Alendronate Sodium Tablets, USP 35 mg are white, capsule shaped, biconvex tablets debossed with 'C223' on one side and plain on the other side.
Alendronate sodium tablets are contraindicated in patients with the following conditions:
- Inability to stand or sit upright for at least 30 minutes
[see Dosage and Administration (
2.6); Warnings and Precautions (
5.1)]
- Hypocalcemia
[see Warnings and Precautions (
5.2)]
- Hypersensitivity to any component of this product. Hypersensitivity reactions including urticaria and angioedema have been reported
[see Adverse Reactions (
6.2)]
.
Alendronate sodium is a white, crystalline, non-hygroscopic powder. It is soluble in water, very slightly soluble in alcohol, and practically insoluble in chloroform.
Each tablet, for oral administration contains: 6.53, 13.05, 45.68, 52.21 or 91.37 mg of alendronate monosodium salt trihydrate, which is the molar equivalent of 5, 10, 35, 40 and 70 mg, respectively, of free acid, and the following inactive ingredients: magnesium stearate, mannitol, microcrystalline cellulose, sodium starch glycolate and starch.
Fracture Intervention Trial: Four-Year Study (patients with low bone mass but without a baseline radiographic vertebral fracture)
This randomized, double-blind, placebo-controlled, 4432-patient study (alendronate sodium, n=2214; placebo, n=2218) further investigated the reduction in fracture incidence due to alendronate sodium. The intent of the study was to recruit women with osteoporosis, defined as a baseline femoral neck BMD at least two standard deviations below the mean for young adult women. However, due to subsequent revisions to the normative values for femoral neck BMD, 31% of patients were found not to meet this entry criterion and thus this study included both osteoporotic and non-osteoporotic women. The results are shown in Table 7 for the patients with osteoporosis.
Table 7: Effect of Alendronate Sodium on Fracture Incidence in Osteoporotic
Baseline femoral neck BMD at least 2 SD below the mean for young adult women
Patients in the Four-Year Study of FIT (patients without vertebral fractureat baseline)
| Percent of Patients
|
| Alendronate Sodium(n=1545)
| Placebo(n=1521)
| AbsoluteReduction in FractureIncidence
| RelativeReduction in FractureRisk (%)
|
Patients with:
|
|
|
|
|
| Vertebral fractures (diagnosed by X-ray)
Number evaluable for vertebral fractures: Alendronate sodium, n=1426; placebo, n=1428
|
|
|
|
|
≥1 new vertebral fracture
| 2.5
| 4.8
| 2.3
| 48
p<0.001,
|
≥2 new vertebral fractures
| 0.1
| 0.6
| 0.5
| 78
p=0.035,
|
Clinical (symptomatic) fractures
|
|
|
|
|
Any clinical (symptomatic) fracture
| 12.9
| 16.2
| 3.3
| 22
p=0.01
|
≥1 clinical (symptomatic) vertebral fracture
| 1.0
| 1.6
| 0.6
| 41 (NS)
Not significant. This study was not powered to detect differences at these sites.
|
Hip fracture
| 1.0
| 1.4
| 0.4
| 29 (NS)
|
Wrist (forearm) fracture
| 3.9
| 3.8
| -0.1
| NS
|
Fracture Results Across Studies
In the Three-Year Study of FIT, alendronate sodium reduced the percentage of women experiencing at least one new radiographic vertebral fracture from 15.0% to 7.9% (47% relative risk reduction, p<0.001); in the Four-Year Study of FIT, the percentage was reduced from 3.8% to 2.1% (44% relative risk reduction, p=0.001); and in the combined U.S./Multinational studies, from 6.2% to 3.2% (48% relative risk reduction, p=0.034).
Alendronate sodium reduced the percentage of women experiencing multiple (two or more) new vertebral fractures from 4.2% to 0.6% (87% relative risk reduction, p<0.001) in the combined U.S./Multinational studies and from 4.9% to 0.5% (90% relative risk reduction, p<0.001) in the Three-Year Study of FIT. In the Four-Year Study of FIT, alendronate sodium reduced the percentage of osteoporotic women experiencing multiple vertebral fractures from 0.6% to 0.1% (78% relative risk reduction, p=0.035).
