Guidelines for diagnosis and management of Paget's disease of bone in Japan

Safety and effectiveness of risedronate in Paget's disease of bone: postmarketing surveillance study in Japan

INTRODUCTION

We conducted an all-case postmarketing surveillance study between 2008 and 2017 to evaluate the safety and effectiveness of risedronate for Paget's disease of bone (PDB) in Japan.

MATERIAL AND METHODS

This study registered all patients who received once-daily risedronate 17.5 mg for the treatment of PDB and collected data over a 48-week follow-up period per treatment cycle for each patient.

RESULTS

The safety analysis set included 184 patients (mean age, 63.7 years), 81 (44.0%) of whom previously received a bisphosphonate. Of them, 41 (22.3%) experienced 72 adverse drug reactions (ADRs), and 8 (4.3%) experienced 14 serious ADRs. Common ADRs included gastrointestinal disorders (20 patients, 10.9%) and hypocalcemia (6 patients, 3.3%). The effectiveness analysis set included 182 patients, 124 of whom completed only one treatment cycle and 58 of whom completed multiple treatment cycles. The proportions of patients who normalized serum alkaline phosphatase (ALP) concentration were 71.1% (113/159 patients) and 67.3% (33/49 patients) for the first and second treatment cycles, respectively. The relapse rate according to ALP levels after the end of treatment for the first cycle was 5.0% (95% confidence interval [CI] = 2.1-11.5) at 24 weeks and 12.9% (95% CI = 7.5-21.7) at 40 weeks. Regarding pain relief, the achievement rates were 70.0% (49/70 patients) and 30.8% (4/13 patients) for the first and second treatment cycles, respectively.

CONCLUSION

To conclude, risedronate 17.5 mg/day is safe and effective for treating patients with PDB in daily practice.

Familial Paget's disease of bone with ocular manifestations and a novel TNFRSF11A duplication variant (72dup27)

INTRODUCTION

Paget's disease of bone (PDB) is a skeletal disorder characterized by disorganized bone remodeling due to abnormal osteoclasts. Tumor necrosis factor receptor superfamily member 11A (TNFRSF11A) gene encodes the receptor activator of nuclear factor kappa B (RANK), which has a critical role in osteoclast function. There are five types of rare PDB and related osteolytic disorders due to TNFRSF11A tandem duplication variants so far, including familial expansile osteolysis (84dup18), expansile skeletal hyperphosphatasia (84dup15), early-onset familial PDB (77dup27), juvenile PDB (87dup15), and panostotic expansile bone disease (90dup12).

MATERIALS AND METHODS

We reviewed a Japanese family with PDB, and performed whole-genome sequencing to identify a causative variant.

RESULTS

This family had bone symptoms, hyperphosphatasia, hearing loss, tooth loss, and ocular manifestations such as angioid streaks or early-onset glaucoma. We identified a novel duplication variant of TNFRSF11A (72dup27). Angioid streaks were recognized in Juvenile Paget's disease due to loss-of-function variants in the gene TNFRSF11B, and thought to be specific for this disease. However, the novel recognition of angioid streaks in our family raised the possibility of occurrence even in bone disorders due to TNFRSF11A duplication variants and the association of RANKL-RANK signal pathway as the pathogenesis. Glaucoma has conversely not been reported in any case of Paget's disease. It is not certain whether glaucoma is coincidental or specific for PDB with 72dup27.

CONCLUSION

Our new findings might suggest a broad spectrum of phenotypes in bone disorders with TNFRSF11A duplication variants.

Mutations in Profilin 1 Cause Early-Onset Paget's Disease of Bone With Giant Cell Tumors

