Efficacy of Neridronic Acid IV and IM in Improving BMD and Reducing Fracture Risk in Postmenopausal Osteoporosis

Osteoporosis is a major health concern that is associated with an increased risk of first and subsequent bone fractures. Untreated osteoporosis results in considerable morbidity. Currently, bisphosphonates are the mainstay of treatment for osteoporosis and the aim of this study was to assess the effects of intravenous (IV) and intramuscular (IM) neridronate (NE) on femoral/lumbar bone mineral density (BMD). Data were collected on age, weight, body mass index, physical activity, smoking, height loss, history of falls, total hip and lumbar BMD, and creatinine clearance. Inclusion criteria were a lumbar or femoral BMD T score < 2.5; Exclusion criteria were secondary osteoporosis, previous osteoporotic fracture, prior bisphosphonates or osteoporosis medications other than calcium or colecalciferol, presence of any concomitant skeletal metabolic disease.

Methods: 164 patients (mean age 64±2.7 years) with postmenopausal osteoporosis confirmed with a lumbar and femoral DEXA BMD scan received NE IV 100mg every 8 weeks for 18 months and subsequently IM NE 25 mg every 4 weeks for 18 months. All patients had gastric or esophageal conditions that contraindicated treatment with oral bisphosphonates (BPs). All subjects received daily calcium 1 g and vitamin D 800 UI. Lumbar and femoral DEXA BMD scans were performed at baseline, 18 months and 36 months. Furthermore, the fracture risk FRAX was calculated at baseline and after 18 and 36 months of therapy.

Results: After 18 months of IV therapy mean ±SD lumbar T-score was significantly increased (baseline -2.8±1.2 vs 18 months -2.6±1.4; p<0.01). Mean ±SD femoral neck T- score was also improved (baseline -2.15±1.1 vs 18 months -2.01±0.5; p<0.05). After an additional 18 months of IM NE the mean ±SD T-score values were lumbar -1.89±0.8 and femur -1.49±1.48; p< 0.01 vs. baseline. FRAX mean value was 14% for major osteoporotic fractures and 5.8% for hip fracture at baseline. After 18 months of therapy FRAX was 12% and 5%, respectively and finally at the end of the study was 10% for major osteoporotic fractures and 3.7% for hip fracture in the group treated continuously with NE IV and 9.8% and 3.9% in group treated with NE IM (P<0.05).

Conclusion: The results of this study confirm the role of NE in the treatment of postmenopausal osteoporosis and indicate the potential usefulness of intramuscular administration in the treatment of these patients.