Thus, alendronate sodiumreduced the incidence of radiographic vertebral fractures in osteoporotic women whether or not they had a previous radiographic vertebral fracture.
Effect on Bone Mineral Density
The bone mineral density efficacy of alendronate sodium 10 mg once daily in postmenopausal women, 44 to 84 years of age, with osteoporosis (lumbar spine bone mineral density [BMD] of at least 2 standard deviations below the premenopausal mean) was demonstrated in four double-blind, placebo-controlled clinical studies of two or three years' duration.
Figure 2 shows the mean increases in BMD of the lumbar spine, femoral neck, and trochanter in patients receiving alendronate sodium 10 mg/day relative to placebo-treated patients at three years for each of these studies.
Figure 2:
3 (1203dd0c 809a 4409 B948 B5e816b8a63a 03)
At three years significant increases in BMD, relative both to baseline and placebo, were seen at each measurement site in each study in patients who received alendronate sodium 10 mg/day. Total body BMD also increased significantly in each study, suggesting that the increases in bone mass of the spine and hip did not occur at the expense of other skeletal sites. Increases in BMD were evident as early as three months and continued throughout the three years of treatment. (See Figure 3 for lumbar spine results.) In the two-year extension of these studies, treatment of 147 patients with alendronate sodium 10 mg/day resulted in continued increases in BMD at the lumbar spine and trochanter (absolute additional increases between years 3 and 5: lumbar spine, 0.94%; trochanter, 0.88%). BMD at the femoral neck, forearm and total body were maintained. Alendronate sodium was similarly effective regardless of age, race, baseline rate of bone turnover, and baseline BMD in the range studied (at least 2 standard deviations below the premenopausal mean).
Figure 3:
4 (1203dd0c 809a 4409 B948 B5e816b8a63a 04)
In patients with postmenopausal osteoporosis treated with alendronate sodium 10 mg/day for one or two years, the effects of treatment withdrawal were assessed. Following discontinuation, there were no further increases in bone mass and the rates of bone loss were similar to those of the placebo groups.
Bone Histology
Bone histology in 270 postmenopausal patients with osteoporosis treated with alendronate sodium at doses ranging from 1 to 20 mg/day for one, two, or three years revealed normal mineralization and structure, as well as the expected decrease in bone turnover relative to placebo. These data, together with the normal bone histology and increased bone strength observed in rats and baboons exposed to long-term alendronate treatment, support the conclusion that bone formed during therapy with alendronate sodium is of normal quality.
Effect on Height
Alendronate sodium, over a three- or four-year period, was associated with statistically significant reductions in loss of height vs. placebo in patients with and without baseline radiographic vertebral fractures. At the end of the FIT studies, the between-treatment group differences were 3.2 mm in the Three-Year Study and 1.3 mm in the Four-Year Study.
Weekly Dosing
The therapeutic equivalence of once-weekly alendronate sodium 70 mg (n=519) and alendronate sodium 10 mg daily (n=370) was demonstrated in a one-year, double-blind, multicenter study of postmenopausal women with osteoporosis. In the primary analysis of completers, the mean increases from baseline in lumbar spine BMD at one year were 5.1% (4.8, 5.4%; 95% CI) in the 70-mg once-weekly group (n=440) and 5.4% (5.0, 5.8%; 95% CI) in the 10-mg daily group (n=330). The two treatment groups were also similar with regard to BMD increases at other skeletal sites. The results of the intention-to-treat analysis were consistent with the primary analysis of completers.
Concomitant Use with Estrogen/Hormone Replacement Therapy (HRT)
The effects on BMD of treatment with alendronate sodium 10 mg once daily and conjugated estrogen (0.625 mg/day) either alone or in combination were assessed in a two-year, double-blind, placebo-controlled study of hysterectomized postmenopausal osteoporotic women (n=425). At two years, the increases in lumbar spine BMD from baseline were significantly greater with the combination (8.3%) than with either estrogen or alendronate sodiumalone (both 6.0%).
