Effect of follow-up raloxifene therapy after denosumab discontinuation in postmenopausal women

Current and emerging bone resorption inhibitors for the treatment of osteoporosis

INTRODUCTION

Osteoporosis is a metabolic skeletal disease characterized by low bone mass and strength, and increased risk for fragility fractures. It is a major health issue in aging populations, due to fracture-associated increased disability and mortality. Antiresorptive treatments are first line choices in most of the cases.

AREAS COVERED

Bone homeostasis is complicated, and multiple factors can compromise skeletal health. Bone turnover is a continuous process regulated by the coupled activities of bone cells that preserves skeletal strength and integrity. Imbalance between bone resorption and formation leads to bone loss and increased susceptibility to fractures. Antiresorptives prevent bone loss and reduce fracture risk, by targeting osteoclastogenesis and osteoclast function and survival. Their major drawback is the coupling of osteoclast and osteoblast activity, due to which any reduction in bone resorption is followed by suppression of bone formation.

EXPERT OPINION

During the last couple of decades significant progress has been made in understanding of the genetic and molecular basis of osteoporosis. Critical pathways and key molecules that mediate regulation of bone resorption have been identified. These factors may underpin novel therapeutic avenues for osteoporosis, but their potential for translation into clinical applications is yet to be tested.

Use of raloxifene as a sequential therapy after romosozumab : an observational study

OBJECTIVE

There have been no studies on the effectiveness of raloxifene as an antiresorptive agentfollowing discontinuation of romosozumab. The aim of this study was to investigate the potential effectiveness of raloxifene following a romosozumab therapy.

METHODS

This study had an observational pre-post design and included 23 patients. Romosozumab 210 mg was administered subcutaneously once every 4 weeks for 12 months, after which all patients received raloxifene 60 mg/day for 24 months. We investigated the incidence of new fractures, safety, and bone mineral density (BMD).

RESULTS

We found no new fractures or adverse events. After the treatment with romosozumab, percent changes from baseline in BMD at the spine and total hip in treatment-naïve patients with primary osteoporosis (the Naïve-P group) were 12.3% and 4.6%, respectively. After subsequent administration of raloxifene, spinal and total hip BMD in the Naïve-P group decreased to baseline levels at 36 months and 30 months, respectively. Six months after switching to raloxifene, the respective percent changes from baseline in spinal and total hip BMD were 12.0% and 5.8%.

CONCLUSION

Romosozumab followed by raloxifene is acceptable for use for only 6 months in the Naïve-P group. However, more aggressive use of this agent is not recommended. J. Med. Invest. 72 : 124-133, February, 2025.

Prevention and Management of Denosumab Discontinuation Rebound Fractures

Denosumab rebound-associated fractures occur in approximately 1 out of 14 patients who discontinue denosumab therapy without sequential antiresorptive therapy. They occur due to excessive bone resorption after missed or delayed denosumab doses. The fractures are multiple and quality of life altering. This phenomenon occurs in all patient populations that use prolonged denosumab therapy. Average delay in denosumab dosing beyond 7 months or discontinuation of denosumab without sequential therapy is associated with increased mortality in retrospective studies. Multiple medication regimens used after the end of denosumab therapy have been shown to substantially reduce the risk of rebound vertebral fractures.

Treating osteoporosis in patients with atypical femoral fracture

Patients who have suffered an atypical femoral fracture while on bisphosphonates or denosumab may continue to be at risk for typical osteoporotic fractures. There are no studies to provide guidance on safe treatment for such patients. Instead, using an illustrative case, 5 principles of management are provided that may lead to decreased osteoporotic fracture risk. The first principle is to discontinue the anti-resorptive medications, which may be challenging for the patient on denosumab because of rebound vertebral fractures reported in patients stopping denosumab. The second principle is to maximize non-pharmacologic management to reduce falls and fractures. Home safety, other methods of fall risk reduction, adequate nutrition, and an exercise prescription should help reduce fracture risk. Investigating potential secondary causes of osteoporosis, particularly if the original workup was not comprehensive, is the third principle because treatment of some specific causes may lower fracture risk. Reviewing the medication list is the fourth principle, with the goal of eliminating drugs that may increase fracture risk, and considering thiazides for some patients, which may lower fracture risk. Finally, some patients may benefit from anabolic therapy. One potential (but not FDA-approved) method is to use long-term cyclic teriparatide or abaloparatide on a 3-mo on, 3-mo off schedule. Tailoring the approach to each patient is important, based on the 5 clinical principles, in the absence of evidence-based management recommendations.

The comparison of alendronate and raloxifene after denosumab (CARD) study: A comparative efficacy trial

Denosumab discontinuation results in accelerated bone remodeling, decreased bone mineral density (BMD), and an increased risk of multiple vertebral fractures. Bisphosphonates are at least partially effective at inhibiting these consequences but there have been no randomized clinical trials assessing the efficacy of alternative antiresorptives.

PURPOSE

The aim of this study was to evaluate the comparative efficacy of alendronate and the SERM, raloxifene, in preventing the post-denosumab high-turnover bone loss.

