IBANDRONATE SODIUM: Package Insert and Label Information (Page 3 of 4)

Gender

The bioavailability and pharmacokinetics of ibandronate are similar in both men and women.

Race

Pharmacokinetic differences due to race have not been studied.

Renal Impairment

Renal clearance of ibandronate in patients with various degrees of renal impairment is linearly related to creatinine clearance (CLcr).

Following a single dose of 0.5 mg ibandronate by intravenous administration, patients with CLcr 40 to 70 mL/min had 55% higher exposure (AUC ) than the exposure observed in subjects with CLcr greater than 90 mL/min. Patients with CLcr less than 30 mL/min had more than a two-fold increase in exposure compared to the exposure for healthy subjects (see DOSAGE AND ADMINISTRATION [2.4]) .

Hepatic Impairment

No studies have been performed to assess the pharmacokinetics of ibandronate in patients with hepatic impairment because ibandronate is not metabolized in the human liver.

Drug Interaction Studies

Products containing calcium and other multivalent cations (such as aluminum, magnesium, iron), including milk, food, and antacids are likely to interfere with absorption of ibandronate, which is consistent with findings in animal studies.

H2 Blockers

A pharmacokinetic interaction study in healthy volunteers demonstrated that 75 mg ranitidine (25 mg injected intravenously 90 and 15 minutes before and 30 minutes after ibandronate administration) increased the oral bioavailability of 10 mg ibandronate by about 20%. This degree of increase is not considered to be clinically relevant.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

In a 104-week carcinogenicity study, doses of 3, 7, or 15 mg/kg/day were administered by oral gavage to male and female Wistar rats (systemic cumulative exposures up to 3.5 and 2 times, respectively, human exposure at the recommended once-monthly oral dose of 150 mg, based on AUC comparison). There were no significant drug-related tumor findings in male or female rats. In a 78-week carcinogenicity study, doses of 5, 20, or 40 mg/kg/day were administered by oral gavage to male and female NMRI mice (cumulative exposures up to 135 and 20 times, respectively, human exposure at the recommended once-monthly oral dose of 150 mg, based on AUC comparison). There were no significant drug-related tumor findings in male or female mice. In a 90-week carcinogenicity study, doses of 5, 20, or 80 mg/kg/day were administered in the drinking water to NMRI mice (cumulative monthly exposures in males and females up to 70 and 115 times, respectively, human exposure at the recommended dose of 150 mg, based on AUC comparison). A dose-related increased incidence of adrenal subcapsular adenoma/carcinoma was observed in female mice, which was statistically significant at 80 mg/kg/day (115 times human exposure at the recommended once-monthly oral dose of 150 mg, based on AUC comparison). The relevance of these findings to humans is unknown.

Mutagenesis

There was no evidence for a mutagenic or clastogenic potential of ibandronate in the following assays: in vitro bacterial mutagenesis assay in Salmonella typhimurium and Escherichia coli (Ames test), mammalian cell mutagenesis assay in Chinese hamster V79 cells, and chromosomal aberration test in human peripheral lymphocytes, each with and without metabolic activation. Ibandronate was not genotoxic in the in vivo mouse micronucleus tests for chromosomal damage.

Impairment of Fertility

In female rats treated from 14 days prior to mating through gestation, decreases in fertility, corpora lutea, and implantation sites were observed at an oral dose of 16 mg/kg/day (13 times human exposure at the recommended once-monthly oral dose of 150 mg, based on AUC comparison).

13.2 Animal Pharmacology

Animal studies have shown that ibandronate is an inhibitor of osteoclast-mediated bone resorption. In the Schenk assay in growing rats, ibandronate inhibited bone resorption and increased bone volume, based on histologic examination of the tibial metaphyses. There was no evidence of impaired mineralization at the highest dose of 5 mg/kg/day (subcutaneously), which is 1000 times the lowest antiresorptive dose of 0.005 mg/kg/day in this model, and 5000 times the optimal antiresorptive dose of 0.001 mg/kg/day in the aged ovariectomized rat. This indicates that ibandronate sodium tablets administered at therapeutic doses is unlikely to induce osteomalacia.

