Effect of Poloxamer 188 vs Placebo on Painful Vaso-Occlusive Episodes in Children and Adults With Sickle Cell Disease: A Randomized Clinical Trial.

Importance: Although effective agents are available to prevent painful vaso-occlusive episodes of sickle cell disease (SCD), there are no disease-modifying therapies for ongoing painful vaso-occlusive episodes; treatment remains supportive. A previous phase 3 trial of poloxamer 188 reported shortened duration of painful vaso-occlusive episodes in SCD, particularly in children and participants treated with hydroxyurea. Objective: To reassess the efficacy of poloxamer 188 for vaso-occlusive episodes. Design, Setting, and Participants: Phase 3, randomized, double-blind, placebo-controlled, multicenter, international trial conducted from May 2013 to February 2016 that included 66 hospitals in 12 countries and 60 cities; 388 individuals with SCD (hemoglobin SS, SC, S-ß0 thalassemia, or S-ß+ thalassemia disease) aged 4 to 65 years with acute moderate to severe pain typical of painful vaso-occlusive episodes requiring hospitalization were included. Interventions: A 1-hour 100-mg/kg loading dose of poloxamer 188 intravenously followed by a 12-hour to 48-hour 30-mg/kg/h continuous infusion (n = 194) or placebo (n = 194). Main Outcomes and Measures: Time in hours from randomization to the last dose of parenteral opioids among all participants and among those younger than 16 years as a separate subgroup. Results: Of 437 participants assessed for eligibility, 388 were randomized (mean age, 15.2 years; 176 [45.4%] female), the primary outcome was available for 384 (99.0%), 15-day follow-up contacts were available for 357 (92.0%), and 30-day follow-up contacts were available for 368 (94.8%). There was no significant difference between the groups for the mean time to last dose of parenteral opioids (81.8 h for the poloxamer 188 group vs 77.8 h for the placebo group; difference, 4.0 h [95% CI, -7.8 to 15.7]; geometric mean ratio, 1.2 [95% CI, 1.0-1.5]; P = .09). Based on a significant interaction of age and treatment (P = .01), there was a treatment difference in time from randomization to last administration of parenteral opioids for participants younger than 16 years (88.7 h in the poloxamer 188 group vs 71.9 h in the placebo group; difference, 16.8 h [95% CI, 1.7-32.0]; geometric mean ratio, 1.4 [95% CI, 1.1-1.8]; P = .008). Adverse events that were more common in the poloxamer 188 group than the placebo group included hyperbilirubinemia (12.7% vs 5.2%); those more common in the placebo group included hypoxia (12.0% vs 5.3%). Conclusions and Relevance: Among children and adults with SCD, poloxamer 188 did not significantly shorten time to last dose of parenteral opioids during vaso-occlusive episodes. These findings do not support the use of poloxamer 188 for vaso-occlusive episodes. Trial Registration: ClinicalTrials.gov Identifier: NCT01737814.

Therapeutic Benefit of Blood Transfusion in a Patient With Novel PGK1 Mutation (c.461T>C [p.L154P]).

Phosphoglycerate kinase (PGK) is glycolytic enzyme critical in the creation of adenosine triphosphate. Mutations in the gene for this enzyme, PGK1, are associated with PGK deficiency, which is characterized by neurologic symptoms, nonhereditary spherocytic hemolytic anemia, and myopathy. We present a 20-year-old male with a novel c.461T>C (p.L154P) PGK1 mutation and clinical disease complicated by anemia and neurological symptoms. There is no recommended treatment for PGK deficiency. Because of our patient's advanced disease progression, we initiated serial blood transfusions and report significant subjective improvement in the patient's physical condition before his passing from PGK deficiency-related complications.

Morbid Obesity as Early Manifestation of Occult Hypothalamic-Pituitary LCH with Delay in Treatment.