METHODS

We conducted an open-label randomized controlled trial in which 51 postmenopausal women at increased risk of fracture were randomized with equal probability to receive 12-months of denosumab 60-mg 6-monthly followed by 12-months of either alendronate 70-mg weekly or raloxifene 60-mg daily. Serum bone remodeling markers were measured at 0,6,12,15,18, and 24 and areal BMD of the distal radius, spine, and hip were measured at 0,12,18 and 24 months.

RESULTS

After denosumab discontinuation, serum markers of bone remodeling remained suppressed when followed by alendronate, but gradually increased to baseline when followed by raloxifene. In the denosumab-to-alendronate group, denosumab-induced BMD gains were maintained at all sites whereas in the denosumab-to-raloxifene group, BMD decreased at the spine by 2.0% (95% CI -3.2 to -0.8, P = 0.003) and at the total hip by 1.2% (-2.1 to -0.4%, P = 0.008), but remained stable at the femoral neck and distal radius and above the original baseline at all sites. The decreases in spine and total hip BMD in the denosumab-to-raloxifene group (but not the femoral neck or distal radius) were significant when compared to the denosumab-to-alendronate group.

CONCLUSIONS

These results suggest that after one year of denosumab, one year of alendronate is better able to maintain the inhibition of bone remodeling and BMD gains than raloxifene.

Sequential Therapy for the Long-Term Treatment of Postmenopausal Osteoporosis

Osteoporosis is a chronic condition characterized by decreased bone mass, loss of skeletal integrity, and increased susceptibility to fracture. Drugs used to treat osteoporosis can be classified as those that block bone resorption (antiresorptive), stimulate bone formation (anabolic), or do both. While all currently approved medications reduce the risk of fragility fractures in high-risk populations, they are generally unable to fully restore bone strength in most patients with established disease. Thus, the majority of patients require disease management over many years. Unfortunately, the continuous use of a single drug has limitations, both in terms of efficacy and safety, and so sequential therapy is commonly required. Given the expanding list of pharmacological agents currently available, careful consideration needs to be given as to which drugs to use and in what sequence. This review will evaluate the differential effects of antiresorptive, bone-forming, and dual-acting drugs when used in specific sequences and will explore the current evidence favoring the initial use of bone-forming/dual-acting drugs followed by antiresorptive medications. This review will also examine the notion that long-term treatment with an antiresorptive drug may diminish the efficacy of subsequent treatment with a bone-forming/dual-acting drug. Finally, this review will explore the current evidence pertaining to the specific issue of how to best prevent the clinical ramifications of denosumab cessation.

Position Statement: Postmenopausal Osteoporosis Treatment Strategies in Korea

Classifying patients with osteoporosis according to fracture risk and establishing adequate treatment strategies is crucial to effectively treat osteoporosis. The Korean Society for Bone and Mineral Research has issued a position statement regarding appropriate treatment strategies for postmenopausal osteoporosis. According to previous fragility fracture history, bone mineral density (BMD) test results, fracture risk assessment tool, and several clinical risk factors, fracture risk groups are classified into low, moderate, high, and very-high-risk groups. In high-risk groups, bisphosphonates (BPs) and denosumab are recommended as first-line therapies. Sequential BP treatment after denosumab discontinuation is required to prevent the rebound phenomenon. In the very high-risk group, anabolic drugs (teriparatide or romosozumab) are recommended as a first-line therapy; sequential therapy with antiresorptive agents is required to maintain BMD gain and reduce fracture risk. Fracture risk was reassessed annually, and the treatment plan was determined based on the results, according to the osteoporosis treatment algorithm for fracture risk.

Similarities and Differences in the Management of Patients with Osteoporotic Vertebral Fractures and Those with Rebound-Associated Vertebral Fractures Following Discontinuation of Denosumab

Rebound-associated vertebral fractures (RVFx) following denosumab discontinuation are typically multiple, are commonly associated with acute sharp pain, increase the risk of imminent fractures, and are pathogenetically different from common osteoporotic vertebral fractures (VFx). A clinically relevant question is whether patients with RVFx should be managed differently from patients with osteoporotic VFx. To address this question, we performed a systematic search of the PubMed database, and we reviewed current evidence on the optimal management of patients with RVFx. For pain relief of patients with RVFx, potent analgesics, often opioids, are essential. Information on the effectiveness of braces in these patients is scarce. Vertebroplasty and kyphoplasty are strongly contraindicated as they confer a substantial risk for new VFx. Exercise may be helpful, but again evidence is lacking. In contrast to patients with osteoporotic VFx, in whom initial treatment with bone-forming agents is recommended, patients with RVFx should initiate treatment with potent antiresorptives. To summarize, patients who have sustained RVFx following denosumab discontinuation are at a very high risk for new fractures, especially VFx. The management of such patients requires a multidisciplinary approach that should not be restricted to pain relief and administration of antiosteoporotic medication, but should also include back protection, early mobilization, and appropriate exercise.

