Teriparatide

Parathyroid hormone and its related peptides in bone metabolism.

Parathyroid hormone (PTH) is an 84-amino-acid peptide hormone that is secreted by the parathyroid gland. It has different administration modes in bone tissue through which it promotes bone formation (intermittent administration) and bone resorption (continuous administration) and has great potential for application in sbone defect repair. PTH regulates bone metabolism by binding to PTH1R. PTH plays an osteogenic role by acting directly on mesenchymal stem cells, cells with an osteoblastic lineage, osteocytes, and T cells. It also participates as an osteoclast by indirectly acting on osteoclast precursor cells and osteoclasts and directly acting on T cells. In these cells, PTH activates the Wnt signaling, cAMP/PKA, cAMP/PKC, and RANKL/RANK/OPG pathways and other signaling pathways. Although PTH(1-34), also known as teriparatide, has been used clinically, it still has some disadvantages. Developing improved PTH-related peptides is a potential solution to teriparatide's shortcomings. The action mechanism of these PTH-related peptides is not exactly the same as that of PTH. Thus, the mechanisms of PTH and PTH-related peptides in bone metabolism were reviewed in this paper.

An injectable liposome-anchored teriparatide incorporated gallic acid-grafted gelatin hydrogel for osteoarthritis treatment.

Intra-articular injection of therapeutics is an effective strategy for treating osteoarthritis (OA), but it is hindered by rapid drug diffusion, thereby necessitating high-frequency injections. Hence, the development of a biofunctional hydrogel for improved delivery is required. In this study, we introduce a liposome-anchored teriparatide (PTH (1-34)) incorporated into a gallic acid-grafted gelatin injectable hydrogel (GLP hydrogel). We show that the GLP hydrogel can form in situ and without affecting knee motion after intra-articular injection in mice. We demonstrate controlled, sustained release of PTH (1-34) from the GLP hydrogel. We find that the GLP hydrogel promotes ATDC5 cell proliferation and protects the IL-1β-induced ATDC5 cells from further OA progression by regulating the PI3K/AKT signaling pathway. Further, we show that intra-articular injection of hydrogels into an OA-induced mouse model promotes glycosaminoglycans synthesis and protects the cartilage from degradation, supporting the potential of this biomaterial for OA treatment.

Denosumab and teriparatide transitions in postmenopausal osteoporosis (the DATA-Switch study): extension of a randomised controlled trial.

Unlike most chronic diseases, osteoporosis treatments are generally limited to a single drug at a fixed dose and frequency. Nonetheless, no approved therapy is able to restore skeletal integrity in most osteoporotic patients and the long-term use of osteoporosis drugs is controversial. Thus, many patients are treated with the sequential use of two or more therapies. The DATA study showed that combined teriparatide and denosumab increased bone mineral density more than either drug alone. Discontinuing teriparatide and denosumab, however, results in rapidly declining bone mineral density. In this DATA-Switch study, we aimed to assess the changes in bone mineral density in postmenopausal osteoporotic women who transitioned between treatments. This randomised controlled trial (DATA-Switch) is a preplanned extension of the denosumab and teriparatide administration study (DATA), in which 94 postmenopausal osteoporotic women were randomly assigned to receive 24 months of teriparatide (20 mg daily), denosumab (60 mg every 6 months), or both drugs. In DATA-Switch, women originally assigned to teriparatide received denosumab (teriparatide to denosumab group), those originally assigned to denosumab received teriparatide (denosumab to teriparatide group), and those originally assigned to both received an additional 24 months of denosumab alone (combination to denosumab group). Bone mineral density at the spine, hip, and wrist were measured 6 months, 12 months, 18 months, and 24 months after the drug transitions as were biochemical markers of bone turnover. The primary endpoint was the percent change in posterior-anterior spine bone mineral density over 4 years. Between-group changes were assessed by one-way analysis of variance in our modified intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00926380. Between Sept 27, 2011, and Jan 28, 2013, eligible women from the DATA study were enrolled into DATA-Switch. Of 83 potential enrollees from the DATA study, 77 completed at least one post-baseline visit. After 48 months, the primary outcome of mean spine bone mineral density increased by 18&#xb7;3% (95% CI 14&#xb7;9-21&#xb7;8) in 27 women in the teriparatide to denosumab group, 14&#xb7;0% (10&#xb7;9-17&#xb7;2) in 27 women the denosumab to teriparatide group, and 16&#xb7;0% (14&#xb7;0-18&#xb7;0) in 23 women in the combination to denosumab group, although this increase did not differ significantly between groups (for between-group comparisons, p=0&#xb7;13 for the teriparatide to denosumab group vs the denosumab to teriparatide group, p=0&#xb7;30 for the teriparatide to denosumab group vs the combination to denosumab group, and p=0&#xb7;41 for the denosumab to teriparatide group vs the combination to denosumab group). For the bone mineral density secondary outcomes, total hip bone mineral density increased more in the teriparatide to denosumab group (6&#xb7;6% [95% CI 5&#xb7;3-7&#xb7;9]) than in the denosumab to teriparatide group (2&#xb7;8% [1&#xb7;3-4&#xb7;2], p=0&#xb7;0002), but had the greatest increase in the combination to denosumab group (8&#xb7;6% [7&#xb7;1-10&#xb7;0]; p=0&#xb7;0446 vs the teriparatide to denosumab group, p<0&#xb7;0001 vs the denosumab to teriparatide group). Similarly, femoral neck bone mineral density increased more in the teriparatide to denosumab group (8&#xb7;3% [95% CI 6&#xb7;1-10&#xb7;5]) and the combination to denosumab group (9&#xb7;1% [6&#xb7;1-12&#xb7;0]) than in the denosumab to teriparatide group (4&#xb7;9% [2&#xb7;2-7&#xb7;5]; p=0&#xb7;0447 for teriparatide to denosumab vs denosumab to teriparatide, p=0&#xb7;0336 for combination to denosumab vs denosumab to teriparatide). Differences between the combination to denosumab group and the teriparatide to denosumab group did not differ significantly (p=0&#xb7;67). After 48 months, radius bone mineral density was unchanged in the teriparatide to denosumab group (0&#xb7;0% [95% CI -1&#xb7;3 to 1&#xb7;4]), whereas it decreased by -1&#xb7;8% (-5&#xb7;0 to 1&#xb7;3) in the denosumab to teriparatide group, and increased by 2&#xb7;8% (1&#xb7;2-4&#xb7;4) in the combination to denosumab group (p=0&#xb7;0075 for the teriparatide to denosumab group vs the combination to denosumab group; p=0&#xb7;0099 for the denosumab to teriparatide group vs the combination to denosumab group). One participant in the denosumab to teriparatide group had nephrolithiasis, classified as being possibly related to treatment. In postmenopausal osteoporotic women switching from teriparatide to denosumab, bone mineral density continued to increase, whereas switching from denosumab to teriparatide results in progressive or transient bone loss. These results should be considered when choosing the initial and subsequent management of postmenopausal osteoporotic patients. Amgen, Eli Lilly, and National Institutes of Health.

