POS1105 EFFECTS OF CHOLECALCIFEROL AND CALCIFEDIOL IN OSTEOPOROTIC WOMEN WITH SECONDARY HYPERPARATHYROIDISM DUE TO SEVERE VITAMIN D DEFICIENCY UNDERGOING ZOLEDRONIC ACID TREATMENT: A RANDOMIZED-CONTROLLED TRIAL

Background: Secondary hyperparathyroidism (sHPTH) due to vitamin D deficiency impairs the bone mineral density (BMD) response alendronate, 1-2 but optimal strategy for its correction in postmenopausal osteoporotic women (PMO) about start zoledronic acid (ZOL) therapy is still unknown. Objectives: To evaluate effects of cholecalciferol (D3) and calcifediol (25OHD) on serum 25-OH-vitamin (s25OHD), parathyroid hormone (PTH) BMD PMO presenting with sHPTH deficiency. Methods: s25OHD <20 ng/ml, (PTH >65 pg/ml) T-score at lumbar spine (LS), femoral neck (FN) or total hip (TH) < -2.5, between -1 -2.5 plus one vertebral/femoral fracture, were randomly assigned receive a therapeutic dose D3 (300.000 IU bolus) followed by 175 mcg/weekly D3, 25OHD alone, 2 months before receiving single intravenous infusion ZOL (5 mg). LS, FN TH was assessed baseline after year from ZOL. Serum calcium, PTH measured baseline, 6- 12-month Adverse clinical events ascertained 3-and 9-month telephone interviews, evaluation. Results: 45 (25OHD N=23, N=22) enrolled over 32 subjects (mean age ±SD 75±10 years, range 51-91) completed 1-year treatment/follow-up N=17, N=15). Most discontinued protocol violation, while three deceased study ending N=1, N=2) reasons not related agents investigated. The characteristics comparable both groups. At mean (±SE) 8±1 ng/ml group group. corresponding figures 111±6 pg/ml 117±5 (D3). Mean increased groups 12-month, being significantly greater (12-month, 56±2 ng/ml) compared 34±2 P<.001) time points (Figure 1). ±SE) decreased groups, lower 46±6 versus 70±6 pg/ml, P=.007), as shown Figure 1. (with significant increases only FN) without differences D3. In calcium remained stable time, those demonstrated increase value close upper limit reference 12-month. No patient reported incident fractures adverse events. Conclusion: Calcifediol mcg weekly appears more potent improving decreasing concentrations (300’000 IU) severe therapy. Further studies are warranted clarify implications improvements long-term similar regimens. References: [1]Barone A et al., J Am Geriatr Soc 2007. [2]Kincse G BMC Musculoskelet Disord 2012. Disclosure Interests: Giulia Botticella: None declared, Monica Pizzonia: Barbara Cossu: Roberta Bruno: Dario Camellino Speakers bureau: AbbVie, Celgene, Janssen-Cilag, Eli Lilly, Medac, Mylan, Novartis, Sanofi, outside submitted work, Giuseppe Girasole Abiogen Pharma Andrea Giusti UCB, Amgen, Kyowa Kirin, Pharma, Consultant of: EffRx Mario Pedrazzoni: Simona Alexovits: Franco Pleitavino: Federico Santolini: Alessio Nencioni: Gerolamo Bianchi Abbvie, BMS, GSK, MSD, Pfizer, Roche, Genzyme, Servier, work.