Long-term effects of a treatment course with oral alendronate of postmenopausal osteoporosis

Alendronate prevents cyclosporin A-induced osteopenia in the rat

Post-transplantation bone disease is an increasingly recognized clinical entity whose etiology is multifactorial. The immunosuppressant agent cyclosporine-A (CsA) has repeatedly been shown experimentally to induce a high-turnover osteopenic state. Alendronate (Alen.) is a new generation bisphosphonate having far greater antiresorptive potency than previous bisphosphonates. It inhibits osteoclast resorption in vitro and in vivo without adversely affecting bone mineralization. This study was designed to investigate whether alendronate could prevent CsA-induced osteopenia in the rat. Forty-eight 8-month-old male Sprague Dawley rats were randomized into four groups to receive the following for 28 days: (1) CsA vehicle (veh.) p.o. daily and alendronate vehicle subcutaneously (s.c.) twice/week, (2) CsA 15 mg/kg p.o. daily and Alen. veh. s.c. twice/week, (3) Alen. 70 micrograms/kg s.c. twice/ week and CsA veh. p.o. daily, and (4) CsA 15 mg/kg p.o. daily and Alen. 70 micrograms/kg s.c. twice/week. Rats were weighed and bled and serum was assayed serially for calcium, PTH, 1,25(OH)2vit.D, and osteocalcin. Tibiae were removed following sacrifice on day 28, after double demeclocycline and calcein labeling, for histomorphometric analysis. Treated groups were compared to the vehicle-treated control. We confirmed previous findings that CsA produces elevated 1,25(OH)2 vitamin D and serum osteocalcin levels. Alendronate treatment by itself decreased osteocalcin by day 28 and resulted in a marginal decrease in serum total calcium on day 14. The histomorphometry findings reconfirmed that the administration of CsA induces a state of high-turnover osteopenia. Alendronate prevented CsA's adverse effects, particularly in maintaining trabecular bone volume, presumably by decreasing bone remodeling. Alendronate would seem to hold therapeutic promise in post-transplantation bone disease.

Can alendronate help my osteoporosis?

Bone is an active tissue, undergoing continuous remodeling to renew and replace the skeleton. Remodeling involves resorption (breakdown) followed by formation.

Bisphosphonate therapy

The bisphosphonates are long-lived synthetic analogs of pyrophosphate, a natural, short-lived inhibitor of bone. Oral doses share similar qualities (ie, they inhibit bone resorption, poor absorption, and potential gastrointestinal irritants), but each one has a unique spectrum of potency and a probable mechanism of action. The parent compound, etidronate, was first used in multicentered trials for the treatment of primary osteoporosis and showed some success in increasing bone density and perhaps controlling fracture rates. The recently approved drug alendronate is a more potent agent than etidronate, produces a greater increase in bone density, and decreases fractures. Oral and intravenous pamidronate have similar positive effects on bone density. Studies with tiludronate, risedronate, and clodronate show similar promise as therapeutic agents.

Effect of three years of oral alendronate treatment in postmenopausal women with osteoporosis

OBJECTIVE

Oral alendronate sodium is a potent, specific inhibitor of osteoclast-mediated bone resorption. To assess its efficacy and safety, a 3-year, randomized, double-blind, multicenter study of 478 postmenopausal women with osteoporosis was conducted.

PATIENTS AND METHODS

Subjects received either placebo, alendronate 5 or 10 mg/day for 3 years, or 20 mg/day for 2 years followed by 5 mg/day for 1 year (20/5 mg). All subjects received 500 mg/day of supplemental calcium. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry (DXA).

RESULTS

After 3 years, alendronate 10 mg induced marked increases in BMD of the lumbar spine (9.6 +/- 0.4%), femoral neck (4.7 +/- 0.7%) and trochanter (7.4 +/- 0.6%) (mean +/- SE; each P < or = 0.001) versus decreases of 0.8 to 1.6% with placebo. Progressive increases at these sites in the alendoronate 10 mg group were significant during both the second and third years. Alendronate 10 mg increased total body BMD (1.6 +/- 0.3%, P < or = 0.001), and prevented loss but did not increase BMD at the 1/3 forearm site. Alendronate 20/5 mg was no more effective, whereas alendronate 5 mg was significantly less effective than 10 mg at all sites. Bone turnover decreased to a stable nadir over 3 months for resorption markers (urine deoxypyridinoline) and over 6 months for formation markers (alkaline phosphatase and osteocalcin). Mean loss of stature was reduced by 41% in alendronate treated subjects (P = 0.01).

