PEGylated Recombinant Adenosine Deaminase Maintains Detoxification and Lymphocyte Counts in Patients with ADA-SCID.

PURPOSE: Metabolic detoxification with enzyme replacement therapy (ERT) promotes immune recovery in patients with adenosine deaminase (ADA)-deficient severe combined immunodeficiency (ADA-SCID). Elapegademase is a PEGylated recombinant bovine ADA ERT developed to replace the now-discontinued bovine-derived pegademase. This study was a 1-way crossover from pegademase to elapegademase in 7 patients with ADA-SCID to assess efficacy and safety outcomes for elapegademase. METHODS: After once-weekly pegademase dosage was adjusted to achieve therapeutic metabolic detoxification and trough ADA activity, patients transitioned to a bioequivalent dose of elapegademase. Maintenance of metabolic detoxification and adequate ADA activity were evaluated periodically. RESULTS: One patient withdrew after 2 doses of an early elapegademase formulation due to injection-site pain caused by EDTA. The 6 remaining patients completed 71-216 weeks of elapegademase therapy with a formulation that did not contain EDTA. In these patients, elapegademase improved ADA activity compared with pegademase and maintained metabolic detoxification. Total lymphocyte counts increased for all completer patients from between 1.2- and 2.1-fold at the end of study compared with baseline. Elapegademase had a comparable safety profile to pegademase; no patient developed a severe infectious complication. Three patients had transient, non-neutralizing antibodies to pegademase, elapegademase, and/or polyethylene glycol ≤ 47 weeks of treatment without effect on trough plasma ADA activity or trough erythrocyte deoxyadenosine nucleotide levels. CONCLUSION: Elapegademase was safe, well tolerated, achieved stable trough plasma ADA activity with weekly dosing, was effective in maintaining metabolic detoxification, and was associated with maintenance or improvements in lymphocyte counts compared with pegademase therapy in patients with ADA-SCID.

Effect of Caspofungin vs Fluconazole Prophylaxis on Invasive Fungal Disease Among Children and Young Adults With Acute Myeloid Leukemia: A Randomized Clinical Trial.

Importance: Children, adolescents, and young adults with acute myeloid leukemia are at high risk of life-threatening invasive fungal disease with both yeasts and molds. Objective: To compare the efficacy of caspofungin vs fluconazole prophylaxis against proven or probable invasive fungal disease and invasive aspergillosis during neutropenia following acute myeloid leukemia chemotherapy. Design, Setting, and Participants: This multicenter, randomized, open-label, clinical trial enrolled patients aged 3 months to 30 years with newly diagnosed de novo, relapsed, or secondary acute myeloid leukemia being treated at 115 US and Canadian institutions (April 2011-November 2016; last follow-up June 30, 2018). Interventions: Participants were randomly assigned during the first chemotherapy cycle to prophylaxis with caspofungin (n = 257) or fluconazole (n = 260). Prophylaxis was administered during the neutropenic period following each chemotherapy cycle. Main Outcomes and Measures: The primary outcome was proven or probable invasive fungal disease as adjudicated by blinded central review. Secondary outcomes were invasive aspergillosis, empirical antifungal therapy, and overall survival. Results: The second interim efficacy analysis and an unplanned futility analysis based on 394 patients appeared to have suggested futility, so the study was closed to accrual. Among the 517 participants who were randomized (median age, 9 years [range, 0-26 years]; 44% female), 508 (98%) completed the trial. The 23 proven or probable invasive fungal disease events (6 caspofungin vs 17 fluconazole) included 14 molds, 7 yeasts, and 2 fungi not further categorized. The 5-month cumulative incidence of proven or probable invasive fungal disease was 3.1% (95% CI, 1.3%-7.0%) in the caspofungin group vs 7.2% (95% CI, 4.4%-11.8%) in the fluconazole group (overall P = .03 by log-rank test) and for cumulative incidence of proven or probable invasive aspergillosis was 0.5% (95% CI, 0.1%-3.5%) with caspofungin vs 3.1% (95% CI, 1.4%-6.9%) with fluconazole (overall P = .046 by log-rank test). No statistically significant differences in empirical antifungal therapy (71.9% caspofungin vs 69.5% fluconazole, overall P = .78 by log-rank test) or 2-year overall survival (68.8% caspofungin vs 70.8% fluconazole, overall P = .66 by log-rank test) were observed. The most common toxicities were hypokalemia (22 caspofungin vs 13 fluconazole), respiratory failure (6 caspofungin vs 9 fluconazole), and elevated alanine transaminase (4 caspofungin vs 8 fluconazole). Conclusions and Relevance: Among children, adolescents, and young adults with acute myeloid leukemia, prophylaxis with caspofungin compared with fluconazole resulted in significantly lower incidence of invasive fungal disease. The findings suggest that caspofungin may be considered for prophylaxis against invasive fungal disease, although study interpretation is limited by early termination due to an unplanned interim analysis that appeared to have suggested futility. Trial Registration: ClinicalTrials.gov Identifier: NCT01307579.

