Breast cancer incidence in postmenopausal women with osteoporosis or low bone mass using arzoxifene.

The Generations trial, a multicenter, placebo-controlled, double-blind trial, compared arzoxifene 20 mg/day and placebo in 9,354 postmenopausal women with osteoporosis (N=5,252) or low bone mass (N=4,102). Primary outcomes were vertebral fracture in the osteoporotic population and invasive breast cancer in all study participants. Here, we report the detailed breast cancer findings from the trial. Breast cancers were detected by annual mammograms and clinical examination. After 48 months follow-up, breast cancer incidence was compared between treatment groups by estrogen receptor (ER) and progesterone receptor (PR) status and baseline risk factors. Baseline breast cancer risk factors, including age, estimated Gail risk, and bone mineral density, were well balanced between treatment groups. A total of 75 breast cancers occurred 53 in the placebo group and 22 in the arzoxifene group (HR 0.41, 95% CI 0.25-0.68, P<0.001). There were 62 invasive breast cancers, 39 identified as invasive ER-positive (placebo 30, arzoxifene 9; HR 0.30, 95% CI 0.14-0.63, P=0.001) and 30 identified as invasive PR-positive (placebo 23, arzoxifene 7; HR 0.30, 95% CI 0.13-0.71, P=0.003). Breast cancer risk reduction with arzoxifene was similar between Gail risk groups (P interaction=0.31) and between low bone mass and osteoporosis groups (P interaction=0.35). Although generally well tolerated, there was a significant increase in venous thromboembolism, vasomotor symptoms, muscle cramps, and some gynecological events with arzoxifene. These findings demonstrate that in this study arzoxifene reduced the risk of ER-positive breast cancer in this population of postmenopausal women with low bone mass or osteoporosis, an effect similar to that seen with other SERMs.

Effects of raloxifene on fracture risk in postmenopausal women: the Raloxifene Use for the Heart Trial.

UNLABELLED: Using data from a randomized placebo-controlled trial of 10,101 postmenopausal women not selected on the basis of osteoporosis, we examined whether the effect of raloxifene treatment on fractures was consistent across categories of fracture risk. Treatment with raloxifene for 5 yr reduced the risk of clinical vertebral fractures, but not nonvertebral fractures, irrespective of the presence or absence of risk factors for fracture. INTRODUCTION: In The Raloxifene Use for The Heart (RUTH) trial, women assigned to raloxifene had a lower risk of clinical vertebral fractures but not nonvertebral fractures. However, it is uncertain whether the effect of raloxifene on fractures in this population not selected for low BMD differs according to risk factors for fractures. MATERIALS AND METHODS: We randomly assigned 10,101 postmenopausal women >or=55 yr of age with documented coronary heart disease or at high risk for coronary events to 60 mg raloxifene daily or placebo and followed them for a median of 5.6 yr. Fractures (nonvertebral and clinical vertebral) were prespecified secondary endpoints that were reported at semiannual visits. Fractures were adjudicated and confirmed using X-ray reports or medical records. RESULTS: There was no difference between raloxifene and placebo groups in risk of nonvertebral fractures (428 versus 438 events; hazard ratio [HR], 0.96; 95% CI, 0.84-1.10), including hip/femur (89 versus 103 events; HR, 0.85; 95% CI, 0.64-1.13) and wrist (107 versus 111 events; HR, 0.95; 95% CI, 0.73-1.24) fractures. Women treated with raloxifene had a lower risk of clinical vertebral fractures (64 versus 97 events; HR, 0.65; 95% CI, 0.47-0.89). The effect of treatment with raloxifene on risk of nonvertebral and clinical vertebral fractures was consistent across fracture risk categories defined at baseline by age, smoking status, physical activity level, prior history of fracture, family history of hip fracture, diabetes mellitus, previous use of hormone therapy, thyroid hormone use, statin use, weight loss, body mass index, or fracture specific summary risk score. CONCLUSIONS: In older women with or at high risk of coronary heart disease not selected on the basis of osteoporosis or increased fracture risk, treatment with raloxifene for 5 yr reduced the risk of clinical vertebral fractures, but not nonvertebral fractures, irrespective of presence or absence of risk factors for fracture.

Fracture incidence and characterization in patients on osteoporosis treatment: the ICARO study.

UNLABELLED: None of the available osteoporosis therapies have been shown to completely abolish the risk of fractures. In clinical practice, the outcome may be even poorer. In 880 patients prescribed with antiresorptives (alendronate, risedronate, and raloxifene) for >1 year, a fragility fracture was recorded in 8.9%/year of them. This incidence is considerably higher than that observed in randomized clinical trials, and it was significantly related to poor compliance and lack of supplementation with calcium and vitamin D. INTRODUCTION: Osteoporotic fracture is one of the most important public health concerns among the elderly. Currently available therapies have been shown to significantly decrease the risk of fracture, although none of them completely abolishes this risk. In clinical practice, poor treatment response may also result from a number of other factors. MATERIALS AND METHODS: The Incidence and ChAracterization of inadequate clinical Responders in Osteoporosis (ICARO) is a multicenter, observational study carried out in Italy. It aimed to analyze, in postmenopausal women with established osteoporosis, the risk factors for an "inadequate clinical response" to drug therapy, defined as the occurrence of new vertebral or nonvertebral fragility fractures in patients prescribed, for at least 1 year, alendronate, risedronate, or raloxifene, with a compliance >50%. RESULTS: In 880 patients treated with antiresorptive agents for a median of 2.0 years (95% CI: 1.0-4.5) years, the "inadequate clinical responder (ICR)" subjects over the observation period were 220 (25%), with an annual incidence of 8.9%. ICRs, compared with "adequate clinical responders (ACRs)," had more pretreatment fractures and were treated longer (2.8 versus 1.8 years; p < 0.001). After multiple adjustment for these confounding factors, significant determinants of inadequate clinical response were a poorer treatment compliance and a less frequent co-administration of calcium and vitamin D supplements. CONCLUSIONS: The incidence of fractures during treatment with antiresorptive agents in a clinical setting is considerably higher than that observed in randomized clinical trials. Inadequate compliance to treatment and lack of supplementation of calcium and vitamin D are major determinants of this poor response.

