superiority of C for disease-free interval (DFI). The difference was even more pronounced (p = 0.009) in the group with less than 8 g/dl of hemoglobin (Hb) at diagnosis before therapy. On the other hand, for patients with more than 8 g/dl Hb at diagnosis, presumably those with T- ALL, no difference in DFI was seen. No difference has been seen so far between maintenance therapies I and C concerning the duration of survival. The patients who were receiving maintenance I when they relapsed and who were consequently retreated by chemotherapy, survived longer from relapse than those patients retreated for relapse while receiving maintenance C.

Comparison of chemotherapy with immunotherapy for maintenance of acute lymphoblastic leukemia in children and adults

Two hundred and seventeen patients, 1-50 yr old, with acute lymphoblastic leukemia in complete remission were randomized to receive a 1-yr consolidation chemotherapy of either type P, comprising 7 different drugs, or type M, consisting of methotrexate interspersed with prednisone and vincristine. Thereafter, they were randomized a second time to receive a 4-yr maintenance of either chemotherapy or immunotherapy, comprised of allogeneic blasts and bacillus Calmette-Guérin (BCG). Consolidation P caused more toxicity than consolidation M. However, comparison between the consolidation therapies P and M showed no significant difference, neither for disease-free interval nor for duration of survival. Chemotherapy showed more lethal toxicity in adults than in children. Comparison between chemotherapy (C) and immunotherapy (I) as maintenance treatment showed a significant (p = 0.016) superiority of C for disease-free interval (DFI). The difference was even more pronounced (p = 0.009) in the group with less than 8 g/dl of hemoglobin (Hb) at diagnosis before therapy. On the other hand, for patients with more than 8 g/dl Hb at diagnosis, presumably those with T-ALL, no difference in DFI was seen. No difference has been seen so far between maintenance therapies I and C concerning the duration of survival. The patients who were receiving maintenance I when they relapsed and who were consequently retreated by chemotherapy, survived longer from relapse than those patients retreated for relapse while receiving maintenance C.

An evaluation of corynebacterium parvum during remission maintenance therapy in pediatric patients with acute lymphoblastic leukemia

The biologic impact and clinical toxicity of Corynebacterium parvum administered at a dose of 5 mg/M2 by intravenous or subcutaneous routes were evaluated in 18 children receiving combination chemotherapy for maintenance of acute lymphoblastic leukemia (ALL) in remission. Several nonspecific immunologic and hematologic parameters were evaluated. Patients were also monitored for changes in cutaneous sensitivity to histamine. No changes in any parameter were observed in patients after only one course of C parvum injection. However, after 6-10 courses, glass-adherent peripheral blood leukocytes of C parvum-treated patients augmented the response of PHA-stimulated autologous lymphocytes. In all nine patients studied who received C parvum injection subcutaneously for at least six months, there were significant increases in the mean bone marrow myelocyte-erythrocyte (ME) volumes compared to pretreatment values. These results suggest that periodic evaluations are desirable in patients receiving repeated administration of C parvum, since changes in immunologic and hematologic responses may be demonstrable only after several injections. In contrast to the reported experience in adults, subcutaneous C parvum administration children was not well tolerated, whereas intravenous infusion was generally well tolerated.