[Hypoparathyroidism].

Hypoparathyroidism and quality of life: Even in adequately substituted patients, hypoparathyroidism (HPT) is associated with impaired quality of life. It has been hypothesized that there is a correlation between reduced quality of life and lack of parathyroid hormone (PTH) in the central nervous system. Positive effects on quality of life have been reported when treating HPT with PTH. Hypoparathyroidism and comorbidities: Comorbidities associated with HPT include an increased risk of nephrolithiasis/nephrocalcinosis and neuro-psychiatric disease. Additionally, cardiovascular risk profile and an increased susceptibility for infections have been reported. Mortality rates seem not to be increased in HPT. Hypoparathyroidism and new therapeutic strategies: Recombinant PTH has not been approved for the treatment of HPT in Europe yet. However, in early 2015, the FDA approved PTH (1-84). Daily subcutaneous delivery of PTH (1-84) and PTH (1-34) (Teriparatide) has emerged as a promising therapeutic tool. However, its use should be restricted to patients insufficiently controlled with the standard treatment consisting of active vitamin d and calcium.

PTH1 receptor agonists for fracture risk: a systematic review and network meta-analysis.

Osteoporosis, defined by reduced bone mineral density and macro- and micro-architectural degradation, leads to increased fracture risk, particularly in aging populations. While randomized controlled trials (RCTs) demonstrate that PTH1 receptor agonists, teriparatide and abaloparatide, are effective at reducing fracture risk, real-world evidence (RWE) remains sparse. This study reviews and compares the anti-fracture efficacy of these agents, against each other and against other osteoporosis treatments using both RCTs and RWE. We systematically searched Medline, Embase, and Cochrane up to May 2024, focusing on RCTs and RWE studies reporting reduction in vertebral, non-vertebral, hip, or all fractures as primary endpoint. A network meta-analysis (NMA) was conducted, first through pairwise meta-analyses of teriparatide versus abaloparatide, then a Bayesian NMA comparing each to other treatments. Safety assessments included adverse events classified by MedDRA, with a particular attention to hypercalcemia and cardiac events. Seventeen studies (11 RCTs, 6 RWE) met inclusion criteria. Teriparatide and abaloparatide were effective in reducing vertebral and non-vertebral fractures in all pairwise meta-analyses versus placebo. Abaloparatide showed an advantage over teriparatide for non-vertebral fractures (OR: 0.87, 95% CI: 0.80-0.95) and hip fractures (OR: 0.81, 95% CI: 0.71-0.93). In the NMA model, teriparatide and abaloparatide were superior to placebo, raloxifene, and calcitonin in reducing vertebral fracture while teriparatide was further superior to denosumab and risedronate. For non-vertebral fracture, abaloparatide was better than any other treatment while teriparatide was only superior to alendronate or placebo. PTH1 analogs were better than placebo at reducing all fractures while no difference was observed for the risk of hip fracture. Both abaloparatide and teriparatide demonstrate comparable safety to other osteoporosis treatments, with no increased cardiovascular risk. This review highlights that PTH1 receptor agonists effectively reduce fracture risk, with abaloparatide offering enhanced benefits for non-vertebral and hip fractures compared to teriparatide. Both agents exhibit acceptable safety profiles, suggesting their valuable role in managing osteoporosis, particularly for high-risk patients.

Arrestins in bone.

Parathyroid hormone (PTH) is the principle regulator of calcium-phosphorus metabolism and bone turnover. Because of its central role in bone remodeling, recombinant human PTH (i.e., Forteo&#xae;; PTH(1-34)) has been developed for the treatment of osteoporosis. PTH(1-34) acts principally through the type I PTH/PTH-related peptide receptor (PTH1R), a classic seven transmembrane G protein-coupled receptor (GPCR). Intermittent treatment with PTH(1-34) promotes osteoblast and osteoclast recruitment through activation of PTH1R with resultant net bone gain. Recent studies have demonstrated that the complex metabolic effects induced by PTH1R stimulation are not entirely a consequence of conventional GPCR signaling. &#x3b2;-Arrestins, in addition to their desensitizing actions, also serve as multifunctional scaffolding proteins linking the PTH1R to signaling molecules independent of classic G protein-mediated second messenger-dependent pathways. In vitro, D-Trp(12), Tyr(34)-bPTH(7-34) [bPTH(7-34)], a &#x3b2;-arrestin-selective biased agonist for the PTH1R, antagonizes G protein signaling but activates arrestin-dependent signaling. In vivo, intermittent administration of bPTH(7-34) to mice induces anabolic bone formation independent of classic G protein-coupled signaling mechanisms. While both the conventional PTH1R agonists, PTH(1-34) and bPTH(7-34), stimulate anabolic bone formation in mice, the latter does not induce hypercalcemia nor does it increase markers of bone resorption. This newly recognized ability of &#x3b2;-arrestins to serve as signal transducers for the PTH1R independent of classic GPCR signaling represents a novel paradigm with therapeutic potential. Exploitation of &#x3b2;-arrestin-biased agonism may offer therapeutic benefit for the treatment of metabolic bone diseases such as osteoporosis with an improved side effect profile.

Potential effects of teriparatide (PTH (1-34)) on osteoarthritis: a systematic review.

Osteoarthritis (OA) is a common and prevalent degenerative joint disease characterized by degradation of the articular cartilage. However, none of disease-modifying OA drugs is approved currently. Teriparatide (PTH (1-34)) might stimulate chondrocyte proliferation and cartilage regeneration via some uncertain mechanisms. Relevant therapies of PTH (1-34) on OA with such effects have recently gained increasing interest, but have not become widespread practice. Thus, we launch this systematic review (SR) to update the latest evidence accordingly. A comprehensive literature search was conducted in PubMed, Web of Science, MEDLINE, the Cochrane Library, and Embase from their inception to February 2022. Studies investigating the effects of the PTH (1-34) on OA were obtained. The quality assessment and descriptive summary were made of all included studies. Overall, 307 records were identified, and 33 studies were included. In vivo studies (n&#x2009;=&#x2009;22) concluded that PTH (1-34) slowed progression of OA by alleviating cartilage degeneration and aberrant remodeling of subchondral bone (SCB). Moreover, PTH (1-34) exhibited repair of cartilage and SCB, analgesic, and anti-inflammatory effects. In vitro studies (n&#x2009;=&#x2009;11) concluded that PTH (1-34) was important for chondrocytes via increasing the proliferation and matrix synthesis but preventing apoptosis or hypertrophy. All included studies were assessed with low or unclear risk of bias in methodological quality. The SR demonstrated that PTH (1-34) could alleviate the progression of OA. Moreover, PTH (1-34) had beneficial effects on osteoporotic OA (OPOA) models, which might be a therapeutic option for OA and OPOA treatment.

