Brincidofovir is highly efficacious in controlling adenoviremia in pediatric recipients of hematopoietic cell transplant.

Cidofovir is preemptively used for controlling adenoviremia and preventing disseminated viral disease in hematopoietic cell transplant (HCT) recipients but does not lead to resolution of viremia without T-cell immune-reconstitution. The lipid-conjugated prodrug of cidofovir, brincidofovir, has improved oral bioavailability and achieves higher intracellular concentrations of active drug. We present retrospective multicenter data comparing the kinetics of viremia and toxicities following preemptive treatment with and brincidofovir in children and adolescents diagnosed with HCT-related adenoviremia. Forty-one episodes (18 = brincidofovir; 23 = cidofovir) of antiviral therapy were observed in 27 patients. The 2 groups had comparable immune-reconstitution and viral burden. Major (≥2 log-reduction in 2 weeks; n = 13) and minor (≥1 to ≤2 log-reduction in 2 weeks; n = 2) virological responses were observed in 15 (83%) brincidofovir episodes compared to only 2 (9%) major virological responses with cidofovir (P < .0001). Brincidofovir mediated major responses in 9 of 11 cidofovir-unresponsive patients and resulted in complete responses (CR) despite significant lymphopenia (Brincidofovir vs cidofovir; CR = 13 (80%) vs 8 (35%); median lymphocyte count = 320/µl vs 910/µl; P < .05). One patient experienced abdominal cramps and diarrhea necessitating interruption of brincidofovir and none developed nephrotoxicity with brincidofovir. Thus, brincidofovir is well-tolerated and highly efficacious in controlling adenoviremia during the lymphopenic phase of HCT.

Administration of G-CSF from day +6 post-allogeneic hematopoietic stem cell transplantation in children and adolescents accelerates neutrophil engraftment but does not appear to have an impact on cost savings.

G-CSF post-allogeneic HSCT accelerates neutrophil engraftment, but evidence that it impacts on cost-related outcomes is lacking. We performed a retrospective child and adolescent single-center cohort study examining G-CSF administration from Day +6 of allogeneic HSCT vs. ad hoc G-CSF use where clinically indicated. Forty consecutive children and adolescents undergoing allogeneic HSCT were included. End-points were as follows: time to engraftment; incidence of acute and chronic GvHD; number of patients alive at Day +100; 180-day TRM; post-transplant days in hospital; and cost of antimicrobials, TPN, and G-CSF usage. Neutrophil engraftment occurred earlier in the group that received G-CSF from Day +6. There was no difference between groups in any of the other end-points with the following exception: the cost of GCSF was significantly higher in the D + 6 G-CSF group. However, median G-CSF cost in this group amounted to only €280. There was a trend towards reduced cost of antimicrobials in the D + 6 G-CSF group, although this did not reach significance (p = 0.13). The median cost per patient of antimicrobial agents between groups differed by €1116. This study demonstrated the administration of G-CSF on Day +6 in pediatric HSCT to be safe. A further study using a larger cohort of patients is warranted to ascertain its true clinico-economic value.

Recent advances in the pathobiology and management of Kasabach-Merritt phenomenon.

Kasabach-Merritt Phenomenon (KMP) refers to the clinical constellation of thrombocytopenia, consumptive coagulopathy and purpura associated with Kaposiform haemangioedothelioma or tufted angioma, but not the more common infantile haemangioma. It shows a variable and unpredictable response to traditional pharmacological agents, such as steroids, vincristine or interferon alpha 2a or 2b. More recently, the interaction between platelets and endothelial cells and the proangiogenic phenotype that results has been recognized to underly the pathogenesis of this disorder. Recent efforts have attempted to target the platelet by using antiplatelet agents and by the withholding of platelet transfusions even in those patients who have significant thrombocytopenia and laboratory evidence of coagulopathy. Excellent response rates and prompt results have been achieved by combining antiplatelet therapy with vincristine, without the need for steroid use. This synergistic approach moves away from the conventional wisdom of treating the underlying lesion to control the coagulopathy. Sirolimus, which is directed against the PI3/AKT/mTOR downstream signalling pathway involved in lymphangiogenesis, has also shown promising results, although further study is needed.