Trabecular Bone Score in Patients With Chronic Glucocorticoid Therapy-Induced Osteoporosis Treated With Alendronate or Teriparatide.

OBJECTIVE: To determine the effect of alendronate (ALN) and teriparatide on trabecular bone score (TBS) in patients with glucocorticoid-induced osteoporosis. METHODS: Patients with chronic glucocorticoid therapy-induced osteoporosis (median 7.5 mg/day prednisone equivalent for ≥90 days) were randomized to receive oral ALN 10 mg/day (n = 214) or subcutaneous teriparatide 20 µg/day (n = 214) for 36 months; 118 patients in the ALN group and 123 patients in the teriparatide group completed treatment. Dual x-ray absorptiometry (DXA) results for 53 patients receiving ALN and 56 patients receiving teriparatide who had DXA scans with adequate resolution to perform TBS analysis and completed 36 months of therapy were blindly analyzed for TBS at baseline and 3, 6, 12, 18, 24, and 36 months. RESULTS: In teriparatide-treated patients, TBS was significantly increased at 18 months compared to baseline, and by 36 months had increased 3.7% (P < 0.05). In ALN-treated patients, there was not a significant change in TBS compared to baseline at any time point. Changes in lumbar spine bone mineral density (BMD) measured by DXA in the subgroup with TBS data were similar to BMD results in the overall study population. At 36 months, increases in lumbar spine BMD were 5.5% and 10.3% in patients treated with ALN and teriparatide, respectively. CONCLUSION: In patients with glucocorticoid-induced osteoporosis, both ALN and teriparatide increased lumbar spine BMD. However, trabecular bone score significantly increased with teriparatide but did not significantly change with ALN. The pathogenesis of glucocorticoid-induced osteoporosis is predominantly reduced bone formation. TBS may represent a sensitive measure to discriminate treatment effects of an anabolic versus an antiresorptive drug in glucocorticoid-induced osteoporosis.

Raloxifene modulates interleukin-6 and tumor necrosis factor-alpha synthesis in vivo: results from a pilot clinical study.

Raloxifene (RAL), a selective estrogen receptor modulator, is indicated for the prevention and treatment of postmenopausal osteoporosis. RAL, by decreasing bone turnover, prevents bone loss and microarchitecture damage, reducing the incidence of osteoporotic fractures. Our previous in vitro data demonstrated that RAL modulates osteoclast activity by, at least in part, an IL-6- and TNF-alpha-dependent mechanism. In this study we evaluated the effects of RAL treatment (60 mg/d) on circulating levels of these cytokines in 14 postmenopausal women with osteoporosis. Lumbar bone density (determined by dual energy x-ray absorptiometry) and IL-6 and TNF-alpha levels were measured before and after 6 and 24 months of therapy. After 24 months, RAL increased bone density. IL-6 and TNF-alpha expression, elevated before treatment, significantly decreased (50% and 30%, respectively) after 6 months. This effect was sustained up to the end of the treatment (75% and 35%, respectively). Thus, our data show that RAL can modulate circulating levels of cytokines involved in osteoclastogenesis and bone resorption, suggesting that modulation of soluble factors could play a pivotal role in the mechanisms of the osteoprotective effect of RAL.

Raloxifene use in clinical practice: efficacy and safety.

OBJECTIVE AND METHODS: In this article, we provide an interdisciplinary concise review of the effects of raloxifene on breast, bone, and reproductive organs, as well as the adverse events that may be associated with its use. RESULTS: Raloxifene has been shown to prevent osteoporosis in postmenopausal women (PMW) with low bone mass and prevent vertebral fractures in those with osteoporosis/low bone mass; it has not been shown to reduce the risk of nonvertebral fractures. Raloxifene reduces the risk of invasive breast cancer in PMW with osteoporosis or at high risk of breast cancer. The risk of venous thromboembolism has been consistently shown to be increased with raloxifene, so it should not be used in women at high risk of venous thromboembolism. Although raloxifene does not increase, nor decrease, the risk of coronary or stroke events overall, in the raloxifene trial of PMW at increased risk of coronary events, the incidence of fatal stroke was higher in women assigned raloxifene versus placebo. CONCLUSIONS: Based on its approved indications, it is appropriate to prescribe raloxifene to prevent or treat osteoporosis, as well as to reduce the risk of invasive breast cancer in PMW with osteoporosis or at high risk of breast cancer. Women at increased risk of both fracture and invasive breast cancer are those most likely to receive a dual benefit with raloxifene. Decision making must involve the incorporation of the woman's personal feelings about the risks and benefits of raloxifene therapy, balanced with her interest in reducing risk of fractures and breast cancer through pharmacological intervention.