A randomized, double-blind, placebo-controlled, single-dose study to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of denosumab administered subcutaneously to postmenopausal Japanese women

Safety, tolerability, and pharmacokinetics/pharmacodynamics of JMT103 in patients with bone metastases from solid tumors

Bone metastases are common complications of solid tumors. The outcome is poor despite major progress in cancer therapies. We describe a multicenter, open-label, phase 1, dose escalation and expansion trial of JMT103, a novel fully humanized receptor activator of nuclear factor kappa-B ligand (RANKL)-targeting monoclonal antibody, in adults with bone metastases from solid tumors. The study assessed the safety, tolerability, and pharmacokinetics/pharmacodynamics of JMT103. Patients received JMT103 at doses of 0.5, 1.0, 2.0, and 3.0 mg/kg every 4 weeks for 3 cycles. Among 59 patients enrolled, 20 and 39 patients participated in the dose-escalation and dose-expansion phases, respectively. One dose-limiting toxicity was observed at 2.0 mg/kg. The maximum tolerated dose was not determined. Treatment-related adverse events were reported in 29 (49.2%) patients, most commonly hypophosphatemia (30.5%), hypocalcemia (23.7%), and hypermagnesemia (10.2%). No treatment-related serious adverse events were reported. Two patients died due to disease progression, which were attributed to gastric cancer and lung neoplasm malignant respectively. Dose proportionality occurred between exposure levels and administered dose was within a dose range of 0.5 to 3.0 mg/kg. The suppression of urinary N-telopeptide corrected for creatinine was rapid, significant, and sustained across all doses of JMT103, with the median change from baseline ranging from –61.4% to –92.2% at day 141. JMT103 was well tolerated in patients with bone metastases from solid tumors, with a manageable safety profile. Bone antiresorptive activity shows the potential of JMT103 for treatment of bone metastases from solid tumors.

Registration No.: NCT03550508; URL: https://www.clinicaltrials.gov/

A Randomized Controlled Dose-Escalation Study of LY06006, a Recombinant Humanized Monoclonal Antibody to RANKL, in Chinese Healthy Adults

Background: This study was conducted to explore the safety, tolerance, pharmacokinetics, pharmacodynamics, and immunogenicity of LY06006, a recombinant humanized monoclonal antibody to RANKL, when administrated subcutaneously in Chinese healthy adults.

Research design and methods: This was a randomized, double-blinded, placebo-controlled, single ascending dose study performed in 32 healthy Chinese adults, who were randomly assigned to receive a single injection dose of 18, 60, 120 mg study drug or placebo with a follow-up of 140–252 days.

Results: No deaths or drug-related serious adverse events occurred. LY06006 was rapidly absorbed in the 60 mg group with a T_max range of 120–480 h and serum LY06006 concentrations decreased slowly 11–13 days after dosing with a long mean (SD) half-life of 389.58 (63.44) h. The most frequent AEs were elevated serum parathyroid hormone (PTH) level (83.3%), hypocalcemia (54.2%), and hypophosphatemia (45.8%). None of the 32 subjects tested positive for anti-drug antibody during the trial.

Conclusion: Single-dose subcutaneous administration of LY06006 was safe and well-tolerated in healthy Chinese adults. C_max showed linear pharmacokinetic characteristics in the dose range of 18–120 mg based on dose-exposure proportionality analysis.

A Novel Case Study of the Use of Real-World Evidence to Support the Registration of an Osteoporosis Product in China

