Effects of four-year cyclic versus two-year daily teriparatide treatment on volumetric bone density and bone strength in postmenopausal women with osteoporosis

Clinical Efficacy and Safety of Teriparatide Versus Alendronate in Postmenopausal Osteoporosis: A Systematic Review of Randomized Controlled Trials

Alendronate, a second-generation bisphosphonate, remains the first-line therapeutic option for postmenopausal osteoporosis. It acts on the bone resorbing osteoclasts causing their apoptosis. This is achieved by producing toxic adenosine triphosphate (ATP) analogues and interfering with the mevalonate pathway. Teriparatide, a recombinant form of parathyroid hormone, is an alternative option to this more conventional drug. It is an anabolic drug that mediates its biological effect via specific, high-affinity membrane cell-surface receptors expressed on the osteoblasts. It promotes bone formation more than bone resorption. Hence, this research was conducted to delineate the effectiveness and clinical safety of teriparatide as compared to alendronate in women suffering from postmenopausal osteoporosis. An extensive search was conducted through PubMed, Google Scholar, Trip (Turning Research into Practice), and Cochrane Central Register of Controlled Trials (CENTRAL) including studies published between August 2017 and October 2024 in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines 2020. The Medical Subject Headings (MeSH) terms and Boolean operators used were "Alendronate" OR "Diphosphonates" OR "Teriparatide" OR "Treatment Outcome" OR "Postmenopause" AND "Osteoporosis". Randomized controlled trials were included in this systematic review. Five full-text articles were ultimately considered and critical appraisal was performed thereon. The annual incidence rate of morphometric vertebral fracture in the sequential therapy (teriparatide) group (0.1020 and 0.1334) was significantly lower than monotherapy (alendronate) (0.1492 and 0.1734). Quality of life (QoL) by week 12 was better in teriparatide than alendronate and no patient encountered any severe adverse effects with teriparatide after 72 weeks of treatment. Thus, based on the results, teriparatide is more effective than alendronate in increasing the bone mineral density (BMD) of L2-4 vertebrae and the hip bone. However, alendronate is better in the case of femoral neck fractures. Furthermore, spinal strength shows a better response in the trabecular than peripheral compartment with teriparatide. Teriparatide is also safer than alendronate due to its lower incidence rate in morphometric vertebral fracture, lack of severe adverse effects and better QoL. Teriparatide showed comparable inhibition of vertebral collapse, increase in BMD, promotion of bone union, and improvement of pain.

Romosozumab versus parathyroid hormone receptor agonists: which osteoanabolic to choose and when?

Osteoanabolic agents are used as a first line treatment in patients at high fracture risk. The PTH receptor 1 (PTH1R) agonists teriparatide (TPTD) and abaloparatide (ABL) increase bone formation, bone mineral density (BMD), and bone strength by activating PTH receptors on osteoblasts. Romosozumab (ROMO), a humanized monoclonal antibody against sclerostin, dramatically but transiently stimulates bone formation and persistently reduces bone resorption. Osteoanabolic agents increase BMD and bone strength while being more effective than antiresorptives in reducing fracture risk in postmenopausal women. However, direct comparisons of the antifracture benefits of osteoanabolic therapies are limited. In a direct comparison of TPTD and ABL, the latter resulted in greater BMD increases at the hip. While no differences in vertebral or non-vertebral fracture risk were observed between the two drugs, ABL led to a greater reduction of major osteoporotic fractures. Adverse event profiles were similar between the two agents except for hypercalcemia, which occurred more often with TPTD. No direct comparisons of fracture risk reduction between ROMO and the PTH1R agonists exist. Individual studies have shown greater increases in BMD and bone strength with ROMO compared with TPTD in treatment-naive women and in women previously treated with bisphosphonates. Some safety aspects, such as a history of tumor precluding the use of PTH1R agonists, and a history of major cardiovascular events precluding the use of ROMO, should also be considered when choosing between these agents. Finally, convenience of administration, reimbursement by national health systems and length of clinical experience may influence patient choice.

A parathyroid hormone related supramolecular peptide for multi-functionalized osteoregeneration

Supramolecular peptide nanofiber hydrogels are emerging biomaterials for tissue engineering, but it is difficult to fabricate multi-functional systems by simply mixing several short-motif-modified supramolecular peptides because relatively abundant motifs generally hinder nanofiber cross-linking or the formation of long nanofiber. Coupling bioactive factors to the assembling backbone is an ideal strategy to design multi-functional supramolecular peptides in spite of challenging synthesis and purification. Herein, a multi-functional supramolecular peptide, P1R16, is developed by coupling a bioactive factor, parathyroid hormone related peptide 1 (PTHrP-1), to the basic supramolecular peptide RADA16-Ⅰ via solid-phase synthesis. It is found that P1R16 self-assembles into long nanofibers and co-assembles with RADA16-Ⅰ to form nanofiber hydrogels, thus coupling PTHrP-1 to hydrogel matrix. P1R16 nanofiber retains osteoinductive activity in a dose-dependent manner, and P1R16/RADA16-Ⅰ nanofiber hydrogels promote osteogenesis, angiogenesis and osteoclastogenesis in vitro and induce multi-functionalized osteoregeneration by intramembranous ossification and bone remodeling in vivo when loaded to collagen (Col) scaffolds. Abundant red blood marrow formation, ideal osteointegration and adapted degradation are observed in the 50% P1R16/Col scaffold group. Therefore, this study provides a promising strategy to develop multi-functional supramolecular peptides and a new method to topically administrate parathyroid hormone or parathyroid hormone related peptides for non-healing bone defects.

Mechanistic advances in osteoporosis and anti-osteoporosis therapies

Osteoporosis is a type of bone loss disease characterized by a reduction in bone mass and microarchitectural deterioration of bone tissue. With the intensification of global aging, this disease is now regarded as one of the major public health problems that often leads to unbearable pain, risk of bone fractures, and even death, causing an enormous burden at both the human and socioeconomic layers. Classic anti-osteoporosis pharmacological options include anti-resorptive and anabolic agents, whose ability to improve bone mineral density and resist bone fracture is being gradually confirmed. However, long-term or high-frequency use of these drugs may bring some side effects and adverse reactions. Therefore, an increasing number of studies are devoted to finding new pathogenesis or potential therapeutic targets of osteoporosis, and it is of great importance to comprehensively recognize osteoporosis and develop viable and efficient therapeutic approaches. In this study, we systematically reviewed literatures and clinical evidences to both mechanistically and clinically demonstrate the state-of-art advances in osteoporosis. This work will endow readers with the mechanistical advances and clinical knowledge of osteoporosis and furthermore present the most updated anti-osteoporosis therapies.