Paget's disease of bone (PDB) is a late-onset chronic progressive bone disease characterized by abnormal activation of osteoclasts that results in bone pain, deformities, and fractures. PDB is very rare in Asia. A subset of PDB patients have early onset and can develop malignant giant cell tumors (GCTs) of the bone (PDB/GCTs), which arise within Paget bone lesions; the result is a significantly higher mortality rate. SQSTM1, TNFRSF11A, OPG, VCP, and HNRNPA2B1 have been identified as pathogenic genes of PDB, and ZNF687 is the only confirmed gene to date known to cause PDB/GCT. However, the molecular mechanism underlying PDB/GCT has not been fully elucidated. Here, we investigate an extended Chinese pedigree with eight individuals affected by early-onset and polyostotic PDB, two of whom developed GCTs. We identified a heterozygous 4-bp deletion in the Profilin 1 (PFN1) gene (c.318_321delTGAC) by genetic linkage analysis and exome sequencing for the family. Sanger sequencing revealed another heterozygous 1-bp deletion in PFN1 (c.324_324delG) in a sporadic early-onset PDB/GCT patient, further proving its causative role. Interestingly, a heterozygous missense mutation of PFN1 (c.335 T > C) was identified in another PDB/GCT family, revealing that not only deletion but also missense mutations in PFN1 can cause PDB/GCT. Furthermore, we established a Pfn1-mutated mouse model (C57BL/6J mice) and successfully obtained Pagetic phenotypes in heterozygous mice, verifying loss of function of PFN1 as the cause of PDB/GCT development. In conclusion, our findings reveal mutations in PFN1 as the pathological mechanism in PDB/GCT, and we successfully established Pfn1-mutated mice as a suitable animal model for studying PDB-associated pathological mechanisms. The identification of PFN1 mutations has great diagnostic value for identifying PDB individuals predisposed toward developing GCTs. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Clinical features, diagnosis and treatment of Paget's disease of bone in mainland China: A systematic review

Paget's disease of bone (PDB) is a metabolic bone disease with distinct geographical and ethnic differences in its pathogenesis. In this study, we aimed to retrospectively analyze the clinical features and the status of diagnosis and treatment of PDB in mainland China to improve the clinician's understanding of this disease. For this purpose, we conducted a systematic review of 118 articles, including a total of 332 patients with PDB. The results showed that the onset age of PDB in mainland China was 46-60 years. The number of male patients in most age groups was slightly higher than that of female patients, but there was no statistical difference (p > 0.05). The gender ratio (male to female) of PDB in mainland China was significantly different from that in Japan (p < 0.05), but not from that in the USA (p > 0.05). The clinical manifestations of PDB patients in mainland China mainly included ostealgia, bone malformation, hearing loss, and fracture, and bisphosphonate was used as the main treatment drug. These findings were similar to those in Japan, UK, and USA. Total alkaline phosphatase (TALP) level was elevated in about 89.7% of patients, and no correlation between TALP level and ostealgia was observed (p > 0.05). In addition, no difference in TALP level between males and females in each group was observed (p > 0.05).

Adult Paget's disease of bone

Adult Paget's disease of bone is the second commonest metabolic bone condition after osteoporosis. The condition is characterised by increased bone cell activity, with bone-resorbing osteoclasts often larger and containing more nuclei than normal and osteoblasts producing increased amounts of disorganised bone. This leads to expanded bone of poor quality possessing both sclerotic and lytic areas. Paget's disease of bone has a strong genetic element, with a family history being noted in 10-20% of cases. A number of genetic defects have been found to be associated with the condition. The most common disease-associated variants identified affect the SQSTM1 gene, providing insights into disease aetiology, with the clinical value of knowledge of SQSTM1 mutation status currently under active investigation. The diagnosis may be suggested by an isolated raised total alkaline phosphatase (ALP) without other identifiable causes. This can be confirmed on plain X-ray and the extent determined by isotope bone scan. The mainstay of treatment are the bisphosphonates, especially intravenous zoledronate which results in long-term suppression of bone turnover. ALP is the usual means of monitoring the condition, although more specific bone turnover markers can be helpful, especially in coincident liver disease. Patients should be followed up to monitor for biochemical relapse or development of complications, which may require medical or surgical intervention.

[Paget's disease of bone-a current review of clinical aspects, diagnostics and treatment]

Paget's disease is a monostotic or polyostotic progressive skeletal disease with a genetic predisposition. The affected bone areas show osseous swelling and often grotesque deformation, chronic pain and fractures. Many cases are asymptomatic for a long time resulting in a late diagnosis. The pathogenesis is still unknown. In addition to a genetic predisposition, viral factors are also discussed. Laboratory tests and imaging are used for diagnosis. The effective principle of medicinal bisphosphonate treatment is to inhibit osteoclastic bone resorption and should be initiated early to prevent secondary complications. This article presents the current knowledge about this rare osteological disease.