On June 23, 2020, Prolia^® (denosumab) was approved by the National Medical Products Administration (NMPA) in the People’s Republic of China as the first monoclonal antibody for the treatment of postmenopausal women with osteoporosis at high risk of fractures. Its brand name in Chinese is 普罗力, a transliteration from the English name “Prolia”, which has an implied meaning of “to give strength to everyone”— a suitable name for a potent anti-resorptive therapy. The approval was supported by a novel marketing authorization application (MAA) that included data from Prolia’s global clinical trial program establishing favorable efficacy and safety, augmented by results from a real-world evidence (RWE) study confirming the effectiveness and safety of Prolia in clinical practice within Taiwan and Hong Kong. Key constructs for this registration-quality RWE study included the fit-for-purpose assessment of data quality, methodology and quantitative assessment of potential biases, good practices of study conduct, and reproducibility of results. Using data from clinical practice in Taiwan and Hong Kong to evaluate the benefits versus risks of Prolia treatment in ethnic Chinese women with postmenopausal osteoporosis, the RWE study results for effectiveness were comparable to efficacy demonstrated in the global clinical trial program and results for safety were consistent with the incidence observed in global post-marketing safety studies. While RWE is often used to monitor postmarket safety of drug products, support health insurance coverage decisions, and inform clinicians on real-world use of medicines, it has not been widely used to support regulatory approval for new medicines in lieu of clinical bridging studies in countries where such studies are required. Well-conducted registrational RWE studies can play a pivotal role in complementing the totality of evidence presented in an MAA. The benefits of such an approach include avoiding the collection of additional placebo-controlled trial data in populations where adequate ethnic characterization of efficacy, effectiveness, and safety may already exist from postmarketing sources, and accelerate access for patients to innovative medicines in important regions. Here, we describe a regulatory case study of a novel MAA incorporating RWE that provided important evidence to confirm the benefit:risk of a new drug and facilitated a label expansion to a new patient population.

Investigating the Use of Denosumab in the Treatment of Acute Charcot Neuroarthropathy

Charcot neuroarthropathy is a devastating condition, most commonly affecting poorly controlled diabetic patients with peripheral neuropathy. Pharmacological options for the condition are currently limited. The purpose of this study was to investigate the potential of Prolia® (denosumab) as a safe and feasible option in the treatment of acute Charcot neuroarthropathy. A total of 7 consecutive subjects were enrolled and followed for 1 year. Subjects received a single one-time injection of denosumab 60 mg. Subjects also received standard of care treatment, which included total contact casting, restricted weightbearing status, and biweekly office visits until normalization of the skin temperature gradient. Overall, the pharmaceutical treatment was generally well-tolerated. One subject developed a diabetic foot infection with cellulitis of the contralateral lower extremity, which occurred following the 6-month follow-up visit and which resolved with oral antibiotics One subject identified transient muscle pain in the same upper extremity which received the injection. Subjects were found to exit the acute phase of the condition at an average of 52.00 ± 17.89 days after their injection, which was defined by normalization of skin temperature to within 2°C of the contralateral foot. Treatment of acute Charcot neuroarthropathy with denosumab was well-tolerated in this open-label, pilot study. The clinical outcomes suggest that the medication may be efficacious, though a larger sample size would be needed to confirm these preliminary results. An adequately-powered, randomized, controlled study may be an appropriate follow-up.

Efficacy and Safety of Denosumab in Osteoporosis or Low Bone Mineral Density Postmenopausal Women

Denosumab, a human monoclonal antibody, acts against the receptor activator of nuclear factor-κB ligand and is a promising antiresorptive agent in patients with osteoporosis. This study aimed to update the efficacy and safety of denosumab vs. placebo in osteoporosis or low bone mineral density (BMD) postmenopausal women. PubMed, Embase, Cochrane library, and ClinicalTrials.gov were searched for randomized controlled trials (RCTs) reporting the efficacy and safety data of denosumab vs. placebo in osteoporosis or low BMD postmenopausal women. A random-effects model was used to calculate pooled weight mean differences (WMDs) or relative risks (RRs) with corresponding 95% confidence intervals (CIs) for treatment effectiveness of denosumab vs. placebo. Eleven RCTs including 12,013 postmenopausal women with osteoporosis or low BMD were preferred for the final meta-analysis. The summary results indicated that the percentage change of BMD in the denosumab group was greater than that of BMD in placebo at 1/3 radius (WMD: 3.43; 95%CI: 3.24–3.62; p < 0.001), femoral neck (WMD: 3.05; 95%CI: 1.78–4.33; p < 0.001), lumbar spine (WMD: 6.25; 95%CI: 4.59–7.92; p < 0.001), total hip (WMD: 4.36; 95%CI: 4.07–4.66; p < 0.001), trochanter (WMD: 6.00; 95%CI: 5.95–6.05; p < 0.001), and total body (WMD: 3.20; 95%CI: 2.03–4.38; p < 0.001). Moreover, denosumab therapy significantly reduced the risk of clinical fractures (RR: 0.57; 95%CI: 0.51–0.63; p < 0.001), nonvertebral fracture (RR: 0.83; 95%CI: 0.70–0.97; p = 0.018), vertebral fracture (RR: 0.32; 95%CI: 0.25–0.40; p < 0.001), and hip fracture (RR: 0.61; 95%CI: 0.37–0.98; p = 0.042). Finally, denosumab did not cause excess risks of adverse events. These findings suggested that postmenopausal women receiving denosumab had increased BMDs and reduced fractures at various sites without inducing any adverse events.