CONCLUSION

The safety profile of alendronate was similar to that of placebo. At 10 mg, there were no trends toward increased frequency of any adverse experience except for abdominal pain, which was usually mild, transient, and resolved with continued treatment. Thus, alendronate appears to be an important advance in the treatment of osteoporosis in postmenopausal women.

Mineral density gain in vertebrae of osteoporotic women on oral pamidronate reverts a year after treatment discontinuance

Long-term treatment with 200 mg dry weight/day of pamidronate (APD) by oral route has been proposed to increase bone mineral density (BMD) in postmenopausal osteoporotic women. However, there is widespread concern over the possibility of bone metabolism "freezing" by protracted use of medication liable to inhibit bone resorption. Accordingly, an open population of 39 osteoporotic women was studied in order to determine BMD variations in lumbar vertebrae and femoral neck and to confirm whether given APD doses increase bone mineralization. A parallel group of osteoporotic women was likewise evaluated to determine the potential reversibility of such effect on discontinuing treatment. Results were beneficial at both skeletal sites in subjects on APD therapy, disclosing at 18 months treatment 9.0% mean peak mineral gain versus basal status at lumbar spine. In the few responders completing 4 years of treatment, mean differences versus basal status were +4.9% in vertebrae and +6.2% at femoral neck. In lumbar vertebrae there was a rapid trend in mineral gain up to 18 months on treatment, which declined thereafter to a quarter of its early rate. Concurrently, in the group of 21 baseline-matched women, effects were evaluated after discontinuing daily APD administration one year (n = 11) or two years (n = 7) later. In both subgroups, there was a loss in lumbar (-7.1% and -9.8% respectively; p<0.01) and femoral neck BMD (-2.2% and -4.2% respectively; p: n.s.) on performing measurement one year after APD withdrawal. Furthermore, after three years treatment and subsequent discontinuance, three patients presented bone loss in lumbar vertebrae and minimal changes at femoral neck one year after APD withdrawal. Therefore, APD induces moderate BMD gain which proves reversible on discontinuing therapy, so that it seems unlikely that this compound should "freeze" bone metabolism to a significant extent. However, the precise degree of such reversibility requires evaluation in larger series.

Effects of oral clodronate on bone mineral density in patients with relapsing breast cancer

The high prevalence of bone metastases in breast cancer and the risk that spinal and femoral osteoporosis may add further morbidity provide a rationale for bisphosphonate therapy in patients with skeletal metastases from mammary carcinoma. We investigated the effects of oral clodronate given during 9 months, with a 24-month follow-up, on bone mineral density (BMD), on biochemical markers of bone remodeling, and on osseous complications in 67 women with documented relapsing breast cancer, aged 58.7 +/- 1.5 years (x +/- SEM). Patients with active cancer disease were randomly allocated to two groups, with or without clodronate treatment (1600 mg/day, orally). Twenty-six women considered in complete remission (52.4 +/- 2.4 years) were also studied. Expressed in deviation from gender- and age-matched normals (z score), base-line BMD at the levels of lumbar spine (LS), femoral neck (FN), and midfemoral shaft (FS) was +0.10 +/- 0.22 vs. -0.12 +/- 0.25, +0.03 +/- 0.19 vs. -0.54 +/- 0.24, and +0.08 +/- 0.14 vs. -0.02 +/- 0.22, in patients with active breast cancer and in subjects in remission, respectively. After 9 months of treatment, fasting urinary calcium to creatinine ratio was lower (0.26 +/- 0.04 vs. 0.40 +/- 0.04 mmol/mmol creatinine, p < 0.02) and serum osteocalcin was stabilized (-2.1 +/- 1.1 vs. +7.0 +/- 3.3 micrograms/L, as compared with pretreatment values, p < 0.02), in the clodronate-treated group. The rate of osseous complications (pathological fracture, hypercalcemic episode, scintigraphic or radiological evidence of metastasis development, chemo- or radiotherapy for bone disease progression) was 28.8 events per 100 patient-year in the clodronate-treated group vs. 39.0 in controls, and 31.5 vs. 40.5, after 9 and 15 months of follow-up, respectively. In 15 women without evident LS bone metastasis (7 clodronate-treated and 8 controls), LS BMD increased in the clodronate-treated group by +5.2 +/- 2.5% vs. -0.3 +/- 1.4%, and +8.1 +/- 4.7 vs. -0.9 +/- 1.7, after 10.3 +/- 0.4 and 17.3 +/- 1.2 months, respectively (p < 0.01), as compared with pretreatment values. These results indicate that clodronate treatment decreased bone turnover and attenuated cancer-related bone morbidity. In addition, clodronate increased LS BMD in apparently unaffected bone of women with relapsing breast cancer.

