Erin Morris

Burkitt's and Burkitt‐like lymphoma in children and adolescents: a review of the Children's Cancer Group Experience

Summary. Historically, the survival of children and adolescents with Burkitts and Burkitt‐like lymphoma had been poor. Recently, short and intensive chemotherapy appears to have improved disease outcome. We therefore reviewed the results of four successive Childrens Cancer Group trials conducted on 470 children with disseminated Burkitts and Burkitt‐like lymphoma. Of the patients studied, the median age was 8 years (0–21 years), the male:female ratio was 4:1, 58% had lactate dehydrogenase (LDH) ≥ 500 IU/l, 23% had M2 or M3 bone marrow (BM), and 12% demonstrated central nervous system involvement. In a multivariate analysis, the 4‐year event‐free survival (EFS) in patients ≥ 15‐years‐old compared with < 15‐year‐old was 34 ± 7 versus 59 ± 2% (P < 0·05), the 4‐year EFS of M2/M3 compared with M1 BM was 38 ± 5 versus 63 ± 3% (P < 0·001), and the 4‐year EFS with LDH ≥ 500 IU/l compared with LDH < 500 IU/l was 49 ± 3 versus 71 ± 4% (P < 0·001). Furthermore, patients treated on the most recent protocol, which was short and more intensive, had a significantly improved survival compared with those on previous trials (4‐year EFS 80 ± 6 versus 54 ± 2%, P < 0·001). In summary, the outcome for childhood Burkitts and Burkitt‐like lymphoma has recently improved with the use of short and intensive B‐cell non‐Hodgkins lymphoma‐directed therapy.

Adolescent non-Hodgkin lymphoma and Hodgkin lymphoma: state of the science.

Lymphoma is the most common malignancy among adolescents, accounting for >25% of newly diagnosed cancers in the 15–19 year age group. Hodgkin lymphoma (HL) accounts for the majority (two‐thirds) of cases, while the remainder of patients have one of four subtypes of non‐Hodgkin lymphoma (NHL): diffuse large B‐cell lymphoma (DLBCL) including primary mediastinal B‐cell lymphoma (PMBL), Burkitt lymphoma (BL), lymphoblastic lymphoma (LL) or anaplastic large cell lymphoma (ALCL). Epidemiology, histology, treatment and outcome differ between HL and NHL, as well as among the various subtypes of NHL. Adolescent lymphoma is particularly interesting because it often shares features with both childhood and adult lymphoma. As medical oncologists and paediatric oncologists often follow divergent treatment plans, disagreements may arise between practitioners as to how best treat the adolescent group. Additional complicating factors associated with the adolescent years, such as lack of insurance, issues pertaining to body image, and concerns about fertility, can also hinder prompt, appropriate medical management. This review details the complexities associated with the diagnosis and treatment of adolescent lymphoma and updates the state of the science, with particular emphasis on epidemiology, diagnosis, and proper management of HL and the various subtypes of NHL.

An Age-Dependent Pharmacokinetic Study of Intravenous and Oral Mycophenolate Mofetil in Combination with Tacrolimus for GVHD Prophylaxis in Pediatric Allogeneic Stem Cell Transplantation Recipients