Long-term and sequential treatment for osteoporosis

Osteoporosis is a skeletal disorder that causes impairment of bone structure and strength, leading to a progressively increased risk of fragility fractures. The global prevalence of osteoporosis is increasing in the ageing population. Owing to the chronic character of osteoporosis, years or even decades of preventive measures or therapy are required. The long-term use of bone-specific pharmacological treatment options, including antiresorptive and/or osteoanabolic approaches, has raised concerns around adverse effects or potential rebound phenomena after treatment discontinuation. Imaging options, risk scores and the assessment of bone turnover during initiation and monitoring of such therapies could help to inform individualized treatment strategies. Combination therapies are currently used less often than 'sequential' treatments. However, all patients with osteoporosis, including those with secondary and rare causes of osteoporosis, as well as specific patient populations (for example, young adults, men and pregnant women) require new approaches for long-term therapy and disease monitoring. New pathophysiological aspects of bone metabolism might therefore help to inform and revolutionize the diagnosis and treatment of osteoporosis.

The real-world adherence of the first-line anti-osteoporosis medications in Taiwan: Visualize the gap between reality and expectations

BACKGROUND

Adherence to anti-osteoporosis medications (AOMs) is crucial. National Health Insurance (NHI) in Taiwan has its own rules of reimbursement rule for AOMs. The midterm adherence remained inconclusive. Here we investigated the adherence according to the initially used AOMs, for three consecutive years.

METHODS

The nationwide cohort study from 2008 to 2018, based on Taiwan's National Health Insurance Research Database, included 336,229 patients. Their adherence, indicated by medication possession ratio (MPR), to the initial AOMs was investigated yearly for three consecutive years. The overall MPRs (OMPR), including the switched AOMs, were also calculated in the first year. The Sankey diagram further visualized the patient flows toward different adherence according to the initial AOMs.

RESULTS

The OMPR in the first year improved if the patients used AOMs with longer dosing intervals. 100%, 68.9%, 40.7%, and 34.0% of the patients started the treatment with zoledronate, denosumab, alendronate, and raloxifene, respectively, had OMPR ≥75% in the first year. In the 3rd year, only 20.89%, 24.13%, and 12.83% of the patients continuously treated with zoledronate, denosumab, and alendronate, respectively, had MPR ≥75%. From the Sankey diagram, we also observed that patients who had poor adherence at one year were inclined to have poor adherence or discontinue antiosteoporosis treatment in the next year.

CONCLUSION

The initial AOMs and the observed adherence may provide clues for optimizing patient treatment. The real-world adherence in Taiwan was far from satisfactory in our study.

Mechanistic advances in osteoporosis and anti-osteoporosis therapies

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

Denosumab Discontinuation

PURPOSE OF REVIEW

To review the pathophysiology, the clinical consequences as well as way of mitigating the effects of denosumab discontinuation.

RECENT FINDINGS

Treatment with denosumab (DMAB) is reversible and upon discontinuation there is a rapid increase in bone turnover and a subsequent bone loss. During this phase of high bone turnover, an increased risk of fractures has been reported. Therefore, treatment with DMAB could be considered life-long. However, side-effects may prompt the need for discontinuation and moreover, treatment with DMAB may have increased BMD to levels where continuing treatment does not provide further fracture risk reduction. Patients stopping DMAB should be offered subsequent antiresorptive treatment with an intense monitoring regimen during the initial year as most of the bone loss occurs within these initial 12 months. In this review, we evaluated the literature published over the past 1 to 3 years investigating DMAB withdrawal with focus on bone turnover markers, bone mineral density, and fracture risk and the transition to other anti-osteoporosis therapies. Furthermore, we summarized the current recommendations of international guidelines. In this review, we evaluated the literature published over the past 1 to 3 years investigating denosumab (DMAB) discontinuation and the transition to other anti-osteoporosis therapies. Additionally, we summarized the current recommendations of international guidelines.

The SARS-CoV-2 main protease (Mpro): Structure, function, and emerging therapies for COVID-19

The main proteases (Mpro), also termed 3-chymotrypsin-like proteases (3CLpro), are a class of highly conserved cysteine hydrolases in β-coronaviruses. Increasing evidence has demonstrated that 3CLpros play an indispensable role in viral replication and have been recognized as key targets for preventing and treating coronavirus-caused infectious diseases, including COVID-19. This review is focused on the structural features and biological function of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease Mpro (also known as 3CLpro), as well as recent advances in discovering and developing SARS-CoV-2 3CLpro inhibitors. To better understand the characteristics of SARS-CoV-2 3CLpro inhibitors, the inhibition activities, inhibitory mechanisms, and key structural features of various 3CLpro inhibitors (including marketed drugs, peptidomimetic, and non-peptidomimetic synthetic compounds, as well as natural compounds and their derivatives) are summarized comprehensively. Meanwhile, the challenges in this field are highlighted, while future directions for designing and developing efficacious 3CLpro inhibitors as novel anti-coronavirus therapies are also proposed. Collectively, all information and knowledge presented here are very helpful for understanding the structural features and inhibitory mechanisms of SARS-CoV-2 3CLpro inhibitors, which offers new insights or inspiration to medicinal chemists for designing and developing more efficacious 3CLpro inhibitors as novel anti-coronavirus agents.