Response of bone mineral density to once-weekly administration of risedronate

Bone mineral density response to long-term bisphosphonate treatment and discontinuation in a real-world clinical service

OBJECTIVE

Bisphosphonate treatment does not increase bone mineral density (BMD) in all subjects particularly at the femoral neck (FN). Our aim was to evaluate the relationship between response to oral bisphosphonate (oBP) at the FN and change in BMD following discontinuation.

METHODS

Data was collected retrospectively from postmenopausal women on oBP for ≥3 years, attending a real-world metabolic clinic at initiation of oBP, discontinuation, and 1-2 years post discontinuation. Improvement in BMD ≥4% in the FN and ≥5% for the lumbar spine (LS) were deemed clinically meaningful and used as least significant change (LSC) values. We divided subjects based on FN BMD response and compared outcomes between responders and non-responders after oBP discontinuation.

RESULTS

Of the 213 subjects, 32.1% showed an increase ≥LSC at the FN compared to 57.1% at the LS on treatment (p<0.0001). FN responders had lower BMD levels at pre-treatment baseline than non-responders both at the FN (0.58 vs. 0.62 g/cm²; p=0.003) and LS (0.76 vs 0.79 g/cm²; p=0.044). Off-treatment, more subjects lost BMD ≥LSC at FN in the responder group than in the non-responder group (37.5% vs. 14.2%; p<0.001). BMD remained above pre-treatment levels in responders after a median follow-up of 1.52 years.

CONCLUSION

BMD response at FN is suboptimal in patients on oBP and is much less common than LS response. FN responders tend to lose the accumulated bone quickly off-treatment, though BMD remains above pre-treatment levels. These observations suggest that new approaches may be needed to optimise osteoporosis management in real-world patients.

Factors associated with inadequate responses to risedronate in Japanese patients with osteoporosis

Factors associated with an inadequate response (IR) to bisphosphonates have been reported in many countries, but not in Japan, where the approved dose is half the global dose. We analyzed factors associated with IR to risedronate in Japanese patients with osteoporosis. This was a post hoc analysis of 1261 Japanese osteoporosis patients who received risedronate for 1 year in phase III trials. IR was defined as more than one new vertebral fracture (VF) and/or negative change in lumbar spine bone mineral density (BMD) at 1 year. Various baseline and follow-up variables were examined for potential contribution to IR. Of the 1261 subjects, 118 exhibited an IR. At baseline, IR was associated with a higher BMD, lower levels of bone turnover markers (BTM) (serum bone-specific alkaline phosphatase, urinary N-terminal telopeptide of type 1 collagen and C-terminal telopeptide of type 1 collagen), and serum 25-hydroxyvitamin D [25(OH)D] below 16 ng/mL. BTM changes were blunted at 6 months in subjects with IR. On simple regression analysis, all the above variables and poor drug adherence were associated with an IR. On multivariate regression analysis, factors associated with IR were high BMD, vitamin D deficiency at baseline and low BTM at baseline, or a decreased BTM response at 6 months. Low serum 25(OH)D and BTM as well as high BMD at baseline were independent predictors of an IR to risedronate in Japan. These results emphasize the importance of the assessment of serum 25(OH)D and BTM in the management of osteoporosis with bisphosphonates.

Relationship between baseline characteristics and response to risedronate treatment for osteoporosis: data from three Japanese phase III trials

We evaluated the influence of baseline age, bone mineral density (BMD), and serum levels of vitamin D on the response to risedronate treatment. Risedronate consistently increased BMD, but our results suggest vitamin D supplementation may be necessary to achieve optimal treatment effect. Furthermore, early intervention may help prevent bone fractures.

INTRODUCTION

We aimed to investigate the influence of baseline age, BMD, and vitamin D insufficiency on the response to risedronate treatment.

METHODS

Data regarding 1447 patients was obtained from the registries of three phase III clinical trials of risedronate. The response to treatment was expressed in terms of BMD increase and occurrence of new vertebral fractures. The patients were stratified by baseline values for age (<65, 65-72, and ≥72 years), lumbar spine BMD T-score (osteoporotic, <-2.5; and non-osteoporotic, ≥- 2.5), and serum levels of 25-hydroxyvitamin D (deficient, <21 ng/mL; and non-deficient, ≥21 ng/mL).

RESULTS

Risedronate consistently increased lumbar spine BMD in all the groups, with similar percentage and absolute increments in all the age tertiles. The percentage, but not absolute, increment in BMD was significantly higher (p = 0.0003) in the osteoporotic than that in the non-osteoporotic patients (baseline). Of the 1330 patients whose baseline serum levels of 25-hydroxyvitamin D were available, 44.7% had vitamin D deficiency (<20 ng/mL), while 89.2% had insufficiency (<30 ng/mL). The percentage and absolute increments in BMD were lower (p < 0.05 and p < 0.01, respectively) in the vitamin D-deficient than those in the non-deficient patients. New vertebral fractures occurred in 1.5 and 0.8% of the osteoporotic and non-osteoporotic patients, respectively (end of the treatment).