Acute graft-versus-host disease (aGVHD) still remains a major limiting factor following allogeneic stem cell transplantation (AlloSCT) in pediatric recipients. Mycophenolate mofetil (MMF), an uncompetitive selective inhibitor of inosine monophosphate dehydrogenase, is a new immunosuppressant agent without major mucosal, hepatic, or renal toxicity compared to other prophylactic aGVHD immunosuppressant drugs. Although there has been an extensive pharmacokinetic (PK) experience with MMF administration following solid organ transplantation in children, there is a paucity of PK data following its use in pediatric AlloSCT recipients. We investigated the safety and PK of MMF as GVHD prophylaxis following intravenous (i.v.) and oral (p.o.) administration (900 mg/m(2) every 6 hours) in conjunction with tacrolimus, after myeloablative (MA) and nonmyeloablative (NMA) conditioning and AlloSCT in 3 distinct age groups of pediatric AlloSCT recipients (0-6 years, 6-12 years, and 12-16 years). Mycophenolic acid (MPA) in plasma samples was measured either by high-performance liquid chromatography (HPLC) or liquid chromatography/mass spectrometry (LC/MS/MS) as we have previously described. Plasma samples were obtained at baseline and at 0.5, 1, 2, 3, 4, and 6 hours after i.v. dosing on days +1, +7, +14, and at 2 time points between day +45 and +100 after p.o. administration post AlloSCT. MPA PK analysis included AUC (0-6 hours), C(max), T(max), C(ss), V(ss), C trough (C(0)), CL, and T((1/2).) Thirty-eight patients, with a median age of 8 years (0.33-16 years), 20/18 M:F ratio, 21/17 malignant/nonmalignant disease, 17/21 MA: NMA conditioning, 16 of 22 related/unrelated allografts. Median time to myeloid and platelet engraftment was 18 and 31 days, respectively. Mean donor chimerism on day +60 and +100 was 83% and 90%, respectively. Probability of developing aGVHD grade II-IV and extensive chronic GVHD (cGVHD) was 54% and 34%, respectively. There was significant intra- and interpatient MMF PK variability. There was a significant increase in i.v. MPA area under the curve (AUC)(0-6 hour) and C(max) (P < .0003) and a significant decrease in CL(ss) (P < .002) and V(ss) (P < .001) on day +14 versus day +7. Children <12 years of age had a significant increase in i.v. MPA T(max) (P = .01), V(ss) (P = .028), and CL(ss) (P < .001) compared to the older age group. There was a trend in increased i.v. MPA CL(ss) following MA versus NMA conditioning (P < .054); i.v. and p.o. MMF administration (900 mg/m(2) every 6 hours) in combination with tacrolimus was well tolerated in pediatric AlloSCT recipients. There was a significant increase in MPA exposure on day +14 versus day +7, suggesting improved enterohepatic recirculation at day +14 post-AlloSCT. Children <12 years of age appear to have a significantly different MPA PK profile compared to older children and adolescents and may require more frequent dosing.

Long-term follow-up of short intensive multiagent chemotherapy without high-dose methotrexate (‘Orange’) in children with advanced non-lymphoblastic non-Hodgkin's lymphoma: a Children's Cancer Group Report

Despite prolonged therapy (18 months), children with advanced non-lymphoblastic, non-Hodgkins lymphoma (NHL) treated on previous Childrens Cancer Group (CCG) trials achieved less than a 60% 5-year event-free survival (EFS). In this study we piloted a shorter but more intensive protocol (‘Orange’) to determine the feasibility, safety, and efficacy of this alternative treatment approach. Thirty-nine children received a CHOP-based induction, etoposide/ifosfamide consolidation, DECAL (dexamethasone, etoposide, cisplatin, cytosine arabinoside (Ara-C) and L-asparaginase) intensification, and either one or two similar but less intense maintenance courses. Patients were stratified to standard-risk (5 months) vs high-risk (7 months) treatment. High risk was defined as either bone marrow disease, CNS disease, mediastinal mass ⩾ one-third thoracic diameter at T5 and/or LDH ⩾2 times institutional upper limits of normal. All other patients were considered to be standard risk. Results were compared with the previous CCG NHL study (CCG-503). Sixteen and 23 patients were considered standard- vs high-risk, respectively. The 5-year EFS and overall survival (OS) were 77 ± 7% and 80 ± 7%, respectively. The 5-year EFS and OS were significantly better in the standard- vshigh-risk subgroups (100% vs 61 ± 11%) (P < 0.003) and (100% vs 65 ± 11%) (P < 0.01), respectively. Lactate dehydrogenase (LDH) ⩾2 × normal (NL) was associated with significantly poorer outcomes (LDH ⩾2 × NL vs <2 × NL) (5-year EFS: 55 ± 12% vs 100%) (P < 0.0004). This CCG hybrid regimen, ‘Orange’, of short and more intensive therapy resulted in a significant improvement in outcomes compared with the previous CCG trial of more prolonged but less intense therapy. This regimen that deletes high-dose methotrexate, if confirmed in a larger trial, could be considered as an alternative treatment approach in children without high tumor burdens (LDH <2 × NL) and Murphy stage III disease.

Reduced intensity and non-myeloablative allogeneic stem cell transplantation in children and adolescents with malignant and non-malignant diseases.

