Gregory C. Williams

Effect of Abaloparatide vs Placebo on New Vertebral Fractures in Postmenopausal Women With Osteoporosis: A Randomized Clinical Trial

IMPORTANCE Additional therapies are needed for prevention of osteoporotic fractures. Abaloparatide is a selective activator of the parathyroid hormone type 1 receptor. OBJECTIVE To determine the efficacy and safety of abaloparatide, 80 μg, vs placebo for prevention of new vertebral fracture in postmenopausal women at risk of osteoporotic fracture. DESIGN, SETTING, AND PARTICIPANTS The Abaloparatide Comparator Trial In Vertebral Endpoints (ACTIVE) was a phase 3, double-blind, RCT (March 2011-October 2014) at 28 sites in 10 countries. Postmenopausal women with bone mineral density (BMD) T score ≤-2.5 and >-5.0 at the lumbar spine or femoral neck and radiological evidence ≥2 mild or ≥1 moderate lumbar or thoracic vertebral fracture or history of low-trauma nonvertebral fracture within the past 5 years were eligible. Postmenopausal women (>65 y) with fracture criteria and a T score ≤-2.0 and >-5.0 or without fracture criteria and a T score ≤-3.0 and >-5.0 could enroll. INTERVENTIONS Blinded, daily subcutaneous injections of placebo (n = 821); abaloparatide, 80 μg (n = 824); or open-label teriparatide, 20 μg (n = 818) for 18 months. MAIN OUTCOMES AND MEASURES Primary end point was percentage of participants with new vertebral fracture in the abaloparatide vs placebo groups. Sample size was set to detect a 4% difference (57% risk reduction) between treatment groups. Secondary end points included change in BMD at total hip, femoral neck, and lumbar spine in abaloparatide-treated vs placebo participants and time to first incident nonvertebral fracture. Hypercalcemia was a prespecified safety end point in abaloparatide-treated vs teriparatide participants. RESULTS Among 2463 women (mean age, 69 years [range, 49-86]), 1901 completed the study. New morphometric vertebral fractures occurred less frequently in the active treatment groups vs placebo. The Kaplan-Meier estimated event rate for nonvertebral fracture was lower with abaloparatide vs placebo. BMD increases were greater with abaloparatide than placebo (all P < .001). Incidence of hypercalcemia was lower with abaloparatide (3.4%) vs teriparatide (6.4%) (risk difference [RD], −2.96 [95%CI, −5.12 to −0.87]; P = .006). [table: see text]. CONCLUSIONS AND RELEVANCE Among postmenopausal women with osteoporosis, the use of subcutaneous abaloparatide, compared with placebo, reduced the risk of new vertebral and nonvertebral fractures over 18 months. Further research is needed to understand the clinical importance of RD, the risks and benefits of abaloparatide treatment, and the efficacy of abaloparatide vs other osteoporosis treatments. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01343004.

Eighteen Months of Treatment With Subcutaneous Abaloparatide Followed by 6 Months of Treatment With Alendronate in Postmenopausal Women With Osteoporosis: Results of the ACTIVExtend Trial