Medical Management of Patients After Atypical Femur Fractures: a Systematic Review and Recommendations From the European Calcified Tissue Society.

Atypical femur fractures (AFFs) are serious adverse events associated with bisphosphonates and often show poor healing. We performed a systematic review to evaluate effects of teriparatide, raloxifene, and denosumab on healing and occurrence of AFF. We retrieved 910 references and reviewed 67 papers, including 31 case reports, 9 retrospective and 3 prospective studies on teriparatide. There were no RCTs. We pooled data on fracture union (n = 98 AFFs on teriparatide) and found that radiological healing occurred within 6 months of teriparatide in 13 of 30 (43%) conservatively managed incomplete AFFs, 9 of 10 (90%) incomplete AFFs with surgical intervention, and 44 of 58 (75%) complete AFFs. In 9 of 30 (30%) nonoperated incomplete AFFs, no union was achieved after 12 months and 4 (13%) fractures became complete on teriparatide. Eight patients had new AFFs during or after teriparatide. AFF on denosumab was reported in 22 patients, including 11 patients treated for bone metastases and 8 without bisphosphonate exposure. Denosumab after AFF was associated with recurrent incomplete AFFs in 1 patient and 2 patients of contralateral complete AFF. Eight patients had used raloxifene before AFF occurred, including 1 bisphosphonate-na&#xef;ve patient. There is no evidence-based indication in patients with AFF for teriparatide apart from reducing the risk of typical fragility fractures, although observational data suggest that teriparatide might result in faster healing of surgically treated AFFs. Awaiting further evidence, we formulate recommendations for treatment after an AFF based on expert opinion.

Efficacy and safety of teriparatide vs. bisphosphonates and denosumab vs. bisphosphonates in osteoporosis not previously treated with bisphosphonates: a systematic review and meta-analysis of randomized controlled trials.

The study found that in osteoporosis patients who had not previously received bisphosphonate treatment and were in a treatment cycle of over 12 months, both teriparatide and denosumab significantly increased bone mineral density compared to bisphosphonates. Additionally, teriparatide was also shown to significantly decrease the risk of fractures. The systematic review and meta-analysis aimed to assess and compare the safety and efficacy of teriparatide vs. bisphosphonates and denosumab vs. bisphosphonates in patients with osteoporosis who had not previously received bisphosphonates. We conducted a search of published literature from inception to May 31, 2023, including databases such as PubMed, Embase, Cochrane Library, CNKI, SinoMed, VIP, and WanFang. The study only included head-to-head randomized controlled trials (RCTs) that compared teriparatide and denosumab with bisphosphonates to treat patients with osteoporosis. Fixed-effect model and random-effect model were used due to clinical heterogeneity. Meta-analysis was performed via Stata 17.0. A total of 6680 patients were enrolled across 23 eligible trials. The results of the meta-analysis showed that teriparatide was superior to bisphosphonates in decreasing the risk of fracture (risk ratio (RR)&#x2009;=&#x2009;0.61, 95% confidence interval (CI) (0.51, 0.74), P&#x2009;<&#x2009;0.001). Denosumab showed no benefit compared to bisphosphonates in reducing the risk of fracture in treating osteoporosis (RR 0.99, 95% CI (0.62, 1.57), P&#x2009;=&#x2009;0.96). Compared with bisphosphonates, teriparatide and denosumab could significantly improve femoral neck, total hip, and lumbar spine bone mineral density (BMD) (P&#x2009;<&#x2009;0.05). Furthermore, teriparatide and denosumab did not increase the incidence of adverse events (teriparatide vs. bisphosphonates, RR 0.92, 95% CI (0.79, 1.08), P&#x2009;=&#x2009;0.32; denosumab vs. bisphosphonates, RR 0.98, 95% CI (0.95, 1.02), P&#x2009;=&#x2009;0.37). Teriparatide is superior to bisphosphonates in decreasing the risk of fracture in patients with osteoporosis. In addition, teriparatide and denosumab were more efficacious than bisphosphonates in increasing the percentage change in BMD at the femoral neck, total hip, and lumbar spine.

Teriparatide: a review.

Traditionally, the management of osteoporosis in men and women has included the use of antiresorptive agents in combination with calcium and vitamin D supplementation. The mechanism of action of teriparatide is unique in that it possesses anabolic properties and therefore builds bone. Since the approval of teriparatide in the United States in 2002, a great deal of interest regarding its use in osteoporosis has developed. This article reviews the information available on the new recombinant human parathyroid hormone teriparatide (hPTH [1-34]), including its clinical pharmacology, mechanism of action, pharmacokinetic properties, clinical efficacy, safety profile, potential drug interactions, contraindications and warnings, dosage and administration, and pharmacoeconomics. The articles included in this review were identified through searches of PubMed and MEDLINE (1966-December 2003) and International Pharmaceutical Abstracts (1970-December 2003). Search terms included teriparatide, Forteo, recombinant human parathyroid hormone (1-34), and osteoporosis. The references of the identified articles were reviewed for additional publications. Specific product information was also obtained from the manufacturer of teriparatide. Teriparatide has been studied in postmenopausal women with osteoporosis, drug-induced osteoporosis (specifically, corticosteroid-induced osteoporosis), and men with osteoporosis. The data available from various clinical trials have shown an increase in both bone mineral density (BMD) and bone mineral content (BMC) with the use of teriparatide compared with placebo. One study found that women treated with the 20-microg dose and the 40-microg dose were 35% and 40%, respectively, less likely to have one or more new nonvertebral fractures compared with placebo (P = 0.02). Another study compared the use of daily teriparatide 40-microg injections versus oral daily alendronate. Results showed that the incidence of nonvertebral fractures was significantly lower in the teriparatide group than the alendronate group (P < 0.05). A study using 20- and 40-microg daily injections of teriparatide was performed in men with osteoporosis. There was a statistically significant increase in lumbar spine BMD of 5.9% in the 20-microg group and 9.0% in the 40-microg group (both, P < 0.001). In the femoral neck, a 1.5% increase in BMD occurred in the 20-microg group (P = 0.021) and a 0.9% increase in the 40-microg group (P < 0.001). A limited number of studies are available assessing the combination of antiresorptive medications and teriparatide; however, the available data suggest that the effects of teriperatide do not require prior stimulation of bone resorption. Teriparatide has been shown clinically to improve BMD and BMC in postmenopausal women and in men. Because of its anabolic capabilities, teriparatide can be used as an alternative to the traditional therapies that are currently available for the treatment of osteoporosis, with scheduled monitoring for adverse effects such as hypercalcemia and urinary calcium excretion. In 1 study, mild hypercalcemia was seen most often 4 to 6 hours after SC injection of teriparatide before returning to normal. Urinary calcium was observed to increase by 30 mg/d (0.75 mmol/d) with teriparatide.