CONCLUSIONS

Therapeutic response in elderly patients is consistent, but early initiation of risedronate treatment may help prevent fractures. Risedronate-induced increase in BMD is lower in patients with vitamin D deficiency, suggesting that vitamin D supplementation is important to achieve optimal treatment response.

Bone material properties in trabecular bone from human iliac crest biopsies after 3- and 5-year treatment with risedronate

Long-term effects of risedronate on bone mineral maturity/crystallinity and collagen cross-link ratio in triple iliac crest biopsies of osteoporotic women were evaluated. In this double-blinded study, 3- and 5-year treatment with risedronate arrested the tissue aging encountered in untreated osteoporosis and in osteoporosis treated with other antiresorptives. This effect may be contributing to risedronate's antifracture efficacy.

INTRODUCTION

Risedronate is widely used in the treatment of osteoporosis. It reduces bone turnover, increases BMD, and decreases fracture risk. To date, there are no data available on the long-term effects of risedronate on bone material properties in humans.

MATERIALS AND METHODS

Osteoporotic women enrolled in the VERT-NA trial received either risedronate (5 mg/day, orally) or placebo for up to 5 years. All subjects received calcium. They also received vitamin D supplementation if deficient at baseline. Triple iliac crest biopsies were collected from a subset of these subjects at baseline, 3 years, and 5 years. Mineral maturity/crystallinity and collagen cross-link ratio was measured in these biopsies using Fourier transform infrared imaging.

RESULTS

Patients that received placebo exhibited increased mineral maturity/crystallinity and collagen cross-link ratio after 3 and 5 years compared with baseline values. On the contrary, patients that received risedronate retained baseline values in both bone material indices throughout. A more spatially detailed analysis revealed that this was achieved mainly through beneficial effects on active bone-forming areas. Surprisingly, patients that received risedronate achieved premenopausal values at bone-forming areas in both indices after 5 years of treatment.

CONCLUSION

Long-term treatment with risedronate affects bone material properties (mineral maturity/crystallinity and collagen cross-link ratio) and arrests the tissue aging apparent in untreated osteoporosis. These changes at the material level of the bone matrix may contribute to risedronate's rapid and sustained antifracture efficacy in osteoporotic patients.

Update on osteoporosis therapy

Osteoporosis is a skeletal disorder characterized by compromised bone strength that predisposes a person to increased fracture risk. Fractures are often associated with increased morbidity, higher mortality, loss of function and even psychological consequences. Pharmacotherapeutic interventions (e.g., bisphosphonates, selective estrogen receptor modulators, calcitonin, and teriparatide) in women with postmenopausal osteoporosis provide substantial reduction in fracture risk over and above risk reduction with calcium and vitamin D supplementation alone. The importance of nutritional support along with an appropriate exercise regimen, avoiding smoking and excessive alcohol use is to be emphasized along with the pharmacologic approach to osteoporosis. Despite the effectiveness of therapy with pharmacologic agents, most patients who start therapy do not remain on treatment for more than 1 year.

Preventing osteoporosis-related fractures: an overview

Osteoporosis is a skeletal disorder characterized by compromised bone strength, which predisposes a person to increased risk of fracture. In the United States, 26% of women aged > or =65 years and >50% of women aged > or =85 years have osteoporosis. Over 1.5 million fractures per year are attributable to osteoporosis; these fractures result in 500,000 hospitalizations, 800,000 emergency room visits, 2.6 million physician visits, 180,000 nursing home placements, and 12 billion dollars to 18 billion dollars in direct healthcare costs each year. Fracture also results in loss of function and has a negative impact on psychological status. In recognition of the importance of bone health, the US Surgeon General has, for the first time, issued a comprehensive report on bone health and treatment. The report recommends a pyramidal approach to osteoporosis treatment that includes calcium and vitamin D supplementation, physical activity, and fall prevention as the first line in fracture prevention. The second level consists of treating secondary causes of osteoporosis; the third and top level consists of pharmacotherapy. Pharmacotherapeutic interventions (e.g., bisphosphonates, selective estrogen receptor modulators, calcitonin, and teriparatide) in women with postmenopausal osteoporosis provide substantial reduction in fracture risk over and above risk reduction with calcium and vitamin D supplementation alone. Despite the effectiveness of therapy, most patients who receive treatment do not remain on treatment for >1 year. An important approach to reducing the rate of fractures is first to target our treatments to patients at high risk for fracture and then to develop strategies to improve treatment continuation rates.

Risedronate for prevention and treatment of osteoporosis in postmenopausal women

Risedronate sodium is an N-containing bisphosphonate that has been approved for the prevention and treatment of osteoporosis in postmenopausal women. An increase in the rate of bone remodelling is a regular feature of oestrogen withdrawal during the menopausal transition, but excessive remodelling leads to bone fragility. Risedronate and similar compounds reduce the rate of bone remodelling by suppressing the action of osteoclasts. The antifracture efficacy of risedronate is impressive. In large clinical trials of postmenopausal women with osteoporosis-related fracture(s) at entry, the risk of incident vertebral and non-vertebral fractures was reduced by approximately 40%. In older women at risk for hip fracture, incident hip fractures were also reduced by approximately 40%. Antifracture efficacy develops within the first 6 months, and treatment has been followed for as long as 5 years without deleterious effects on bone. We await reports of experience with risedronate in 'real-world' cases of greater complexity (i.e., in patients with co-morbidities and medications that would have excluded them from published clinical trials).

