The authors observed the group of 180 post-menopausal women treated with 60 mg of denosumab applied subcutaneously every 6th (120 women) or every 7th week (60 women) for the period of 2 years. Dosing régime was selected randomly. Examination of bone markers, DXA, spine X-ray for elimination of compressive fractures, hip X-ray for evaluation of femur microarchitecture were performed at the beginning of treatment. Denosumab treatment was started in patients with -2,5 T-score in spine or hip with proven compressive fracture in the area of TH or LS or where significant decrease of bone mineral density (6 a more % yearly) was observed during previous sufficient calcium and vitamin D substitution.
Bone turnover markers were evaluated one week before next denosumab injection. BMD was measured every year and comparison was made within the same dosing régime and between the dosing régimes.
Significant decrease of PINP was indicated in the 6 months dosing group already after 6 months of treatment. Significant changes of CTX, ALP and osteocalcin were achieved after 1 year. Changes of BMD were similar after 12 months in spine in both groups (3%) and greater gain in BMD was observed after 24 month in 7 month group (6% vs 5%).
In the 6 months dosing group were in first year 0% increase in total hip BMD and 4% in femoral neck in comparison with 4% and 2% in second year.
In 7 months interval we observed 1% change in first year in total hip BMD and 4% in femoral neck, in second year 3% in total hip and 2% in femoral neck.
In the 7 months dosing group bone markers changed significantly after 1 year. There were no significant changes between both groups in BMD. Both groups were same in terms of initial BMD, age and fracture risk based on FRAX.
Prolonged dosing régime of denosumab to 7 months seems to be more suitable for postmenopausal women with normal level of bone markers. Considering the long term treatment this régime might be more effective in prevention of atypical fractures or osteonecrosis of jaw while maintaining long term patient compliance.
Disclosure: The authors declared no competing interests.