Teriparatide-induced atrial tachycardia.

We present the case of a patient who presented with worsening chest pain and tachycardia. We were able to monitor her remotely through her pacemaker. She had been started on the injectable medication teriparatide (Forteo) and since then she had an increase in her symptoms. She was found to have intermittent atrial tachycardia with 1:1 conduction and occasional atrioventricular block transiently, coinciding with her injection of teriparatide. This specific-associated arrhythmia has yet to be described.

Stability of lyophilized teriparatide, PTH(1-34), after reconstitution.

The peptide teriparatide, also known as parathyroid hormone (1-34), PTH(1-34), was developed for intranasal delivery, requiring extended stability of the reconstituted product for up to four weeks at room temperature. Lyophilized formulations of PTH(1-34), containing glycine and trehalose and using lactate as the buffer, are stable for months upon storage. However, the physical stability of the peptide after reconstitution unexpectedly varied considerably, depending on peptide concentration and storage temperature, with precipitation seen within two to four weeks in some samples. By comparison, equivalent samples that did not undergo lyophilization did not display any precipitation upon storage in the liquid state for as long as twelve weeks. PTH(1-34) appears to adopt a higher order structure that is perturbed by the combined stresses of freezing and drying, leading to greater propensity to aggregate, which is accentuated at higher peptide concentrations and at higher temperatures. The precipitation seems to be correlated with increased amounts of subvisible particles. This study shows the importance of peptide conformation in long-term stability and illustrates the ability of lyophilization to cause increased propensity to aggregate, even in a peptide.

[PTH preparations].

Parathyroid hormone(PTH) is essential for maintaining serum calcium level. PTH increases serum calcium partly by enhancing bone resorption. Therefore, persistent excessive actions of PTH result in cortical bone loss by increased bone resorption. In contrast, intermittent injections of PTH preparations increase trabecular bone mainly by enhancing bone formation. Teriparatide is a peptide with 34 amino acids corresponding to the N-terminal portion of PTH. Both once daily and once weekly subcutaneous injections of teriparatide are available in Japan. Teriparatide was shown to prevent vertebral fractures. In addition, once daily injections of teriparatide also reduce non-vertebral fractures. However, there still remain several unanswered questions about the precise mechanisms of actions of teriparatide preparations.

Recombinant human PTH 1-34 (Forteo): an anabolic drug for osteoporosis.

Forteo (teriparatide of rDNA origin), a genetically engineered fragment of parathyroid hormone, is the first of a new class of drugs to treat osteoporosis. The drug's anabolic action increases bone turnover, stimulating osteoblasts to a greater extent than osteoclasts, and reducing both vertebral and nonvertebral fractures. However, a number of issues about its use remain unanswered.

Teriparatide (forteo) for osteoporsis.

Teriparatide (Forteo) for osteoporosis.

Emerging anabolic treatments in osteoporosis.

Anabolic treatment that remodels bone tissue and restores bone biomechanical competence is essential in the treatment of osteoporosis. In addition, long term antiresorptive therapy may have limitations because of the reduced renewal of bone tissue. The only pure anabolic drugs available at present are intact PTH (1-84) (Preotact&#xae;) and the truncated PTH (1-34) (Teriparatide, Forteo&#xae;) while strontium ranelate may possess antiresorptive as well as anabolic properties. The marketed antiresorptive and anabolic antiosteoporotic drugs have limitations in their use due to adverse effects or to the occurrence of rare but severe late complications. Furthermore, indications may be restricted by co-existing diseases or treatment duration may be limited. However, new anabolic drugs are being developed mimicking the effect of PTH, or targeting the calcium sensing receptor (CaSR) or the Wnt/&#x3b2;-catenin signalling pathway. The PTH mimetics are truncated or altered PTH fragments, parathyroid hormone related peptide (PTHrP) and calcilytics stimulating endogenous PTH secretion. Calcimimetics (e.g. strontium) and calcilytics (e.g. lithium) may also affect bone cells directly through the CaSR. The Wnt pathway that stimulates osteoblastic proliferation, differentiation and function may be activated by neutralizing antibodies to secreted inhibitors of Wnt signalling (e.g. Sclerostin or Dickkopf) or by small molecules (e.g. lithium) that inhibits the glycogen synthase kinase 3&#x3b2; mediated degradation of &#x3b2;-catenin. Finally, blocking of activin A by soluble receptor fusion proteins has been shown to increase bone mass by a dual anabolic-antiresorptive action. The present paper summarises the physiological background and the present evidence for these effects.

PTH treatment in hypoparathyroidism.

Hypoparathyroidism (HypoPT) is one of the few major hormone deficiency diseases that are not usually treated with the missing hormone. Bovine parathyroid hormone (PTH) has been purified and used as experimental treatment, as long back as in 1928 by Fuller Albright. Treatment, however, was abolished mainly because of antibody formation and costs. The recent approval of fully humanized truncated parathyroid hormone (Teriparatide, PTH (1-34)) and intact parathyroid hormone (Preotact, PTH(1-84)) for treatment of osteoporosis, has made the PTH drugs more accessible and thereby made clinical trials with PTH treatment of HypoPT feasible. Resent clinical trials have shown that treatment with PTH (1-34) and PTH (1-84) can stabilize plasma calcium, normalize plasma phosphate and reduce urine excretion of calcium. Furthermore, it seems that some patients with hypoPT experience an improved quality of life when treated with PTH compared with conventional treatment with 1&#x3b1;-hydroxylated vitamin D metabolites and calcium supplements.

Teriparatide (human PTH1-34) compensates for impaired fracture healing in COX-2 deficient mice.

