Intramuscular neridronate in postmenopausal women with low bone mineral density

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.

Monthly Intramuscular Neridronate for the Treatment of Postmenopausal Osteoporosis: Results of a 6-Year Prospective Italian Study

PURPOSE

Oral bisphosphonates (BPs) are the most commonly used medications for osteoporosis (OP), but their poor gastrointestinal (GI) absorption and tolerance hamper compliance. Intramuscular (IM) neridronate (NE), an amino-BP, is an easy-to-administer, effective, and safe alternative to oral BPs. We assessed the 6-year effects of monthly IM NE on bone mineral density (BMD) and bone turnover biomarkers (BMs) in postmenopausal OP.

METHODS

This single-center, prospective study enrolled postmenopausal osteoporotic outpatients with gastric intolerance to BPs (based on Tuscany Region's law GRT n. 836 20/10/2008). They received 25 mg IM NE once a month (with vitamin D and calcium if necessary) for 6 years. BMD was evaluated at lumbar spine (L1-L4), femoral neck (FN), and total femur (TF) at baseline (BL) and every 12 months afterwards. At BL, month 3, and every 12 months after BL, total and ionized calcium, vitamin D, parathyroid hormone 1-84, bone alkaline phosphatase (BALP), osteocalcin, and N- and C-terminal telopeptides were assayed.

RESULTS

Overall, 60 women (mean age: 62.3 ± 7.5 years) received monthly IM NE for 6 years, with vitamin D and calcium supplementation in 81.3% of cases. Compared to BL, BMD increased significantly already after 1 year at all sites (4.5 ± 0.9% for L1-L4, 4.5 ± 0.8% for TF, and 2.1 ± 0.6% for FN, P ≤ 0.05), and the changes were maintained over time, whereas FN further improved up to year 3 and remained stable afterwards (P ≤ 0.05). All BMs, except for total calcium and BALP, progressively decreased over time (P ≤ 0.05). No fractures and significant adverse events were reported.

CONCLUSION

The monthly administration of IM NE represents a manageable and effective option, in terms of BMD and bone BM improvement, for the long-term treatment of postmenopausal OP women with gastric intolerance to BPs. This trial is registered with ClinicalTrials.gov Identifier: NCT03699150.

Successful neridronate therapy in pregnancy-associated osteoporosis

Pregnancy-associated osteoporosis is a rare condition. The pathogenesis is probably multifactorial but has not yet been completely clarified. In this case report, a 38-year-old woman was referred to hospital after suffering an acute, non-traumatic back pain one month after delivering her first child. The radiological examination revealed four vertebral fractures. Bone mineral density was reduced, particularly at spine level. Biochemical tests were within normal range, except for increased urinary deoxypyridinoline and a slight reduction of the serum 25-OH vitamin D level. The patient was treated with neridronate, calcium and cholecalciferol. After one month, the patient was free of pain and DXA measurement after six months showed a marked recovery of bone mineral density at the spine and hip level.