Objective To assess the efficacy and safety of 18 months of subcutaneous abaloparatide (ABL‐SC) or placebo (PBO) followed by 6 months of alendronate (ALN) (preplanned interim analysis). Patients and Methods ACTIVExtend, an extension of ACTIVE, enrolled patients who completed 18 months of ABL‐SC or PBO in ACTIVE to receive up to 24 additional months of open‐label ALN; there was 1 month between the studies to re‐consent patients. Results Of 1243 eligible ACTIVE patients, 1139 (92%) were enrolled in ACTIVExtend beginning November 20, 2012. These results are from a prespecified 6‐month interim analysis (cutoff date, June 2, 2015); the study is ongoing. Findings indicated percentages of patients with new morphometric vertebral fractures: PBO/ALN, 4.4% vs ABL‐SC/ALN, 0.55%; relative risk reduction, 87% (relative risk, 0.13; 95% CI, 0.04–0.41; P<.001). Kaplan‐Meier estimated rates of nonvertebral fractures were PBO/ALN, 5.6% vs ABL‐SC/ALN, 2.7%; risk reduction, 52% (hazard ratio [HR], 0.48; 95% CI, 0.26–0.89; log‐rank P=.02). There was also a 58% risk reduction of major osteoporotic fractures (HR, 0.42; 95% CI, 0.21–0.85; log‐rank P=.01) and a 45% risk reduction of clinical fractures (HR, 0.55; 95% CI, 0.33–0.92; log‐rank P=.02) in the ABL‐SC/ALN group vs the PBO/ALN group. At 25 months, bone mineral density percentage change from ACTIVE baseline for ABL‐SC/ALN vs PBO/ALN was as follows: lumbar spine, 12.8%; total hip, 5.5%; femoral neck, 4.5% vs 3.5%, 1.4%, 0.5%, respectively (group differences at all sites P<.001). Conclusion Use of ABL‐SC for 18 months followed by ALN for 6 months improved bone mineral density and reduced fracture risk throughout the skeleton and may be an effective treatment option for postmenopausal women with osteoporosis. Trial Registration clinicaltrials.gov Identifier: NCT01657162.

Effects of Abaloparatide-SC on Fractures and Bone Mineral Density in Subgroups of Postmenopausal Women With Osteoporosis and Varying Baseline Risk Factors.

Abaloparatide‐SC is a novel 34–amino acid peptide created to be a potent and selective activator of the parathyroid hormone receptor type 1 (PTHR1) signaling pathway. In the Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE) Phase 3 trial (NCT01343004), abaloparatide reduced new morphometric vertebral fractures by 86% compared with placebo (p < 0.001) and nonvertebral fractures by 43% (p = 0.049) in postmenopausal women with osteoporosis. Abaloparatide‐SC increased bone mineral density (BMD) 3.4% at the total hip, 2.9% at the femoral neck, and 9.2% at the lumbar spine at 18 months (all p < 0.001 versus placebo). The analysis reported here was designed to evaluate whether fracture risk reductions and BMD accrual were consistent across different levels of baseline risk. Risk factor subgroups were predefined categorically for BMD T‐score of the lumbar spine, total hip, and femoral neck (≤–2.5 versus >–2.5 and ≤–3.0 versus >–3.0), history of nonvertebral fracture (yes versus no), prevalent vertebral fracture (yes versus no), and age (<65 versus 65 to <75 versus ≥75 years) at baseline. Forest plots show that there were no clinically meaningful interactions between any of the baseline risk factors and the treatment effect of abaloparatide‐SC on new morphometric vertebral fractures, nonvertebral fractures, or BMD increases. Abaloparatide provides protection against fractures consistently across a wide variety of ages and baseline risks, including those with and without prior fractures, and it has potential utility for a broad group of postmenopausal women with osteoporosis.

ACTIVExtend: 24 Months of Alendronate after 18 Months of Abaloparatide or Placebo for Postmenopausal Osteoporosis.

Abstract Purpose In women with postmenopausal osteoporosis, we investigated the effects of 24 months of treatment with alendronate (ALN) following 18 months of treatment with abaloparatide (ABL) or placebo (PBO). Methods Women who completed ABL or PBO treatment in ACTIVE were eligible to receive up to 24 months of ALN. We evaluated the incidence of vertebral and nonvertebral fractures and changes in bone mineral density (BMD) during the entire 43-month period from ACTIVE baseline to the end of ACTIVExtend and for the 24-month extension only. Results Five hundred fifty-eight women from ACTIVE’s ABL group and 581 from its PBO group (92% of ABL and PBO completers) were enrolled. During the full 43-month treatment period, 0.9% of evaluable women in the ABL/ALN group experienced a new radiographic vertebral fracture vs 5.6% of women in the PBO/ALN group, an 84% relative risk reduction (RRR, P < 0.001). Kaplan–Meier incidence rates for other reported fracture types were significantly lower for ABL/ALN vs PBO/ALN (all P < 0.05). Gains in BMD achieved during ACTIVE were further increased during ACTIVExtend. For ACTIVExtend only, RRR for vertebral fractures was 87% with ABL/ALN vs PBO/ALN (P = 0.001). Adverse events were similar between groups. A supplemental analysis for regulatory authorities found no hip fractures in the ABL/ALN group vs five in the PBO/ALN group. Conclusions Eighteen months of ABL followed by 24 months of ALN reduced the risk of vertebral, nonvertebral, clinical, and major osteoporotic fractures and increased BMD. Sequential ABL followed by ALN appears to be an effective treatment option for postmenopausal women at risk for osteoporosis-related fractures.