Genetic ablation of cyclooxygenase-2 (COX-2) in mice is known to impair fracture healing. To determine if teriparatide (human PTH1-34) can promote healing of Cox-2-deficient fractures, we performed detailed in vivo analyses using a murine stabilized tibia fracture model. Periosteal progenitor cell proliferation as well as bony callus formation was markedly reduced in Cox-2-/- mice at day 10 post-fracture. Remarkably, intermittent PTH1-34 administration increased proliferation of periosteal progenitor cells, restored callus formation on day 7, and enhanced bone formation on days 10, 14 and 21 in Cox-2-deficient mice. PTH1-34 also increased biomechanical torsional properties at days 10 or 14 in all genotypes, consistent with enhanced bony callus formation by radiologic examinations. To determine the effects of intermittent PTH1-34 for callus remodeling, TRAP staining was performed. Intermittent PTH1-34 treatment increased the number of TRAP positive cells per total callus area on day 21 in Cox-2-/- fractures. Taken together, the present findings indicate that intermittent PTH1-34 treatment could compensate for COX-2 deficiency and improve impaired fracture healing in Cox-2-deficient mice.

Teriparatide for severe osteoporosis.

To review the pharmacology, toxicology, pharmacokinetics, pharmacodynamics, efficacy, safety, therapeutic controversies, administration, patient counseling, and formulary recommendations for teriparatide (rDNA origin). A MEDLINE search (1966-May 2003) of articles using the key words parathyroid hormone and osteoporosis, parathyroid hormone and fracture, and teriparatide was conducted to identify relevant literature in the English language. Additional references were obtained from bibliographies of those articles. Some clinical trial data not yet published were obtained from the manufacturer. All articles obtained from the data sources were reviewed; all data deemed relevant were included. Teriparatide, recombinant human parathyroid hormone (1-34) [rhPTH (1-34)], is the first anabolic agent to treat postmenopausal women with osteoporosis and men with idiopathic or hypogonadal osteoporosis who are at high risk for osteoporotic fracture. Daily subcutaneous injections of teriparatide significantly increase both spine and hip bone-mineral density (BMD) while decreasing the incidence of fractures in both women and men. Common adverse effects noted with teriparatide use were nausea, headache, dizziness, and arthralgias. An increased incidence of osteosarcoma in rats during preclinical trials with teriparatide led to a black box warning for the drug. Teriparatide substantially increases spine and hip BMD and may offer additional benefits to patients with severe osteoporosis. Clinical trials comparing teriparatide with other available agents to treat osteoporosis are needed to more clearly define its place in therapy. Long-term safety and efficacy are not known.

Spotlight on teriparatide in osteoporosis.

Recombinant teriparatide (Forteo; Forsteo) is an anabolic (bone-forming) agent. Studies have shown that subcutaneous teriparatide 20 microg/day is effective in women with postmenopausal osteoporosis, men with idiopathic or hypogonadal osteoporosis, and patients with glucocorticoid-induced osteoporosis. Teriparatide improves bone mineral density (BMD) and alters the levels of bone formation and resorption markers; histomorphometric studies have shown teriparatide-induced effects on bone structure, strength, and quality. Subcutaneous teriparatide 20 microg/day administered over a treatment period of 11-21 months was effective in reducing the risk of fractures and improving BMD in men with idiopathic or hypogonadal osteoporosis, women with postmenopausal osteoporosis, and patients with glucocorticoid-induced osteoporosis. Furthermore, the beneficial effects of teriparatide on vertebral fracture prevention and BMD appear to persist following treatment cessation. Teriparatide is generally well tolerated and treatment compliance rates are favorable. However, current limitations on the length of treatment and the high acquisition cost mean that teriparatide is best reserved for the treatment of patients with osteoporosis at high risk of fracture, or for patients with osteoporosis who have unsatisfactory responses to or intolerance of other osteoporosis therapies.

Real-world evidence indicates romosozumab use is associated with a greater reduction in osteoporotic fractures than PTH (1-34) analogs in women.

To compare the effectiveness of romosozumab (ROMO) with parathyroid hormone (PTH) receptor agonists [teriparatide (TPTD)/abaloparatide (APTD)] in reducing fracture risk following osteoporosis treatment. A TriNetX cohort study assessed fracture and mortality risks using Kaplan-Meier analysis with hazard ratios (HRs) and 95% confidence intervals (CIs). After propensity score matching (n&#x2009;=&#x2009;2,258 pairs), ROMO users had lower risks of osteoporotic fractures (HR: 0.711, 95% CI: 0.542-0.931) and hypercalcemia (HR&#x2009;=&#x2009;0.707, 95% CI: 0.511-0.977) compared with PTH receptor agonists. Five subgroup analyses demonstrated a reduced fracture risk in the ROMO cohort among women (HR: 0.738), patients aged&#x2009;&#x2265;&#x2009;65&#xa0;years (HR: 0.652), individuals with a history of prior fractures (HR: 0.659), and those without chronic kidney disease (CKD) (HR: 0.731). Sensitivity analyses confirmed the robustness of the findings across different covariate adjustments, data sources, and extended follow-up, consistently showing a lower risk of hypercalcemia and nonsignificant trends toward reduced fracture risk in the ROMO cohort. Compared with PTH analogs, ROMO offers stronger short-term protection against osteoporotic fractures and hypercalcemia, particularly in older women with prior fractures. Nonetheless, cardiovascular safety, calcium metabolism, and sequential therapy require careful consideration for individualized treatment.

Drugs for postmenopausal osteoporosis.

A Phase 3 Multicenter, Double-Blind Study Comparing Efficacy, Safety, Immunogenicity, and Pharmacokinetics of Alkem's Biosimilar Teriparatide Versus Reference Teriparatide in Postmenopausal Osteoporosis.

