Pharmacodynamics and pharmacokinetics of oral salmon calcitonin in the treatment of osteoporosis

ABSTRACT

Introduction: Salmon calcitonin (sCT) has been used for the treatment of postmenopausal osteoporosis for over 30 years. It is available in injectable and intranasal formulations. Two oral formulations have recently been developed.

Areas covered: The basis for oral sCT’s bioavailability rests with a carrier molecule (8-(N-2-hydroxy-5-chloro-benzoyl)-amino-caprylic acid) or an acid-resistant enteric coating (Eudragit® polymer containing citric acid). With these formulations, sCT is resistant to gastric acid, and thus becomes available for absorption at the higher pH of the small intestine. Even though the changes in bone mineral density and bone turnover markers are greater with oral compared to nasal sCT, it shows only minor effects on these surrogate markers.

Expert opinion: Oral sCT is attractive in concept as it is would be more convenient to patients than other routes of administration. While there may be other advantages to the oral formulation such as improving bone mineral density to a greater extent than nasal CT, anti-fracture efficacy has not been shown in a recent major clinical trial. Together with the possibility of an association between the drug and cancer and the availability of antiresorptive drug classes that are clearly more efficacious than sCT, successful development of oral sCT as a treatment for postmenopausal osteoporosis is uncertain.

KEYWORDS:

• 5-CNAC
• bone mineral density
• calcitonin
• Eudragit
• fracture
• osteoporosis
• treatment

Declaration of interests

L. Bandeira has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. EM Lewiecki has received institutional grant/research support from Amgen, Merck, and Eli Lilly; he has served on scientific advisory boards for Amgen, Merck, Eli Lilly, Radius Health, AgNovos Healthcare, Alexion, Shire, and AbbVie; he serves on the speakers’ bureau for Shire. JP Bilezikian is a consultant for Amgen, Radius, Lilly, and Merck and receives research support from Shire Pharmaceuticals. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.