Geography of Fracture Incidence in Postmenopausal Women with Osteoporosis Treated with Abaloparatide

Geographic heterogeneity has been observed in fracture risk and efficacy of therapeutic intervention in postmenopausal osteoporosis. The objectives of these analyses were to assess across geographic and ethnic subgroups the heterogeneity of fracture incidence and baseline risk, and consistency of effect of abaloparatide-SC vs placebo on fracture risk reduction in the 18-month, phase 3, multinational, ACTIVE randomized controlled trial. Prespecified exploratory analyses of geographic subgroups (North America, South America, Europe, Asia) and post hoc analyses of ethnic subgroups (Hispanic or Latino, other) of postmenopausal women with osteoporosis enrolled in the abaloparatide-SC and placebo cohorts (n = 1645) were performed. Country-specific FRAX models were used to calculate 10-year absolute fracture risks. Relative risk reductions for vertebral fractures and hazard ratios for non-vertebral, clinical, and major osteoporotic fractures were calculated. Forest plots were constructed to assess treatment-by-subgroup interactions for each geographic region and ethnicity. Baseline prevalence of vertebral fractures was similar across geographies; baseline prevalence of non-vertebral fractures was more variable. Ten-year major osteoporosis fracture and hip fracture risks were variable across and within regions. The effects of abaloparatide-SC on reducing the risk of vertebral, non-vertebral, clinical, and major osteoporotic fractures were similar across regions, and for Hispanic or Latino vs other ethnicities. A limitation was the limited power to detect interactions with few events. In conclusion, despite geographic variability in fracture incidence and risk at baseline, no differences were detected in the effects of abaloparatide-SC in reducing vertebral, non-vertebral, clinical, and major osteoporotic fracture risk across assessed geographic regions and ethnicities.

Abaloparatide is an Effective Treatment Option for Postmenopausal Osteoporosis: Review of the Number Needed to Treat Compared with Teriparatide

Abaloparatide (ABL) is a 34-amino acid peptide designed to be a selective activator of the parathyroid hormone receptor type 1 signaling pathway. In the Abaloparatide Comparator Trial In Vertebral Endpoints (ACTIVE), subcutaneous ABL reduced the risk of new vertebral, nonvertebral, clinical, and major osteoporotic fracture compared with placebo and of major osteoporotic fracture compared with teriparatide. To further evaluate the effectiveness of ABL, we calculated the number needed to treat (NNT) to prevent one fracture using ACTIVE data. To estimate the potential effectiveness of ABL in populations at higher fracture risk than in ACTIVE, we calculated NNT for vertebral fracture using reference populations from historical placebo-controlled trials, assuming an 86% relative risk reduction in vertebral fracture with ABL treatment as observed in ACTIVE. NNT was calculated as the reciprocal of the absolute risk reduction in ACTIVE. The projected NNT for ABL in other populations was calculated based on incidence rate (IR) for vertebral fractures in the placebo arms of the FREEDOM (placebo IR 7.2%), FIT-1 (placebo IR 15.0%), and FIT-2 (placebo IR 3.8%) trials. NNT for ABL in ACTIVE was 28 for vertebral, 55 for nonvertebral, 37 for clinical, and 34 for major osteoporotic fracture. NNT for these fracture types for teriparatide in ACTIVE were 30, 92, 59, and 75, respectively. Using placebo IRs from FREEDOM, FIT-1, and FIT-2, projected NNTs for vertebral fracture with ABL were 17, 8, and 31. These data are useful for further evaluating ABL for the treatment of osteoporosis in postmenopausal women.