The primary purpose of this study was to compare the efficacy and safety of proposed biosimilar teriparatide with reference teriparatide in patients of postmenopausal osteoporosis. The secondary objectives were to assess the pharmacodynamic response of study drugs in postmenopausal osteoporosis and to assess the pharmacokinetic profile of biosimilar and reference teriparatide in a subset of subjects (a total of 30 evaluable subjects i.e., 15 subjects in reference arm and 15 subjects in biosimilar arm). A prospective, active-controlled, randomized, double-blind, phase III study included postmenopausal women (50-80&#x2009;years of age) with at least 5&#x2009;years since menopause diagnosed with osteoporosis (T-SCORE&#x2009;&#x2264;&#x2009;-2.5 SD at lumbar spine or femoral neck) randomized 2:1 to receive either Alkem's biosimilar teriparatide or reference teriparatide 20&#x2009;&#x3bc;g once daily subcutaneously for 48&#x2009;weeks. All subjects received calcium 1000&#x2009;mg and vitamin D3 500 IU once daily orally. The primary efficacy endpoint was percent change in bone mineral density (BMD) at lumbar spine and femoral neck from baseline to 48&#x2009;weeks. Safety outcomes, pharmacokinetics, and immunogenicity were also evaluated. Secondary endpoints included change from baseline in pharmacodynamic parameters like serum P1NP, which were analyzed at randomization, at week 12, 24, and 48. In total, 177 patients (114 in biosimilar group and 63 in reference group) were randomized. The percent change from baseline to 48&#x2009;weeks in lumbar spine BMD (least square mean [LSM] &#xb1; standard error [SE]) was 8.58%&#x2009;&#xb1;&#x2009;0.85 in the biosimilar group and 8.02%&#x2009;&#xb1;&#x2009;1.23 in the reference group. The estimated between-group difference (95% confidence interval [CI]) was -0.56% (-2.43% to 3.54%) within the prespecified noninferiority margin (- 2.43%), which indicates noninferiority of biosimilar teriparatide compared to reference teriparatide. The percent change in femoral neck BMD from baseline to 48&#x2009;weeks (LSM&#x2009;&#xb1;&#x2009;SE) was 3.94%&#x2009;&#xb1;&#x2009;0.83 in the biosimilar group and 2.50%&#x2009;&#xb1;&#x2009;1.20 in the reference group. The estimated between-group difference (95% CI) was 1.44% (-1.44% to 4.32%) within the prespecified noninferiority margin (-1.44%) indicating noninferiority of biosimilar teriparatide compared to reference teriparatide. Changes in P1NP (serum procollagen type 1 N terminal pro-peptide) were also similar between the groups. Safety profiles, including immunogenicity, were comparable. This study established noninferiority, along with comparable safety and immunogenicity between Alkem's biosimilar teriparatide and reference teriparatide in patients with postmenopausal osteoporosis. CTRI number: CTRI/2018/05/014254.

Use of parathyroid hormone in hypoparathyroidism.

Hypoparathyroidism is a disorder characterized by hypocalcemia, deficient PTH, and abnormal bone remodeling. Standard treatment of hypoparathyroidism consists of oral calcium and vitamin D supplementation. However, maintaining serum calcium levels can be a challenge. In addition, concerns exist regarding hypercalciuria and ectopic calcifications that can be associated with such treatment. Hypoparathyroidism is the only classic endocrine deficiency disease for which the missing hormone, PTH, is not yet an approved treatment. This review focuses on the use of PTH in the treatment of hypoparathyroidism, in the form of teriparatide [PTH(1-34)] and the full-length molecule, PTH(1-84). Studies in hypoparathyroid subjects demonstrate that PTH(1-34) and PTH(1-84) lower or abolish supplemental calcium and vitamin D requirements as well as increase markers of bone turnover. Densitometric and histomorphometric studies in some subjects treated with PTH(1- 34) and PTH(1-84) show an improvement in bone-remodeling dynamics and return of bone metabolism toward normal levels. Given the chronic nature of hypoparathyroidism, and the expectation that PTH will be used for extended periods of time in hypoparathyroidism, further studies are needed to determine the long-term safety of PTH therapy in this population.

Orthopedic uses of teriparatide.

Teriparatide is a drug currently approved for treating patients with osteoporosis who are at high risk for future fracture. In the treatment of osteoporosis, teriparatide works as an anabolic agent stimulating bone formation throughout the skeleton by principally enhancing osteoblast-derived bone formation relative to osteoclast-derived bone resorption. The net effect is increased bone mass. For patients with a fracture, a similar process of increased bone formation is required transiently at the fracture site for repair. Teriparatide has been investigated in animal models and in patients as a potential agent to enhance fracture repair. In addition, evidence that teriparatide enhances chondrogenesis has generated interest in using the agent for articular cartilage repair. Research is currently underway to understand the effects teriparatide may have on mesenchymal stem cells, and on other effects that have been reported anecdotally in patients using the drug for osteoporosis care, including the healing of fracture nonunions and a decreased incidence of back pain. We review the current animal and human reports available on the uses of teriparatide in musculoskeletal diseases beyond osteoporosis.

PTH 1-34 promoted bone formation by regulating iron metabolism in unloading-induced bone loss.

PTH 1-34 (teriparatide) is approved by FDA for the treatment of postmenopausal osteoporosis. Iron overload is a major contributing factor for bone loss induced by unloading. Whether iron metabolism is involved in the regulation of PTH 1-34 on unloading-induced osteoporosis has not yet been reported. Here, we found that PTH 1-34 attenuated bone loss in unloading mice. PTH 1-34 regulated the disturbance of iron metabolism in unloading mice by activating Nrf2 and further promoting hepcidin expression in the liver. In addition, the Nrf2 inhibitor selectively blocked hepcidin expression in the liver of unloading mice, which neutralized the inhibitory effect of PTH 1-34 on bone loss and the recovery of iron metabolism in unloading mice. Finally, we found that PTH 1-34 promoted the differentiation and inhibited apoptosis of osteoblasts by regulating iron metabolism and maintaining redox balance under unloading conditions. Our results suggested that PTH 1-34 promoted bone formation by regulating iron metabolism under unloading conditions.

Off-Label Use of Teriparatide in Spine.

Teriparatide belongs to osteo-anabolic compounds and has been used in recent years to treat patients with osteoporosis, with the benefits of increased&#xa0;bone density. Its osteo-anabolic action has led to the investigation of the use of teriparatide for the improvement of bone quality. Apart from the enhancement of fracture union, teriparatide has been extensively studied in the promotion of fusion rate after spinal fusion. This study summarizes the preclinical and clinical results of the off-label use of teriparatide in the spine, and specifically its intermittent administration after instrumented spinal arthrodesis along with its impact on the spinal bone quality and spinal bone mineral density.

Mini-review: new therapeutic options in hypoparathyroidism.

Hypoparathyroidism is a disorder characterized by hypocalcemia and low or absent parathyroid hormone (PTH). While standard treatment of hypoparathyroidism consists of oral calcium and vitamin D supplementation, maintaining serum calcium levels can be a challenge, and concerns exist regarding hypercalciuria and ectopic calcifications that can be associated with such treatment. Hypoparathyroidism is the only classic endocrine deficiency disease for which the missing hormone, PTH, is not yet an approved treatment. This mini-review focuses on the use of PTH in the treatment of hypoparathyroidism. There are two available formulations of PTH: teriparatide [human PTH(1-34)] and the full-length molecule, PTH(1-84). Both PTH(1-34) and PTH(1-84) lower supplemental vitamin D requirements and increase markers of bone turnover. Densitometric and histomorphometric studies in some subjects treated with PTH(1-84) demonstrate improvement in abnormal bone-remodeling dynamics and return of bone metabolism toward normal euparathyroid levels. Further detailed examination of skeletal features following therapy with the different treatment regimens and data regarding the effect of PTH on quality of life measures are under active investigation.

