title: Thrombopoietin Receptor Agonist Use in Children: Data From the Pediatric ITP Consortium of North America ICON2 Study.
abstract: Data on second-line treatment options for pediatric patients with immune thrombocytopenia (ITP) are limited. Thrombopoietin receptor agonists (TPO-RA) provide a nonimmunosuppressive option for children who require an increased platelet count.
  
  
  
  We performed a multicenter retrospective study of pediatric ITP patients followed at ITP Consortium of North America (ICON) sites to characterize TPO-RA use.
  
  
  
  Seventy-nine children had a total of 87 treatments (28 eltrombopag, 43 romiplostim, and eight trialed on both). The majority had primary ITP (82%) and most (60.8%) had chronic ITP. However, 22% had persistent ITP and 18% had newly diagnosed ITP. During the first 3 months of treatment, 89% achieved a platelet count ≥ 50 × 10(9) /l (86% romiplostim, 81% eltrombopag, P = 0.26) at least once in the absence of rescue therapy. The average time to a response was 6.4 weeks for romiplostim and 7.0 weeks for eltrombopag (P = 0.83). Only 40% of patients demonstrated a stable response with consistent dosing over time. An intermittent response with constant dose titration was seen in 15%, and an initial response that waned to no response was seen in 13%. Significant adverse events were minimal with the exception of two patients with thrombotic events and one who developed a neutralizing antibody.
  
  
  
  Our results demonstrate that TPO-RA agents are being used in children with ITP of varying duration and severity. The response was similar to clinical trials, but the sustainability of response varied. Future studies need to focus on the ideal timing and rationale for these medications in pediatric patients.
authors.affiliation: Division of Pediatric Hematology/Oncology/Stem Cell Transplantation and New York Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, New York.
authors.forename: Cindy
authors.initials: C
authors.lastname: Neunert
authors.affiliation: Texas Children's Hematology Center, Baylor College of Medicine, Houston, Texas.
authors.forename: Jenny
authors.initials: J
authors.lastname: Despotovic
authors.affiliation: Division of Pediatric Hematology/Oncology, Oregon Health and Sciences University, Portland, Oregon.
authors.forename: Kristina
authors.initials: K
authors.lastname: Haley
authors.affiliation: Department of Pediatrics and The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Michele P
authors.initials: MP
authors.lastname: Lambert
authors.affiliation: St. Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Kerri
authors.initials: K
authors.lastname: Nottage
authors.affiliation: Division of Pediatric Hematology/Oncology and Benioff Children's Hospital, University of California San Francisco, San Francisco, California.
authors.forename: Kristin
authors.initials: K
authors.lastname: Shimano
authors.affiliation: Aflac Cancer Center and Blood Disorders Service, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Bennett
authors.affiliation: Division of Pediatric Hematology/Oncology, University of Ottawa, Ottawa, Ontario.
authors.forename: Robert
authors.initials: R
authors.lastname: Klaassen
authors.affiliation: Division of Pediatric Hematology/Oncology, University of Arkansas for Medical Sciences at Arkansas Children's Hospital, Little Rock, Arkansas.
authors.forename: Kimo
authors.initials: K
authors.lastname: Stine
authors.affiliation: Division of Hematology/Oncology, Feinberg School of Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.
authors.forename: Alexis
authors.initials: A
authors.lastname: Thompson
authors.affiliation: CHU Ste-Justine, Montreal University, Montreal, Quebec, Canada.
authors.forename: Yves
authors.initials: Y
authors.lastname: Pastore
authors.affiliation: Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, Massachusetts.
authors.forename: Travis
authors.initials: T
authors.lastname: Brown
authors.affiliation: Clinical Research Center, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Forbes
authors.affiliation: Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, Massachusetts.
authors.forename: Rachael F
authors.initials: RF
authors.lastname: Grace
mesh_terms: D000293:Adolescent; D001565:Benzoates / Q000009:adverse effects / Q000627:therapeutic use*; D002648:Child; D005260:Female; D006801:Humans; D006834:Hydrazines / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D010976:Platelet Count; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood / Q000188:drug therapy*; D011720:Pyrazoles / Q000009:adverse effects / Q000627:therapeutic use*; D011961:Receptors, Fc / Q000627:therapeutic use*; D053628:Receptors, Thrombopoietin / Q000819:agonists*; D011993:Recombinant Fusion Proteins / Q000009:adverse effects / Q000627:therapeutic use*; D012189:Retrospective Studies; D013926:Thrombopoietin / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D001565:Benzoates; D006834:Hydrazines; D011720:Pyrazoles; D011961:Receptors, Fc; D053628:Receptors, Thrombopoietin; D011993:Recombinant Fusion Proteins; D013926:Thrombopoietin; C488777:romiplostim; C520809:eltrombopag
keywords: ICON; immune thrombocytopenia; pediatrics; thrombopoietin receptor agonists; treatment