Protein-tyrosine phosphatase activity regulates osteoclast formation and function: inhibition by alendronate

Alendronate (ALN), an aminobisphosphonate used in the treatment of osteoporosis, is a potent inhibitor of bone resorption. Its molecular target is still unknown. This study examines the effects of ALN on the activity of osteoclast protein-tyrosine phosphatase (PTP; protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48), called PTPepsilon. Using osteoclast-like cells generated by coculturing mouse bone marrow cells with mouse calvaria osteoblasts, we found by molecular cloning and RNA blot hybridization that PTPepsilon is highly expressed in osteoclastic cells. A purified fusion protein of PTPepsilon expressed in bacteria was inhibited by ALN with an IC50 of 2 microM. Other PTP inhibitors--orthovanadate and phenylarsine oxide (PAO)-inhibited PTPepsilon with IC50 values of 0.3 microM and 18 microM, respectively. ALN and another bisphosphonate, etidronate, also inhibited the activities of other bacterially expressed PTPs such as PTPsigma and CD45 (also called leukocyte common antigen). The PTP inhibitors ALN, orthovanadate, and PAO suppressed in vitro formation of multinucleated osteoclasts from osteoclast precursors and in vitro bone resorption by isolated rat osteoclasts (pit formation) with estimated IC50 values of 10 microM, 3 microM, and 0.05 microM, respectively. These findings suggest that tyrosine phosphatase activity plays an important role in osteoclast formation and function and is a putative molecular target of bisphosphonate action.

Osteoporosis: the need for comprehensive treatment guidelines

Osteoporosis is a debilitating disease that results in nearly 1.3 million fractures per year in the United States. The cost of treating these fractures has been estimated to be as high as $10 billion per year. These costs are expected to more than double during the next 50 years unless comprehensive programs of prevention and treatment are initiated. Both pharmacologic and nonpharmacologic interventions (eg, diet and exercise) have been shown to have a significant impact on the incidence of osteoporosis, depending on the time of their application. Unfortunately, osteoporosis is often not diagnosed until after fractures have occurred, when it may be too late for treatment to have a major impact. To be most effective, therapy should be started early, before serious bone loss has occurred. Because of its efficacy and relatively low acquisition cost, long-term hormone replacement therapy (HRT) is considered first-line pharmacologic therapy for the prevention of osteoporosis. However, for various reasons, less than 25% of US women who might benefit from HRT are receiving it. Aside from HRT, the only other products approved by the US Food and Drug Administration for the treatment of osteoporosis are salmon calcitonin and alendronate. Several other agents are under development, including sustained-release fluoride and other products in the bisphosphonate class. The development and adoption of early detection programs and treatment guidelines are crucial to help ease the economic burden of osteoporosis. These guidelines should incorporate preventive measures such as diet and exercise, risk assessment through proper screening programs, and the appropriate use of pharmaceutical products. The purpose of this paper is to discuss relevant economic issues associated with osteoporosis and discuss the need for a management algorithm that could be used to more efficiently prevent and treat this disease. We conclude that further modeling is needed to determine which programs and treatments are most cost-effective within each at-risk subgroup. As clinicians better understand the need for preventive care and the advantages of the various pharmacologic therapies, patients with osteoporosis will receive higher-quality and more efficient medical care.

