title: Improvement in biomarkers of bone formation during infliximab therapy in pediatric Crohn's disease: results of the REACH study.
abstract: OBJECTIVE
  Crohn's disease (CD) is associated with altered bone metabolism. This study examined changes in bone formation and resorption after infliximab induction and associations between bone biomarkers, linear growth, and disease activity (Pediatric Crohn's Disease Activity Index [PCDAI]) after 54 weeks of infliximab therapy.
  
  
  METHODS
  One hundred twelve subjects ages 6-17 years with moderate to severe CD received infliximab induction (5 mg/kg/dose) at weeks 0, 2, and 6; week-10 responders were randomized to infliximab every 8 or every 12 weeks maintenance therapy. Serum bone-specific alkaline phosphatase (BSAP), N-terminal propeptide of type 1 collagen (P1NP), urine C-telopeptide of collagen cross-links (CTX-1), and deoxypyrodinoline (DPD) were collected at baseline and 10 weeks. PCDAI and height z-scores were assessed at baseline and at 10 and 54 weeks.
  
  
  RESULTS
  Models were adjusted for bone age, gender, height, and steroid use. Baseline BSAP and P1NP levels were negatively associated with PCDAI (both P = .01). BSAP and P1NP increased during induction (both P < .001) and were associated with 54-week increases in height z-score (P < .05 and P < .001, respectively). Improvements in P1NP were associated with 54-week decreases in PCDAI (P = .01). CTX-1 and DPD also increased during induction (P < .001 and P = .01, respectively) but were not associated with changes in PCDAI. Changes in CTX-1 were associated with improvements in height z-score (P < .002).
  
  
  CONCLUSIONS
  Infliximab therapy is associated with dramatic increases in BSAP and P1NP, consistent with inhibition of tumor necrosis factor-alpha effects on osteoblasts. The increases in CTX-1 and DPD likely reflect coupling of bone formation and resorption and increases in linear growth.
authors.affiliation: Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia, Philadelphia, PA 19014, USA. thayu@email.chop.edu
authors.forename: Meena
authors.initials: M
authors.lastname: Thayu
authors.forename: Mary B
authors.initials: MB
authors.lastname: Leonard
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Hyams
authors.forename: Wallace V
authors.initials: WV
authors.lastname: Crandall
authors.forename: Subra
authors.initials: S
authors.lastname: Kugathasan
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Otley
authors.forename: Allan
authors.initials: A
authors.lastname: Olson
authors.forename: Jewel
authors.initials: J
authors.lastname: Johanns
authors.forename: Colleen W
authors.initials: CW
authors.lastname: Marano
authors.forename: Robert B
authors.initials: RB
authors.lastname: Heuschkel
authors.forename: Gigi
authors.initials: G
authors.lastname: Veereman-Wauters
authors.forename: Anne M
authors.initials: AM
authors.lastname: Griffiths
authors.forename: Robert N
authors.initials: RN
authors.lastname: Baldassano
mesh_terms: D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D024042:Collagen Type I / Q000097:blood / Q000652:urine; D003424:Crohn Disease / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage / Q000627:therapeutic use*; D000069285:Infliximab; D008297:Male; D010012:Osteogenesis / Q000187:drug effects*; D010455:Peptides / Q000652:urine; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D024042:Collagen Type I; D007155:Immunologic Factors; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D000069285:Infliximab; D000469:Alkaline Phosphatase