Clodronate: new directions of use

Clodronate is the father of bisphosphonates. For over three decades it has been subject of study in biological and clinical areas, proving to be an extremely interesting molecule from different points of view. It has been the first drug for osteoporosis that can be administered pulsatorily (once every 15 days or once a week). This, along with good tolerability, has been the first cause of its success, when there were no solid data in literature about its antifracture efficacy. There are three published studies that prove its antifracture effect: two by McCloskey published in 2004 and 2007 on BMR, and our study about fracture prevention in corticosteroids OP. In these studies a dose of 800 mg/day orally administered or 100 mg/week I.M. was used, and they are basically the same if you consider that clodronate absorption, orally administered, is on average 1.9%. However, a series of works where higher doses were used (1600 mg orally administered) with greater effectiveness on bone mass, especially in higher risk populations, lead us to consider the use of 200 mg i.m. formulation. First of all, we proved densitometric equivalence of 200 mg i.m./14 days and 100 mg i.m./week in a first study; then, in a second study, we proved a greater densitometric efficacy of 200 mg/week compared to 100 mg/week, clearer at femoral level, where the drug had not proven to prevent femoral fracture because of inadequate bone mass increase at that level. Moreover, as for ibandronate case, monthly dose was doubled compared to pivotal trial, in order to maximize the effects on femoral bone mass and therefore prevent femoral fractures. Consequently, on the basis of the risk envelope, whether it is identified according to BMD and the presence of one risk factor at least or more correctly identified through risk chart (FRAX or DeFRA), you can put forward a differential use of 100 mg i.m. and 200 mg i.m., weekly, "off-label" or every 14 days, adjusting doses in relation to fracture risk and painful symptoms gravity, as well as improving its ease of use and therefore assist compliance. Common experience and clinical and biological works have proved that clodronate has an analgesic effect that can be increased by doubling the doses. The analgesic effect is present not only with patients with fractures, but also with patients suffering from osteoarthritis or arthritis. Therefore, the drug would fit well in the therapeutic program of rheumatic patient, also because of its symptomatic effects. Clodronate at small doses (2 mg) could also have protective effects on cartilage (introduction of intra-articular formulation is expected) and at 10-100 fold higher doses it has certainly anti-inflammatory effects and more specifically antimacrophage and anticytokine effects (IL-1, IL-6, TNFalpha, PGE). These effects are amplified by putting clodronate in monolayer liposomes. This drug, therefore, has to be considered as adjuvant in arthritis therapy, whose origin can be linked to a strong osteoclastic activation caused by an increase of cytokines and the RANKL/OPG relationship. It is clear that clodronate can work on cytokine at first and on osteoclastic effector in the end. The drug has been used "off-label" for decades intravenously in complex regional pain syndrome (CRPS type 1) in relation to schemes that change according to different Authors and according to cumulative doses ranging from 3 to 5 g. The introduction on the market of the 200 mg i.m. formulation could allow to get more practical but equally effective schemes. For example, we used this scheme: 200 mg/day for 10 days and then 200 mg every other day for 20 days (cumulative dose of 4 g in a month). Said scheme can be repeated in the following months in particular cases. Results, as for efficacy and lack of relapses, show that clodronate is the leader drug for this syndrome. In recent years, relationship between costs and benefits has started to matter, especially after the creation of some algorithms, such as FRAX, that let us choose patients with a higher fracture risk in 10 years, and after pharmaceutic-economic models that let us calculate FRAX intervention threshold, on the basis of drug price and monitoring, antifracture efficacy, quality of life and how much a community can or wants to spend. In this respect, a sub-analysis of McCloskey's study on people over the age of 75, conducted on 3974 subjects, shows that clodronate is more efficient with patients with a higher fracture risk, calculated according to FRAX. Furthermore, another study by McCloskey revealed that, for a 100-pound/year drug (very similar to clodronate), 'cost effective' intervention threshold is about 7-10%. In conclusion, clodronate prevents fractures, decrease osteo-articular pain, is easy to handle, tolerable and had a great cost/benefit relationship.

Clinical development of neridronate: potential for new applications

Neridronate is an aminobisphosphonate, licensed in Italy for the treatment of osteogenesis imperfecta (OI) and Paget's disease of bone (PDB). A characteristic property of neridronate is that it can be administered both intravenously and intramuscularly, providing a useful system for administration in homecare. In this review, we discuss the latest clinical results of neridronate administration in OI and PDB, as well as in osteoporosis and other conditions. We will focus in particular on the latest evidence of the effect of neridronate on treatment of complex regional pain syndrome type I.

Lower fracture risk in older men with higher sclerostin concentration: a prospective analysis from the MINOS study

Sclerostin is synthesized by osteocytes and inhibits bone formation. We measured serum sclerostin levels in 710 men aged 50 years and older. Bone mineral density (BMD) was measured at the lumbar spine, hip, and distal forearm. Serum sclerostin increased with age (unadjusted r = 0.30, p < 0.001). After adjustment for age, weight, and bioavailable 17β-estradiol, serum sclerostin correlated positively with BMD (r = 0.24 to 0.35, p < 0.001) and negatively with the levels of bone turnover markers (r = - 0.09 to - 0.23, p < 0.05 to 0.001). During a 10-year follow-up, 75 men sustained fragility fractures. Fracture risk was lower in the two upper quintiles of sclerostin combined versus three lower quintiles combined (6.1 versus 13.5%, p < 0.01). We compared fracture risk in the two highest quintiles combined versus three lower quintiles combined using the Cox model adjusted for age, weight, leisure physical activity, BMD, bone width (tubular bones), prevalent fracture, prevalent falls, ischemic heart disease, and severe abdominal aortic calcification. Men with higher sclerostin concentration had lower fracture risk (adjusted for hip BMD, hazard ratio [HR] = 0.55, 95% confidence interval [CI] 0.31 to 0.96, p < 0.05). The results were similar in 47 men with major fragility fractures (adjusted for lumbar spine BMD: HR = 0.39, 95% CI 0.17 to 0.90, p < 0.05). Men who had higher sclerostin and higher BMD (two highest quintiles) had lower risk of fracture compared with men who had lower BMD and lower sclerostin levels (three lower quintiles) (HR = 0.24, 95% CI 0.10 to 0.62, p < 0.005). Circulating sclerostin was not associated with mortality rate or the incidence of major cardiovascular events. Thus, in older men, higher serum sclerostin levels are associated with lower risk of fracture, higher BMD, and lower bone turnover rate.

