Effect on fracture incidence
Data on the effects of FOSAMAX on fracture incidence are derived
from three clinical studies: 1) U.S. and Multinational combined: a study of
patients with a BMD T-score at or below minus 2.5 with or without a prior
vertebral fracture, 2) Three-Year Study of the Fracture Intervention Trial
(FIT): a study of patients with at least one baseline vertebral fracture, and 3)
Four-Year Study of FIT: a study of patients with low bone mass but without a
baseline vertebral fracture.
To assess the effects of FOSAMAX on the incidence of vertebral fractures
(detected by digitized radiography; approximately one third of these were
clinically symptomatic), the U.S. and Multinational studies were combined in an
analysis that compared placebo to the pooled dosage groups of FOSAMAX
(5 or 10 mg for three years or 20 mg for two years followed by 5 mg for one
year). There was a statistically significant reduction in the proportion of
patients treated with FOSAMAX experiencing one or more new vertebral fractures
relative to those treated with placebo (3.2% vs. 6.2%; a 48% relative risk
reduction). A reduction in the total number of new vertebral fractures (4.2 vs.
11.3 per 100 patients) was also observed. In the pooled analysis, patients who
received FOSAMAX had a loss in stature that was statistically significantly less
than was observed in those who received placebo (-3.0 mm vs. -4.6 mm).
The Fracture Intervention Trial (FIT) consisted of two studies in
postmenopausal women: the Three-Year Study of patients who had at least one
baseline radiographic vertebral fracture and the Four-Year Study of patients
with low bone mass but without a baseline vertebral fracture. In both studies of
FIT, 96% of randomized patients completed the studies (i.e., had a closeout
visit at the scheduled end of the study); approximately 80% of patients were
still taking study medication upon completion.
Fracture Intervention Trial: Three-Year Study
(patients with at least one baseline radiographic vertebral fracture)
This randomized, double-blind, placebo-controlled, 2027-patient
study (FOSAMAX, n=1022; placebo, n=1005) demonstrated that treatment with
FOSAMAX resulted in statistically significant reductions in fracture incidence
at three years as shown in the table below.
Effect of FOSAMAX on Fracture Incidence in the Three-Year Study of FIT (patients with vertebral fracture at baseline)
|
FOSAMAX (n=1022)
| Percent of Patients
Placebo (n=1005)
| Absolute Reduction in Fracture Incidence
| Relative Reduction in Fracture Risk %
|
Patients with: Vertebral fractures (diagnosed by X-ray)* ≥ 1 new vertebral fracture |
7.9
|
15.0
|
7.1
|
47† |
| ≥ 2 new vertebral fractures | 0.5
| 4.9
| 4.4
| 90† |
Clinical (symptomatic) fractures Any clinical (symptomatic) fracture | 13.8
| 18.1
| 4.3
| 26‡
|
| ≥ 1 clinical (symptomatic) vertebral fracture | 2.3
| 5.0
| 2.7
| 54§ |
Hip fracture
| 1.1
| 2.2
| 1.1
| 51¶ |
Wrist (forearm) fracture
| 2.2
| 4.1
| 1.9
| 48¶ |
* Number evaluable for vertebral fractures: FOSAMAX, n=984; placebo, n=966
† p less than 0.001
‡ p=0.007
§ p less than 0.01
¶ p less than 0.05
Furthermore, in this population of patients with baseline vertebral fracture,
treatment with FOSAMAX significantly reduced the incidence of hospitalizations
(25.0% vs. 30.7%).
In the Three-Year Study of FIT, fractures of the hip occurred in 22 (2.2%) of
1005 patients on placebo and 11 (1.1%) of 1022 patients on FOSAMAX, p=0.047. The
figure below displays the cumulative incidence of hip fractures in this study.
Cumulative Incidence of Hip Fractures in the
Three-Year Study of FIT (patients with radiographic vertebral fracture at
baseline)
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 (FOSAMAX, n=2214; placebo, n=2218) further investigated the reduction in
fracture incidence due to FOSAMAX. 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 the table
below for the patients with osteoporosis.