Long-term daily or once-monthly intermittent administration of ibandronate to ovariectomized rats or monkeys was associated with suppression of bone turnover and increases in bone mass. In both rats and monkeys, vertebral BMD, trabecular density, and biomechanical strength were increased dose-dependently at cumulative monthly doses up to 8 times (rat) or 6 times (monkey) the recommended human once-monthly oral dose of 150 mg, based on body surface area (mg/m 2) or area under the curve (AUC) comparison. In monkeys, ibandronate maintained the positive correlation between bone mass and strength at the ulna and femoral neck. New bone formed in the presence of ibandronate had normal histologic structure and did not show mineralization defects.

14 CLINICAL STUDIES

14.1 Treatment of Postmenopausal Osteoporosis

Daily Dosing

The effectiveness and safety of ibandronate sodium tablets were demonstrated in a randomized, double-blind, placebo-controlled, multinational study (Treatment Study) of 2946 women aged 55 to 80 years, who were on average 21 years postmenopause, who had lumbar spine BMD 2 to 5 SD below the premenopausal mean (T-score) in at least one vertebra [L1 to L4], and who had 1 to 4 prevalent vertebral fractures. Ibandronate sodium tablets were evaluated at oral doses of 2.5 mg daily and 20 mg intermittently. The main outcome measure was the occurrence of new radiographically diagnosed vertebral fractures after 3 years of treatment. The diagnosis of an incident vertebral fracture was based on both qualitative diagnosis by the radiologist and quantitative morphometric criterion. The morphometric criterion required the dual occurrence of 2 events: a relative height ratio or relative height reduction in a vertebral body of at least 20%, together with at least a 4 mm absolute decrease in height. All women received 400 international units vitamin D and 500 mg calcium supplementation per day.

Effect on Fracture Incidence

Ibandronate sodium tablets 2.5 mg daily significantly reduced the incidence of new vertebral (primary efficacy measure) and of new and worsening vertebral fractures. Over the course of the 3-year study, the risk for vertebral fracture was 9.6% in the placebo-treated women and 4.7% in the women treated with ibandronate sodium tablets 2.5 mg (p<0.001) (see Table 3).

Table 3 Effect of Ibandronate Sodium Tablets on the Incidence of Vertebral Fracture in the 3-Year Osteoporosis Treatment Study*
Proportion of Patients with Fracture (%)
Placebo n=975 Ibandronate sodium tablets 2.5 mg Daily n=977 Absolute Risk Reduction (%) 95% CI Relative Risk Reduction (%) 95% CI

New Vertebral Fracture

9.6

4.7

4.9

52**

0-3 Year

(2.3, 7.4)

(29, 68)

New and Worsening Vertebral Fracture

10.4

5.1

5.3

52

0-3 Year

(2.6, 7.9)

(30, 67)

Clinical (Symptomatic) Vertebral Fracture

5.3

2.8

2.5

49

0-3 Year

(0.6, 4.5)

(14, 69)

* The endpoint value is the value at the study’s last time point, 3 years, for all patients who had a fracture identified at that time; otherwise, the last postbaseline value prior to the study’s last time point is used.

** p=0.0003 vs. placebo

Ibandronate sodium tablets 2.5 mg daily did not reduce the incidence of nonvertebral fractures (secondary efficacy measure). There was a similar number of nonvertebral osteoporotic fractures at 3 years reported in women treated with ibandronate sodium tablets 2.5 mg daily [9.1%, (95% CI: 7.1%, 11.1%)] and placebo [8.2%, (95% CI: 6.3%, 10.2%)]. The two treatment groups were also similar with regard to the number of fractures reported at the individual nonvertebral sites: pelvis, femur, wrist, forearm, rib, and hip.

Bone Mineral Density (BMD)

Ibandronate sodium tablets significantly increased BMD at the lumbar spine and hip relative to treatment with placebo. In the 3-year osteoporosis treatment study, ibandronate sodium tablets 2.5 mg daily produced increases in lumbar spine BMD that were progressive over 3 years of treatment and were statistically significant relative to placebo at 6 months and at all later time points. Lumbar spine BMD increased by 6.4% after 3 years of treatment with 2.5 mg daily ibandronate sodium tablets compared with 1.4% in the placebo group. Table 4 displays the significant increases in BMD seen at the lumbar spine, total hip, femoral neck, and trochanter compared to placebo.