Morbid obesity presents unique challenges in managing additional disease processes. A 16-year-old male with a history of central diabetes insipidus (DI) and hypothyroidism developed destructive lesions in both his right mandible and brain, which were not discovered until the patient presented for tinnitus, 8 years after his initial diagnosis with DI. Langerhans cell histiocytosis (LCH) was diagnosed on pathologic biopsy. The patient's initial body mass index (BMI) was 54.5 kg/m(2) so a unique treatment approach with single agent cladribine (2-CdA) was offered as traditional steroid therapy could worsen his endocrine dysfunction. The patient presented with neurodegenerative sequelae from the central LCH, possibly due to a delay in diagnosis and therapy. This case highlights difficulties in managing obese patients in an oncology setting and provides an illustrative case of how obesity may mask other comorbid conditions. Close supervision of complex obese patients with coordinated endocrinology and oncology care is vital. For the primary care practitioner, monitoring abrupt changes in BMI with serial cranial imaging may lead to a prompt diagnosis and prevention of further neurodegenerative effects. The use of 2-CdA was found to successfully bring the patient's LCH into remission without the additional risks of steroid therapy in a morbidly obese patient.

Unrelated bone marrow transplant for congenital amegakaryocytic thrombocytopenia: report of two cases and review of the literature.

CAMT is a very rare cause of thrombocytopenia in infants. Most of the patients will progress to marrow failure. Allogeneic stem cell transplant remains the only curative therapy. We present two patients with CAMT who underwent an unrelated donor bone marrow transplant, one after developing marrow failure and another early in the course of the disease. Both patients tolerated the transplant with minimal toxicity and durable engraftment. We also present a comprehensive review of the literature for unrelated donor transplant for this condition.

Compound heterozygous c-Mpl mutations in a child with congenital amegakaryocytic thrombocytopenia: functional characterization and a review of the literature.

OBJECTIVE: To genetically and functionally characterize mutations of c-Mpl that lead to thrombocytopenia in a child with congenital amegakaryocytic thrombocytopenia. MATERIALS AND METHODS: We identified two c-Mpl mutations in a child with clinical features of congenital amegakaryocytic thrombocytopenia, one a previously described mutation in the extracellular domain (R102P) and the other a novel mutation leading to truncation of the receptor after the box 1 homology domain (541Stop). Cell line models were created to examine the ability of the mutant receptors to signal in response to thrombopoietin and thrombopoietin-like agonists. RESULTS: Data from cell-line models indicate that c-Mpl R102P does not support significant signaling in response to thrombopoietin due to impaired trafficking of the mutant receptor to the cell surface. Alternative thrombopoietic agents do not circumvent this block to signaling, likely due to the inaccessibility of the receptor. In addition, previous data indicate that c-Mpl 541Stop does not support intracellular signaling due to the loss of critical intracellular domains. CONCLUSIONS: This case demonstrates two different mechanisms by which c-Mpl mutations can impair thrombopoietin signaling, and suggests that mutations in the extracellular domain will not be rescued by c-Mpl agonists if they interfere with normal receptor expression.

The inv(16) cooperates with ARF haploinsufficiency to induce acute myeloid leukemia.

The inv(16) is one of the most frequent chromosomal translocations associated with acute myeloid leukemia (AML) and creates a chimeric fusion protein consisting of most of the runt-related X1 co-factor, core binding factor beta fused to the smooth muscle myosin heavy chain MYH11. Expression of the ARF tumor suppressor is regulated by runt-related X1, suggesting that the inv(16) fusion protein (IFP) may repress ARF expression. We established a murine bone marrow transplant model of the inv(16) in which wild type, Arf+/-, and Arf-/- bone marrow were engineered to express the IFP. IFP expression was sufficient to induce a myelomonocytic AML even when expressed in wild type bone marrow, yet removal of only a single allele of Arf greatly accelerated the disease, indicating that Arf is haploinsufficient for the induction of AML in the presence of the inv(16).