Allogeneic hematopoietic stem cell transplant (AlloSCT) from related or unrelated histocompatible donors has been well established as potentially curative therapy for children and adolescents with selected malignant and non‐malignant diseases. In the malignant setting non‐myeloablative (NMA)/reduced intensity (RI)‐AlloSCT eradicates malignant cells through a graft versus malignancy effect provided by alloreactive donor T‐lymphocytes and/or natural killer cells. In patients with non‐malignant diseases NMA/RI AlloSCT provides enough immunosuppression to promote engraftment and correct underlying genetic defects. In children, myeloablative AlloSCT is not only associated with acute short‐term toxicities but also long‐term late complications such as growth retardation, infertility, and secondary malignancies. NMA/RI‐AlloSCT in children may be associated with reduction in use of blood products, risk of infections, transplant‐related mortality, and length of hospitalization. Despite the success of RI‐AlloSCT in adults, large prospective and/or randomized multicenter studies are necessary in children and adolescent recipients to define the appropriate patient population, optimal conditioning regimens, cost‐benefits, survival and differences in short‐term and long‐term effects compared to conventional myeloablative conditioning. Pediatr Blood Cancer 2008;50:1–8.

Dysregulation of Expression of Immunoregulatory and Cytokine Genes and Its Association with the Immaturity in Neonatal Phagocytic and Cellular Immunity

Background: Innate and adaptive immunity is comprised of cellular and humoral factors that provide rapid protection against microbial invasion. However, immaturity of innate and adaptive immune responses in the perinatal period predisposes the neonate to increased infectious morbidity and mortality from a variety of organisms. Objectives: To elucidate dysregulation of expression of various immunoregulatory and cytokine genes and its association with the immaturity in neonatal phagocytic cellular immunity. Methods: Comparison of protein production and mRNA of granulocyte macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-12, IL-15 and IL-18 in adult peripheral blood (APB) mononuclear cells (MNC) and cord blood (CB) MNC was studied. Effects of hematopoietic growth factors (HGFs, GM-CSF, M-CSF, G-CSF, IL-11) were studied in vivo in rats as well as randomized controlled studies conducted in neonates. Oligonucleotide microarrays were used to study gene expression patterns of activated CB and APB monocytes and dendritic cells. Results and Conclusions: We demonstrated dysregulation of various immunoregulatory and cytokine genes in CB MNC. This dysregulation may in part explain the immaturity of neonatal cell-mediated immunity. There are probably various dysregulated cytokines yet to be discovered. Biological agents such as IL-2, IL-12, IL-11 and/or IL-18 alone or in combination with HGFs should be considered for future studies to identify new approaches to enhance neonatal host defense, and thereby decrease the incidence of neonatal sepsis and the consequent high risk of morbidity and mortality.

A comparison of immune reconstitution and graft-versus-host disease following myeloablative conditioning versus reduced toxicity conditioning and umbilical cord blood transplantation in paediatric recipients

Immune reconstitution appears to be delayed following myeloablative conditioning (MAC) and umbilical cord blood transplantation (UCBT) in paediatric recipients. Although reduced toxicity conditioning (RTC) versus MAC prior to allogeneic stem cell transplantation is associated with decreased transplant‐related mortality, the effects of RTC versus MAC prior to UCBT on immune reconstitution and risk of graft‐versus‐host disease (GVHD) are unknown. In 88 consecutive paediatric recipients of UCBT, we assessed immune cell recovery and immunoglobulin reconstitution at days +100, 180 and 365 and analysed risk factors associated with acute and chronic GVHD. Immune cell subset recovery, immunoglobulin reconstitution, and the incidence of opportunistic infections did not differ significantly between MAC versus RTC groups. In a Cox model, MAC versus RTC recipients had significantly higher risk of grade II–IV acute GVHD [Hazard Ratio (HR) 6·1, P = 0·002] as did recipients of 4/6 vs. 5–6/6 HLA‐matched UCBT (HR 3·1, P = 0·03), who also had significantly increased risk of chronic GVHD (HR 18·5, P = 0·04). In multivariate analyses, MAC versus RTC was furthermore associated with significantly increased transplant‐related (Odds Ratio 26·8, P = 0·008) and overall mortality (HR = 4·1, P = 0·0001). The use of adoptive cellular immunotherapy to accelerate immune reconstitution and prevent and treat opportunistic infections and malignant relapse following UCBT warrants further investigation.

