Two-year results of once-weekly administration of alendronate 70 mg for the treatment of postmenopausal osteoporosis

Interventions to enhance medication adherence

BACKGROUND

People who are prescribed self-administered medications typically take less than half the prescribed doses. Efforts to assist patients with adherence to medications might improve the benefits of prescribed medications, but also might increase their adverse effects.

OBJECTIVES

To update a review summarizing the results of randomized controlled trials (RCTs) of interventions to help patients follow prescriptions for medications for medical problems, including mental disorders but not addictions.

SEARCH STRATEGY

Computerized searches were updated to September 2004 without language restriction in MEDLINE, EMBASE, CINAHL, The Cochrane Library, International Pharmaceutical Abstracts (IPA), PsycINFO and SOCIOFILE. We also reviewed bibliographies in articles on patient adherence and articles in our personal collections, and contacted authors of original and review articles on the topic.

SELECTION CRITERIA

Articles were selected if they reported an unconfounded RCT of an intervention to improve adherence with prescribed medications, measuring both medication adherence and treatment outcome, with at least 80% follow-up of each group studied and, for long-term treatments, at least six months follow-up for studies with positive initial findings.

DATA COLLECTION AND ANALYSIS

Study design features, interventions and controls, and results were extracted by one reviewer and confirmed by at least one other reviewer. We extracted adherence rates and their measures of variance for all methods of measuring adherence in each study, and all outcome rates and their measures of variance for each study group, as well as levels of statistical significance for differences between study groups, consulting authors and verifying or correcting analyses as needed.

MAIN RESULTS

For short-term treatments, four of nine interventions reported in eight RCTs showed an effect on both adherence and at least one clinical outcome, while one intervention reported in one RCT significantly improved patient compliance, but did not enhance the clinical outcome. For long-term treatments, 26 of 58 interventions reported in 49 RCTs were associated with improvements in adherence, but only 18 interventions led to improvement in at least one treatment outcome. Almost all of the interventions that were effective for long-term care were complex, including combinations of more convenient care, information, reminders, self-monitoring, reinforcement, counseling, family therapy, psychological therapy, crisis intervention, manual telephone follow-up, and supportive care. Even the most effective interventions did not lead to large improvements in adherence and treatment outcomes. Six studies showed that telling patients about adverse effects of treatment did not affect their adherence.

AUTHORS' CONCLUSIONS

Improving short-term adherence is relatively successful with a variety of simple interventions. Current methods of improving adherence for chronic health problems are mostly complex and not very effective, so that the full benefits of treatment cannot be realized. High priority should be given to fundamental and applied research concerning innovations to assist patients to follow medication prescriptions for long-term medical disorders.

Review of Treatment Modalities for Postmenopausal Osteoporosis

This review summarizes and updates data presented at recent annual Southern Medical Association conferences on postmenopausal osteoporosis. As part of any osteoporosis treatment program, it is important to maintain adequate calcium and 25-hydroxyvitamin D levels either through diet or supplementation. Among the available pharmacologic therapies, the bisphosphonates alendronate and risedronate have demonstrated the most robust fracture risk reductions-approximately 40 to 50% reduction in vertebral fracture risk, 30 to 40% in nonvertebral fracture risk, and 40 to 60% in hip fracture risk. Ibandronate, a new bisphosphonate, has demonstrated efficacy in reducing vertebral fracture risk. Salmon calcitonin nasal spray and raloxifene demonstrated significant reductions in vertebral fracture risk in pivotal studies. Teriparatide significantly reduced vertebral and nonvertebral fracture risk. Drugs on the horizon include strontium ranelate, which has been shown to reduce vertebral and nonvertebral fracture risk, and zoledronic acid, an injectable bisphosphonate that increased bone density with once-yearly administration.

Alendronate improves bone mineral density in primary biliary cirrhosis: a randomized placebo-controlled trial

Bone loss is a well-recognized complication of primary biliary cirrhosis (PBC). Although it has been suggested that alendronate might improve bone mineral density (BMD) in PBC, no randomized placebo-controlled trial has been conducted. The primary aim of this study was to compare the effects of alendronate versus placebo on BMD and biochemical measurements of bone turnover in patients with PBC-associated bone loss. We conducted a double-blinded, randomized, placebo-controlled trial. Patients with a PBC and BMD t score of less than -1.5 were randomized to receive 70 mg per week of alendronate or placebo over 1 year. BMD of the lumbar spine and proximal femur were measured at entry and at 1 year. Changes from baseline in BMD and biochemical measurements of bone turnover were assessed. Thirty-four patients were enrolled. Seventeen patients were randomized to each arm. After 1 year, a significantly larger improvement (P = .005) in spine BMD was observed in the alendronate group (0.09 +/- 0.03 g/cm2 SD from baseline) compared with the placebo group (-0.003 +/- 0.02 g/cm2 SD from baseline). A larger improvement (P = .046) was also observed in the femoral BMD of alendronate patients versus placebo. BMD changes were independent of concomitant estrogen therapy. The rate of adverse effects was similar in both groups. In conclusion, in patients with PBC-related bone loss, alendronate significantly improves BMD compared with placebo. Although in this study oral alendronate appears to be well tolerated in patients with PBC, larger studies are needed to formally evaluate safety.

Efficacy and Tolerability of Alendronate Once Weekly in Asian Postmenopausal Osteoporotic Women

BACKGROUND:

Osteoporosis has become a major health problem worldwide, and the incidence is rising in Asian countries. The aminobisphosphonates are potent inhibitors of bone resorption and are currently the mainstay of treatment for postmenopausal osteoporosis. Dosing frequency will likely affect tolerability and adherence to treatment.

OBJECTIVE:

To assess the tolerability and efficacy of a once-weekly aminobisphosphonate preparation in improving bone mineral density (BMD) and bone turnover markers in osteoporotic Asian women.

METHODS:

Chinese postmenopausal women with osteoporosis were randomized to receive either alendronate 70 mg once weekly plus calcium carbonate 500 mg daily (n = 29%) or calcium carbonate 500 mg daily (n = 29%) for one year. BMD was measured by dual energy X-ray absorptiometry. Markers of bone formation and bone resorption included plasma total alkaline phosphatase and urine N-telopeptides.

