Prevention of osteoporosis with nasal salmon calcitonin: Effect of anti-salmon calcitonin antibody formation
The amino acid sequence of salmon calcitonin (SCT) differs considerably from that of the human hormone and specific antibodies (Ab) develop in a significant proportion of patients after parenteral or nasal administration of SCT. Controversy remains regarding the functional importance of these Ab. We report on the development of specific anti-SCT Ab in a population of postmenopausal women receiving nasal SCT for prevention of postmenopausal bone loss, and compare the effects of nasal SCT in women with or without Ab. Thirty-nine per cent of women developed Ab after 6 months of treatment with SCT, 52% after 12 months, and 61% after 18 and 24 months. After 24 months the AB titre was 3.47−17.7×10−9 M/l (mean ±SD: 13.3±3.1×10−9 M/l). No significant differences appeared between the changes in lumbar bone mineral density (BMD) measured in the whole population (n=44) (mean±SD: + 1.06±3.9%), the patients without Ab (n=17) (+0.05±3.7%) or in those with Ab (n=27) (+1.7±4.6%). During the same period, a control population randomly assigned to a 500 mg/day calcium intake showed a significant loss of lumbar BMD (−4.57±4.9%) (p<0.01). In conclusion, in healthy postmenopausal women nasal SCT seems to maintain the same preventive effect against bone loss whether or not Ab are present.