Bisphosphonate treatment of postmenopausal osteoporosis is associated with a dose dependent increase in serum sclerostin

The benefits coming from long-term treatment of postmenopausal osteoporosis with bisphophonates are limited by a coupled decrease in bone formation. The objective of this study is to determine whether this decrease in bone formation is associated with changes in serum levels of the WNT signaling antagonist sclerostin or Dickkopf-1 (DKK1). This is an ancillary observation from patients participating in a 12 months, phase 2, randomized clinical trial. We analyzed 107 patients given either monthly intramuscular neridronate (12.5, 25 or 50 mg) or placebo. Serum C-terminal telopeptide of type I collagen (sCTX, a bone-resorption marker) decreased by 61%, 75% and 73% in the 12.5, 25 and 50 mg dose groups, respectively. Mean changes in bone alkaline phosphatase (bAP) at 12 months were -47%, -60.0% and -52.6% in the groups receiving 12.5, 25 or 50 mg neridronate, respectively. Serum DKK1 remained unchanged at all time points in the 3 groups. Serum sclerostin increased versus placebo group gradually and significantly only in patients treated with 25 or 50 mg neridronate monthly, reaching 138-148% of baseline values (P<0.001). Changes in serum sclerostin at 12 months were negatively correlated with changes in bAP (P<0.001) even when data were adjusted for sCTX changes and only treated patients were included. In conclusions, decreased bone formation after several months of bisphosphonate therapy is associated with increased serum levels of sclerostin. This might suggest that Wnt signaling may play a role in the coupling between resorption and formation.

Long-term effects of neridronate and its discontinuation in patients with primary hyperparathyroidism

In patients with primary hyperparathyroidism (PHPT) not suitable for surgical correction, a skeletal protection with bisphosphonates is considered a reasonable option, but the long-term effects after treatment discontinuation are not well known. Sixty postmenopausal women with PHPT were given 400-600 IU vitamin D(3) daily and 100 mg neridronate IV every 2 months for 2 years with 2 additional years of follow-up without antiresorptive therapies. Bone mineral density (BMD) progressively rose by 6.7 ± 7.6% (SD) and by 2.9 ± 4.5% at the spine and femoral neck, respectively. During follow-up, mean BMD progressively fell, but after 2 years it was still 3.9 ± 5.5% higher than baseline values at the spine. Bone alkaline phosphatase and serum C-telopeptide of type I collagen decreased significantly within 6 months (28 and 49% versus baseline, respectively) and rose to baseline values within 6-12 months during follow-up. Serum PTH significantly rose from baseline during treatment, but it remained significantly higher than baseline during follow-up. The PTH changes were significantly correlated with serum 25-hydroxyvitamin D (25OHD) levels. In conclusion, in this study we observed that in patients with mild PHPT treatment with bisphosphonates is associated with the expected changes in bone-turnover markers and that the significant increases of both hip and spine BMD are partially maintained for at least 2 years after treatment discontinuation at the vertebral site. The marked increases in serum PTH levels, particularly in subjects with low 25OHD levels, persist after treatment discontinuation and this raises the suspicion that this might reflect a worsening of PHPT.

Comparison of intravenous and intramuscular neridronate regimens for the treatment of Paget disease of bone

Aminobisphosphonates actually represent the most common treatment for Paget disease of bone (PDB). In a previous study we demonstrated that either zoledronic acid (4 mg) or neridronate (200 mg) given as a single intravenous infusion showed a similar short-term efficacy in achieving biochemical remission in up to 90% of patient nonresponders to pamidronate. In this study we compared the long-term (36 months) effects of a same neridronate dose (200 mg) given as an intravenous (100-mg infusion for 2 consecutive days) or intramuscular (25-mg injection weekly for 2 months) regimen in 56 patients with active PDB. All patients were advised to receive calcium plus vitamin D supplementation throughout the study period. At 6 months, 92.6% and 96.5% of patients receiving intravenous and intramuscular neridronate, respectively, achieved a therapeutic response [defined as normalization of alkaline phosphatase (ALP) levels or a reduction of at least 75% in total ALP excess]. The response to treatment was significantly correlated with baseline ALP and 25-hydroxyvitamin D [25(OH)D] levels at 6 months. The decrease in ALP levels was highest in patients with higher baseline total or bone-specific ALP levels and with higher 25(OH)D levels at 6 months. Response rates were maintained at 12 months but decreased progressively at 24 and 36 months without significant differences between the two neridronate regimens. Both regimens were well tolerated. The only relevant side effect was an acute-phase response occurring in 14% of the patients. In conclusion, these results indicate that a 200-mg intramuscular neridronate course has a similar efficacy as an intravenous infusion of the same dose for the treatment of PDB and might be of particular value for patients intolerant to oral bisphosphonates and unwilling or unable to undergo intravenous infusions.