RESULTS:

Treatment with alendronate 70 mg once weekly for one year resulted in significant BMD improvement of 6.1% at the spine, 5.6% at the femoral neck, and 3.5% at the total hip. There was no significant change in the BMD values in the calcium group (spine 1.4%, femoral neck −0.2%, total hip 0%). The BMD response in the alendronate group was significantly different from that in the calcium group at all time points, and the difference was detectable as early as after 3 months of treatment (ANOVA p < 0.001%). The changes remained significant after adjusting for age, age at menarche, and years since menopause (p < 0.001%). Similarly, the reductions in bone markers at 12 months were significantly different between the 2 treatment groups (plasma total alkaline phosphatase: alendronate 27.9%, calcium 5.4%; urine N-telopeptide: alendronate 55.6%, calcium 11.2%; both p < 0.001%). The alendronate regimen was well tolerated, without significant adverse events.

CONCLUSIONS:

The results confirmed that once-weekly alendronate was efficacious in increasing BMD and reducing bone turnover and was well tolerated in Asian women.

Pharmacokinetics/pharmacodynamics of bisphosphonates: use for optimisation of intermittent therapy for osteoporosis

Bisphosphonates suppress osteoclast-mediated bone resorption and are widely used in the management of osteoporosis. Daily oral administration of alendronic acid and risedronic acid have been shown to reduce the risk of vertebral and non-vertebral fractures. Once-weekly regimens with these bisphosphonates are pharmacologically equivalent to daily regimens. Regimens with treatment-free intervals longer than 1 week present an attractive therapeutic option as they may offer additional patient convenience and long-term adherence to treatment. However, until recently, such regimens, usually referred to as intermittent or cyclical, have not shown any convincing antifracture efficacy in clinical trials, probably because of the empirical manner in which the design of these regimens has been approached. Investigation of pharmacokinetics/pharmacodynamics of bisphosphonates may help in the design of effective intermittent dosage regimens. Bisphosphonates are poorly absorbed from the gastrointestinal tract and about 50% of the absorbed drug is taken up selectively by the skeleton, while the rest is excreted unaltered in urine. Bisphosphonates exert their action at the bone surface, where they are taken up by the osteoclasts during bone resorption. Therefore, when describing the pharmacokinetics of bisphosphonates in relation to the pharmacodynamics, the amount of bisphosphonate at the skeleton should be accounted for. Few of the reported clinical pharmacokinetic studies addressed this issue. This is partly due to the absence of study design elements to account for skeletal binding of the drugs. Pharmacokinetic studies have also been hampered by technical difficulties in determining the concentration of bisphosphonates in serum and urine. Moreover, most clinical pharmacokinetic (but also pharmacokinetic/pharmacodynamic) studies have primarily used noncompartmental analysis, leaving out the distinct advantages of modelling and simulation techniques. Clinically, the primary action of bisphosphonates can be assessed by the measurement of biochemical markers of bone resorption. Recent studies indicate that the pattern of these markers during bisphosphonate treatment may be predictive of antifracture efficacy; however, only limited data are available for the development of pharmacokinetic/pharmacodynamic models that are able to predict the response of these markers to different treatment regimens with bisphosphonates. Recently, pharmacokinetic/pharmacodynamic models for response to bisphosphonates have been described and, at present, some of them are being used in the design of bisphosphonate regimens with long drug-free intervals.

Monthly oral ibandronate therapy in postmenopausal osteoporosis: 1-year results from the MOBILE study

Once-monthly (50/50, 100, and 150 mg) and daily (2.5 mg; 3-year vertebral fracture risk reduction: 52%) oral ibandronate regimens were compared in 1609 women with postmenopausal osteoporosis. At least equivalent efficacy and similar safety and tolerability were shown after 1 year.

INTRODUCTION

Suboptimal adherence to daily and weekly oral bisphosphonates can potentially compromise therapeutic outcomes in postmenopausal osteoporosis. Although yet to be prospectively shown in osteoporosis, evidence from randomized clinical trials in several other chronic conditions shows that reducing dosing frequency enhances therapeutic adherence. Ibandronate is a new and potent bisphosphonate with antifracture efficacy proven for daily administration and also intermittent administration with a dose-free interval of >2 months. This report presents comparative data on the efficacy and safety of monthly and daily oral ibandronate regimens.

MATERIALS AND METHODS

MOBILE is a 2-year, randomized, double-blind, phase III, noninferiority trial. A total of 1609 women with postmenopausal osteoporosis were assigned to one of four oral ibandronate regimens: 2.5 mg daily, 50 mg/50 mg monthly (single doses, consecutive days), 100 mg monthly, or 150 mg monthly.

RESULTS

After 1 year, lumbar spine BMD increased by 3.9%, 4.3%, 4.1%, and 4.9% in the 2.5, 50 /50, 100, and 150 mg arms, respectively. All monthly regimens were proven noninferior, and the 150 mg regimen superior, to the daily regimen. All monthly regimens produced similar hip BMD gains, which were larger than those with the daily regimen. All regimens similarly decreased serum levels of C-telopeptide, a biochemical marker of bone resorption. Compared with the daily regimen, a significantly larger proportion of women receiving the 100 and 150 mg monthly regimens achieved predefined threshold levels for percent change from baseline in lumbar spine (6%) or total hip BMD (3%). All regimens were similarly well tolerated.

CONCLUSIONS

Monthly ibandronate is at least as effective and well tolerated as the currently approved daily ibandronate regimen in postmenopausal osteoporosis.

Treatment preference and tolerability with alendronate once weekly over a 3-month period: an Israeli multi-center study

BACKGROUND AND AIMS

Osteoporosis is a chronic condition requiring long-term treatment, for which compliance is not easy to achieve. 70 mg of alendronate once weekly (alendronate OW) provides equivalent efficacy to treatment with 10 mg of alendronate once a day (alendronate OD); however, there are relatively few data regarding patient and physician preferences for once-weekly vs daily dosing. The aim of this study was to measure compliance, convenience, tolerance and relative preference of alendronate OW treatment among post-menopausal women with osteoporosis and physician satisfaction, compared with previous treatment with alendronate OD.

METHODS

This open-label, prospective multi-center trial was conducted at 14 hospitals and 150 primary-care community clinics in Israel. Post-menopausal osteoporotic women (n = 3710), who had been treated for at least 1 month with alendronate OD during the preceding year, were treated with alendronate OW for 12 weeks. Convenience, satisfaction, tolerance and relative preference of alendronate OW during the trial, compared with past experience with alendronate OD, were recorded.