RANKL as a target for the treatment of osteoporosis

Osteoporosis is characterized by compromised bone strength, predisposing to an increased risk of fracture. Because bone is constantly remodeled, and bone mass and structure are determined by the balance between bone resorption and bone formation, it is important to maintain normal bone turnover. Therefore, therapies that reduce bone resorption have been the mainstream of osteoporosis treatment. Receptor activator of nuclear factor-kappa B ligand (RANKL)-RANK signaling was found to play a pivotal role in the regulation of osteoclastic bone resorption, and inhibition of RANKL-RANK system has become an important therapeutic target for the treatment of osteoporosis. Denosumab, a fully human monoclonal anti-RANKL neutralizing antibody, is developed as a drug for the treatment of osteoporosis. This review summarized pharmacokinetic and pharmacodynamic properties of denosumab, clinical studies including phase 2 dose-ranging and its extension study, phase 3 fracture prevention study (FREEDOM) with extension up to 10 years, studies on male osteoporosis (ADAMO study), and on glucocorticoid-induced osteoporosis, along with relevant clinical studies in Japan. In addition, mechanism of denosumab action that can explain its long-term sustained effects, combination and sequential treatment as well as the problems in discontinuation of denosumab, and finally safety of denosumab therapy is discussed.

Safety and pharmacokinetics of a biosimilar of denosumab (KN012): Phase 1 and bioequivalence study in healthy Chinese subjects

BACKGROUND

KN012 is a proposed biosimilar candidate for the reference drug denosumab, with the brand name Prolia®. This study explored the tolerance, variability, and pharmacokinetics (PK) of denosumab and its biosimilar in healthy Chinese subjects.

RESEARCH DESIGN AND METHODS

A randomized, double-blind, parallel, two-arm study was performed to analyze the bioequivalence of denosumab biosimilar (60 mg) compared with denosumab.

RESULTS

The PK properties of denosumab biosimilar were similar to those of denosumab. When denosumab biosimilar was compared to denosumab, the geometric mean ratios (GMRs) of C_max, AUC_0-t, and AUC_0-∞ were 98.74%, 102.54%, and 102.18%, respectively, and the 90% confidence interval was observed to be within 80-125%. The inter-subject variability ranged from 31.4% to 34.6%. Five subjects in the denosumab biosimilar group and one subject in the denosumab group were positive for anti-drug antibodies (ADAs) and negative for neutralizing antibodies (NAbs). Adverse reactions were observed in 100% (52 subjects) and 94.0% (47 subjects) of the subjects in the denosumab biosimilar and denosumab groups, respectively. Reductions in the blood calcium and phosphate levels were the most common adverse reactions.

CONCLUSION

The PK characteristics were comparable for the denosumab biosimilar and denosumab groups. Their safety profiles were also similar.

TRIAL REGISTRATION

: The trial is registered at the Chinese Clinical Trial website (http://www.chinadrugtrials.org.cn/index.html #CTR20181231).