Neurofibromin interacts with the cytoplasmic Dynein Heavy Chain 1 in melanosomes of human melanocytes.

Neurofibromin (NF1) is encoded by the NF1 tumour suppressor gene. Mutations result in a disorder known as Neurofibromatosis Type 1 (NF-1), and patients are often diagnosed due to the presence of unusual pigmentary patterns that include Café au lait macules (CALMs). Little is known about how loss of NF1 results in pigmentary defects in melanocytes. We sought to identify novel NF1 interacting proteins and elucidate the molecular mechanisms underlying the pigmentary defects. The cytoplasmic Dynein Heavy Chain 1 (DHC) was found to interact with NF1 along microtubules in vesicular structures identified to be melanosomes. Our studies suggest that NF1 is involved in melanosomal localization, and that disruptions in NF1-DHC interactions may contribute to the abnormal pigmentary features commonly associated with this debilitating syndrome.

A novel neurofibromin (NF1) interaction with the leucine-rich pentatricopeptide repeat motif-containing protein links neurofibromatosis type 1 and the French Canadian variant of Leigh's syndrome in a common molecular complex.

Loss-of-function mutations and deletions in the neurofibromin tumor suppressor gene (NF1) cause neurofibromatosis type 1 (NF-1), the most common inherited syndrome of the nervous system in humans, with a birth incidence of 1:3,000. The most visible features of NF-1 are the neoplastic manifestations caused by the loss of Ras-GTPase-activating protein (Ras-GAP) activity mediated through the GAP-related domain (GRD) of neurofibromin (NF1), the protein encoded by NF1. However, the syndrome is also characterized by cognitive dysfunction and a number of developmental abnormalities. The molecular etiology of many of these nonneoplastic phenotypes remains unknown. Here we show that the tubulin-binding domain (TBD) of NF1 is a binding partner of the leucine-rich pentatricopeptide repeat motif-containing (LRPPRC) protein. These two proteins complex with Kinesin 5B, hnRNP A2, Staufen1, and Myelin Basic Protein (MBP) mRNA, likely in RNA granules. This interaction is of interest in that it links NF-1 with Leigh's syndrome, French Canadian variant (LSFC), an autosomal recessive neurodegenerative disorder that arises from mutations in the LRPPRC gene. Our findings provide clues to how loss or mutation of NF1 and LRPPRC may contribute to the manifestations of NF-1 and LSFC.

Pediatric dosing of rituximab revisited: serum concentrations in opsoclonus-myoclonus syndrome.

To longitudinally assess serum concentrations of rituximab, it was administered intravenously to 25 children with opsoclonus-myoclonus syndrome at 375 mg/m2 on each of 4 consecutive weeks with (Group I and II) or without (Group III) conventional immunotherapy. Serum rituximab levels, drawn before and after each infusion and at later intervals, were analyzed by enzyme-linked immunosorbent assay. Rituximab concentration increased stepwise with each infusion, dropping by the next infusion, thereby forming 4 discrete peaks (Cmax) and troughs (Cmin). It then fell precipitously to trace levels at 4 months. However, Cmax and Cmin curves differed significantly between groups. Compared with the youngest children (Group I), the oldest (Group III) had a 34% lower rituximab concentration at the fourth infusion, 45% less IgM depletion 1 month later, and received 20% less rituximab when the dose was recalculated as mg/kg. Serum IgM and rituximab levels were negatively correlated. Peak rituximab concentration did not correlate with adrenocorticotropic hormone dose. These results indicate that the degree of serum IgM depletion is a useful indicator for rituximab dose equivalency in children of different ages. They also suggest that pediatric rituximab dosing should be based on body weight, not surface area. (ClinicalTrials.gov NCT00244361).

Invasive mould infections: a multi-disciplinary update.

