Single infusion of neridronate (6-amino-1-hydroxyhexylidene-1,1-bisphosphonate) in patients with active rheumatoid arthritis: effects on disease activity and bone resorption markers

The Rationale for Using Neridronate in Musculoskeletal Disorders: From Metabolic Bone Diseases to Musculoskeletal Pain

Neridronate or ((6-amino-1-hydroxy-1-phosphonohexyl) phosphonic acid) is an amino-bisphosphonate (BP) synthetized in Italy in 1986. Bisphosphonates are molecules with a P-C-P bond in their structure that allows strong and selectively binding to hydroxyapatite (HAP) as well as osteoclasts inhibition through different mechanisms of action. Neridronate was initially used to treat Paget disease of the bone, demonstrating effectiveness in reducing bone turnover markers as well as pain. The interesting molecular properties of neridronate foster its wide use in several other conditions, such as osteogenesis imperfecta, and osteoporosis. Thanks to the unique safety and efficacy profile, neridronate has been used in secondary osteoporosis due to genetic, rheumatic, and oncological diseases, including in pediatric patients. In the last decade, this drug has also been studied in chronic musculoskeletal pain conditions, such as algodystrophy, demonstrating effectiveness in improving extraskeletal outcomes. This review highlights historical and clinical insights about the use of neridronate for metabolic bone disorders and musculoskeletal pain conditions.

Effect of neridronate in osteopenic patients after heart, liver or lung transplant: a multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Transplantation (Tx) is an effective therapeutic option in patients with end-stage organ failure and osteoporosis and related fractures are a recognized complication in these patients. Aim of this study was to evaluate the efficacy of neridronate in patients with reduced bone mass after Tx of the heart, liver or lung.

METHODS

In this multicenter randomized double-blind controlled trial (RCT), 22 patients were treated with neridronate (25 mg i.m./month) and 17 received placebo. All patients received daily oral calcium (500 mg) and vitamin D (400 IU). Dual-energy X-ray absorptiometry (DXA) was evaluated at 0, 6 and 12 months and markers of bone turnover at 0, 3, 6, 9 and 12 months.

RESULTS

Thirty-nine patients (11 heart Tx, 21 liver Tx, 7 lung Tx), aged 49.3±9.1 years, with a T-score <-2.0 SD at lumbar spine or femoral level were included. In neridronate-treated patients, a significant increase in lumbar bone mineral density (BMD) was observed after 12 months vs. placebo control (0.92±0.13 g/cm² vs. 0.84±0.08 g/cm²; P=0.005). Femur and hip BMD remained unchanged between groups. Total alkaline phosphatase, bone alkaline phosphatase and beta-cross-laps significantly decreased over the 12 months in neridronate-treated patients vs. placebo, respectively (107.4±74 U/L vs. 157.6±107.1 U/L, P=0.002; 5.7±3.3 µg/L vs. 11.7±4.3 µg/L, P<0.001 and 0.25±0.13 ng/mL vs. 0.73±0.57 ng/mL, P<0.001). No difference was observed between neridronate and placebo groups regarding safety profile.

CONCLUSIONS

This is the first RCT that demonstrates the efficacy of neridronate in increasing bone density and reducing bone turnover in organ Tx recipients with significant skeletal morbidity.

Basic research and clinical applications of bisphosphonates in bone disease: what have we learned over the last 40 years?