Table 4 Mean Percent Change in BMD from Baseline to Endpoint in Patients Treated Daily with Ibandronate Sodium Tablets 2.5 mg or Placebo in the 3-Year Osteoporosis Treatment Study *
Placebo Ibandronate sodium tablets 2.5 mg Daily
*
The endpoint value is the value at the study’s last time point, 3 years, for all patients who had BMD measured at that time; otherwise, the last postbaseline value prior to the study’s last time point is used.

Lumbar Spine

1.4 (n=693)

6.4 (n=712)

Total Hip

-0.7 (n=638)

3.1 (n=654)

Femoral Neck

-0.7 (n=683)

2.6 (n=699)

Trochanter

0.2 (n=683)

5.3 (n=699)

Bone Histology

The effects of ibandronate sodium tablets 2.5 mg daily on bone histology were evaluated in iliac crest biopsies from 16 women after 22 months of treatment and 20 women after 34 months of treatment.

The histological analysis of bone biopsies showed bone of normal quality and no indication of osteomalacia or a mineralization defect.

Once-Monthly Dosing

The effectiveness and safety of ibandronate sodium tablets once-monthly were demonstrated in a randomized, double-blind, multinational, noninferiority trial in 1602 women aged 54 to 81 years, who were on average 18 years postmenopause, and had L2 to L4 lumbar spine BMD T-score below -2.5 SD at baseline. The main outcome measure was the comparison of the percentage change from baseline in lumbar spine BMD after 1 year of treatment with once-monthly ibandronate (100 mg, 150 mg) to daily ibandronate (2.5 mg). All patients received 400 international units vitamin D and 500 mg calcium supplementation per day.

Ibandronate sodium tablets 150 mg once-monthly (n=327) was shown to be noninferior to ibandronate sodium tablets 2.5 mg daily (n=318) in lumbar spine BMD in a 1-year, double-blind, multicenter study of women with postmenopausal osteoporosis. In the primary efficacy analysis (per-protocol population), the mean increases from baseline in lumbar spine BMD at 1 year were 3.86% (95% CI: 3.40%, 4.32%) in the 2.5 mg daily group and 4.85% (95% CI: 4.41%, 5.29%) in the 150 mg once-monthly group; the mean difference between 2.5 mg daily and 150 mg once-monthly was 0.99% (95% CI: 0.38%, 1.60%), which was statistically significant (p=0.002). The results of the intent-to-treat analysis were consistent with the primary efficacy analysis. The 150 mg once-monthly group also had consistently higher BMD increases at the other skeletal sites compared to the 2.5 mg daily group.

14.2 Prevention of Postmenopausal Osteoporosis

Daily Dosing

The safety and effectiveness of ibandronate sodium tablets 2.5 mg daily for the prevention of postmenopausal osteoporosis were demonstrated in a randomized, double-blind, placebo-controlled 2-year study (Prevention Study) of 653 postmenopausal women without osteoporosis at baseline. Women were aged 41 to 82 years, were on average 8.5 years postmenopause, and had lumbar spine BMD T-scores greater than -2.5. Women were stratified according to time since menopause (1 to 3 years, greater than 3 years) and baseline lumbar spine BMD (T-score: greater than -1, -1 to -2.5). The study compared daily ibandronate sodium tablets at three dose levels (0.5 mg, 1.0 mg, 2.5 mg) with placebo. All women received 500 mg of supplemental calcium per day.

The primary efficacy measure was the change in BMD of lumbar spine after 2 years of treatment. Ibandronate sodium tablets 2.5 mg daily resulted in a mean increase in lumbar spine BMD of 3.1% compared with placebo following 2 years of treatment. Increases in BMD were seen at 6 months and at all later time points. Irrespective of the time since menopause or the degree of pre-existing bone loss, treatment with ibandronate sodium tablets resulted in a higher BMD response at the lumbar spine compared with placebo across all four baseline strata [time since menopause (1 to 3 years, greater than 3 years) and baseline lumbar spine BMD (T-score: greater than -1, -1 to -2.5)].

Compared with placebo, treatment with ibandronate sodium tablets 2.5 mg daily increased BMD of the total hip by 1.8%, the femoral neck by 2.0%, and the trochanter by 2.1%.

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