title: A 2-Year, Longitudinal, Prospective Study of the Effects of Eltrombopag on Bone Marrow in Patients with Chronic Immune Thrombocytopenia.
abstract: BACKGROUND
  The long-term effects of eltrombopag on bone marrow (BM) reticulin and/or collagen deposition in previously treated adults with chronic immune thrombocytopenia (ITP) were assessed.
  
  
  METHODS
  Three BM biopsies were collected at baseline and after 1 and 2 years of eltrombopag treatment. Specimens were centrally processed, stained for reticulin and collagen, independently reviewed by 2 hematopathologists, and rated according to the European Consensus 0-3 scale of marrow fibrosis (MF).
  
  
  RESULTS
  Of 162 patients enrolled, 93 completed all 3 protocol-specified BM biopsies. All patients with a baseline assessment were negative for collagen. Of 159 patients assessed at baseline, 150 (94%) had normal reticulin (MF-0) and 9 (6%) had minimally increased reticulin (MF-1). After 2 years, 83/93 patients (89%) with BM biopsies had MF-0, 10 (11%) had MF-1, and none had MF-2 or MF-3. Five out of 127 patients (4%) at 1 year and 1 out of 93 (1%) at 2 years had collagen deposition. None of the patients had clinical symptoms typical of BM dysfunction or abnormalities of clinical concern based on white blood cell count or peripheral blood smear.
  
  
  CONCLUSIONS
  For most patients with chronic ITP, eltrombopag is not associated with clinically relevant increases in BM reticulin or collagen formation.
authors.affiliation: Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Russell K
authors.initials: RK
authors.lastname: Brynes
authors.forename: Raymond S M
authors.initials: RS
authors.lastname: Wong
authors.forename: Maung M
authors.initials: MM
authors.lastname: Thein
authors.forename: Kalpana K
authors.initials: KK
authors.lastname: Bakshi
authors.forename: Paul
authors.initials: P
authors.lastname: Burgess
authors.forename: Dickens
authors.initials: D
authors.lastname: Theodore
authors.forename: Attilio
authors.initials: A
authors.lastname: Orazi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001565:Benzoates / Q000008:administration & dosage*; D001706:Biopsy; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D002908:Chronic Disease; D003094:Collagen / Q000378:metabolism*; D005260:Female; D006801:Humans; D006834:Hydrazines / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D011720:Pyrazoles / Q000008:administration & dosage*; D012155:Reticulin / Q000378:metabolism*
chemical_list: D001565:Benzoates; D006834:Hydrazines; D011720:Pyrazoles; D012155:Reticulin; D003094:Collagen; C520809:eltrombopag