Effect of a sequential treatment combining abaloparatide and alendronate for the management of postmenopausal osteoporosis

The recently published results of the sequential treatment of postmenopausal osteoporotic women with subcutaneous abaloparatide (80 µg/day) (ABL) for 18 months followed by 6 months of oral alendronate (70 mg/week) (ALN) support the administration of an anti-resorptive agent after completion of a treatment course with an osteoanabolic agent. The ABL/ALN sequence resulted in greater bone mineral density gains at all skeletal sites and in a reduction of vertebral, non-vertebral, major and clinical fractures compared to what is observed after 18 months of placebo followed by 6 months of ALN. Whereas questions remained unanswered about the ideal anti-resorptive agent to be used after ABL, the optimal duration of the administration of the anti-resorptive drug or the potential interest of re-initiating a course of ABL after a limited administration of ALN, these results support the use of the ABL/ALN sequence in the management of postmenopausal osteoporosis.     

Emerging anabolic agents in the treatment of osteoporosis

Introduction: Osteoporosis is a common skeletal disease with serious consequences due to osteoporotic fractures and high costs to society for post-fracture care. Most patients at high risk for fracture are not receiving care to reduce fracture risk. The osteoporosis treatment gap has reached crisis proportions. Strategies to reduce the treatment gap include systematic methods for identifying and treating high risk patients, better education of patients and healthcare providers, better use of currently available drugs, and development of new drugs to treat osteoporosis.

Areas covered: Two osteoanabolic agents with novel mechanisms of action have recently completed phase 3 clinical trials. The efficacy and safety findings of these studies are reviewed. Abaloparatide, a synthetic analog of parathyroid hormone-related protein, has received regulatory approval for the treatment of postmenopausal women with osteoporosis at high risk for fracture. Romosozumab, a humanized monoclonal antibody to sclerostin, an endogenous inhibitor of bone formation, is under regulatory review.

Expert opinion: Osteoanabolic therapy for osteoporosis can restore, at least in part, the degradation of bone microarchitecture that is a hallmark of this disease. The emergence of new osteoanabolic compounds expands the treatment options for patients at high risk for fracture.     

Abaloparatide Comparator Trial In Vertebral Endpoints (ACTIVE) confirms that abaloparatide is a valuable addition to the armamentarium against osteoporosis

The recently published Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE) assessed the efficacy and safety of abaloparatide (80 µg daily subcutaneous) (ABL) vs placebo during 18 months, in postmenopausal osteoporosis. Teriparatide (20 µg daily subcutaneous) (TPD) was used as an open label active comparator. The results of the study suggest that ABL increases bone mineral density more than TPD and reduces major osteoporotic fractures to a greater extent than TPD with a more rapid onset of action. These outcomes combined with a positive safety profile make ABL an interesting addition to the armamentarium against postmenopausal osteoporosis.     

甲状旁腺素相关肽治疗绝经后骨质疏松症的研究进展

甲状旁腺素相关肽(parathyroid hormone-related peptide,PTHrP)是人体内存在的一种分泌蛋白,它因与甲状旁素(parathyroid hormone,PTH)在分子结构和信号传导方面有很高的同源性,作为潜在的骨形成促进剂运用于治疗骨质疏松症。PTHrp通过各种信号传导通路调控骨代谢,发挥影响成骨细胞和破骨细胞的作用。并已在动物试验中被证实能有效地促进骨骼合成,改善骨微结构,提高骨量以及增加骨强度。相关药物Abaloparatide的临床研究证实其可显著增加骨密度,改善骨代谢,降低骨折风险,对绝经后骨质疏松有一定的治疗效果。     

Efficacy and safety of abaloparatide for the treatment of post-menopausal osteoporosis

Introduction: Osteoporosis is a skeletal disorder characterized by loss of bone mass and strength affecting up to 30–50% of postmenopausal women worldwide. Current therapeutic options include antiresorptives such as aminobisphosphonates or denosumab and osteoanabolic compounds such as teriparatide.

Areas covered: In this review, the authors summarize the clinical development, safety and efficacy profile of abaloparatide, a new osteoanabolic agent recently marketed in the US for the treatment of postmenopausal osteoporosis in women who are at high risk for fracture or who fail antiresorptive therapy.

Expert opinion: Abaloparatide is a 1-34 PTH related peptide-like molecule that has been modified in order to potentiate the osteoanabolic effect. In its pivotal phase 3 trial in postmenopausal women with osteoporosis, subcutaneous abaloparatide 80 mcg/day reduced the risk of vertebral, nonvertebral, major osteoporotic, and clinical fractures compared with placebo and reduced the risk of major osteoporotic fractures compared with teriparatide. These results, together with a reduced prevalence of hypercalcemia and a lower cost of the marketed compound, point toward improved cost effectiveness with abaloparatide versus teriparatide. However, some concerns have been raised due to a somewhat higher occurrence of adverse effects (particularly with palpitations and increased heart rate) or the resultant discontinuation due to these adverse effects when compared to teriparatide.     

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).

Investigational anabolic agents for the treatment of osteoporosis: an update on recent developments

Introduction: Teriparatide, a PTH analogue, was the first anabolic agent to be approved for the treatment of osteoporosis in 2002. Abaloparatide was also recently approved by the FDA. The need for other anabolic agents is still unmet.

Areas covered: In this review, we discuss target molecules and recent advances in the field of anabolic therapy for osteoporosis. PTH and PTHrP analogues binding to the PTH receptor and different routes of administration of teriparatide to avoid the burden of daily subcutaneous injections are discussed. We also review antibodies targeting suppressors of the Wnt pathway such as sclerostin and Dickopff-1.

Expert opinion: The development of alternative ways of administering PTH receptor ligands is a promising field, especially via the transdermal route. Other more promising molecules are still at very early stages of development. FDA recently requested more data on Romosozumab.     

Comparing the incidence of bone tumors in rats chronically exposed to the selective PTH type 1 receptor agonist abaloparatide or PTH(1–34)

Prolonged treatment with human parathyroid hormone (hPTH) in rats results in development of bone tumors, though this finding has not been supported by clinical experience. The PTH type 1 receptor agonist abaloparatide, selected for its bone anabolic activity, is under clinical development to treat postmenopausal women with osteoporosis. To determine the carcinogenic potential of abaloparatide, Fischer (F344) rats were administered SC daily abaloparatide at doses of 0, 10, 25, and 50 μg/kg or 30 μg/kg hPTH(1–34) as a positive control for up to 2 years. Robust increases in bone density were achieved at all abaloparatide doses and with hPTH(1–34). Comprehensive histopathological analysis reflected a comparable continuum of proliferative changes in bone, mostly osteosarcoma, in both abaloparatide and hPTH(1–34) treated rats. Comparing the effects of abaloparatide and hPTH(1–34) at the 25 and 30 μg/kg respective doses, representing similar exposure multiples to the human therapeutic doses, revealed similar osteosarcoma-associated mortality, tumor incidence, age at first occurrence, and metastatic potential. There were no increases in the incidence of non-bone tumors with abaloparatide compared to vehicle. Thus, near life-long treatment with abaloparatide in rats resulted in dose and time dependent formation of osteosarcomas, with a comparable response to hPTH(1–34) at similar exposure.