RESULTS

Overall, 96% of the patients preferred the alendronate OW regimen to the 10-mg daily dosage. Nearly all (98%) the patients who completed 12 weeks of treatment, including 77% of patients who had previously discontinued daily treatment due to intolerance, were willing to continue the alendronate OW regimen. Patient-reported compliance with dosing instructions was over 98%. Alendronate OW was well tolerated; only 2.8% of patients discontinued, due to adverse events. Physicians were highly satisfied with the once-weekly dosing regimen, and recommended continued treatment with alendronate OW for 99% of the patients.

CONCLUSIONS

The majority of post-menopausal women with osteoporosis, including those who were previously intolerant to alendronate OD, preferred alendronate OW to the once-daily dosing regimen. It is important to consider patient preference when selecting the appropriate treatment for osteoporosis.

Effect of L-000845704, an alphaVbeta3 integrin antagonist, on markers of bone turnover and bone mineral density in postmenopausal osteoporotic women

The alphaVbeta3 integrin (vitronectin receptor) plays a pivotal role in bone resorption. We hypothesized that L-000845704, an alphaVbeta3 integrin antagonist, would potently inhibit bone resorption, thereby increasing bone mass as assessed by bone mineral density (BMD) in women with postmenopausal osteoporosis. In a multicenter, randomized, double-blind, placebo-controlled, 12-month study, 227 women (average 63 yr) with low lumbar spine or femoral neck BMD were randomly assigned to receive 100 or 400 mg L-000845704 once daily (qd), 200 mg L-000845704 twice daily (bid), or placebo. L-000845704 increased lumbar spine BMD (2.1, 3.1, and 3.5% for the 100-mg-qd, 400-mg-qd, and 200-mg-bid treatment groups, respectively, vs. -0.1% for placebo; P < 0.01 all treatments vs. placebo). Only 200 mg L-000845704 bid significantly increased BMD at the hip (1.7 vs. 0.3% for placebo; P < 0.03) and femoral neck (2.4 vs. 0.7% for placebo; P < 0.05). No L-000845704 group increased total body BMD. All doses of L-000845704 resulted in a similar approximately 42% decrease from baseline of N-telopeptide cross-links (P < 0.001 vs. placebo). L-000845704 was generally well tolerated; adverse events resulting in discontinuation from the study were relatively infrequent. In conclusion, the antiresorptive effect of the alphaVbeta3 integrin antagonist L-000845704 translated into significant increases in lumbar spine BMD. Furthermore, 200 mg L-000845704 bid provided efficacy at the hip sites. These data suggest that the alphaVbeta3 integrin antagonist L-000845704 could be developed as an effective therapeutic agent for osteoporosis.

Treatment of Postmenopausal Osteoporosis

Osteoporosis is a major public health burden. The most devastating outcome of osteoporosis is fracture, which results in increased morbidity and mortality. These fractures most often occur in the vertebrae and indicate an increased risk of future vertebral and hip fractures. Consequently, it is important to identify patients at risk for fracture and to intervene with pharmacologic therapies, lifestyle changes, or both to reduce the frequency of the first or subsequent fracture. Moreover, because osteoporosis is a chronic condition requiring long-term therapy, factors that increase compliance and improve safety and efficacy outcomes should be considered when treatment is selected. The bisphosphonates alendronate and risedronate can substantially reduce the risk of both hip and vertebral fractures. Furthermore, these agents are available in once-weekly formulations that provide patients with a convenient alternative to a daily dosage regimen. Alendronate and the selective estrogen-receptor modulator raloxifene provide considerable vertebral fracture protection after 1 year of treatment, and risedronate markedly reduces the rate of vertebral and nonvertebral fractures after 6 months of treatment. Data suggest that calcitonin-salmon nasal spray also reduces the risk of vertebral, but not nonvertebral, fractures. Raloxifene decreases the risk of nonvertebral fracture, but only in women with severe prevalent vertebral fractures. Although evidence supports the efficacy of hormone therapy, the risks should be carefully considered before treatment is begun. In addition to the antiresorptive therapies, teriparatide is a daily injectable anabolic treatment that is effective in reducing the risk of vertebral and nonvertebral fractures. Therefore, clinicians and patients have several options for reducing the risk of fracture and achieving optimal dosing convenience.

Postmenopausal osteoporosis and alendronate

Osteoporosis is a systemic metabolic disorder associated with a decreased bone mass and resistance. Bisphosphonates suppress bone resorption and bone turnover by a mechanism that depends on their structure. They are characterized by low gastrointestinal absorption. In postmenopausal women, alendronate (ALN) reduces bone resorption markers and increases bone mineral density (BMD) in the lumbar spine, femoral neck, and total body. Individuals receiving ALN have been studied for up to 10 years with an apparent linear increase in BMD over that time period estimated at 13.7% at the lumbar spine. Treatment with ALN reduced the risk of both vertebral and non-vertebral fractures, including hip fractures, in postmenopausal women with osteoporosis. Direct comparisons of the results obtained with different antiresortive agents is difficult, because the designs of the respective studies, populations and other factors. However, the meta-analysis of available publications seems to indicate that ALN reduces the relative risk of vertebral fractures in a greater proportion than any other agent. Furthermore, ALN prevents the reduction in BMD after hormone replacement therapy discontinuation.

Discovery, clinical development, and therapeutic uses of bisphosphonates

OBJECTIVE

To review the literature concerning the history, development, and therapeutic uses of bisphosphonates.

DATA SOURCES

English-language articles were identified through a search of MEDLINE (through December 2004) using the key word bisphosphonate. Reference lists of pivotal studies, reviews, and full prescribing information for the approved agents were also examined.

STUDY SELECTION AND DATA EXTRACTION

Selected studies included those that discussed the discovery and initial applications of bisphosphonates, as well as their historical development, pharmacokinetic and pharmacodynamic properties, and current therapeutic uses.

DATA SYNTHESIS

Bisphosphonates structurally resemble pyrophosphates (naturally occurring polyphosphates) and have demonstrated similar physicochemical effects to pyrophosphates. In addition, bisphosphonates reduce bone turnover and resist hydrolysis when administered orally. The information gained from initial work with etidronate generated a considerable scientific effort to design new and more effective bisphosphonates. The PCP moiety in the general bisphosphonate structure is essential for binding to hydroxyapatite and allows for a number of chemical variations by changing the 2 lateral side chains (designated R(1) and R(2)). The R(1) side chain determines binding affinity to hydroxyapatite, and the R(2) side chain determines antiresorptive potency. Accordingly, each bisphosphonate has its own characteristic profile of activity.

CONCLUSIONS

The bisphosphonates reduce bone turnover, increase bone mass, and decrease fracture risk and therefore have a significant place in the management of skeletal disorders including osteoporosis, Paget's disease, bone metastases, osteogenesis imperfecta, and heterotopic ossification.