Effect of FOSAMAX on Fracture Incidence in Osteoporotic* Patients in the Four-Year Study of FIT (patients without vertebral fracture at baseline)
|
FOSAMAX (n=1545)
| Percent of Patients
Placebo (n=1521)
| Absolute Reduction in Fracture Incidence
| Relative Reduction in Fracture Risk (%)
|
Patients with:
|
|
|
|
|
| Vertebral fractures (diagnosed by X-ray)† |
|
|
|
|
| ≥ 1 new vertebral fracture | 2.5
| 4.8
| 2.3
| 48‡ |
| ≥ 2 new vertebral fractures | 0.1
| 0.6
| 0.5
| 78§ |
Clinical (symptomatic) fractures
|
|
|
|
|
Any clinical (symptomatic) fracture
| 12.9
| 16.2
| 3.3
| 22¶ |
| ≥ 1 clinical (symptomatic) vertebral fracture | 1.0
| 1.6
| 0.6
| 41(NS)# |
Hip fracture
| 1.0
| 1.4
| 0.4
| 29(NS)# |
Wrist (forearm) fracture
| 3.9
| 3.8
| -0.1
| NS# |
* Baseline femoral neck BMD at least 2 SD below the mean for young adult women
† Number evaluable for vertebral fractures: FOSAMAX, n=1426; placebo, n=1428
‡ p less than 0.001
§ p=0.035
¶ p=0.01
# Not significant. This study was not powered to detect differences at these
sites.
Fracture results across studies
In the Three-Year Study of FIT, FOSAMAX reduced the percentage of
women experiencing at least one new radiographic vertebral fracture from 15.0%
to 7.9% (47% relative risk reduction, p less than 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).
FOSAMAX reduced the percentage of women experiencing multiple (two or more)
new vertebral fractures from 4.2% to 0.6% (87% relative risk reduction,
p less than 0.001) in the combined U.S./Multinational studies and from 4.9% to 0.5%
(90% relative risk reduction, p less than 0.001) in the Three-Year Study of FIT. In the
Four-Year Study of FIT, FOSAMAX reduced the percentage of osteoporotic women
experiencing multiple vertebral fractures from 0.6% to 0.1% (78% relative risk
reduction, p=0.035).
Thus, FOSAMAX reduced the incidence of radiographic vertebral fractures in
osteoporotic women whether or not they had a previous radiographic vertebral
fracture.
FOSAMAX, 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.
Bone histology
Bone histology in 270 postmenopausal patients with osteoporosis
treated with FOSAMAX 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 FOSAMAX is of normal quality.
Men
The efficacy of FOSAMAX in men with hypogonadal or idiopathic
osteoporosis was demonstrated in two clinical studies.
A two-year, double-blind, placebo-controlled, multicenter study of FOSAMAX 10
mg once daily enrolled a total of 241 men between the ages of 31 and 87 (mean,
63). All patients in the trial had either: 1) a BMD T-score less than or equal to -2 at the femoral
neck and ≤-1 at the lumbar spine, or 2) a baseline osteoporotic fracture and a
BMD T-score less than or equal to -1 at the femoral neck. At two years, the mean increases relative
to placebo in BMD in men receiving FOSAMAX 10 mg/day were significant at the
following sites: lumbar spine, 5.3%; femoral neck, 2.6%; trochanter, 3.1%; and
total body, 1.6%. Treatment with FOSAMAX also reduced height loss (FOSAMAX,
-0.6 mm vs. placebo, -2.4 mm).
A one-year, double-blind, placebo-controlled, multicenter study of once
weekly FOSAMAX 70 mg enrolled a total of 167 men between the ages of 38 and 91
(mean, 66). Patients in the study had either: 1) a BMD T-score less than or equal to -2 at the
femoral neck and less than or equal to -1 at the lumbar spine, 2) a BMD T-score less than or equal to -2 at the lumbar
spine and less than or equal to -1 at the femoral neck, or 3) a baseline osteoporotic fracture and a
BMD T-score less than or equal to -1 at the femoral neck. At one year, the mean increases relative to
placebo in BMD in men receiving FOSAMAX 70 mg once weekly were significant at
the following sites: lumbar spine, 2.8%; femoral neck, 1.9%; trochanter, 2.0%;
and total body, 1.2%. These increases in BMD were similar to those seen at one
year in the 10 mg once-daily study.
In both studies, BMD responses were similar regardless of age (greater than or equal to 65 years vs.
less than 65 years), gonadal function (baseline testosterone less than 9 ng/dL vs. greater than or equal to 9
ng/dL), or baseline BMD (femoral neck and lumbar spine T-score less than or equal to -2.5 vs.
greater than -2.5).
Prevention of osteoporosis in postmenopausal
women
Prevention of bone loss was demonstrated in two double-blind,
placebo-controlled studies of postmenopausal women 40-60 years of age. One
thousand six hundred nine patients (FOSAMAX 5 mg/day; n=498) who were at least
six months postmenopausal were entered into a two-year study without regard to
their baseline BMD. In the other study, 447 patients (FOSAMAX 5 mg/day; n=88),
who were between six months and three years postmenopause, were treated for up
to three years. In the placebo-treated patients BMD losses of approximately 1%
per year were seen at the spine, hip (femoral neck and trochanter) and total
body. In contrast, FOSAMAX 5 mg/day prevented bone loss in the majority of
patients and induced significant increases in mean bone mass at each of these
sites (see figures below). In addition, FOSAMAX 5 mg/day reduced the rate of
bone loss at the forearm by approximately half relative to placebo. FOSAMAX
5 mg/day was similarly effective in this population regardless of age, time
since menopause, race and baseline rate of bone turnover.