Human natural killer cells in health and disease

Natural killer (NK) cells are an essential component of the innate immune system and play a critical role in tumor immune surveillance. NK cells express their own repertoire of receptors (NKRs) that bind to major histocompatibility class I or class I‐like molecules. The balance of signals from stimulation or inhibition of NKRs determines the ability of NK cells to lyse specific targets. In haploidentical stem cell transplantation with purified stem cells, NK cell alloreactivity (killer immunoglobulin‐like receptor [KIR] mismatch) has been demonstrated to reduce the risk of relapse in acute myeloid leukemia. There is a need for adequately powered prospective randomized studies to determine the usefulness of NK cells as adoptive immunotherapy, optimal NK cell doses and timing of administration. Further studies are required to determine optimal selection of donors and recipients, both on NKR matching/mismatching, undergoing haploidentical and unrelated hematopoetic stem cell transplantation. Pediatr Blood Cancer 2007;49:615–623.

Minimal disease assessment in the treatment of children and adolescents with intermediate-risk (Stage III/IV) B-cell non-Hodgkin lymphoma: a children’s oncology group report

Children/adolescents with mature B‐cell non‐Hodgkin lymphoma (B‐NHL) have an excellent prognosis but relapses still occur. While chromosomal aberrations and/or clonal immunoglobulin (Ig) gene rearrangements may indicate risk of failure, a more universal approach was developed to detect minimal disease (MD). Children/adolescents with intermediate‐risk B‐NHL were treated with French‐British‐American/Lymphome Malins de Burkitt 96 (FAB/LMB96) B4 modified chemotherapy and rituximab. Specimens from diagnosis, end of induction (EOI), and end of therapy (EOT) were assayed for MD. Initial specimens were screened for IGHV family usage with primer pools followed by individual primers to identify MD. Thirty‐two diagnostic/staging specimens screened positive with primer pools and unique IGHV family primers were identified. Two patients relapsed; first relapse (4 months from diagnosis) was MD‐positive at EOI, the second (36 months from diagnosis) was MD‐positive at EOT. At EOI, recurrent rates were similar between the MRD‐positive and MRD‐negative patients (P = 0·40). At EOT, only 13/32 patients had MRD data available with one relapse in the MRD‐positive group and no recurrences in the MRD‐negative group (P = 0·077). The study demonstrated molecular‐disseminated disease in which IgIGHV primer pools could be used to assess MD. This feasibility study supports future investigations to assess the validity and significance of MD screening in a larger cohort of patients with intermediate‐risk mature B‐NHL.

Sequential administration of sargramostim and filgrastim in pediatric allogeneic stem cell transplantation recipients undergoing myeloablative conditioning

Abstract: G‐CSF and GM‐CSF both hasten myeloid engraftment post‐MA‐alloSCT; however, GM‐CSF is earlier acting and less expensive. The objective was to evaluate efficacy/safety of sequential administration of GM‐CSF followed by G‐CSF in children post‐MA‐alloSCT. From January 2001 to June 2005, 31 children received 32 MA‐alloSCT: mean age 6.65 yr; MRD BM or PBSC vs. related or unrelated UCB 11:21; malignant vs. non‐malignant disorders 22:10. GM‐CSF (250 μg/m2 IV QD) began on day of stem cell infusion. GM‐CSF was switched to G‐CSF (10 μg/kg IV QD) when WBC ≥ 300/mm3 × 2 days. G‐CSF continued until ANC ≥ 2500/mm3 × 2 days, then tapered to maintain ANC ≥ 1000/mm3. Median time to myeloid engraftment (ANC ≥ 500/mm3 × 3 days) was 17 days [13 days vs. 24 days, MRD BM/PBSC vs. UCB (p < 0.0001)], occurring at a median time of two days after switch to G‐CSF. Clinically relevant adverse events were bone pain (n = 8) and large pleural effusion (n = 1). It was estimated that sequential GM‐CSF/G‐CSF was cost‐effective compared with G‐CSF alone [cost‐savings of