Treatment of osteoporosis in chronic kidney disease and end-stage renal disease

As glomerular filtration rate (GFR) declines from age-related bone loss or disease that specifically induces a decline in GFR, there are a number of metabolic bone conditions that may accompany the decline in GFR. These metabolic bone conditions span a spectrum from mild-to-severe secondary hyperparathyroidism in early stages of chronic kidney disease (CKD) to the development of additional heterogeneous forms of bone diseases each with its distinctly quantitative bone histomorphometric characteristics. Osteoporosis can also develop in patients with CKD and ESRD for many reasons beyond age-related bone loss and postmenopausal bone loss. The diagnosis of osteoporosis in patients with severe CKD or end-stage renal disease (ESRD) is not as easy to do as it is in patients with postmenopausal osteoporosis (PMO)--neither fragility fractures nor The World Health Organization bone mineral density criteria can be used to diagnose osteoporosis in this population since all forms of renal bone disease may fracture or have low "T scores". The diagnosis of osteoporosis in patients with CKD/ESRD must be done by first the exclusion of the other forms of renal osteodystrophy, by biochemical profiling or by double tetracycline-labeled bone biopsy; and the finding of low trabecular bone volume. In such patients, preliminary data would suggest that oral bisphosphonates seem to be safe and effective down to GFR levels of 15 mL/min. In patients with stage 5 CKD who are fracturing because of osteoporosis or who are on chronic glucocorticoids, reducing the oral bisphosphonate dosage to half of its usual prescribed dosing for PMO seems reasonable from known bisphosphonate pharmacokinetics, though we do need better scientific data to fully understand bisphosphonate usage in this population.

The Role of Calcium in Osteoporosis Drug Therapy

Great advances have been made in the field of osteoporosis treatment and prevention in recent years that have led to the availability of powerful new drugs. These drugs are viewed by patients and physicians as a major breakthrough in the management of osteoporosis. Unfortunately, this view has led many to ignore the importance of concurrent calcium supplementation to ensure the maximum benefit from these drugs, as evidenced by the recent decline in use of calcium supplements. As the majority of patients fail to consume the minimum recommended dietary intake of calcium, it is critical to recommend calcium supplements to raise total daily calcium intake to the levels needed to ensure maximum efficacy of osteoporosis treatments. Furthermore, osteoporosis drug labeling should be strengthened to encourage proper use of these drugs in combination with calcium supplements.

Rapid prevention of vertebral fractures associated with osteoporosis

Osteoporosis affects postmenopausal women and patients on glucocorticoid therapy. Fractures are the most devastating outcome. Patients who experience an osteoporotic vertebral fracture are at substantial risk of experiencing another within 1 year. Risk can be reduced rapidly with antiresorptives. Risedronate reduced the risk of vertebral fracture in patients with post-menopausal or glucocorticoid-induced osteoporosis after 1 year by up to 71% in prospective studies. In post hoc analyses, significant reductions in clinical vertebral fractures were demonstrated after 6 months with risedronate and 1 year with alendronate and raloxifene. Rapid reduction in fracture risk is achievable with the potent therapeutic agents available.

The roles of bone mineral density, bone turnover, and other properties in reducing fracture risk during antiresorptive therapy

Osteoporosis is a skeletal disorder characterized by compromised bone strength and increased risk of fracture. Properties related to bone strength include rate of bone turnover, bone mineral density, geometry, microarchitecture, and mean degree of mineralization. These properties (with or without bone density) are sometimes collectively referred to as bone quality. Antiresorptive agents may reduce fracture risk by several separate but interrelated effects on these individual properties. For example, antiresorptive agents have been reported to reduce bone turnover, stabilize or increase bone density, preserve or improve microarchitecture, reduce the number or size of resorption sites, and improve mineralization. Although changes in bone architecture and mineralization are not currently measurable in clinical practice, bone turnover is assessed easily in vivo and affects the other bone properties. Moreover, antiresorptive therapies that produce larger decreases in bone turnover markers together with larger increases in bone mineral density are associated with greater reductions in fracture risk, especially at sites primarily composed of cortical bone such as the hip. Reductions in fracture risk are the most convincing evidence of good bone quality. Data from well-designed randomized clinical trials with up to 10 years of continuous antiresorptive therapy have shown that certain antiresorptive agents effectively reduce fracture risk and (together with extensive preclinical data) suggest no deleterious effects on bone quality.

Upper gastrointestinal tolerability of once weekly alendronate 70 mg with concomitant non-steroidal anti-inflammatory drug use

BACKGROUND

Both oral bisphosphonates and non-steroidal anti-inflammatory drugs have the potential to irritate the upper gastrointestinal mucosa, and are frequently used by the same patient population.

AIM

To determine the rate of upper gastrointestinal adverse events with once weekly alendronate 70 mg and concomitant non-steroidal anti-inflammatory drug use.

METHODS

A post hoc analysis was performed on 222 patients who received both medications concomitantly during a 3-month placebo-controlled study. A total of 450 (224 alendronate; 226 placebo) postmenopausal women and men with osteoporosis were randomized. Concomitant non-steroidal anti-inflammatory drug users were defined as patients who received > or =7 continuous days of any dose of a dual cyclo-oxygenase-1 and cyclo-oxygenase-2 inhibiting non-steroidal anti-inflammatory drug, a selective cyclo-oxygenase-2 inhibitor, or aspirin. A survival analysis was performed, and significance assessed. Logistic regression was used to assess consistency of treatment effect on rate of upper gastrointestinal adverse events across non-steroidal anti-inflammatory drug subgroups.

RESULTS

Similar percentages of alendronate (52.7%) and placebo (46.0%) patients used non-steroidal anti-inflammatory drugs regularly. Among concomitant non-steroidal anti-inflammatory drug users, 11 alendronate and 11 placebo patients experienced upper gastrointestinal adverse events (9.3% and 10.8%, respectively, P = 0.744). Logistic regression revealed no significant interaction (P = 0.722) between alendronate and concomitant non-steroidal anti-inflammatory drug use.

CONCLUSION

Based on this subgroup analysis, once weekly alendronate 70 mg used concomitantly with non-steroidal anti-inflammatory drugs, did not increase upper gastrointestinal adverse events relative to placebo over 3-months.