Diagnosis and Management of Paget's Disease of Bone in Adults: A Clinical Guideline

An evidence-based clinical guideline for the diagnosis and management of Paget's disease of bone (PDB) was developed using GRADE methodology, by a Guideline Development Group (GDG) led by the Paget's Association (UK). A systematic review of diagnostic tests and pharmacological and nonpharmacological treatment options was conducted that sought to address several key questions of clinical relevance. Twelve recommendations and five conditional recommendations were made, but there was insufficient evidence to address eight of the questions posed. The following recommendations were identified as the most important: 1) Radionuclide bone scans, in addition to targeted radiographs, are recommended as a means of fully and accurately defining the extent of metabolically active disease in patients with PDB. 2) Serum total alkaline phosphatase (ALP) is recommended as a first-line biochemical screening test in combination with liver function tests in screening for the presence of metabolically active PDB. 3) Bisphosphonates are recommended for the treatment of bone pain associated with PDB. Zoledronic acid is recommended as the bisphosphonate most likely to give a favorable pain response. 4) Treatment aimed at improving symptoms is recommended over a treat-to-target strategy aimed at normalizing total ALP in PDB. 5) Total hip or knee replacements are recommended for patients with PDB who develop osteoarthritis in whom medical treatment is inadequate. There is insufficient information to recommend one type of surgical approach over another. The guideline was endorsed by the European Calcified Tissues Society, the International Osteoporosis Foundation, the American Society of Bone and Mineral Research, the Bone Research Society (UK), and the British Geriatric Society. The GDG noted that there had been a lack of research on patient-focused clinical outcomes in PDB and identified several areas where further research was needed. © 2019 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Long-term control of Paget's disease of bone with low-dose, once-weekly, oral bisphosphonate preparations, in a "real world" setting

PURPOSE

Bisphosphonates are the mainstay of the treatment of Paget's disease of bone (PDB). Clinical practice guidelines recommend treatment with intravenous zoledronic acid or high-dose oral nitrogen bisphosphonates (N-BPs). We present our long-term experience treating PDB patients with lower than recommended oral doses of N-BPs, equivalent to once-weekly doses used for treating osteoporosis.

METHODS

PDB patients were seen, between 1990 and 2015 at the endocrine clinic of an academic medical center. Diagnosis was established according to accepted criteria. Patients were initially treated with alendronate 70 mg/week or risedronate 35 mg/week. Whenever the initial dose failed to produce remission, the dosage was increased to twice a week the respective dose.

RESULTS

Patients were followed for a mean of 11.9 years (range: 1.7-24.8). Out of 96 treatment courses with N-BPs, 89% were with alendronate and 11% with risedronate. Remission was achieved in 84% of the courses with alendronate 70 mg/week. 90% of those who did not achieve remission subsequently responded to 140 mg/week. Out of the 8 treatment courses with risedronate 35 mg/week, 87% achieved remission, and the 2 patients who did not achieve remission subsequently responded to 70 mg/week. The median duration of remissions following 3-4 months courses of alendronate 70 mg/week or risedronate 35 mg/week was 8.8 months (IQR: 5.5, 14.8).

CONCLUSION

In a large proportion of "real world" PDB patients, remission can be achieved with once-weekly, "osteoporosis doses" of alendronate or risedronate.

Adult Paget's disease of bone: a review

Adult PD of bone is the second commonest metabolic bone condition after osteoporosis. The condition is characterized by increased bone cell activity, with bone-resorbing osteoclasts often larger and containing more nuclei than normal, and osteoblasts producing increased amounts of disorganized bone. This leads to expanded bone of poor quality possessing both sclerotic and lytic areas. PD of bone has a strong genetic element, with a family history being noted in 10-20% of cases. A number of genetic defects have been found to be associated with the condition. The most common disease-associated variants identified affect the SQSTM1 gene, providing insights into disease aetiology, with the clinical value of knowledge of SQSTM1 mutation status currently under active investigation. The diagnosis may be suggested by an isolated raised total ALP without other identifiable causes. This can be confirmed on plain X-rays and the extent determined by isotope bone scan. The mainstays of treatment are the bisphosphonates, especially i.v. zoledronate, which results in long-term suppression of bone turnover. ALP is the usual means of monitoring the condition, although more specific bone turnover markers can be helpful, especially in coincident liver disease. Patients should be followed up to monitor for biochemical relapse or development of complications, which may require medical or surgical intervention.