It is now 40 years since bisphosphonates (BPs) were first used in the clinic. So, it is timely to provide a brief review of what we have learned about these agents in bone disease. BPs are bone-specific and have been classified into two major groups on the basis of their distinct molecular modes of action: amino-BPs and non-amino-BPs. The amino-BPs are more potent and they inhibit farnesyl pyrophosphate synthase (FPPS), a key enzyme of the mavalonate/cholesterol biosynthetic pathway, while the non-amino-BPs inhibit osteoclast activity, by incorporation into non-hydrolyzable analogs of ATP. Both amino-BPs and non-amino-BPs can protect osteoblasts and osteocytes against apoptosis. The BPs are widely used in the clinic to treat various diseases characterized by excessive bone resorption, including osteoporosis, myeloma, bone metastasis, Legg-Perthes disease, malignant hyperparathyroidism, and other conditions featuring bone fragility. This review provides insights into some of the adverse effects of BPs, such as gastric irritation, osteonecrosis of the jaw, atypical femoral fractures, esophageal cancer, atrial fibrillation, and ocular inflammation. In conclusion, this review covers the biochemical and molecular mechanisms of action of BPs in bone, particularly the discovery that BPs have direct anti-apoptotic effects on osteoblasts and osteocytes, and the current situation of BP use in the clinic.

Bisphosphonates: focus on inflammation and bone loss

Bisphosphonates are pharmacological compounds that have been used for the prevention and treatment of several pathological conditions including osteoporosis, primary hyperparathyroidism, osteogenesis imperfecta, and other conditions characterized by bone fragility. Many studies have been performed to date to analyze their effects on inflammation and bone remodelling and related pathologies. The aim of this review is, starting from a background on inflammatory processes and bone remodelling, to give an update on the use of bisphosphonates, outlining the possible side effects and proposing new trends for the future. Starting from a brief introduction on inflammation and bone remodelling, we collect and analyze studies involving the use of bisphosphonates for treatment of inflammatory conditions and pathologies characterized by bone loss. Selected articles, including reviews, published between 1976 and 2011, were chosen from Pubmed/Medline on the basis of their content. Bisphosphonates exert a selective activity on inflammation and bone remodelling and related pathologies, which are characterized by an excess in bone resorption. They improve not only skeletal defects, but also general symptoms. Bisphosphonates have found clinical application preventing and treating osteoporosis, osteitis deformans (Paget's disease of bone), bone metastasis (with or without hypercalcaemia), multiple myeloma, primary hyperparathyroidism, osteogenesis imperfecta, and other conditions that feature bone fragility. Further clinical studies involving larger cohorts are needed to optimize the dosage and length of therapy for each of these agents in each clinical field in order to be able to maximize their properties concerning modulation of inflammation and bone remodelling. In the near future, although "old" bisphosphonates will reach the end of their patent life, "new" bisphosphonates will be designed to specifically target a pathological condition.

Pharmacodynamics of bisphosphonates in arthritis

Inflammatory arthritis is a group of autoimmune diseases characterized by chronic inflammation of the joints. Rheumatoid arthritis, the most common form of arthritis, is associated with local joint destruction and systemic bone loss. Osteoclasts, the only cells of the body able to resorbe bone, are key players in these two types of bone loss. Bisphosphonates are analogs of pyrophosphate that inhibit osteoclast action and bone resorption. They are indicated in pathology associated with excess resorption. Besides their effect on bone they also exhibit extra-osseous properties, acting on tumor cells, inflammation and angiogenesis. As a result, they have been trialed in the context of arthritis. It is now clear that they do not have any significant direct effect on disease activity or pain. If their indication in the prevention of glucocorticoid-induced osteoporosis is clear, any beneficial effects on bone erosions are still controversial but interesting preliminary results warrant further investigations.

Extra-skeletal effects of bisphosphonates

Bisphosphonates are pharmacological agents which are currently used both in osteoporosis than in other pathological conditions characterised by an increased bone resorption, such as Paget's disease of bone, malign hypocalcaemia during myeloma, osteolytic bone metastasis and fibrous dysplasia of bone. The most important biological effect of bisphosphonates is the reduction of bone remodelling through the inhibition of osteoclastic activity, but there are many clinical and experimental evidences of extra-skeletal biological effects of bisphosphonates. It has been shown that bisphosphonates exert their effects not only on bone tissue cells, but also on those of the immune system with an "immuno-modulating" effect, influencing the production of pro- and anti-inflammatory cytokines and changing the molecular expression involved in the immune processes and anti-inflammatory response. Although the available data are conflicting, there are several reports concerning the beneficial effects of bisphosphonates in controlling the progression of chronic joint inflammatory diseases, suggesting a wider use for these therapeutic agents in clinical practice.