A Phase I, Randomized, Single-Dose Study to Evaluate the Biosimilarity of QL1206 to Denosumab Among Chinese Healthy Subjects

Objective

This study was conducted to explore the tolerance, variability, pharmacokinetics (PK), and pharmacodynamics (PD) of denosumab biosimilar (QL1206) in healthy Chinese subjects.

Methods

This is a randomized, double-blind, two-arm, parallel study performed to examine the bioequivalence of denosumab biosimilar, QL1206, with that of Xgeva^® (Denosumab) as a reference drug. A single dose of 120 mg/kg of the denosumab biosimilar or Xgeva^® was administered to the subjects, who were followed up for 134 days.

Results

Similar PK properties as those of Xgeva^® were exhibited by QL1206. When compared to QL1206 with Xgeva^®, the 90% confidence intervals of the ratios for C_max, AUC_0-t, and AUC_0-∞ were observed to be within 80-125%. The inter-subject variability (inter-CV) ranged from 29% to 39.5%. Six and three subjects in the QL1206 and Xgeva^® groups were found to be positive for the ADA and negative for the NAb, respectively. The CTX1 concentration-time profiles appeared similar (about 80% decrease from 48 hours to134 days) between the QL1206 and Xgeva^® groups. Adverse events (AEs) were observed in 92.6% and 93.4% of subjects in the QL1206 and Xgeva^® groups, respectively. Reduction in blood calcium level was found to be the most common AE recorded, with an incidence of 72.8% versus 72.4% in the QL1206 and Xgeva^® groups, respectively.

Conclusion

Similar PK and PD characteristics were exhibited by QL1206 as compared to those of Xgeva^®. The inter-CV was slightly large. The safety profiles of denosumab biosimilars and Xgeva^® were found to be similar.

New paradigm for expediting drug development in Asia

Some Asian regulators currently require Phase I data in Asians before joining global Phase II/III trials. Here, we discuss inherent limitations of Phase I ethnic sensitivity studies (ESS) to identify potential interethnic differences. We review recent new drug applications (NDAs) for Japan and China to critically assess the value of separate ESSs in Asian populations. Given that the observed value of ESS was limited, we propose a new global drug development paradigm: if relevant safety, pharmacokinetic (PK), and pharmacogenetic (PG) data are available from the original Phase I study population, it might be possible to extrapolate those data to Asian populations for their inclusion in Phase II/III trials, without an ESS. This could help to streamline drug development in Asia while still addressing regulatory requirements.

Dynamics of Bone Cell Interactions and Differential Responses to PTH and Antibody-Based Therapies

We propose a mathematical model describing the dynamics of osteoblasts and osteoclasts in bone remodeling. The goal of this work is to develop an integrated modeling framework for bone remodeling and bone cell signaling dynamics that could be used to explore qualitatively combination treatments for osteoporosis in humans. The model has been calibrated using 57 checks from the literature. Specific global optimization methods based on qualitative objectives have been developed to perform the model calibration. We also added pharmacokinetics representations of three drugs to the model, which are teriparatide (PTH(1-34)), denosumab (a RANKL antibody) and romosozumab (a sclerostin antibody), achieving excellent goodness-of-fit of human clinical data. The model reproduces the paradoxical effects of PTH on the bone mass, where continuous administration of PTH results in bone loss but intermittent administration of PTH leads to bone gain, thus proposing an explanation of this phenomenon. We used the model to simulate different categories of osteoporosis. The main attributes of each disease are qualitatively well captured by the model, for example changes in bone turnover in the disease states. We explored dosing regimens for each disease based on the combination of denosumab and romosozumab, identifying adequate ratios and doses of both drugs for subpopulations of patients in function of categories of osteoporosis and the degree of severity of the disease.

Pharmacokinetics, pharmacodynamics, safety, and tolerability of single-dose denosumab in healthy Chinese volunteers: A randomized, single-blind, placebo-controlled study

Background

Denosumab is a fully human monoclonal antibody against receptor activator of nuclear factor kappa-B ligand, a cytokine essential for the formation, function and survival of osteoclasts. This study assessed the pharmacokinetics, pharmacodynamics, safety and tolerability of single-dose denosumab (60 and 120 mg) in healthy Chinese volunteers.