The effects on BMD when alendronate sodium was added to stable doses (for at least one year) of HRT (estrogen ± progestin) were assessed in a one-year, double-blind, placebo-controlled study in postmenopausal osteoporotic women (n=428). The addition of alendronate sodium 10 mg once daily to HRT produced, at one year, significantly greater increases in lumbar spine BMD (3.7%) vs. HRT alone (1.1%).
In these studies, significant increases or favorable trends in BMD for combined therapy compared with HRT alone were seen at the total hip, femoral neck, and trochanter. No significant effect was seen for total body BMD.
Histomorphometric studies of transiliac biopsies in 92 subjects showed normal bone architecture. Compared to placebo there was a 98% suppression of bone turnover (as assessed by mineralizing surface) after 18 months of combined treatment with alendronate sodium and HRT, 94% on alendronate sodium alone, and 78% on HRT alone. The long-term effects of combined alendronate sodium and HRT on fracture occurrence and fracture healing have not been studied.
Bone Histology
Bone histology was normal in the 28 patients biopsied at the end of three years who received alendronate sodium at doses of up to 10 mg/day.
Weekly Dosing
The therapeutic equivalence of once weekly alendronate sodium 35 mg (n=362) and alendronate sodium 5 mg daily (n=361) was demonstrated in a one-year, double-blind, multicenter study of postmenopausal women without osteoporosis. In the primary analysis of completers, the mean increases from baseline in lumbar spine BMD at one year were 2.9% (2.6, 3.2%; 95% CI) in the 35-mg once-weekly group (n=307) and 3.2% (2.9, 3.5%; 95% CI) in the 5-mg daily group (n=298). The two treatment groups were also similar with regard to BMD increases at other skeletal sites. The results of the intention-to-treat analysis were consistent with the primary analysis of completers.
After one year, significant increases relative to placebo in BMD were seen in the combined studies at each of these sites in patients who received alendronate sodium 5 mg/day. In the placebo-treated patients, a significant decrease in BMD occurred at the femoral neck (-1.2%), and smaller decreases were seen at the lumbar spine and trochanter. Total body BMD was maintained with alendronate sodium 5 mg/day. The increases in BMD with alendronate sodium 10 mg/day were similar to those with alendronate sodium 5 mg/day in all patients except for postmenopausal women not receiving estrogen therapy. In these women, the increases (relative to placebo) with alendronate sodium 10 mg/day were greater than those with alendronate sodium 5 mg/day at the lumbar spine (4.1% vs. 1.6%) and trochanter (2.8% vs. 1.7%), but not at other sites. Alendronate sodium was effective regardless of dose or duration of glucocorticoid use. In addition, alendronate sodium was similarly effective regardless of age (less than 65 vs. greater than or equal to 65 years), race (Caucasian vs. other races), gender, underlying disease, baseline BMD, baseline bone turnover, and use with a variety of common medications.
Bone histology was normal in the 49 patients biopsied at the end of one year who received alendronate sodium at doses of up to 10 mg/day.
Of the original 560 patients in these studies, 208 patients who remained on at least 7.5 mg/day of prednisone or equivalent continued into a one-year double-blind extension. After two years of treatment, spine BMD increased by 3.7% and 5.0% relative to placebo with alendronate sodium 5 and 10 mg/day, respectively. Significant increases in BMD (relative to placebo) were also observed at the femoral neck, trochanter, and total body.
After one year, 2.3% of patients treated with alendronate sodium 5 or 10 mg/day (pooled) vs. 3.7% of those treated with placebo experienced a new vertebral fracture (not significant). However, in the population studied for two years, treatment with alendronate sodium (pooled dosage groups: 5 or 10 mg for two years or 2.5 mg for one year followed by 10 mg for one year) significantly reduced the incidence of patients with a new vertebral fracture (alendronate sodium 0.7% vs. placebo 6.8%).