Bisphosphonate therapy in rheumatoid arthritis

Focal bone damage and generalized bone loss are features of rheumatoid arthritis (RA). The introduction of TNFalpha antagonists has radically improved the management of RA by providing a means of slowing or preventing the occurrence of focal bone damage. However, some patients with severe RA have contraindications to TNFalpha antagonist therapy and others either fail to respond or fail to tolerate TNFalpha antagonists. In addition, whether TNFalpha antagonists effectively combat generalized bone loss remains unknown. Bisphosphonates can prevent generalized bone loss. Their main target is the osteoclast, which has been identified as the culprit in focal bone damage caused by inflammatory diseases. As a result, the potential effects of bisphosphonates on focal bone damage related to RA are generating strong interest. Although results from the few studies in humans have been disappointing, new insights into the mechanisms of action of amino-bisphosphonates and recent data obtained in animals, most notably with new-generation bisphosphonates, have rekindled the hope that bisphosphonates may be beneficial in RA. We review herein the main studies of the effects of bisphosphonate therapy on focal bone damage and generalized bone loss in patients with RA.

Bisphosphonate therapy improves the outcome of conventional periodontal treatment: results of a 12-month, randomized, placebo-controlled study

BACKGROUND

Bone loss in periodontitis results from inflammatory reactions that stimulate osteoclastic bone resorption. Bisphosphonates inhibit bone resorption and increase bone mass. This study evaluated the effect of bisphosphonate therapy as an adjunct to non-surgical periodontal treatment in patients with moderate to severe chronic periodontitis.

METHODS

Patients were randomized (2:1) to one of two bisphosphonate therapies or placebo for 1 year. All patients received non-surgical periodontal treatment (scaling, root planing) and periodontal maintenance therapy every 3 months. Clinical assessments at baseline and 6 and 12 months included clinical attachment level (CAL), probing depth (PD), and bleeding on probing (BOP). Periodontal bone mass was assessed by dental radiographs at baseline and 12 months using fractal analysis and digital subtraction radiography (DSR).

RESULTS

Seventy patients were randomized, 43 to the bisphosphonate group and 27 to the placebo group. Bisphosphonate therapy significantly improved CAL, PD, and BOP relative to the placebo group during the 6- to 12-month period (CAL, P = 0.0002; PD, P = 0.0156; BOP, P = 0.0079). There was no difference in the change in periodontal bone mass between the bisphosphonate and placebo groups as measured by fractal analysis and DSR.

CONCLUSION

These data suggest that bisphosphonate treatment improves the clinical outcome of non-surgical periodontal therapy and may be an appropriate adjunctive treatment to preserve periodontal bone mass.

Effects of rheumatoid arthritis on bone

The effects of rheumatoid arthritis on bone include structural joint damage (erosions) and osteoporosis. The latter may lead to increased risk for fractures, which are associated with increased morbidity and mortality. Osteoporosis in rheumatoid arthritis is characterized by a complexity of risk factors, including primary osteoporosis risk factors in addition to inflammation, immobilization, and use of corticosteroids. Quantitative assessment of periarticular and generalized bone loss in rheumatoid arthritis may be reliable indicators of future disease course and potential response variables in intervention studies. The osteoclast cell in rheumatoid arthritis plays a crucial role in the development of erosions and periarticular and generalized osteoporosis, suggested to be mediated through the osteoprotegerin/receptor activator of Nuclear Factor (NF)-kappabeta/receptor activator of NF-kappabeta ligand signaling system. Based on an improved understanding of this biology, new treatment opportunities exist.