The effect of prophylactic treatment with risedronate on stress fracture incidence among infantry recruits

When subjected to strains or strain rates higher than usual, the bone remodels to repair microdamage and to strengthen itself. During the initial resorption phase of remodeling, the bone is transitorily weakened and microdamage can accumulate leading to stress fracture. To determine whether short-term suppression of bone turnover using bisphosphonates can prevent the initial loss of bone during the remodeling response to high bone strain and strain rates and potentially prevent stress fracture, we conducted a randomized, double-blind, placebo-controlled trial of 324 new infantry recruits known to be at high risk for stress fracture. Recruits were given a loading dose of 30 mg of risedronate or placebo daily for 10 doses during the first 2 weeks of basic training and then a once a week maintenance dose for the following 12 weeks. Recruits were monitored by biweekly orthopedic examinations during 15 weeks of basic training for stress fractures. Bone scans for suspected tibial and femoral stress fractures and radiographs for suspected metatarsal stress fractures were used to verify stress fracture occurrence. By the intention-to-treat analysis and per-protocol analysis, there was no statistically significant difference in the tibial, femoral, metatarsal, or total stress fracture incidence between the treatment group and the placebo. We conclude that prophylactic treatment with risedronate in a training population at high risk for stress fracture using a maintenance dosage for the treatment of osteoporosis does not lower stress fracture risk.

Osteoporosis management in the new millennium

The prevalence of osteoporosis in all US postmenopausal women is 17%, and it is as high as 30% in women older than 65. All postmenopausal women should be encouraged to have adequate daily calcium and vitamin D intake, to exercise regularly, and to avoid tobacco and excessive alcohol use. Although the clinical impact and cost-effectiveness of osteoporosis screening tools remain to be established, a rational approach based on current evidence involves using National Osteoporosis Foundation guidelines, Simple Calculated Osteoporosis Risk Estimation, or Osteoporosis Risk Assessment Instrument clinical decision rules to decide when a postmenopausal woman should undergo further evaluation.

Injectable bisphosphonates in the treatment of postmenopausal osteoporosis

Osteoporosis is a "silent" disease and the patient has usually no clue of it until the occurrence of a fragility fracture. Prevention requires a continuous daily treatment that could be uncomfortable to the patient. Besides the recently introduced weekly oral schedules, injectable bisphosphonates have often been used as an off-label option to ameliorate compliance. In general, although with different efficiency, almost all injectable bisphosphonates can improve bone mineral density and suppress bone resorption markers. The effect of intravenous infusions of bisphosphonates are, to a large extent, similar to equivalent intramuscular administrations, but doses and dosing intervals represent the critical issues. Pain at the injection site and acute phase reactions are relatively common to intramuscular clodronate and intravenous infusions of nitrogen-containing bisphosphonates, respectively. Under certain circumstances, intermittent treatment with injectable bisphosphonates might represent a feasible alternative when compliance is at risk.

Oral weekly ibandronate prevents bone loss in postmenopausal women

OBJECTIVES

To investigate the efficacy, safety, and dose-response of once-weekly oral ibandronate in the prevention of postmenopausal bone loss.

DESIGN

This was a multi-centre, placebo-controlled, double-blind, randomized, 24-month phase II/III dose-finding study.

SETTING

Primary care units in 14 osteoporosis centres.

SUBJECTS

A total of 630 women were stratified into four strata according to time since menopause (TSM, 1-3 vs. >3 years) and baseline bone mineral density (BMD; normal: T-score > or =1 vs. osteopenic: -2.5 < or = T-score < or = 1) of the lumbar spine.

INTERVENTIONS

Within each stratum women were further randomized to receive once-weekly ibandronate (5, 10, or 20 mg week-1) or placebo for 24 months.

MAIN OUTCOME MEASURES

Efficacy parameters were the relative changes from baseline in spine (L1-4) and hip BMD, and biochemical markers of bone turnover (serum and urinary C-telopeptide of collagen type I (CTx), osteocalcin, and alkaline phosphatase) measured by dual energy X-ray absorptiometry and enzyme immunoassays, respectively.

RESULTS

Once-weekly therapy with ibandronate induced dose-dependent increases in spine and hip BMD. At month 24, differences between the relative changes in spine and hip BMD induced by 20 mg ibandronate and placebo was 4.0 and 2.7%, respectively. Similar or more pronounced differences were seen in osteopenic women of TSM 1-3 years (5.3 and 3.5%) and of TSM >3 years (3.5 and 2.9%), respectively. A dose-dependent suppression of all biochemical markers of bone turnover was observed with significant decreases in the 20 mg dose groups of all strata at month 24. The overall safety results indicated that once-weekly oral ibandronate was well-tolerated at all three doses.

CONCLUSION

Once-weekly oral therapy with 20 mg ibandronate provides an effective and safe therapy for the prevention of postmenopausal bone loss.