Systemic fungal infections remain a significant cause of mortality in neutropenic and immunocompromised patients, despite advances in their diagnosis and treatment. The incidence of such infections is rising due to the use of intensive chemotherapy regimens in patients with solid tumours or haematological cancers, the increasing numbers of allogeneic haematopoietic stem cell and solid organ transplants, and the use of potent immunosuppressive therapy in patients with autoimmune disorders. In addition, the epidemiology of systemic fungal infections is changing, with atypical species such as Aspergillus terreus and zygomycetes becoming more common. Treatment has traditionally focused on empirical therapy, but targeted pre-emptive therapy in high-risk patients and prophylactic antifungal treatment are increasingly being adopted. New treatments, including lipid formulations of amphotericin B, second-generation broad-spectrum azoles, and echinocandins, offer effective antifungal activity with improved tolerability compared with older agents; the potential impact of these treatments is reflected in their inclusion in current treatment and prophylaxis guidelines. New treatment strategies, such as aerosolized lipid formulations of amphotericin B, may also reduce the burden of mortality associated with systemic fungal infections. The challenge is to identify ways of coupling potentially effective treatments with early and reliable identification of patients at highest risk of infection.

A study of rituximab and ifosfamide, carboplatin, and etoposide chemotherapy in children with recurrent/refractory B-cell (CD20+) non-Hodgkin lymphoma and mature B-cell acute lymphoblastic leukemia: a report from the Children's Oncology Group.

BACKGROUND: To estimate the response rate and therapy related toxicities of the anti-CD20 monoclonal antibody rituximab when combined with chemotherapy including ifosfamide, carboplatin, and etoposide (ICE) in patients with relapsed and refractory B-cell non-Hodgkin lymphoma and mature B-cell acute lymphoblastic leukemia (B-ALL). METHODS: Patients received rituximab and ICE for 1-3 cycles, depending upon response. Rituximab (375 mg/m(2)) was given on day 1 and 3 of each cycle (day 1 only for cycle 3), with ifosfamide (3,000 mg/m(2)) and etoposide (100 mg/m(2)) given on days 3, 4, and 5 and carboplatin (635 mg/m(2)) given on day 3 only. RESULTS: Twenty-one patients were enrolled, of whom 20 were eligible and evaluable. Although hematologic toxicities were common, only one patient was removed from study due to prolonged myelosuppression. Toxicities related to infusions of rituximab were frequent but manageable. Of the six eligible patients with diffuse large B-cell lymphoma, three achieved complete remission (CR), one had stable disease (SD), and two had progressive disease (PD). Of the 14 eligible patients with Burkitt lymphoma and B-ALL, there were four complete responses (CR), five partial responses (PR), one SD, and four with PD. Thus, the CR/PR rate for the entire group was 12/20 (60%). Following completion of protocol therapy six patients were able to proceed to consolidation with high-dose therapy and stem cell rescue. CONCLUSIONS: The combination of rituximab and ICE chemotherapy was associated with an encouraging objective response (OR) rate and an acceptable toxicity profile.

Proteomics: present and future implications in neuro-oncology.

PROTEOMICS, IN ITS broadest mandate, is the study of proteins and their functions. As the "workhorses" of the genome, proteins govern normal cellular structure and function. Protein function is not just a reflection of its expression level; it is also the cumulative result of many post-transcriptional (splicing) and post-translational events that together determine cellular localization, interactions, and longevity. The composition and variability of the proteome is vastly more complex than the corresponding genome. It is this proteome variation that helps define an organism and the unique characteristics that separate one individual from another. Aberrations in protein function, which alter normal cellular structure and function, are the ultimate basis of disease, including cancer. Therefore, an understanding of protein networks through a systems biology approach of proteomics is necessary to understand normal and abnormal cellular function, with the goal of performing rational therapeutic interventions. In this review, we focus on two emerging proteomic technologies: mass spectrometry and bioluminescence resonance energy transfer. In addition to reviewing the principles and potential utilization of these two techniques, we highlight their application in neuro-oncology research.

Chronic immune thrombocytopenic purpura in children: assessment of rituximab treatment.

