title: Pharmacokinetic and Pharmacodynamic Characteristics of Subcutaneously Applied PTH-1-37.
abstract: OBJECTIVE
  Parathyroid hormone (PTH) derivatives exert pronounced renal and osteoanabolic properties when given intermittently. The current study was performed to assess the pharmacokinetic and pharmacodynamic properties as well as safety of subcutaneously applied PTH-1-37 after repeated dosing in healthy subjects.
  
  
  METHODS
  This randomized, double-blind, dose-escalating, placebo and active comparator controlled study was conducted in 33 healthy postmenopausal women. Subjects were allocated to one of five treatment options: 10, 20, or 40 µg PTH-1-37, 20 µg PTH-1-34 or placebo, administered as once daily subcutaneous doses for three days. Plasma drug concentrations and serum levels of endogenous PTH-1-84, and calcium as markers of biological activity were monitored during the treatment.
  
  
  RESULTS
  PTH was absorbed rapidly from the subcutaneous tissue with a median tmax of 30 minutes for 20 and 40 µg of PTH-1-37. tmax was 45 minutes for 20 µg PTH-1-34. Elimination half-lives were estimated as 76 ± 34 min and 70 ± 13 min for 20 µg and 40 µg PTH-1-37 (mean ± SD), and 78 ± 34 for 20 µg PTH-1-34. Both PTH fragments (PTH-1-37 and PTH-1-34) increased serum calcium. For PTH-1-37 the effect on serum calcium was dose-dependent. Suppression of endogenous PTH-1-84 was seen after the application of both PTH-1-37 and PTH-1-34. During the study period, the subjects experienced no unexpected or serious adverse events.
  
  
  CONCLUSIONS
  PTH-1-37 is rapidly absorbed after s.c. injection, has a short plasma elimination half-life, and does not accumulate during multiple dosing. Biological activity was demonstrated by rising serum calcium and decreasing endogenous PTH-1-84 in blood plasma. The study drugs were well tolerated and safe. Our investigation presents data that PTH-1-37 is an excellent drug candidate for intervening with syndromes of dysregulation of calcium metabolism.
authors.affiliation: IPF PharmaCeuticals GmbH, Hannover, Germany.
authors.forename: Wolf-Georg
authors.initials: WG
authors.lastname: Forssmann
authors.forename: Hanns-Christian
authors.initials: HC
authors.lastname: Tillmann
authors.forename: Dieter
authors.initials: D
authors.lastname: Hock
authors.forename: Kristin
authors.initials: K
authors.lastname: Forssmann
authors.forename: Corrado
authors.initials: C
authors.lastname: Bernasconi
authors.forename: Ulf
authors.initials: U
authors.lastname: Forssmann
authors.forename: Rudolf
authors.initials: R
authors.lastname: Richter
authors.forename: Berthold
authors.initials: B
authors.lastname: Hocher
authors.forename: Andreas
authors.initials: A
authors.lastname: Pfützner
mesh_terms: D002118:Calcium / Q000097:blood / Q000378:metabolism; D002128:Calcium Metabolism Disorders / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006207:Half-Life; D064368:Healthy Volunteers; D006801:Humans; D007279:Injections, Subcutaneous; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D010281:Parathyroid Hormone; D010446:Peptide Fragments; C094316:parathyroid hormone (1-37); C035747:parathyroid hormone (1-38); D002118:Calcium