Treatment of metabolic bone disease in patients with chronic renal disease: A perspective for rheumatologists

As glomerular filtration rate (GFR) declines from age-related bone loss or disease that specifically induces a decline in GFR, there are a number of metabolic bone conditions that may accompany the decline in GFR. These metabolic bone conditions span a spectrum from mild-to-severe secondary hyperparathyroidism in early stages of chronic kidney disease (CKD) to the development of additional heterogeneous forms of bone diseases each with distinctly quantitative bone histomorphometric characteristics. Osteoporosis can also develop in patients with CKD and end-stage renal disease (ESRD) for many reasons beyond age-related bone loss and postmenopausal (PMO) bone loss. Diagnosing osteoporosis in patients with severe CKD or ESRD is not as easy to do as it is in patients with PMO. The diagnosis of osteoporosis in patients with CKD/ESRD must be done by first excluding other forms of renal osteodystrophy, through biochemical profiling or by double tetracycline-labeled bone biopsy and the finding of low trabecular bone volume. In such patients oral bisphosphonates seem to be safe and effective down to GFR levels of 15 mL/min. In patients with stage 5 CKD, who are fracturing because of osteoporosis or who are on chronic glucocorticoids, reducing the oral bisphosphonate dosage to half of its usual prescribed dosing for PMO seems reasonable from known bisphosphonate pharmacokinetics. However, we need better scientific data to fully understand bisphosphonate usage in this population. This paper deals with the evidence available to understand management of patients with CKD and opinions on what might be a reasonable clinical approach where evidence is currently lacking.

Pharmacological Management of Severe Postmenopausal Osteoporosis

The most devastating consequence of osteoporosis is bone fracture, particularly at the vertebral or femoral level. As defined by the WHO, patients with osteoporosis who have had one or more fragility fractures have severe osteoporosis. Those who sustain a vertebral fracture represent a particularly vulnerable group whose risk of another vertebral fracture within the following year is increased by a factor of 3-5. In addition, the presence of a vertebral fracture is associated with an increased risk of hip fracture. In light of these data, treatment of established osteoporosis is extremely important to prevent other fragility fractures. This review examines the therapies approved by the US FDA for the treatment of osteoporosis that have been shown to reduce the incidence of new fractures in patients with established osteoporosis. We evaluated the mechanisms of action, available formulations, efficacy in preventing fractures and increasing bone mineral density (BMD), duration of treatment, adverse effects and contraindications to use of alendronic acid (alendronate), risedronic acid (risedronate), calcitonin, raloxifene and teriparatide. All these drugs are able to prevent new vertebral fractures in patients with established osteoporosis. Only alendronic acid and risedronic acid have also been shown to reduce the risk of fracture at the femoral level, but they are contraindicated in patients with upper gastrointestinal diseases. Calcitonin is a good option in subjects with back pain because of its analgesic effect. Raloxifene is useful when patients have high plasma lipid levels or a family history of breast cancer. Teriparatide is indicated in subjects with very low BMD and multiple vertebral fractures. Patient characteristics should determine selection of therapy but the decision is always difficult and fraught with uncertainty.

Optimizing Administration of Bisphosphonates in Women with Postmenopausal Osteoporosis

Bisphosphonates have been approved in the US as oral medication for the treatment of osteoporosis for about 10 years. Efficacy data exists for fracture reduction for the commonly used oral bisphosphonates but not for intravenous formulations. Based on the mechanism of action that appears to allow for longer intervals between doses, it has been possible to extend the treatment choices from the original more demanding daily oral dose to an array of options including oral weekly and more recently monthly treatment (so-called cyclical therapy) and intravenous treatment with various administration regimens. The possibility of treatment with an annual (or less frequent) intravenous administration with zoledronic acid exists. Compliance, adverse effects, and efficacy vary with each administration regimen.

Clinical Pharmacology of Potent New Bisphosphonates for Postmenopausal Osteoporosis

Bisphosphonates are potent inhibitors of bone resorption, used in most bone diseases associated with high bone resorption levels. Several bisphosphonates, developed to prevent and treat postmenopausal osteoporosis, increase bone mineral density and decrease biochemical markers of bone turnover, and more importantly, reduce fracture risk. Alendronate and risedronate have proven their efficacy to reduce vertebral and hip fracture risk among postmenopausal osteoporotic women, using daily regimens. Weekly intermittent schedules, however, are now most commonly prescribed, because they have shown pharmacologic equivalence to the daily regimen. Ibandronate has been the first bisphosphonate to demonstrate vertebral fracture risk reduction using an intermittent regimen. Studies using ibandronate as intravenous injections every 3 months are under way. Zoledronic acid may also be an attractive option for the treatment of postmenopausal osteoporosis if a large ongoing trial proves that a single annual injection of this compound allows osteoporotic fracture risk reduction.

Therapeutic effects of alendronate 35 mg once weekly and 5 mg once daily in Japanese patients with osteoporosis: a double-blind, randomized study

The efficacy and safety of treatment with oral alendronate (ALN) 35 mg once weekly for 52 weeks were compared with those of ALN 5 mg once daily in a double-blind, randomized, multicenter study of Japanese patients with involutional osteoporosis. The primary efficacy end point was the percent change from baseline in the lumbar spine (L1-L4) bone mineral density (BMD) after 52 weeks of treatment. In this study, 328 patients were randomized to ALN 5 mg once daily (160 patients) or ALN 35 mg once weekly (168 patients). The adjusted mean percent change from baseline in lumbar spine (L1-L4) BMD after 52 weeks of treatment was 5.8% and 6.4% in the once-daily group and the once-weekly group, respectively (both P < 0.001). The 95% confidence interval for the difference in spine BMD change between the two treatment groups was -0.31% to 1.48%, indicating that the two regimens were therapeutically equivalent, since the confidence interval fell entirely within the predefined equivalence criterion (+/-1.5%). The time course of the spine BMD increase was also similar for both regimens. Regarding total hip BMD, mean changes from baseline at 52 weeks were 2.8% and 3.0% in the once-daily group and the once-weekly group, respectively. In addition, the bone markers (urinary deoxypyridinoline, urinary type-I collagen N-telopeptides, and serum bone-specific alkaline phosphatase) were reduced to a similar level by either treatment throughout the treatment period. The tolerability and safety profiles were also similar between the treatment groups. Taken together, we conclude that the efficacy and safety of the ALN 35-mg once-weekly regimen are therapeutically equivalent to those of the ALN 5-mg once-daily regimen.