OBJECTIVES: This study examined the efficacy and safety of rituximab in children with chronic immune thrombocytopenic purpura. STUDY DESIGN: Twenty-four patients, 2 to 19 years of age, with platelet counts <30,000/mcL (microliter 2), received 375 mg/m 2 rituximab in 4 weekly doses. Platelet response was characterized as complete (CR) if a count >150,000/mcL was achieved; partial (PR) if 50,000 to 150,000/mcL; minimal (MR) if the count increased by >20,000/mcL to a peak count >30,000/mcL but <50,000/mcL; or no response (NR). RESULTS: Fifteen of 24 patients (63%) achieved a CR lasting 4 to 30 months, 9 of which are ongoing. Two had PRs lasting 4 and 6 months; 2 had MRs lasting 5 and 8 months, and 5 did not respond. Pruritus, urticaria, and throat tightness (but no respiratory distress) occurred with the first infusion in a small number of children. Three patients had serum sickness after the first, second, and third infusions, respectively. No increased frequency or severity of infections was seen, although immunoglobulin levels decreased to below the normal range in 6 of 14 cases. CONCLUSIONS: Rituximab may be a useful treatment for chronic immune thrombocytopenic purpura in children with a >50% CR rate lasting an average of 13 months, with 9 of 15 CRs ongoing (8 lasted 6 months or longer). There was no substantial toxicity other than transient serum sickness.

Efficacy and safety of amphotericin B lipid complex in 548 children and adolescents with invasive fungal infections.

BACKGROUND: The safety and efficacy of amphotericin B lipid complex injection (ABELCET; Enzon Pharmaceuticals, Piscataway, NJ) was assessed in 548 children and adolescents 0-20 years of age who were enrolled in the Collaborative Exchange of Antifungal Research (CLEAR) registry. To our knowledge, this is the largest series of pediatric patients treated for invasive mycoses with a single agent. All patients had cancer or had received a bone marrow, cord blood or solid organ transplant and were treated with amphotericin B lipid complex for documented or suspected fungal infection. METHODS: The CLEAR database was queried for all patients 0-20 years of age from 1996 to 2000. Data gathered included demographic variables, underlying disease type, reasons for the use of amphotericin B lipid complex injection, dosing information, clinical response and renal effects. RESULTS: Most patients were either intolerant of or refractory to conventional antifungal therapy, and almost one-half were neutropenic at treatment onset. Of the 548 patients, 300 (54.7%) were transplant recipients and 393 (71.7%) had received one or more concomitant nephrotoxins. Candida and Aspergillus were the most commonly isolated species in patients with proven or probable infections. Response data were evaluable for 255 of the 285 patients with documented single or multiple pathogens. A complete (cured) or partial (improved) response was achieved in 54.9% of patients, with an additional 16.9% of patients having a stable outcome. Among patients with proven Aspergillus infection, the response rates (cured + improved) were 40.5 and 37.5% in transplant and nontransplant patients, respectively. When stable responses were added, the response rates were 48.6 and 71.9%, respectively. There were few clinically significant deleterious effects on renal function. There was no significant difference between the rates of new hemodialysis versus baseline hemodialysis. Elevations in serum creatinine of >1.5 x baseline and >2.5 x baseline values were seen in 24.8 and 8.8% of all patients, respectively. CONCLUSIONS: The safety and efficacy data from this large pediatric population support the use of amphotericin B lipid complex injection for treatment of invasive fungal infections in immunocompromised children and adolescents, including the high risk subgroup of transplant recipients. The overall response rate and safety profile in pediatric patients who were largely intolerant of or refractory to conventional antifungal therapy were consistent with earlier reported findings of smaller trials.

Intraindividual variability in busulfan pharmacokinetics in patients undergoing a bone marrow transplant: assessment of a test dose and first dose strategy.