Bisphosphonates for Paget's disease of bone in adults

BACKGROUND

Bisphosphonates are considered to be the treatment of choice for people with Paget's disease of bone. However, the effects of bisphosphonates on patient-centred outcomes have not been extensively studied. There are insufficient data to determine whether reducing and maintaining biochemical markers of bone turnover to within the normal range improves quality of life and reduces the risk of complications.

OBJECTIVES

To assess the benefits and harms of bisphosphonates for adult patients with Paget's disease of bone.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, ISI Web of Knowledge and trials registers up to March 2017. We searched regulatory agency published information for rare adverse events.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of bisphosphonates as treatment for Paget's disease in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, extracted data and assessed studies for risk of bias. We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included 20 trials (25 reports, 3168 participants). Of these, 10 trials (801 participants) compared bisphosphonates (etidronate, tiludronate, ibandronate, pamidronate, olpadronate, alendronate, risedronate, zoledronate) versus placebo, seven compared two bisphosphonates (992 participants), one trial compared a bisphosphonates with a bisphosphonate plus calcitonin (44 participants), and two studies, the largest trial (1331 participants) and its interventional extension study (502 participants), compared symptomatic treatment and intensive treatment where the goal was to normalise alkaline phosphatase.Most studies were assessed at low or unclear risk of bias. Six of 10 studies comparing bisphosphonates versus placebo were assessed at high risk of bias, mainly around incomplete outcome data and selective outcome reporting.Participant populations were reasonably homogeneous in terms of age (mean age 66 to 74 years) and sex (51% to 74% male). Most studies included participants who had elevated alkaline phosphatase levels whether or not bone pain was present. Mean follow-up was six months.Bisphosphonates versus placeboBisphosphonates tripled the proportion (31% versus 9%) of participants whose bone pain disappeared (RR 3.42, 95% confidence interval (CI) 1.31 to 8.90; 2 studies, 205 participants; NNT 5, 95% CI 1 to 31; moderate-quality evidence). This result is clinically important. Data were consistent when pain change was measured as any reduction (RR 1.97, 95% CI 1.29 to 3.01; 7 studies, 481 participants).There was uncertainty about differences in incident fractures: 1.4% fractures occurred in the bisphosphonates group and none in the placebo group (RR 0.89, 95% CI 0.18 to 4.31; 4 studies, 356 participants; very low-quality evidence).None of the studies reported data on orthopaedic surgery, quality of life or hearing thresholds.Results regarding adverse effects and treatment discontinuation were uncertain. There was a 64% risk of mild gastrointestinal adverse events in intervention group participants and 48% in the control group (RR 1.32, 95% CI 0.91 to 1.92; 6 studies, 376 participants; low-quality evidence). The likelihood of study participants discontinuing due to adverse effects was slightly higher in intervention group participants (4.4%) than the control group (4.1%) (RR 1.01, 95% CI 0.41 to 2.52; 6 studies, 517 participants; low-quality evidence). Zoledronate was associated with an increased risk of transient fever or fatigue (RR 2.57, 95% CI 1.21 to 5.44; 1 study, 176 participants; moderate-quality evidence).Bisphosphonates versus active comparatorMore participants reported pain relief with zoledronate than pamidronate (RR 1.30, 95% CI 1.10 to 1.53; 1 study, 89 participants; NNT 5, 95% CI 3 to 11) or risedronate (RR 1.36, 95% CI 1.06 to 1.74; 1 study, 347 participants; NNT 7, 95% CI 4 to 24; very low quality evidence). This result is clinically important.There was insufficient evidence to confirm or exclude differences in adverse effects of bisphosphonates (RR 1.05, 95% CI 0.95 to 1.76; 2 studies, 437 participants; low-quality evidence) and treatment discontinuation (2 studies, 437 participants) (RR 2.04, 95% CI 0.43 to 9.59; 2 studies, 437 participants; very low-quality evidence).Intensive versus symptomatic treatmentThere was no consistent evidence of difference to response in bone pain, bodily pain or quality of life in participants who received intensive versus symptomatic treatment.Inconclusive results were observed regarding fractures and orthopaedic procedures for intensive versus symptomatic treatment (intensive treatment for fracture: RR 1.84, 95% CI 0.76 to 4.44; absolute risk 8.1% versus 5.2%; orthopaedic procedures: RR 1.58, 95% CI 0.80 to 3.11; absolute risk 5.6% versus 3.0%; 1 study, 502 participants; low-quality evidence).There was insufficient evidence to confirm or exclude an important difference in adverse effects between intensive and symptomatic treatment (RR 1.05, 95% CI 0.79 to 1.41; low-quality evidence).There was insufficient evidence to confirm or exclude an important difference of risk of rare adverse events (including osteonecrosis of the jaw) from the regulatory agencies databases.