Comparison of the effects of alendronate and risedronate on bone mineral density and bone turnover markers in postmenopausal osteoporosis

The aim of the study was to compare the effects of once-weekly alendronate sodium and daily risedronate sodium treatment on bone mineral density (BMD) and bone turnover markers in postmenopausal osteoporotic subjects. For this purpose, 50 patients were included in this study and randomly classified into two groups. Group I (n=25) received risedronate (5 mg/day) and group II (n=25) received alendronate Na (70 mg/week). The study duration was limited to 12 months. The efficacy of the treatment was evaluated by BMD measurements at spine and hip at 6th and 12th months of the treatment, as well as by the measurement of bone turnover markers such as serum osteocalcin (OC), bone-specific alkaline phosphatase (BASP), urine deoxypyridinoline (DPD) and calcium/creatine ratio in 24-h urine at 1st, 3rd, 6th and 12th months. The evaluation of the changes in BMD in all regions revealed a significant increase in BMD in both groups compared to baseline values except for spine (L2-L4) in alendronate group at 6th and 12th month and femoral neck in risedronate group at 6th month. However, the difference in percentage increase in BMD measurements was not statistically significant between the two groups at 6th and 12th months. In both groups, serum OC, BSAP and urine DPD were found to be significantly attenuated at 1st month of the treatment period, and continued to be lowered throughout the 3rd, 6th and 12th months (P<0.05). However, there was no statistically-significant difference between both groups of patients (P>0.05). In conclusion, our results suggest that both treatment protocols provide treatment options of similar efficiency for postmenopausal osteoporosis, and have almost-similar effects in enhancing the BMD and in slowing the bone turnover. Risedronate seems to have a more potent effect in the spinal region than that of alendronate, although this potency was not statistically significant.

Bone loss and the evolving role of bisphosphonate therapy in prostate cancer

Androgen deprivation therapy (ADT) can result in significant loss of bone mineral density (BMD) but to date, there are no prospective studies that document the true severity of bone loss and resulting fracture rates. In the general population, however, the incidence of low BMD is increasing in elderly men. Men suffer more morbidity and mortality from fractures associated with low BMD than women. Problems of underdiagnosis and undertreatment in men can be addressed with enhanced awareness of the risk factors for bone loss in men and the available treatment options. Guidelines for diagnosis of low BMD in women can probably be applied to men. Treatment options have not been studied as extensively in men. For men treated with ADT for prostate cancer, however, use of intravenous zoledronic acid at the initiation of ADT has been shown to prevent and even reverse bone loss. Although the routine use of bisphosphonates to prevent bone loss is not yet recommended, zoledronic acid is a logical choice of therapy in men who have low BMD at baseline or who develop bone loss during the course of therapy. In addition to its effects on BMD, zoledronic acid has also been shown to decrease skeletal morbidity in men with metastatic hormone-refractory prostate cancer. Whether zoledronic acid or other bisphosphonates might actually prevent or delay the development of bone metastases remains to be studied in randomized clinical trials.

Bone safety of long-term bisphosphonate treatment

Bisphosphonates (BPs) are widely used in osteoporosis and other bone diseases. Treatment of osteoporosis would, in many instances, involve continued use of BP for a number of years, so it is pertinent to examine skeletal consequences of long-term BP use. Through a non-systematic review of the literature, this commentary considers the reduction in bone turnover and retention in the skeleton with regard to the long-term safety of BP use. BPs normalize bone turnover rates within weeks and no further suppression is seen during long term use, documented up to 10 years. This indicates that the BP retained in bone does not augment or contribute to the pharmacological activity of newly administered BP. Therefore, pharmacologically, long term treatment is not different from short term treatment. Multiple studies have shown that reductions in bone turnover are associated with increased bone density, more homogeneous mineralization, and reduced fracture risk. The amount of BP retained in bone after 10 years of alendronate treatment was estimated at 75 mg per 2 kg mineral, using a pharmacokinetic model for a dose of 10 mg per day. This small fraction, which is unevenly distributed between cancellous and cortical bone, seems unlikely to change bone mechanical properties. Taken together, the known mechanism of action of potent BPs and the experience accrued from treating a large number of patients, including up to 10 years follow-up in controlled trials, have identified only beneficial BP effects on bone.

Understanding treatments for bone loss and bone metastases in patients with prostate cancer: a practical review and guide for the clinician

Prostate cancer patients are at risk for developing bone loss and bone metastases. Clinicians prescribing ADT should appreciate the potential effects of ADT on BMD as well as the morbidity and mortality that can result from osteoporotic fractures. Measures to address the evaluation of patients and when to treat patients with significant bone loss have been discussed. Bisphosphonates effectively prevent loss of BMD in prostate cancer patients. Treatment of prostate cancer patients with established bone metastases with zoledronic acid should be considered strongly based on the results of the Saad study and other studies of patients with bone metastases with other malignancies. Zoledronic acid is approved by the US FDA for use in men with metastatic hormone-refractory prostate cancer and in the European Union for any patient with bone metastases, including prostate cancer patients,because of the beneficial impact of zoledronic acid on skeletal-related events. There is no validated method to determine which patients might benefit most from bisphosphonate therapy in this setting. Many questions about the use of bisphosphonate therapy in men with prostate cancer must be addressed, both in terms of the use in bone loss and bone metastases. These questions include: What is the optimal timing of therapy? Which bisphosphonate is best? What is the best dose and dose schedule? Do bisphosphonates effectively decrease skeletal fracture rates in patients with osteoporosis? How long should patients receive therapy? Are bisphosphonate "holidays" warranted? What are the long-term skeletal and renal toxicities? Is there a role for sequencing bisphosphonate therapy either before or after chemotherapy? Is bisphosphonate therapy synergistic with certain chemotherapy or other bone-targeted therapies? Which patients are the most likely to benefit from bisphosphonate therapy? What are clinically significant endpoints of bisphosphonate trials in patients with metastatic disease? Does inhibiting bone turnover also inhibit formation of bone metastases? Preliminary work in these areas has been completed, but more questions than answers are available. Given the rising costs of health care, it is imperative that these questions be addressed to best use the health care dollar while offering high-risk patients the best available therapy. At present, no data suggest that bisphosphonates should be used routinely to prevent BMD loss in men with normal BMD or to prevent the development of bone metastases in men with biochemical relapse. Continuing trials may give us guidance in the future.