Busulfan systemic exposure correlates with regimen-related toxicity, engraftment and relapse in select patients receiving high-dose oral busulfan (HD-BU) (1 mg/kg dose or 40 mg/m dose every 6 h for 16 doses) as part of a preparative regimen for bone marrow transplantation. Therapeutic drug monitoring is frequently conducted after the first HD-BU dose in order to determine necessary dose adjustments. Limitations with this method include the need for rapid determination of busulfan plasma concentration and difficulties with estimating apparent oral clearance in patients who exhibit delayed absorption of HD-BU. This pharmacokinetic study was conducted to evaluate the ability of the apparent oral clearance obtained after administering a lower (0.25 mg/kg) test dose and the traditional (1 mg/kg) first dose to predict the dose required to achieve a desired area under the concentration-time curve (AUC) at steady-state (13th dose). In addition, the pharmacokinetic parameters of test, first and 13th dose were compared to assess intrasubject variability. Twenty-nine patients received a test dose of oral busulfan (0.25 mg/kg) the day immediately prior to initiation of HD-BU. Busulfan serum concentrations were measured following the test, first and 13th doses using gas chromatography with electron capture detection. The AUC and apparent oral clearance were calculated using non-compartmental analysis. Therapeutic drug monitoring following the first dose of HD-BU was conducted for clinical purposes in six patients, and dose adjustment between the first and 13th dose occurred in only two patients. The dose-corrected test dose and first dose AUC and apparent oral clearance were not bioequivalent (two one-sided t-tests, +/-20%). The first dose and 13th dose AUC and apparent oral clearance were also not bioequivalent. Six of the 29 patients receiving HD-BU dose based on weight (1 mg/kg) would have achieved a steady-state AUC of 3600-5400 ng x h/ml, a frequently used target AUC, as compared to eight and 13 patients if their dose was based on the apparent oral clearance following the test dose and first dose HD-BU, respectively. Monitoring busulfan concentrations after a test dose or a first dose provides a better estimate of the dose needed to achieve the target steady-state AUC as compared to traditional weight-based dosing. However, significant intraindividual variability exists in the apparent oral clearance of busulfan and follow-up therapeutic drug monitoring is recommended particularly if the desired target AUC range is narrow.

Autologous transplantation for diffuse aggressive non-Hodgkin lymphoma in first relapse or second remission.

We evaluated the results of high-dose chemotherapy and autologous hematopoietic stem cell transplantation in patients with diffuse aggressive non-Hodgkin lymphoma (NHL) in first relapse (Rel 1) or second complete remission (CR 2). Data were evaluated from the Autologous Blood and Marrow Transplant Registry on 429 patients with diffuse aggressive NHL who underwent transplantation in Rel 1 or CR 2. Transplantations were performed between 1989 and 1996 and were reported to the Autologous Blood and Marrow Transplant Registry by 93 centers in North and South America. The probability of 3-year survival was 44% (95% confidence interval [CI], 33%-55%). The probability at 3 years of progression-free survival was 31% (95% CI, 27%-36%). Patients who underwent transplantation in CR 2 had a 3-year probability of progression-free survival of 38% (95% CI, 30%-46%) compared with 28% (95% CI, 22%-33%) for those who were not in remission at the time of transplantation (P <.001). In multivariate analysis, chemotherapy resistance, increased lactic dehydrogenase at diagnosis, an interval of <12 months from diagnosis to relapse, age >or=40 years, and use of myeloid growth factors to accelerate posttransplantation bone marrow recovery were adverse predictors of survival. High-dose chemotherapy and autologous hematopoietic stem cell transplantation for patients with diffuse aggressive NHL in CR 2 or Rel 1 resulted in better outcome for patients with chemotherapy-sensitive disease, longer relapse-free intervals, and age <40 years. Exposure to myeloid growth factors to accelerate recovery for recipients of bone marrow grafts may increase the risk of disease progression or death.

An expanded phase I/II trial of cyclophosphamide, etoposide, and carboplatin plus total body irradiation with autologous marrow or stem cell support for patients with hematologic malignancies.

The major cause for failure of autologous stem cell transplantation for hematologic malignancies is the risk of recurrent disease. As a result, new treatment regimens that include novel agents or combinations of agents and approaches are needed. The current report describes a large Phase I/II, single-center trial that includes 60 patients with a variety of hematologic malignancies. These patients received a fixed dose of carboplatin (1 g/m(2)/d x 72 hours by CI) etoposide (600 mg/m(2)/d x 3 days) and cyclophosphamide (2 g/m(2)/d x 3 days), plus escalating doses of total body irradiation (TBI) (at 1000, 1200, and 1295 cGy) over 3 days. Eleven patients received infusion of autologous marrow, 32 received peripheral blood stem cells, and 17 patients received both. The maximum tolerated dose of this regimen was a radiation dose of 1200 cGy given in 200-cGy fractions BID x 3 days. The dose-limiting toxicity was mucositis, with 97% of patients requiring narcotic analgesia for mouth pain. Overall treatment-related mortality was 6.7%, with 2 of the 4 deaths occurring in a group of 9 patients aged 60 and older. Responses were seen in all patient groups, but the most encouraging outcomes were seen in 12 patients with high-risk or advanced acute myelocytic lymphoma (AML), 7 of whom remain alive and free of disease beyond 5 years. This regimen is intensive and causes considerable mucositis but is otherwise well tolerated and has demonstrated activity in a number of hematologic malignancies, especially AML.