Odanacatib for the treatment of postmenopausal osteoporosis: results of the LOFT multicentre, randomised, double-blind, placebo-controlled trial and LOFT Extension study.

BACKGROUND: Odanacatib, a cathepsin K inhibitor, reduces bone resorption while maintaining bone formation. Previous work has shown that odanacatib increases bone mineral density in postmenopausal women with low bone mass. We aimed to investigate the efficacy and safety of odanacatib to reduce fracture risk in postmenopausal women with osteoporosis. METHODS: The Long-term Odanacatib Fracture Trial (LOFT) was a multicentre, randomised, double-blind, placebo-controlled, event-driven study at 388 outpatient clinics in 40 countries. Eligible participants were women aged at least 65 years who were postmenopausal for 5 years or more, with a femoral neck or total hip bone mineral density T-score between -2·5 and -4·0 if no previous radiographic vertebral fracture, or between -1·5 and -4·0 with a previous vertebral fracture. Women with a previous hip fracture, more than one vertebral fracture, or a T-score of less than -4·0 at the total hip or femoral neck were not eligible unless they were unable or unwilling to use approved osteoporosis treatment. Participants were randomly assigned (1:1) to either oral odanacatib (50 mg once per week) or matching placebo. Randomisation was done using an interactive voice recognition system after stratification for previous radiographic vertebral fracture, and treatment was masked to study participants, investigators and their staff, and sponsor personnel. If the study completed before 5 years of double-blind treatment, consenting participants could enrol in a double-blind extension study (LOFT Extension), continuing their original treatment assignment for up to 5 years from randomisation. Primary endpoints were incidence of vertebral fractures as assessed using radiographs collected at baseline, 6 and 12 months, yearly, and at final study visit in participants for whom evaluable radiograph images were available at baseline and at least one other timepoint, and hip and non-vertebral fractures adjudicated as being a result of osteoporosis as assessed by clinical history and radiograph. Safety was assessed in participants who received at least one dose of study drug. The adjudicated cardiovascular safety endpoints were a composite of cardiovascular death, myocardial infarction, or stroke, and new-onset atrial fibrillation or flutter. Individual cardiovascular endpoints and death were also assessed. LOFT and LOFT Extension are registered with ClinicalTrials.gov (number NCT00529373) and the European Clinical Trials Database (EudraCT number 2007-002693-66). FINDINGS: Between Sept 14, 2007, and Nov 17, 2009, we randomly assigned 16 071 evaluable patients to treatment: 8043 to odanacatib and 8028 to placebo. After a median follow-up of 36·5 months (IQR 34·43-40·15) 4297 women assigned to odanacatib and 3960 assigned to placebo enrolled in LOFT Extension (total median follow-up 47·6 months, IQR 35·45-60·06). In LOFT, cumulative incidence of primary outcomes for odanacatib versus placebo were: radiographic vertebral fractures 3·7% (251/6770) versus 7·8% (542/6910), hazard ratio (HR) 0·46, 95% CI 0·40-0·53; hip fractures 0·8% (65/8043) versus 1·6% (125/8028), 0·53, 0·39-0·71; non-vertebral fractures 5·1% (412/8043) versus 6·7% (541/8028), 0·77, 0·68-0·87; all p<0·0001. Combined results from LOFT plus LOFT Extension for cumulative incidence of primary outcomes for odanacatib versus placebo were: radiographic vertebral fractures 4·9% (341/6909) versus 9·6% (675/7011), HR 0·48, 95% CI 0·42-0·55; hip fractures 1·1% (86/8043) versus 2·0% (162/8028), 0·52, 0·40-0·67; non-vertebral fractures 6·4% (512/8043) versus 8·4% (675/8028), 0·74, 0·66-0·83; all p<0·0001. In LOFT, the composite cardiovascular endpoint of cardiovascular death, myocardial infarction, or stroke occurred in 273 (3·4%) of 8043 patients in the odanacatib group versus 245 (3·1%) of 8028 in the placebo group (HR 1·12, 95% CI 0·95-1·34; p=0·18). New-onset atrial fibrillation or flutter occurred in 112 (1·4%) of 8043 patients in the odanacatib group versus 96 (1·2%) of 8028 in the placebo group (HR 1·18, 0·90-1·55; p=0·24). Odanacatib was associated with an increased risk of stroke (1·7% [136/8043] vs 1·3% [104/8028], HR 1·32, 1·02-1·70; p=0·034), but not myocardial infarction (0·7% [60/8043] vs 0·9% [74/8028], HR 0·82, 0·58-1·15; p=0·26). The HR for all-cause mortality was 1·13 (5·0% [401/8043] vs 4·4% [356/8028], 0·98-1·30; p=0·10). When data from LOFT Extension were included, the composite of cardiovascular death, myocardial infarction, or stroke occurred in significantly more patients in the odanacatib group than in the placebo group (401 [5·0%] of 8043 vs 343 [4·3%] of 8028, HR 1·17, 1·02-1·36; p=0·029, as did stroke (2·3% [187/8043] vs 1·7% [137/8028], HR 1·37, 1·10-1·71; p=0·0051). INTERPRETATION: Odanacatib reduced the risk of fracture, but was associated with an increased risk of cardiovascular events, specifically stroke, in postmenopausal women with osteoporosis. Based on the overall balance between benefit and risk, the study's sponsor decided that they would no longer pursue development of odanacatib for treatment of osteoporosis. FUNDING: Merck Sharp & Dohme Corp, a subsidiary of Merck & Co, Inc, Kenilworth, NJ, USA.