Rational use of oral bisphosphonates for the treatment of osteoporosis

Osteoporosis has become a major public health concern worldwide. Significant morbidity, mortality, and health expenditures are associated with osteoporotic fractures. Evidence from randomized controlled trials and meta- analyses supports the efficacy and safety of oral bisphosphonates as first-line pharmacologic agents for the prevention and treatment of osteoporosis. This article reviews the evidence demonstrating the beneficial effects of etidronate, alendronate, and risedronate on improving bone mass and preventing fractures in individuals with or at risk for osteoporosis. Issues surrounding dosing intervals and optimal duration of therapy are also discussed. We conclude that the nitrogen-containing bisphosphonates alendronate and risedronate are safe and efficacious agents in preventing and treating osteoporosis. They are superior to cyclical etidronate in improving appendicular bone mass, and in reducing future risk for nonvertebral fractures. Once-weekly dosing options with alendronate and risedronate are effective and reduce serious adverse drug effects, and therefore, are welcome additions to our therapeutic armamentarium.

Efficacy of intermittent low dose alendronate in Thai postmenopausal osteoporosis

Alendronate has been proven to be effective in the prevention and treatment of postmenopausal osteoporosis with the recommended daily dose of 10 mg. However, a constraining requirement for dosing limited its general acceptance in treatment. Since alendronate is potent and has a long half-life, weekly administration of alendronate in lower total doses might be safer and more convenient. The purpose of this study was to determine the efficacy of low dose once-weekly 20 mg alendronate in Thai postmenopausal women with osteoporosis. Thirty-nine postmenopausal women with osteoporosis received alendronate 20 mg once a week plus 750 mg elemental calcium daily. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at baseline and 6 and 12 months after treatment. Serum C-terminal telopeptide of type I collagen (CTx-I) was measured by electrochemiluminescence immunoassay at baseline and 3 months after treatment. By the end of 1 year, once weekly 20 mg alendronate significantly increased vertebral BMD (+6.2%, p < 0.001 vs baseline) from baseline whereas there was a reduction of 60.7% in serum CTx-I at 3 months. However, the BMD at femur did not increase significantly (+0.64%). Conclusion. Low-dose intermittent once-weekly 20 mg alendronate was effective, cost saving and had a good safety profile in increasing vertebral BMD and stabilizing BMD at the femoral neck in postmenopausal osteoporosis.

Efficacy of Alendronate in Adults with Cystic Fibrosis with Low Bone Density

As adults with cystic fibrosis (CF) have enjoyed incremental increases in longevity over the last few decades, they have also been suffering from low bone density and its clinical manifestations, fractures and kyphosis. We conducted a placebo-controlled, randomized, double-blinded trial of alendronate (10 mg/day orally) (n = 24) compared with placebo (n = 24) for 1 year in 48 patients to improve bone mineral density at the spine as the primary endpoint. All patients received 800 IU of cholecalciferol and 1,000 mg of calcium carbonate. Both groups were similar in age, sex, CF mutations, bone density T scores, renal function, and body mass index at study onset. The alendronate-treated patients gained (mean +/- SD) 4.9 +/- 3.0% and 2.8 +/- 3.2% bone density after 1 year versus placebo, which lost (mean +/- SD) 1.8 +/- 4.0% and 0.7 +/- 4.7%, in spine and femur bone density, respectively (p < or = 0.001 for the spine; p = 0.003 for the femur). Urine N-telopeptide, a bone resorption marker, levels declined in the treatment group more than in the control group (p = 0.002), consistent with the known antiresorptive effects of bisphosphonates. Alendronate was more effective than placebo in improving spine and femur bone mineral density and is a promising agent for the long-term prevention and management of bone disease in patients with CF.

Weekly Oral Alendronic Acid in Male Osteoporosis

OBJECTIVE

To evaluate the efficacy and tolerability of alendronic acid 70mg once weekly for the treatment of male osteoporosis.

PATIENTS AND METHODS

This randomised, double-blind, placebo-controlled, 12-month trial compared the effect of alendronic acid 70mg once weekly or placebo (randomised 2 : 1) on bone mineral density (BMD) in 167 men with spine or hip BMD at least 2 standard deviations (SD) below the mean for young normal white males or nontraumatic fracture. All patients received calcium and vitamin D (colecalciferol). We measured lumbar spine, hip and total body BMD, and biochemical markers of bone turnover. Fractures were collected as adverse events.

RESULTS

Alendronic acid 70mg once weekly produced significant BMD increases from baseline of 4.3% at the spine, 2.1% at the femoral neck, 2.4% at the trochanter, and 1.4% at the total body, which were all significantly greater than placebo (p < 0.05). The increase at the lumbar spine was significant relative to baseline and placebo after 6 months of treatment (p < 0.001). The treatment effect was consistent regardless of BMD, age, height, weight, body mass index (BMI) and hypogonadal status at baseline. Alendronic acid significantly decreased biochemical markers of bone turnover relative to baseline and placebo. Alendronic acid was generally well tolerated, with an incidence of gastrointestinal adverse events similar to placebo.

CONCLUSION

Alendronic acid 70mg administered once weekly is an effective and convenient alternative to daily dosing for the treatment of male osteoporosis.

Management of Bone Loss in Men With Prostate Cancer

PURPOSE

Bone loss is increasingly recognized as a common occurrence in men receiving androgen deprivation therapy (ADT) for prostate cancer. Skeletal metabolism and osteoporosis in men, assessment of bone mineral density (BMD), effects of ADT on BMD, management strategies and potential therapies for osteopenia or osteoporosis in men with prostate cancer are reviewed.

MATERIALS AND METHODS

Relevant literature is reviewed concerning bone loss and osteoporosis in men with and without prostate cancer, techniques of assessing BMD, data on bone loss and fracture risk and management strategies.

RESULTS

The incidence of osteoporotic fractures usually increases a decade later in men than in women. ADT causes significant loss of BMD, which may hasten the development of osteoporosis. Men who are treated with hormonal therapy for an increasing prostate specific antigen and who may live for many years should have baseline BMD assessments. Osteopenia or osteoporosis should be treated to minimize the risk of osteoporotic fracture. Treatment with zoledronic acid seems appropriate since it has been shown to increase BMD in men treated with ADT and to reduce the rate of skeletal related events in men with early hormone refractory prostate cancer with metastatic disease.

CONCLUSIONS

Monitoring BMD is warranted in men contemplating or receiving ADT but prophylactic therapy to prevent bone loss currently is not recommended. Men with evidence of significant bone loss who are receiving ADT should be treated. Zoledronic acid is a logical choice based on available data.

Use of highly potent bisphosphonates in the treatment of osteoporosis

Bisphosphonates are effective inhibitors of bone remodeling. In the clinical setting, these agents prevent bone loss, preserve bone architecture, and improve bone strength. Clinically significant reduction in the risk of spine and nonspine fractures is observed in patients known to be at risk for fracture. When administered appropriately, these drugs are well tolerated and have an excellent safety profile. Potent bisphosphonates are now the preferred treatment option to reduce the fracture risk in men and women with involutional and glucocorticoid-induced osteoporosis.