Methods

This randomized (3:3:2), single-blind, placebo-controlled study enrolled healthy Chinese volunteers to receive single subcutaneous injection of denosumab 60 mg, 120 mg, or placebo. Study consisted of screening period (up to 21 days), treatment and assessment period (19 weeks), and an end-of-study visit (at week 26). Denosumab pharmacokinetics and pharmacodynamics parameters were estimated using non-compartmental analysis. Safety and tolerability were assessed throughout the study.

Results

A total of 63 volunteers received the study treatment and 62 (98.4%) completed the study. Denosumab serum concentrations peaked at around Day 10 with dose-proportional increase from 60 mg to 120 mg. The mean terminal half-life of denosumab 60 mg and 120 mg was 15 days and 26 days, respectively. The serum C-terminal cross-linking telopeptide of type I collagen concentration-time profiles were similar (>80% decrease within 5 days) between denosumab 60 mg and 120 mg groups. The most commonly reported adverse event (AE) was decreased blood calcium levels (denosumab 60 mg, n = 13; denosumab 120 mg, n = 13; placebo, n = 1); however only one volunteer had calcium level below the abnormality value of potential clinical importance and none of the volunteers developed symptoms of hypocalcemia. The majority of AEs were of mild to moderate intensity. There were no deaths, serious AEs, or withdrawal from study due to AEs. No clinically significant findings in vital signs or electrocardiogram were observed.

Conclusions

Both denosumab 60 mg and 120 mg were well tolerated with no new safety concerns identified in healthy Chinese volunteers with similar pharmacokinetics and pharmacodynamics profiles to that of Caucasians.

Trial registration

ClinicalTrial.gov NCT02135640

Denosumab for the Treatment of Mastocytosis-Related Osteoporosis: A Case Series

The purpose of this study was to investigate the therapeutic effect of denosumab, an anti-RANKL monoclonal antibody for the treatment of bone loss in indolent systemic mastocytosis (ISM) patients intolerant to bisphosphonates. Four patients underwent upon informed consent a treatment with denosumab 60 mg administered subcutaneously every 6 months with the same regimen used for postmenopausal osteoporosis. Bone mineral density (BMD) was measured at lumbar and femoral sites at baseline and after 1 year. C-terminal telopeptide of collagen type I (CTX), bone alkaline phosphatase (bALP) and tryptase serum level were determined at baseline and after 12 months with fasting blood samples withdrawals. BMD increased significantly at both sites during the 12 months; all the patients had an important decrease of serum CTX and of lesser extent of bALP serum levels. After denosumab treatment, a decrease in serum tryptase level was observed in all the patients. No adverse events or new fractures occurred. Denosumab seems to be a valid alternative for the treatment of bone loss in ISM. RANKL might be of key importance in the pathogenesis of ISM bone involvement.

Recent advances in the management of osteoporosis

There has been substantial progress in the management of patients with osteoporosis and the prevention of osteoporotic fractures. Currently available strong anti-resorptive agents are bisphosphonates and an anti-receptor activator of nuclear factor-kappa B ligand (RANKL) antibody, denosumab. Although bisphosphonates and denosumab both inhibit bone resorption and prevent vertebral and non-vertebral fractures, their mechanisms of action are different. Whereas bisphosphonates’ effects on bone mineral density and fracture peak around 3 to 5 years and become plateaued, those of denosumab are maintained for up to 10 years. There are differences in the modes of action of these two drugs. Bisphosphonates accumulate on the mineralized bone surface and are released by the acid environment under osteoclastic bone resorption, whereas denosumab is not accumulated on bone but directly binds RANKL and inhibits its binding to the receptor RANK. Thus, the reduction in denosumab concentration 4 to 6 months after injection may enable RANK to bind to RANKL, where it is highly expressed, such as in damaged bone regions. As anabolic agents, only teriparatide has been available for a long time, but abaloparatide, a synthetic analog of PTHrP(1–34), is currently under development. Because of the difference in the preferential binding conformations of PTH1 receptor between teriparatide and abaloparatide, the latter shows anabolic effects with fewer bone resorptive effects. Romosozumab, an anti-sclerostin antibody, inhibits the action of sclerostin, a canonical Wnt signal inhibitor secreted from osteocytes, and enhances canonical Wnt signaling. Romosozumab robustly increases vertebral and proximal femoral bone mineral density within 12 months and inhibits vertebral and clinical fractures in patients with osteoporosis by enhancing bone formation and inhibiting bone resorption. In this review, we summarize the recent advances in therapeutic agents for the treatment of osteoporosis and discuss future prospects with their use.