A phase 2, randomized, placebo-controlled, dose-ranging study of the calcium-sensing receptor antagonist MK-5442 in the treatment of postmenopausal women with osteoporosis.

CONTEXT: MK-5442 is an orally bioavailable calcium-sensing receptor antagonist that is hypothesized to stimulate bone formation by stimulating endogenous secretion of a pulse of PTH. Earlier clinical and preclinical studies demonstrated increased bone mineral density (BMD) after treatment. OBJECTIVE: Our objective was to identify a dose of MK-5442 that produces osteoanabolic effects without excessive hypercalcemia. DESIGN AND SETTING: This was a randomized, double-blind, placebo-controlled, parallel-group trial of private or institutional practice. PARTICIPANTS AND INTERVENTION: In total, 383 postmenopausal women with osteoporosis were administered daily oral MK-5442 (2.5, 5, 7.5, 10, or 15 mg) or placebo. MAIN OUTCOME MEASURES: Serum PTH and calcium, bone turnover markers, areal BMD, and safety were evaluated. RESULTS: A dose-dependent transient increase in PTH occurred after an MK-5442 dose and lasted more than 3.5 hours. Compared with placebo, significant increases in bone formation markers (serum procollagen 1 N-terminal peptide and bone-specific alkaline phosphatase) were observed by 6 months, whereas bone resorption markers (serum C-telopeptide of type 1 collagen, urine N-telopeptides of type 1 collagen) initially decreased but were also significantly increased by 6 months. Despite the biochemical marker changes suggestive of an anabolic response, there were no statistically significant differences between any dose of MK-5442 and placebo in percent change from baseline at month 6 in any of the BMD endpoints. The frequency of hypercalcemia (trough serum calcium ≥ 10.8 mg/dL) was greater with higher MK-5442 doses. CONCLUSION: In postmenopausal women with low bone mass, treatment with MK-5442 resulted in transient pulses of PTH. Bone formation markers increased quickly and bone resorption markers decreased temporarily, suggestive of an anabolic window. However, there were no increases in BMD versus placebo.

MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study.

Most elderly patients admitted for hip fracture suffer functional decline. Previous studies with MK-0677 in hip fracture patients suggested possible benefits to functional recovery. This is a randomized, double-blind study of 123 elderly hip fracture patients assigned to receive 25mg/day of MK-0677 (n = 62) or placebo (n = 61). Primary outcomes were a rank analysis of change during the study in objective functional performance measurements and insulin-like growth factor-1 (IGF-1) levels in blood. At 24-weeks, the mean stair climbing power increased by 12.5 W in the MK-0677 group (95% confidence interval (CI) = -10.95-35.88; p = 0.292) compared with placebo. Gait speed increased by a 0.7-score difference in the means (95% CI = 0.17-1.28; p = 0.011). There was no improvement in MK-0677 treated patients in several other functional performance measures. The MK-0677 group experienced fewer falls during the study compared to placebo and smaller number of patients who had any falls (p = 0.096). Levels of IGF-1 in treated patients increased by 51.4 ng/ml (95% CI = 34.42-68.44; p < 0.001) compared to placebo. Trial was terminated early due to a safety signal of congestive heart failure in a limited number of patients. In hip fracture patients treated with 25mg/day MK-0677, the increase in plasma IGF-1 levels was not paralleled by improvement in most functional performance measures. MK-0677 has an unfavorable safety profile in this patient population.

PCPT: Evidence that finasteride reduces risk of most frequently detected intermediate- and high-grade (Gleason score 6 and 7) cancer.

OBJECTIVES: To determine the effect of finasteride relative to placebo on prostate cancer (PCa) risk at each individual Gleason score in the Prostate Cancer Prevention Trial using a post hoc generalization of a prespecified, exploratory, biopsy sampling density-adjusted analysis. METHODS: The Prostate Cancer Prevention Trial enrolled 18 882 men aged >or=55 years with a prostate-specific antigen level of <3.0 ng/mL and normal digital rectal examination findings, and randomized them to finasteride 5 mg daily or placebo. PCa data from evaluable biopsies obtained within 7 years plus

Detection bias due to the effect of finasteride on prostate volume: a modeling approach for analysis of the Prostate Cancer Prevention Trial.