Alendronate treatment for osteoporosis: a review of the clinical evidence

Bisphosphonates have recently gained an increasing role in the management of osteoporosis. The aminobisphosphonate, alendronate has recently been introduced as a new agent for the treatment of postmenopausal osteoporosis. This paper reviews the clinical evidence for the use of this agent and seeks to assess its place in osteoporosis management.

Alendronate treatment of the postmenopausal osteoporotic woman: effect of multiple dosages on bone mass and bone remodeling

BACKGROUND

The effects of the aminobisphosphonate alendronate sodium on bone mass and markers of bone remodeling were investigated.

PATIENTS AND METHODS

In a multicenter, randomized, double-blind, placebo-controlled, 2-year study, 188 postmenopausal women, aged 42 to 75 years, with low bone mineral density (BMD) of the lumbar spine were randomly assigned to 1 of 6 daily treatment groups: placebo for 2 years, alendronate 5 or 10 mg for 2 years, alendronate 20 or 40 mg for 1 year followed by placebo for 1 year, or alendronate 40 mg for 3 months followed by 2.5 mg for 21 months. All subjects were given 500 mg/d of elemental calcium as calcium carbonate.

RESULTS

At each dose, alendronate produced significant reductions in markers of bone resorption and formation, and significantly increased bone mass at the lumbar spine, hip, and total body, as compared with decreases (significant at lumbar spine) in subjects receiving placebo. In the 10-mg group, mean urinary deoxypyridinoline/creatinine had declined by 47% at 3 months, and mean serum osteocalcin by 53% at 6 months. Mean changes in BMD over 24 months with 10 mg alendronate were +7.21% +/- 0.49% for the lumbar spine, +5.27% +/- 0.70% for total hip, and +2.53% +/- 0.68% for total body (each P < 0.01) compared to changes of -1.35% +/- 0.61%, -1.20% +/- 0.64% and -0.31% +/- 0.44% at these sites, respectively, with placebo treatment. Progressive increases in BMD of both lumbar spine and total hip were observed in the second year of treatment with 10 mg alendronate (both P < 0.05).

CONCLUSION

Alendronate, a potent inhibitor of bone resorption, reduces markers of bone remodeling and significantly increases BMD at the lumbar spine, hip, and total body, and is well tolerated at therapeutic doses (5 or 10 mg daily) in the treatment of osteoporosis in postmenopausal women.

Clinical utility of a wheat-germ precipitation assay for determination of bone alkaline phosphatase concentrations in patients with different metabolic bone diseases

Bone alkaline phosphatase was evaluated by wheat-germ lectin precipitation in several clinical conditions. The study included 33 premenopausal healthy women, 46 postmenopausal apparently healthy women, 19 growing children, 24 patients with Paget's disease, 31 patients with primary hyperparathyroidism and 66 patients with hepatobiliary diseases. In postmenopausal women the mean T score (i.e.: the number of SD below or above the mean for premenopausal women) was 2.6 +/- 1.3 (SD) for bone alkaline phosphatase and 1.61 +/- 1.21 for total alkaline phosphatase (p < 0.001). The T score for bone alkaline phosphatase provided a better discrimination from normals for both Paget's disease (22.1 +/- 27.8 versus 12.8 +/- 16 p < 0.001) and primary hyperparathyroidism (8.2 +/- 4.3 versus 4.6 +/- 3.7 p < 0.005 for bone alkaline phosphatase and total alkaline phosphatase respectively). After treatment with intravenous bisphosphonate the percent decrease of bone alkaline phosphatase was larger than that of total alkaline phosphatase both in patients with Paget's disease (-46% versus -72% p < 0.01) and in patients with primary hyperparathyroidism (-21% versus -47% p < 0.02) and an estimate of the precision (delta mean/SD of the delta mean) for bone alkaline phosphatase was 1.9-3.7 times higher than that of total alkaline phosphatase. In twelve osteoporotic patients treated for six months with oral alendronate the decrease in bone turnover was detected with significantly higher precision with bone alkaline phosphatase than with total alkaline phosphatase (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)