Clofarabine monotherapy in aggressive, relapsed and refractory Langerhans cell histiocytosis.

Over 50% of patients with systemic LCH are not cured with front-line therapies, and data to guide salvage options are limited. We describe 58 patients with LCH who were treated with clofarabine. Clofarabine monotherapy was active against LCH in this cohort, including heavily pretreated patients with a systemic objective response rate of 92.6%, higher in children (93.8%) than adults (83.3%). BRAFV600E+ variant allele frequency in peripheral blood is correlated with clinical responses. Prospective multicentre trials are warranted to determine optimal dosing, long-term efficacy, late toxicities, relative cost and patient-reported outcomes of clofarabine compared to alternative LCH salvage therapy strategies.

Safety, pharmacokinetics, and pharmacodynamics of panobinostat in children, adolescents, and young adults with relapsed acute myeloid leukemia.

BACKGROUND: Novel therapies are urgently needed for pediatric patients with relapsed acute myeloid leukemia (AML). METHODS: To determine whether the histone deacetylase inhibitor panobinostat could be safely given in combination with intensive chemotherapy, a phase 1 trial was performed in which 17 pediatric patients with relapsed or refractory AML received panobinostat (10, 15, or 20 mg/m2 ) before and in combination with fludarabine and cytarabine. RESULTS: All dose levels were tolerated, with no dose-limiting toxicities observed at any dose level. Pharmacokinetic studies demonstrated that exposure to panobinostat was proportional to the dose given, with no associations between pharmacokinetic parameters and age, weight, or body surface area. Among the 9 patients who had sufficient (>2%) circulating blasts on which histone acetylation studies could be performed, 7 demonstrated at least 1.5-fold increases in acetylation. Although no patients had a decrease in circulating blasts after single-agent panobinostat, 8 of the 17 patients (47%), including 5 of the 6 patients treated at dose level 3, achieved complete remission. Among the 8 complete responders, 6 (75%) attained negative minimal residual disease status. CONCLUSIONS: Panobinostat can be safely administered with chemotherapy and results in increased blast histone acetylation. This suggests that it should be further studied in AML.

Acute Megakaryoblastic Leukemia with Trisomy 21 and Tetrasomy 21 Clones in a Phenotypically Normal Child with Mosaic Trisomy 21.

Pediatric acute megakaryoblastic leukemia (AMKL) is a rare subtype of acute myeloid leukemia (AML) that may be divided into two subgroups: (1) Down syndrome- (DS-) related AMKL which generally has a favorable prognosis and (2) non-DS-related AMKL which generally has a poorer outcome. We report a phenotypically normal child with AMKL with trisomy 21 (T21) and tetrasomy 21 clones. Subsequently, she was diagnosed with mosaic T21. She underwent reduced-intensity therapy with good outcome. We review the literature regarding AMKL-associated cytogenetic abnormalities and AMKL in association with DS. We suggest evaluation for mosaic T21 in phenotypically normal pediatric patients with T21-positive AML.

Participation in pediatric oncology research protocols: Racial/ethnic, language and age-based disparities.

BACKGROUND: Survival rates in pediatric oncology have improved dramatically, in part due to high patient participation in clinical trials. Although racial/ethnic inequalities in clinical trial participation have been reported in adults, pediatric data and studies comparing participation rates by socio-demographic characteristics are scarce. The goal of this study was to assess differences in research protocol participation for childhood cancer by age, sex, race/ethnicity, parental language, cancer type, and insurance status. PROCEDURE: Data on enrollment in any protocol, biospecimen, or therapeutic protocols were collected and analyzed for newly diagnosed pediatric patients with cancer from 2008-2012 at Rady Children's Hospital. RESULTS: Among the 353 patients included in the analysis, 304 (86.1%) were enrolled in any protocol. Enrollment in biospecimen and therapeutic protocols was 84.2% (261/310) and 81.1% (206/254), respectively. Logistic regression analyzes revealed significant enrollment underrepresentation in any protocol for Hispanics compared to Non-Hispanic whites (81% vs. 91%; Odds Ratio [OR], 0.43; 95% Confidence Interval [CI], 0.21-0.90; P = 0.021) and among children of Spanish-speaking vs. English-speaking parents (78% vs. 89%; OR, 0.45; 95%CI, 0.23-0.87; P = 0.016). Compared to patients aged 0-4 years, significant underrepresentation was also found among patients 15-21 years old (92% vs.72%; OR, 0.21; 95% CI, 0.09-0.48; P < 0.001). Similar trends were observed when analyzing enrollment in biospecimen and therapeutic protocols separately. CONCLUSIONS: There was significant underrepresentation in protocol participation for Hispanics, children of Spanish-speaking parents, and patients ages 15-21. Research is needed to understand barriers to research participation among these groups underrepresented in pediatric oncology clinical trials.

Insulin infusion to treat severe hypertriglyceridemia associated with pegaspargase therapy: a case report.

We describe a pediatric patient with acute leukemia who developed an uncommon but significant metabolic consequence of pegaspargase therapy-severe hypertriglyceridemia (hyperTG). We also relate our experience with continuous insulin infusion treatment for pegaspargase-induced hyperTG. This treatment approach led to a decrease in triglycerides from 4640 mg/dL on admission to 522 mg/dL at discharge 9 days later. Genetic testing revealed that our patient was an apolipoprotein E 3/4 heterozygote. Our review of the literature suggests that apolipoprotein E polymorphism may influence the development of hyperlipidemia in acute lymphoblastic leukemia patients receiving asparaginase therapy and may identify patients at high risk for developing asparaginase-induced hyperTG.

Methemoglobinemia associated with dapsone therapy in a child with pneumonia and chronic immune thrombocytopenic purpura.

This report describes a case of methemoglobinemia in association with dapsone therapy. The patient, an immunocompromised child with chronic immune thrombocytopenic purpura, presented with fever, cough, perioral cyanosis, bilateral lower lobe rales, and low O2 saturation by pulse oximetry (89%). His medications included prednisone and rituximab for chronic immune thrombocytopenic purpura, and dapsone for Pneumocystis carinii pneumonia prophylaxis. Because of his lack of dyspnea and tachypnea, and the temporal association of his perioral cyanosis with the initiation of dapsone therapy, a methemoglobin (MetHb) level was obtained and found to be elevated at 9.6%. The authors discuss the mechanism and treatment of methemoglobinemia secondary to dapsone. They also stress the importance of monitoring for signs and symptoms of methemoglobinemia in immunocompromised patients on dapsone therapy for P. carinii pneumonia prophylaxis.

Thrombocytopenia and severe hyperbilirubinemia in the neonatal period secondary to congenital thrombotic thrombocytopenic purpura and ADAMTS13 deficiency.

Congenital thrombotic thrombocytopenic purpura (TTP) is an inherited form of TTP due to the deficiency of von Willebrand factor (vWF) cleaving protease ADAMTS13. The authors describe two children with congenital TTP who presented with thrombocytopenia, hemolytic anemia, elevated LDH levels, and schistocytes on peripheral blood smear. In both children, the diagnosis of the disease was delayed despite neonatal histories significant for thrombocytopenia, anemia, and severe hyperbilirubinemia. Severely decreased ADAMTS13 activity (<0.1 U/mL), the absence of an inhibitor to the protease, and partial deficiency found in the parents confirmed the diagnosis of congenital TTP. The authors suggest that congenital TTP should be considered in the differential diagnosis for newborns presenting with severe hyperbilirubinemia, anemia, and thrombocytopenia.