BACKGROUND: The Prostate Cancer Prevention Trial (PCPT) demonstrated a 24.8% reduction in the 7-year prevalence of prostate cancer among patients treated with finasteride (5 mg daily) compared with that among patients treated with placebo; however, a 25.5% increase in the prevalence of high-Gleason grade tumors was observed, the clinical significance of which is unknown. One hypothesized explanation for this increase is that finasteride reduced prostate volume, leading to detection of more high-grade tumors due to increased sampling density. This possibility was investigated in an observational reanalysis of the PCPT data, with adjustment for sampling density. METHODS: A logistic model for the association of high-grade (Gleason score 7-10) prostate cancer with baseline covariates and/or baseline covariates plus prostate volume and number of cores obtained at biopsy was developed using the placebo group (n = 4775) of the PCPT. This model was then applied to the finasteride group (n = 5123) to compare the predicted and observed numbers of high-grade tumors in that group. In a second approach, odds ratios (ORs) for prostate cancer in the finasteride versus placebo groups calculated from binary and polytomous logistic regression models that contained or excluded covariates for gland volume and number of needle cores were compared. RESULTS: Median prostate volume was 25% lower in the finasteride group (median = 25.1 cm3) than in the placebo group (median = 33.5 cm3). The logistic model developed in the placebo group showed that the likelihood of detection of high-grade prostate cancer decreased as volume increased (for each 10 cm3 increase in prostate volume, OR = 0.81, 95% confidence interval [CI] = 0.74 to 0.90). Based on this model, 239 high-grade prostate cancers were predicted in the finasteride group, whereas 243 were observed, a non-statistically significant difference. Among all participants, the odds ratios for high-grade cancer in the finasteride versus placebo groups decreased from 1.27 (95% CI = 1.05 to 1.54) with adjustment for baseline covariates to 1.03 (95% CI = 0.84 to 1.26) following additional adjustment for gland volume and number of biopsy cores in binary outcome models and from 1.14 (95% CI = 0.94 to 1.38) to 0.88 (95% CI = 0.72 to 1.09) following these adjustments in the polytomous models. CONCLUSIONS: Although analyses using postrandomization data require cautious interpretation, these results suggest that sampling density bias alone could explain the excess of high-grade cancers among the finasteride-assigned participants in the PCPT.

Significant differential effects of alendronate, estrogen, or combination therapy on the rate of bone loss after discontinuation of treatment of postmenopausal osteoporosis. A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Combination therapy with alendronate and estrogen for 2 years increases bone mineral density at the spine and hip more than does therapy with either agent alone. Changes in bone mineral density after discontinuation of therapy have not been compared directly. OBJECTIVE: To determine the rate of bone loss when therapy with alendronate, estrogen, or both agents is discontinued. DESIGN: Double-blind, placebo-controlled discontinuation trial. SETTING: 18 U.S. centers. PATIENTS: 244 postmenopausal, hysterectomized women 44 to 77 years of age. INTERVENTION: 2 years of therapy with alendronate, 10 mg/d (n = 92); conjugated estrogen, 0.625 mg/d (n = 143); alendronate and conjugated estrogen (n = 140); or placebo (n = 50). At year 3, women were allocated into five groups: Twenty-eight women continued to take placebo and 44 women continued to take combination therapy, but 50 women taking alendronate, 81 taking conjugated estrogen, and 41 taking combination therapy were switched to placebo. MEASUREMENTS: Bone mineral density and biochemical markers of bone turnover. RESULTS: Women taking alendronate or combination therapy who were switched to placebo for year 3 of the study maintained bone mass. Bone mineral density in these women was 4.1% (CI, 2.6% to 5.7%) and 6.6% (CI, 5.0% to 8.2%) higher, respectively, at the spine (P < 0.001 for both treatment comparisons) and 3.5% (CI, 2.3% to 4.6%) and 3.0% (CI, 1.8% to 4.2%) higher, respectively, at the trochanter (P < 0.001 for both treatment comparisons) than that in women previously taking estrogen who were switched to placebo. In contrast, women who were taking estrogen and were switched to placebo during year 3 experienced a 4.5% decrease at the spine (95% CI, -5.0% to -4.0%) and a 2.4% decrease at the trochanter (CI, -2.7% to -2.1%) (P < 0.001 for both changes). Compared with women who took placebo for 3 years, women who took estrogen for 2 years and were then switched to placebo had a bone mineral density that was 2.9% higher (CI, 1.2% to 4.6%) at the spine (P < 0.05) and 2.9% higher (CI, 1.6% to 4.2%) at the trochanter (P < 0.001). Changes in biochemical markers during year 3 did not differ among the groups that discontinued active treatment. CONCLUSIONS: Accelerated bone loss is seen after withdrawal of estrogen therapy but not after withdrawal of alendronate or combination therapy. The differential effects after withdrawal of therapy should be considered in the management of postmenopausal osteoporosis.