AUTHORS' CONCLUSIONS

We found moderate-quality evidence that bisphosphonates improved pain in people with Paget's disease of bone when compared with placebo. We are uncertain about the results of head-to-head studies investigating bisphosphonates. We found insufficient evidence of benefit in terms of pain or quality of life from intensive treatment. Information about adverse effects was limited, but serious side effects were rare, and rate of withdrawals due to side effects was low.

A FKBP5 mutation is associated with Paget's disease of bone and enhances osteoclastogenesis

Paget's disease of bone (PDB) is a common metabolic bone disease that is characterized by aberrant focal bone remodeling, which is caused by excessive osteoclastic bone resorption followed by disorganized osteoblastic bone formation. Genetic factors are a critical determinant of PDB pathogenesis, and several susceptibility genes and loci have been reported, including SQSTM1, TNFSF11A, TNFRSF11B, VCP, OPTN, CSF1 and DCSTAMP. Herein, we report a case of Chinese familial PDB without mutations in known genes and identify a novel c.163G>C (p.Val55Leu) mutation in FKBP5 (encodes FK506-binding protein 51, FKBP51) associated with PDB using whole-exome sequencing. Mutant FKBP51 enhanced the Akt phosphorylation and kinase activity in cells. A study of osteoclast function using FKBP51^V55L KI transgenic mice proved that osteoclast precursors from FKBP51^V55L mice were hyperresponsive to RANKL, and osteoclasts derived from FKBP51^V55L mice displayed more intensive bone resorbing activity than did FKBP51^WT controls. The osteoclast-specific molecules tartrate-resistant acid phosphatase, osteoclast-associated receptor and transcription factor NFATC1 were increased in bone marrow-derived monocyte/macrophage cells (BMMs) from FKBP51^V55L mice during osteoclast differentiation. However, c-fos expression showed no significant difference in the wild-type and mutant groups. Akt phosphorylation in FKBP51^V55L BMMs was elevated in response to RANKL. In contrast, IκB degradation, ERK phosphorylation and LC3II expression showed no difference in wild-type and mutant BMMs. Micro-CT analysis revealed an intensive trabecular bone resorption pattern in FKBP51^V55L mice, and suspicious osteolytic bone lesions were noted in three-dimensional reconstruction of distal femurs from mutant mice. These results demonstrate that the mutant FKBP51^V55L promotes osteoclastogenesis and function, which could subsequently participate in PDB development.

Computer-assisted quantitative evaluation of bisphosphonate treatment for Paget's disease of bone using the bone scan index

The purpose of the present study was to analyze the effect of treatment of Paget's disease of bone (PDB) with bone scintigraphy using a computer-assisted diagnosis system (BONENAVI) that quantitatively evaluates bone metabolism. Seven patients with PDB (three male, four female; average age, 60 years; age range, 33–80 years) underwent bone scintigraphy and measurement of serum alkaline phosphatase (ALP), bone-specific ALP (BAP), serum cross-linked N-telopeptide (NTx) of type I collagen, urinary NTx, and deoxypyridinoline (DPD) before and after bisphosphonate treatment. Bone scan index (BSI), artificial neural network (ANN) value, and hotspot number (HSn) were calculated using BONENAVI software. Mean follow-up period was 22 months (range, 11–35 months). Among three BONENAVI parameters (ANN, BSI, and HSn), only BSI was significantly lower after bisphosphonate treatment as compared with before. All bone metabolic markers excluding DPD were significantly lower following bisphosphonate treatment than before. Bone formation markers (ALP and BAP) were significantly lower than bone resorption markers (U-NTx and S-NTx). The correlation of BONENAVI parameters with four bone metabolic markers was analyzed before and after bisphosphonate treatment. Before treatment, the majority of the four markers did not correlate with the BONENAVI parameters. In contrast, post-treatment ALP, BAP, and U-NTx were significantly correlated with BSI and HSn. To the best of our knowledge, this is the first study to evaluate the treatment of PDB by bone scintigraphy using a computer-assisted diagnosis system that quantitatively evaluates bone metabolism. The findings demonstrated that, using BONENAVI software, bone scintigraphy is able to quantitatively and spatially evaluate the bisphosphonate treatment effect, particularly in patients with polyostotic PDB.