Combined Pharmacologic Therapy in Postmenopausal Osteoporosis.

Antiresorptive agents for treating postmenopausal osteoporosis include selective estrogen receptor modulator (SERM), bisphosphonates and denoumab. Teriparatide is the only Food and Drug Administration-approved anabolic agent. Synergistic effects of combining teriparatide with an antiresorptive agent have been proposed and studied. This article reviews the trial designs and the outcomes of combination therapies. Results of the combination therapy for teriparatide and bisphosphonates were mixed; while small increases of bone density were observed in the combination therapy of teriparatide and estrogen/SERM and that of teriparatide and denosumab. Those clinical studies were limited by small sample sizes and lack of fracture outcomes.

Nutritional activation of the Nrf2-Pth1r axis by pyrroloquinoline quinone enhances peak bone mass and potentiates teriparatide in osteoporosis.

Peak bone mass (PBM) critically determines lifelong skeletal health. We showed that dietary supplementation with pyrroloquinoline quinone (PQQ) - a water-soluble bioactive compound that activates nuclear factor erythroid 2-related factor 2 (Nrf2) signaling - during pregnancy or post-weaning enhances PBM acquisition in wild-type mice, subsequently attenuating age-related bone loss and improving mechanical strength. Mechanistically, PQQ-activated Nrf2 binds directly to the parathyroid hormone 1 receptor (Pth1r) promoter, upregulating its transcription and augmenting PTH-induced osteogenesis. Pth1r overexpression rescues the impaired osteogenesis of Nrf2-deficient bone marrow mesenchymal stem cells (BMSCs). Teriparatide's (PTH 1-34) anabolic effects are markedly compromised in Nrf2-deficient mice and human BMSCs, underscoring Nrf2's essential role in PTH-mediated bone formation. Notably, PQQ and PTH 1-34 co-administration synergistically enhances skeletal anabolism in aged mice beyond PTH 1-34 monotherapy. These results establish the PQQ-Nrf2-Pth1r axis as a key regulator of bone mass accrual and suggest PQQ as a promising adjunct to teriparatide for osteoporosis.

New insights into the role of teriparatide.

Parathyroid hormone (PTH) is secreted by the parathyroid glands and is an important regulator of blood calcium concentrations. Synthesis and secretion of PTH are stimulated by a decrease in blood calcium. PTH has three actions: 1) to increase the release of calcium from bone, 2) to reduce renal clearance of calcium, and 3) to stimulate the production of 1,25 (OH)2D3. Human parathyroid hormone is a single chain polypeptide with 84 amino acids and a molecular weight of 9425 Da. The N-terminal region, 1-34, is biologically active and sufficient for regulation of mineral ion homeostasis (1). Recombinant teriparatide {human PTH(1-34) [hPTH (1-34)]}, currently the only bone-forming osteoporosis drug available for clinical use, increases bone turnover with a greater stimulation of formation than resorption (2). Bone turnover markers also rise during treatment with teriparatide (TPTD), with markers of bone formation rising early and rapidly, followed by rises in bone resorption markers.

Teriparatide [PTH(1-34)] strengthens the proximal femur of ovariectomized nonhuman primates despite increasing porosity.

OVX monkeys treated for 18 months with 1 or 5 microg/kg/d teriparatide [PTH (1-34)] had significantly stronger proximal femora relative to ovariectomized controls. Teriparatide enhancement of cortical area, cortical width, and trabecular bone volume seemed to more than compensate for the dose-dependent increase in cortical porosity. Beneficial effects of teriparatide treatment on the proximal femur persisted beyond the treatment period and may extend to the marrow. We conducted a detailed quantitative analysis of the effects of teriparatide on the proximal femur of ovariectomized monkeys. Teriparatide increased bone mass, enhanced structural architecture, and strengthened the hip, despite increasing cortical porosity. Monkeys were treated with vehicle (sham or OVX controls), 1 microg/kg/day teriparatide [parathyroid hormone (1-34); PTH1], or 5 microg/kg/day teriparatide (PTH5) for 18 months or for 12 months followed by 6 months of treatment withdrawal (PTH1W and PTH5W, respectively). Excised proximal femora were analyzed by microCT, conventional histomorphometry, and biomechanics. The femoral neck showed significant reduction in trabecular bone volume (BV/TV) for OVX compared with sham, whereas PTH1 BV/TV was restored to sham levels and PTH5 BV/TV was greater than sham and OVX. The withdrawal groups had BV/TVs intermediate between sham and OVX. PTH1 had trabecular number (Tb.N) greater than OVX, and PTH5 Tb.N was greater than sham and OVX. The withdrawal groups had Tb.Ns intermediate between sham and OVX. No differences between groups were observed for trabecular orientation or trabecular thickness. Teriparatide dose-dependently increased bone formation rate and activation frequency in the femoral neck. Cellular composition analyses suggested a tendency of ovariectomy to increase adiposity of marrow by 100%, whereas PTH tended to reduce adipocyte number and increase osteoblast number compared with OVX. Analyses of the cortex showed dose-dependent elevation of cortical porosity, which was consistent with enhanced bone turnover with treatment. Cortical porosity was reduced after withdrawal of teriparatide, because PTH1W cortical porosity was lower than OVX, whereas PTH5W cortical porosity was intermediate between sham and OVX. Increased cortical porosity did not weaken the proximal femora. Biomechanics showed that ovariectomy weakened proximal femora compared with sham, but PTH1, PTH5, and PTH1W were stronger than OVX and not different from sham. PTH5W strength was intermediate between sham and OVX. Therefore, teriparatide had beneficial effects on the proximal femur, despite increasing cortical porosity. Cortical porosity did not adversely affect the mechanical integrity of the proximal femora, because enhanced cortical area and trabecular bone volume more than compensated for the porosity. Much of the beneficial effects of teriparatide were retained after 6 months withdrawal from treatment. PTH effects on the femoral neck were not limited to bone but may include inhibition of OVX-stimulated adiposity of the marrow.

Teriparatide (PTH 1-34) treatment increases peripheral hematopoietic stem cells in postmenopausal women.

