Functional significance of antibody formation after long-term salmon calcitonin therapy.

Twenty patients with Paget's disease were challenged with porcine (PCT) and salmon (SCT) calcitonin before and after 6 months SCT therapy. Acute hypocalcaemia was clearly related to the prevailing rate of bone turnover but responses to PCT showed that treatment had not disturbed this relationship. Although antibodies to SCT developed in eight patients during the period of treatment the acute hypocalcaemic response to SCT was not diminished in relation to bone turnover. It is suggested that antibodies which develop during the course of SCT therapy do not necessarily exert a functionally effective neutralizing action.