Osteoporosis Prevention Studies in Postmenopausal
Women
The therapeutic equivalence of once weekly FOSAMAX 35 mg (n=362) and FOSAMAX
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.
Bone histology
Bone histology was normal in the 28 patients biopsied at the end
of three years who received FOSAMAX at doses of up to 10 mg/day.
Concomitant use with estrogen/hormone replacement
therapy (HRT)
The effects on BMD of treatment with FOSAMAX 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 FOSAMAX alone (both 6.0%).
The effects on BMD when FOSAMAX 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 FOSAMAX 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 FOSAMAX and HRT, 94% on FOSAMAX alone, and 78% on HRT alone. The
long-term effects of combined FOSAMAX and HRT on fracture occurrence and
fracture healing have not been studied.
Glucocorticoid-induced osteoporosis
The efficacy of FOSAMAX 5 and 10 mg once daily in men and women
receiving glucocorticoids (at least 7.5 mg/day of prednisone or equivalent) was
demonstrated in two, one-year, double-blind, randomized, placebo-controlled,
multicenter studies of virtually identical design, one performed in the United
States and the other in 15 different countries (Multinational [which also
included FOSAMAX 2.5 mg/day]). These studies enrolled 232 and 328 patients,
respectively, between the ages of 17 and 83 with a variety of
glucocorticoid-requiring diseases. Patients received supplemental calcium and
vitamin D. The following figure shows the mean increases relative to placebo in
BMD of the lumbar spine, femoral neck, and trochanter in patients receiving
FOSAMAX 5 mg/day for each study.
Studies in Glucocorticoid-Treated Patients: Increase
in BMD: FOSAMAX 5 mg/day at One Year
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 FOSAMAX
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 FOSAMAX
5 mg/day. The increases in BMD with FOSAMAX 10 mg/day were similar to those with
FOSAMAX 5 mg/day in all patients except for postmenopausal women not receiving
estrogen therapy. In these women, the increases (relative to placebo) with
FOSAMAX 10 mg/day were greater than those with FOSAMAX 5 mg/day at the lumbar
spine (4.1% vs. 1.6%) and trochanter (2.8% vs. 1.7%), but not at other sites.
FOSAMAX was effective regardless of dose or duration of glucocorticoid use. In
addition, FOSAMAX 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 FOSAMAX 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 FOSAMAX 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 FOSAMAX 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
FOSAMAX (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 (FOSAMAX 0.7% vs. placebo 6.8%).
Paget's disease of bone
The efficacy of FOSAMAX 40 mg once daily for six months was
demonstrated in two double-blind clinical studies of male and female patients
with moderate to severe Paget's disease (alkaline phosphatase at least twice the
upper limit of normal): a placebo-controlled, multinational study and a U.S.
comparative study with etidronate disodium 400 mg/day. The following figure
shows the mean percent changes from baseline in serum alkaline phosphatase for
up to six months of randomized treatment.
Studies in Paget's Disease of Bone: Effect on Serum
Alkaline Phosphatase of FOSAMAX 40 mg/day Versus Placebo or Etidronate 400
mg/day
At six months the suppression in alkaline phosphatase in patients treated
with FOSAMAX was significantly greater than that achieved with etidronate and
contrasted with the complete lack of response in placebo-treated patients.
Response (defined as either normalization of serum alkaline phosphatase or
decrease from baseline greater than or equal to 60%) occurred in approximately 85% of patients treated
with FOSAMAX in the combined studies vs. 30% in the etidronate group and 0% in
the placebo group. FOSAMAX was similarly effective regardless of age, gender,
race, prior use of other bisphosphonates, or baseline alkaline phosphatase
within the range studied (at least twice the upper limit of normal).
Bone histology was evaluated in 33 patients with Paget's disease treated with
FOSAMAX 40 mg/day for 6 months. As in patients treated for osteoporosis (see Clinical Studies, Treatment of osteoporosis in
postmenopausal women, Bone histology), FOSAMAX did not impair
mineralization, and the expected decrease in the rate of bone turnover was
observed. Normal lamellar bone was produced during treatment with FOSAMAX, even
where preexisting bone was woven and disorganized. Overall, bone histology data
support the conclusion that bone formed during treatment with FOSAMAX is of
normal quality.