title: Effects of teriparatide retreatment in osteoporotic men and women.
abstract: BACKGROUND
  The stimulatory effect of teriparatide on bone mineral density (BMD) and bone turnover is initially exuberant, but then diminishes.
  
  
  OBJECTIVE
  Our objective was to determine whether retreating with teriparatide after a drug-free period can restore the initial exuberant response to teriparatide.
  
  
  METHODS
  This was a planned extension of a randomized controlled trial conducted in a single university hospital.
  
  
  METHODS
  Subjects previously participated in a 30-month randomized trial comparing the effects of alendronate (group 1), teriparatide (group 2), or both (group 3) on BMD and bone turnover in men and women with low BMD (phase 1). Subjects who completed phase 1 on their assigned therapy entered phase 2 (months 30-42), during which teriparatide was stopped in groups 2 and 3. Teriparatide was administered to all subjects during months 42 to 54 (phase 3).
  
  
  METHODS
  We compared changes in BMD and markers of bone turnover (serum osteocalcin, N-terminal propeptide of type 1 collagen, and N-telopeptide) between phase 1 and 3 in subjects receiving teriparatide alone.
  
  
  RESULTS
  Posterior-anterior and lateral spine BMD increased 12.5 +/- 1.5 and 16.9 +/- 1.7%, respectively, during the first 12 months of teriparatide administration and 5.2 +/- 0.8 and 6.2 +/- 1.8%, respectively, during teriparatide retreatment (P < 0.001 and P = 0.001). Increases in osteocalcin (P < 0.001), N-terminal propeptide of type 1 collagen (P < 0.001), and N-telopeptide (P < 0.001) were greater during the first period of teriparatide administration.
  
  
  CONCLUSIONS
  The response to teriparatide is attenuated when readministered after a 12-month hiatus.
authors.affiliation: Endocrine Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. jfinkelstein@partners.org
authors.forename: Joel S
authors.initials: JS
authors.lastname: Finkelstein
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Wyland
authors.forename: Benjamin Z
authors.initials: BZ
authors.lastname: Leder
authors.forename: Sherri-Ann M
authors.initials: SM
authors.lastname: Burnett-Bowie
authors.forename: Hang
authors.initials: H
authors.lastname: Lee
authors.forename: Harald
authors.initials: H
authors.lastname: Jüppner
authors.forename: Robert M
authors.initials: RM
authors.lastname: Neer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019386:Alendronate / Q000008:administration & dosage / Q000009:adverse effects; D000465:Algorithms; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy*; D019233:Retreatment; D019379:Teriparatide / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D050071:Bone Density Conservation Agents; D004338:Drug Combinations; D019379:Teriparatide; D019386:Alendronate