Denosumab for the treatment of osteoporosis

Denosumab, a specific inhibitor of RANK ligand, is a novel therapy for postmenopausal osteoporosis and related disorders. An extensive clinical development program has evaluated the clinical efficacy and safety of denosumab with several thousand patients being followed for up to 10 years. Combined with more than six years of postmarketing experience, these studies provide substantial confidence that denosumab is a convenient and appropriate treatment for patients, including Asians, at high risk for fracture. This review will summarize the clinical development of denosumab and lessons learned since its approval for clinical use in 2010.

Smad4 is required to inhibit osteoclastogenesis and maintain bone mass

Bone homeostasis is maintained as a delicate balance between bone-resorption and bone-formation, which are coupled to maintain appropriate bone mass. A critical question is how bone-resorption is terminated to allow bone-formation to occur. Here, we show that TGFβs inhibit osteoclastogenesis and maintain bone-mass through Smad4 activity in osteoclasts. We found that latent-TGFβ1 was activated by osteoclasts to inhibit osteoclastogenesis. Osteoclast-specific Smad4 conditional knockout mice (Smad4-cKO) exhibited significantly reduced bone-mass and elevated osteoclast formation relative to controls. TGFβ1-activation induced expression of Irf8 and Bcl6, both of which encode factors inhibiting osteoclastogenesis, by blocking their negative regulator, Prdm1, in osteoclasts in a Smad4-dependent manner. Reduced bone-mass and accelerated osteoclastogenesis seen in Smad4-cKO were abrogated by Prdm1 deletion. Administration of latent-TGFβ1-Fc to wild-type mice antagonized LPS-induced bone destruction in a model of activated osteoclast-mediated bone destruction. Thus, latent-TGFβ1-Fc could serve as a promising new therapeutic agent in bone diseases marked by excessive resorption.

Denosumab: a review of its use in postmenopausal women with osteoporosis

Subcutaneous denosumab (Prolia(®) [USA, Europe]; Pralia(®) [Japan]) once every 6 months is indicated in several countries for the treatment of postmenopausal women with osteoporosis at increased or high risk for fractures (featured indication). In some countries, it is also indicated for use in postmenopausal women who have failed or are intolerant to other osteoporosis treatments. In several international, phase III trials (≤3 years' duration) involving more than 12,000 women with postmenopausal osteoporosis or low bone mineral density (BMD), including Asian studies, denosumab was an effective and generally well tolerated treatment. Relative to placebo, denosumab treatment significantly reduced the risk of vertebral, nonvertebral and hip fractures and increased BMD at all skeletal sites evaluated, including the lumbar spine and total hip. Furthermore, the benefits of denosumab treatment were generally evident after the first dose and were maintained during up to 8 years of treatment in an ongoing extension study. The tolerability profile of denosumab during this extension phase was consistent with that observed during the initial 3-year FREEDOM trial. At 12 months, denosumab treatment increased BMD at the total hip, lumbar spine and/or femoral neck and reduced markers of bone turnover to a significantly greater extent than oral bisphosphonates in women who were essentially bisphosphonate-naive and in those who had switched from alendronate to denosumab treatment. Further clinical experience, including an ongoing postmarketing safety study, will more fully define the long-term safety of denosumab. In the meantime, denosumab is an important option for the treatment of women with postmenopausal osteoporosis at increased or high-risk of fractures, including in women at increased risk of fracture who are unable to take other osteoporosis treatments.