Cells of the osteoblast lineage play an important role in regulating the hematopoietic stem cell (HSC) niche and early B-cell development in animal models, perhaps via parathyroid hormone (PTH)-dependent mechanisms. There are few human clinical studies investigating this phenomenon. We studied the impact of long-term daily teriparatide (PTH 1-34) treatment on cells of the hematopoietic lineage in postmenopausal women. Twenty-three postmenopausal women at high risk of fracture received teriparatide 20 mcg sc daily for 24 months as part of a prospective longitudinal trial. Whole blood measurements were obtained at baseline, 3, 6, 12, and 18 months. Flow cytometry was performed to identify hematopoietic subpopulations, including HSCs (CD34+/CD45(moderate); ISHAGE protocol) and early transitional B cells (CD19+, CD27-, IgD+, CD24[hi], CD38[hi]). Serial measurements of spine and hip bone mineral density (BMD) as well as serum P1NP, osteocalcin, and CTX were also performed. The average age of study subjects was 64&#x2009;&#xb1;&#x2009;5 years. We found that teriparatide treatment led to an early increase in circulating HSC number of 40%&#x2009;&#xb1;&#x2009;14% (p&#x2009;=&#x2009;0.004) by month 3, which persisted to month 18 before returning to near baseline by 24 months. There were no significant changes in transitional B cells or total B cells over the course of the study period. In addition, there were no differences in complete blood count profiles as quantified by standard automated flow cytometry. Interestingly, the peak increase in HSC number was inversely associated with increases in bone markers and spine BMD. Daily teriparatide treatment for osteoporosis increases circulating HSCs by 3 to 6 months in postmenopausal women. This may represent a proliferation of marrow HSCs or increased peripheral HSC mobilization. This clinical study establishes the importance of PTH in the regulation of the HSC niche within humans. &#xa9; 2014 American Society for Bone and Mineral Research.

Drugs for postmenopausal osteoporosis.

Long-term cancer surveillance: results from the Forteo Patient Registry Surveillance Study.

The Forteo Patient Registry estimated the incidence of osteosarcoma in US patients treated with teriparatide and enrolled in the study between 2009 and 2019. No incident cases of osteosarcoma were identified among patients registered, and the crude incidence rate was 0 (95% confidence interval [CI], 0-10.2) cases per million person-years. The prospective, voluntary Forteo Patient Registry was established to estimate the incidence of osteosarcoma in patients who have received treatment with teriparatide (Forteo). Information on US adults prescribed teriparatide and enrolled in the Forteo Patient Registry 2009-2019 was linked with data from participating state cancer registries annually (2010-2019) to identify incident osteosarcoma cases using a standardized linkage algorithm. Teriparatide exposure was ascertained from self-reported data that included teriparatide initiation and demographics necessary to complete linkage. Osteosarcoma cases diagnosed on or after January 1, 2009, were identified by participating state cancer registries. The crude incidence rate (IR) and standardized incidence ratio (SIR) of observed cases to the expected number of cases adjusted to the background rate (3 per million person-years) and corresponding 95% CIs for the occurrence of osteosarcoma were calculated whereby the cumulative amount of person-time observed was adjusted for mortality. Data for 75,247 enrolled patients (representing 361,763 cumulative person-years) were linked to each of 42 participating state cancer registries (covering 93% of the US population), which included information on 6180 cases of osteosarcoma. No matches with incident cases of osteosarcoma following registry enrollment were found. The crude IR was 0 (95% CI, 0-10.2) cases per million person-years and the SIR was 0 (95% CI, 0-3.0). The ability to draw conclusions about the incidence of osteosarcoma among patients participating in the registry was limited due to the smaller than expected amount of patient follow-up time and the fact that no cases were identified.

Teriparatide in Fracture Non-Unions.

The use of teriparatide in the management of fracture disorders is poorly documented. This study aims to show that teriparatide administration may improve the healing process in patients with nonunions after open fixation of traumatic fractures of the lower limb. Four patients received Teriparatide for management of non-unions after open fixation of traumatic fractures of the lower limb. Teriparatide administration resulted in adequate bone callus over the site of nonunion in all the patients, and clinical and radiographic evidence of sound union. The efficacy of teriparatide in delayed or non unions is still unclear. It may induce an angiogenetic response which counteracts the features responsible for development of non-union. Level IV, therapeutic case series.

Gli1+ progenitors mediate bone anabolic function of teriparatide via Hh and Igf signaling.

Teriparatide is the most widely prescribed bone anabolic drug in the world, but its cellular targets remain incompletely defined. The Gli1+ metaphyseal mesenchymal progenitors (MMPs) are a main source for osteoblasts in postnatal growing mice, but their potential response to teriparatide is unknown. Here, by lineage tracing, we show that teriparatide stimulates both proliferation and osteoblast differentiation of MMPs. Single-cell RNA sequencing reveals heterogeneity among MMPs, including an unexpected chondrocyte-like osteoprogenitor (COP). COP expresses the highest level of Hedgehog (Hh) target genes and the insulin-like growth factor 1 receptor (Igf1r) among all cell clusters. COP also expresses Pth1r and further upregulates Igf1r upon teriparatide treatment. Inhibition of Hh signaling or deletion of Igf1r from MMPs diminishes the proliferative and osteogenic effects of teriparatide. The study therefore identifies COP as a teriparatide target wherein Hh and insulin-like growth factor (Igf) signaling are critical for the osteoanabolic response in growing mice.

Teriparatide: a review of its use in osteoporosis.

Recombinant teriparatide (Forteo; Forsteo) is an anabolic (bone forming) agent. Studies have shown that subcutaneous teriparatide 20 microg/day is effective in women with postmenopausal osteoporosis, men with idiopathic or hypogonadal osteoporosis and patients with glucocorticoid-induced osteoporosis. Teriparatide improves bone mineral density (BMD) and alters the levels of bone formation and resorption markers; histomorphometric studies showed teriparatide-induced effects on bone structure, strength and quality. Subcutaneous teriparatide 20 microg/day administered over a treatment period of 11-21 months was effective in reducing the risk of fractures in and in improving BMD in men with idiopathic or hypogonadal osteoporosis, women with postmenopausal osteoporosis and patients with glucocorticoid-induced osteoporosis. Furthermore, the beneficial effects of teriparatide on vertebral fracture prevention and BMD appear to persist following treatment cessation. Teriparatide is generally well tolerated and treatment compliance rates are favourable. However, current limitations on the length of treatment and the high acquisition cost mean that teriparatide is best reserved for the treatment of patients with osteoporosis at high risk of fracture, or for patients with osteoporosis who have unsatisfactory responses to or intolerance of other osteoporosis therapies.