FRI0499 EFFICACY OF POSTMENOPAUSAL OSTEOPOROSIS TREATMENT BY COMBINATION OF DENOSUMAB WITH PLAIN VITAMIN D OR WITH ANALOG OF VITAMIN D ALFACALCIDOL

Background The superiority of the treatment of osteoporosis (OP), using the combination of alendronate (ALN) and alfacalcidol (1αD3) to ALN treatment with cholecalciferol (D3) in both genders, has been demonstrated1. Objectives To compare the efficacy of two-year OP treatment with denosumab (DMAb) with D3 to the treatment of DMAb with 1αD3. Methods Retrospective study included 58 postmenopausal OP patients treated at the Institute of Rheumatology in Belgrade. Average age was 74.5 ± 16.22 years, bone density (BMD) on the lumbar spine (L1L4) was 1.102 ± 0.0878g/cm2, total hip (TH) 0.728 ± 0.0324g/cm2, femoral neck (FN) was 0,600 ± 0.1281g/cm2, and the bone quality expressed as trabecular bone score (TBS) was 1.222 ± 0.3457, at study inclusion. BMD and TBS were measured using Hologic Prodigy DXA device. All women had primary OP, and 50% had fracture in the adult age. Average serum level 25 (OH) D3 was 29.8 ± 6.67ng/mL. Out of all, 68.4% patients had previous OP treatment, during 4.2 ± 3.45 years, 55.2% had used oral bisphosphonates (BF), 8.62% parenteral BF, 3.44% strontium ranelate, while one patient (1.72%) received a full course of teriparatide. Patients were asigned by the doctor’s decision to be treated either by combination of DMAb 60mg s.c. every 6 months and D3 800-1000 IU daily (N = 29) or DMAb and 1αD3 1μg daily (N = 29). Safety was monitored clinically and laboratory at six-month intervals - serum calcium (Ca), ionised Ca, phosphorus, 24 hours of calciuria, incidence of falls and fractures. Serum 25 (OH) D3 and parathormone (PTH) were observed once a year, as well as BMD and TBS. Analytical statistical analysis was done by student t - test and Fisher ‘s test. Results The patients were mutualy comparable in term of age, previous fractures, BMD and TBS, laboratory findings, previous OP treatment. After 2 years of study treatment, there was no significant difference in the increase in BMD on the L1L4 between DMAb plus D3 and DMAb plus 1αD3 group (6.4% vs. 6.5%), as well as on the TH (3.3% vs 3.4%). Statistically significantly higher BMD on FN (2.0% vs 5.9%, p Conclusion DMAb in combination with 1αD3 is more effective and equally safe OP treatment compared to DMAb with D3, in term of increasing FN BMD and improvement of bone micro-architecture. References [1] Ringe JD, Farahmand P, Schacht E, Rozehnal A. Superiority of a combined treatment of Alendronate and Alfacalcidol compared to the combination of Alendronate and plain vitamin D or Alfacalcidol alone in established postmenopausal or male osteoporosis (AAC-Trial). Rheumatol Int.2007;27(5):425-34 Disclosure of Interests Katarina Pasalic: None declared, Snezana Novkovic: None declared, Katarina Gosic: None declared, Nemanja Damjanov Grant/research support from: AbbVie, Pfizer and Roche, Consultant for: Abbvie, Gedeon Richter, Merck, Novartis, Pfizer and Roche., Speakers bureau: Abbvie, Gedeon Richter, Merck, Novartis, Pfizer and Roche.