Three-year denosumab treatment in postmenopausal Japanese women and men with osteoporosis: results from a 1-year open-label extension of the Denosumab Fracture Intervention Randomized Placebo Controlled Trial (DIRECT)

SUMMARY

A 12-month extension phase of DIRECT in Japanese subjects with osteoporosis showed that total 3 years of denosumab treatment in Japanese postmenopausal women and men with osteoporosis was associated with low fracture rates, persistent bone turnover marker (BTM) reductions, continuous bone mineral density (BMD) increases, and a favorable overall benefit/risk profile.

INTRODUCTION

The DIRECT trial demonstrated that 2 years of treatment with denosumab 60 mg subcutaneously every 6 months significantly reduced the incidence of vertebral fracture compared to placebo in Japanese postmenopausal women and men with osteoporosis. The purpose of this study is to evaluate the efficacy and safety of denosumab treatment for up to 3 years.

METHODS

This study includes a 2-year randomized, double-blind, placebo-controlled phase and a 1-year open-label extension phase in which all subjects received denosumab. The data correspond to 3 years of denosumab treatment in subjects who received denosumab (long-term group) and 1 year of denosumab treatment in subjects who received placebo (cross-over group) in the double-blind phase.

RESULTS

Eight hundred and ten subjects who completed the double-blind phase enrolled into the extension phase, and 775 subjects completed the study. All subjects received denosumab with daily supplements of calcium and vitamin D. The cumulative 36-month incidences of new or worsening vertebral fractures and new vertebral fractures were 3.8 and 2.5 %, respectively, in the long-term group. In this group, the BMD continued to increase, and the reduction in BTMs was maintained. In the cross-over group, comparable BMD increases and BTMs reductions to those of in their first year of the long-term group were confirmed. Adverse events did not show a notable increase with long-term denosumab administration. One event of osteonecrosis of the jaw occurred in the cross-over group.

CONCLUSIONS

Three-year denosumab treatment in Japanese subjects with osteoporosis showed a favorable benefit/risk profile.

Application of human FcRn transgenic mice as a pharmacokinetic screening tool of monoclonal antibody

1. For drug discovery, useful screening tools are essential to select superior candidates. Here, we evaluated the applicability of transgenic mice expressing human neonatal Fc receptor (FcRn) (hFcRn Tgm) as a pharmacokinetic screening tool of therapeutic monoclonal antibodies (mAbs) and Fc-fusion proteins that overcomes the species difference in FcRn binding. 2. Marketed 11 mAbs and 2 Fc-fusion proteins were intravenously administered to hFcRn Tgm and WT mice. The half-lives in hFcRn Tgm and WT mice were compared with those in human obtained from literature. The linear half-lives in human and monkey were also calculated by nonlinear pharmacokinetic analysis. For comparison, correlations of half-lives between monkey and human were also evaluated. 3. The half-lives of mAbs and Fc-fusion proteins after intravenous administration ranged from 1.1 to 13.2 days in hFcRn Tgm and from 1.2 to 30.3 days in WT mice. The half-lives in human correlated more closely with those in hFcRn Tgm than in WT mice and monkey. 4. Our results suggest that hFcRn Tgm are a valuable and useful tool for pharmacokinetic screening of mAbs and Fc-fusion proteins in the preclinical stage. Furthermore, we believe that hFcRn Tgm are broadly applicable to preclinical pharmacokinetic screening of mAbs-based therapeutics.