Co-morbidity in rheumatoid arthritis

Rheumatoid arthritis (RA) affects approximately 0.5-1% of the population and imposes substantial societal costs including an increased risk of work-related disability and accelerated mortality. It is increasingly clear that RA-related co-morbidities, including cardiovascular disease (CVD), infection, osteoporosis, lymphoproliferative malignancy, and peptic ulcer disease, serve as major determinants of disease-associated outcome. In this review, the impact of these select co-morbidities on RA outcome is discussed. In addition, this review explores potential mechanisms underlying their association with RA, the possible iatrogenic role of agents used to treat the disease, and measures aimed at both prevention and treatment of disease-specific co-morbidity.

The aging spine: new technologies and therapeutics for the osteoporotic spine

Osteoporosis results in low-energy fractures of the spine. The load necessary to cause a vertebral fracture is determined by the characteristics related to the vertebral body structure, mineral content, and quality of bone. Radiographic techniques centered on dual X-ray absorptiometry (DXA) permit a determination of bone mass and fracture risk. Current medical therapies principally using bisphosphonate and pulsatile PTH profoundly decrease the risk of fracture (50+%). Fall prevention strategies can further decrease the possibility of fracture. A comprehensive approach to osteoporosis can favorably alter the disease.

Bisphosphonates: new indications and methods of administration

In the course of 2002, several new studies were published confirming the efficacy of bisphosphonate drugs in fracture prevention in patients with osteoporosis. Further evidence was provided of their long duration of action, making intermittent administration possible. The potent bisphosphonate zoledronate can be given at intervals of as long as 1 year and produces changes in bone density and in markers of bone turnover comparable with those seen with conventional daily oral dosing with alendronate or risedronate. If such regimens are proven to prevent fractures, their convenience is likely to result in their widespread adoption and potentially an increase in compliance with these medications. Further evidence has been presented documenting the value of bisphosphonates in preventing the skeletal complications of malignancy, and possibly in reducing mortality in patients with breast cancer. The role of bisphosphonates in osteogenesis imperfecta was further confirmed, and novel roles in ankylosing spondylitis, myelofibrosis, and hypertrophic pulmonary osteoarthropathy were suggested.

Comparison of change in bone resorption and bone mineral density with once-weekly alendronate and daily risedronate: a randomised, placebo-controlled study

OBJECTIVE

To compare the effects of alendronate (ALN) 70 mg once weekly (OW) and risedronate (RIS) 5 mg daily between-meal dosing on biochemical markers of bone turnover and bone mineral density (BMD) in postmenopausal women with osteoporosis.

RESEARCH DESIGN AND METHODS

This was a 3-month, randomised, double-blind, placebo-controlled study with a double-blind extension to 12 months. The study enrolled 549 postmenopausal women (ALN 219, RIS 222 and placebo (PBO) 108) who were > or =60 years of age at outpatient centres.

MAIN OUTCOME MEASURES

The primary endpoint was reduction in urine N-telopeptides of type 1 collagen (NTx) corrected for creatinine level at 3 months. Secondary parameters included change in BMD at the spine and hip at 6 and 12 months, NTx at 1, 6 and 12 months, and serum bone-specific alkaline phosphatase (BSAP) at 1, 3, 6 and 12 months. Adverse experiences (AEs) were recorded throughout the study for an assessment of treatment safety profiles and tolerability.

RESULTS

Over 3 months, ALN produced a significantly greater mean reduction in urine NTx than did RIS (-52% vs -32%, p < 0.001), which was maintained at 12 months. ALN produced a significantly greater mean BMD increase than did RIS at 6 months, and it was maintained at 12 months at the lumbar spine (4.8% vs 2.8%, p < 0.001) and total hip (2.7% vs 0.9%, p < 0.001), as well as at the trochanter and femoral neck. Significant reductions in BSAP with ALN compared to RIS were maintained over the 12 months of treatment. Study size did not allow for meaningful assessment of differences in fracture rates. Tolerability was generally similar between ALN, RIS and PBO, and the incidence of upper GI AEs causing discontinuation and oesophageal AEs was similar in the ALN and RIS groups.

CONCLUSION

In this study, ALN 70 mg OW produced a 50% greater reduction in bone resorption as measured by urine NTx and significantly greater increases in lumbar spine and hip BMD than did RIS 5 mg daily. The treatments had similar safety profiles and were generally well-tolerated. Additional studies are needed comparing OW ALN with OW RIS, which became available after the commencement of the present study.

Disintegration/dissolution profiles of copies of Fosamax (alendronate)

OBJECTIVE

Poor quality has been reported for some generics and other copies of original products. We performed a pilot study to compare the disintegration/dissolution profiles of FOSAMAX (alendronate) 70 mg tablets with those of copies of FOSAMAX that were manufactured outside the United States.

RESEARCH DESIGN AND METHODS

We used the standard United States Pharmacopeia (USP) disintegration method to evaluate FOSAMAX 70 mg tablets and 13 copies. At least 12 (n = 12) dosage units were tested for each product (except Fosmin, n = 10). The dissolution profiles of FOSAMAX and one representative copy were also compared.

RESULTS

Nine copies (Osteomax, Defixal, Fosmin, Endronax, Osteomix, Genalmen, Fixopan, Osteoplus, and Fosval) disintegrated two- to ten-fold faster than FOSAMAX. Three other copies (Neobon, Regenesis, and Ostenan) disintegrated at least five-fold slower than FOSAMAX. Neobon is a softgel capsule, so special consideration was given to this different dosage form. One copy (Arendal) did not fall into either category but exhibited potentially large inter- and intra-lot variability. Dissolution of alendronate from Regenesis lagged behind that from FOSAMAX.

CONCLUSION

Slower disintegration may reduce efficacy because bisphosphonates must be taken in the fasting state and contact with food or even certain beverages severely reduces bioavailability. Faster disintegration (or the use of gel-caps or other alterations to the drug formulation) could increase the risk of esophagitis, an adverse event associated with prolonged contact of the esophagus with bisphosphonates. These disintegration and dissolution results suggest that important differences may exist between FOSAMAX and its copies with regard to bioavailability, pharmacokinetics, and clinical efficacy and safety profiles. Additional testing is warranted to evaluate the pharmacokinetics and clinical safety of these copies.