A review of denosumab for the treatment of osteoporosis

Osteoporosis is an age-related systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility. Bone remodeling involves two types of cells: osteoblasts and osteoclasts. Receptor activator of nuclear factor-κB ligand (RANKL) is a key regulator of the formation and function of bone-resorbing osteoclasts, and its cell surface receptor, receptor activator of nuclear factor-κB (RANK), is expressed by both osteoclast precursors and mature osteoclasts. Denosumab is a fully human monoclonal anti-RANKL antibody that inhibits the binding of RANKL to RANK, thereby decreasing osteoclastogenesis and bone-resorbing activity of mature osteoclasts. Although there are many medications available for the treatment of osteoporosis, inhibition of RANKL by denosumab has been shown to significantly affect bone metabolism. Denosumab appears to be a promising, highly effective, and safe parenteral therapy with good adherence for osteoporosis. Moreover, denosumab may be cost-effective therapy compared with existing alternatives. Therefore, in this review, we focus on studies of denosumab and the risks and benefits identified for this type of treatment for osteoporosis.

Bone homeostasis and breast cancer: implications for complex therapy and the maintenance of bone integrity

The standard of care in bone metastases is antiresorptive therapy. If present in the bone, tumor cells induce a vicious cycle by stimulating the osteoclasts, which further accelerates tumor progression. The widely-used bisphosphonates or the new therapeutic option, denosumab an inhibitor of the receptor activator of NF-κB ligand (RANKL), interrupt this vicious cycle, inhibit tumor growth, and in clinical practice prevent skeleton-related events. Adjuvant oncological therapy, including chemotherapy and endocrine manipulations (ovarian ablation and tamoxifen in premenopausal, and aromatase inhibitors in postmenopausal women), increases the bone turnover and the risk of fracture. Awareness is essential for the diagnosis and treatment of cancer therapy-induced bone loss, or its prevention with appropriate calcium and vitamin D supplementation. A new possibility has been suggested for the prevention of relapse: the use of bisphosphonates in the adjuvant setting. Three large studies and their meta-analyses indicate that the inhibition of bone remodeling prevents the growth of dormant tumor cells and cancer relapse in the population of postmenopausal patients with a low-estrogen environment in the skeleton. The similar potential of a RANKL inhibitor is currently under evaluation. Since the maintenance of bone integrity is necessary for the prevention of both therapy-related side-effects and progression of the disease, the management of breast cancer at any stage requires a careful consideration of the bone homeostasis.

Clinical review. Comparative effectiveness of drug treatments to prevent fragility fractures: a systematic review and network meta-analysis

CONTEXT

Osteoporosis and osteopenia are associated with increased fracture incidence.

OBJECTIVE

The aim of this study was to determine the comparative effectiveness of different pharmacological agents in reducing the risk of fragility fractures.

DATA SOURCES

We searched multiple databases through 12/9/2011.

STUDY SELECTION

Eligible studies were randomized controlled trials enrolling individuals at risk of developing fragility fractures and evaluating the efficacy of bisphosphonates, teriparatide, selective estrogen receptor modulators, denosumab, or calcium and vitamin D.

DATA EXTRACTION

Reviewers working independently and in duplicate determined study eligibility and collected descriptive, methodological quality, and outcome data.

DATA SYNTHESIS

This network meta-analysis included 116 trials (139,647 patients; median age, 64 yr; 86% females and 88% Caucasians; median follow-up, 24 months). Trials were at low to moderate risk of bias. Teriparatide had the highest risk reduction of fractures (odds ratios, 0.42, 0.30, and 0.50 for hip, vertebral, and nonvertebral fractures, respectively) and the highest probability of being ranked first for efficacy (probabilities of 42, 49, and 79% for hip, vertebral, and nonvertebral fractures, respectively). However, differences to denosumab, zoledronate, risedronate, ibandronate, and alendronate were not statistically significant. Raloxifene and bazedoxifene were likely less effective, although these data were limited. Calcium and vitamin D were ineffective given separately but reduced the risk of hip fractures if given in combination (odds ratio, 0.81; 95% confidence interval, 0.68–0.96).

CONCLUSIONS

Teriparatide, bisphosphonates, and denosumab are most effective in reducing the risk of fragility fractures. Differences in efficacy across drugs are small; therefore, patients and clinicians need to consider their associated harms and costs.