Isolated inclusion body myopathy caused by a multisystem proteinopathy-linked hnRNPA1 mutation

Objective:

To identify the genetic cause of isolated inclusion body myopathy (IBM) with autosomal dominant inheritance in 2 families.

Methods:

Genetic investigations were performed using whole-exome and Sanger sequencing of the heterogeneous nuclear ribonucleoprotein A1 gene (hnRNPA1). The clinical and pathologic features of patients in the 2 families were evaluated with neurologic examinations, muscle imaging, and muscle biopsy.

Results:

We identified a missense p.D314N mutation in hnRNPA1, which is also known to cause familial amyotrophic lateral sclerosis, in 2 families with IBM. The affected individuals developed muscle weakness in their 40s, which slowly progressed toward a limb-girdle pattern. Further evaluation of the affected individuals revealed no apparent motor neuron dysfunction, cognitive impairment, or bone abnormality. The muscle pathology was compatible with IBM, lacking apparent neurogenic change and inflammation. Multiple immunohistochemical analyses revealed the cytoplasmic aggregation of hnRNPA1 in close association with autophagosomes and myonuclei. Furthermore, the aberrant accumulation was characterized by coaggregation with ubiquitin, sequestome-1/p62, valosin-containing protein/p97, and a variety of RNA-binding proteins (RBPs).

Conclusions:

The present study expands the clinical phenotype of hnRNPA1-linked multisystem proteinopathy. Mutations in hnRNPA1, and possibly hnRNPA2B1, will be responsible for isolated IBM with a pure muscular phenotype. Although the mechanisms underlying the selective skeletal muscle involvement remain to be elucidated, the immunohistochemical results suggest a broad sequestration of RBPs by the mutated hnRNPA1.

Clinical efficacy of oral risedronate therapy in Japanese patients with Paget's disease of bone

Paget's disease of bone (PDB) is a chronic disorder characterized by localized bone regions with excessive bone turnover. Although oral risedronate (17.5 mg daily for 8 weeks) was recently approved in Japan, its efficacy is not well understood. We retrospectively examined the efficacy of oral risedronate in PDB patients in a clinical setting. Eleven patients whose serum alkaline phosphatase (ALP) level exceeded the upper limit of the normal range were treated. Patients whose ALP levels normalized and remained so for 12 months after therapy initiation were defined as responders. Treatment was repeated if bone pain recurred or if serum ALP levels increased at least 25% above the nadir. Six patients (55%) were responsive to the therapy. A higher prevalence of skull lesions, higher serum calcium levels at treatment initiation and antecedent treatments of bisphosphonates were predictors of resistance against the therapy. Fresh frozen serum samples obtained from some treatment sessions were evaluated for metabolic bone markers such as bone-specific ALP (BAP), type I procollagen N-terminal pro-peptide (PINP), N-treminal crosslinking telopeptide of type I collagen and C-treminal crosslinking telopeptide of type I collagen (CTX). A significant reduction of P1NP preceded that of serum ALP levels in the responders, which was followed by a similar occurrence for BAP and osteocalcin (BGP) levels. A temporary decrease in CTX levels was noted. No significant changes in markers (including ALP level) were observed in non-responder and repeat-treatment groups. P1NP levels may be more useful than ALP levels in assessing treatment efficacy. Repeat treatment effectiveness for the repeat-treatment group was limited.

Paget disease of bone in Japanese patients: a report of three cases

Paget disease of bone (PDB) is a bone metabolic disorder causing pain, fractures, and deformity. Its incidence is estimated to be 1 to 2% in Caucasians older than 55 years, but in Asian populations the incidence is rare. We report on 2 female and one male Japanese patients aged 46 to 73 years with PDB. One patient had monostotic disease with pain around the shoulder and the other 2 were asymptomatic. All patients had elevated alkaline phosphatase (ALP) levels (range, 629-957 U/L). Two patients responded to oral bisphosphonate treatment and achieved normalised ALP levels and pain relief. One patient with polyostotic disease did not show any change in ALP levels. The diagnosis of the disease and the indications for bisphosphonate treatment are discussed.

Midterm outcome of risedronate therapy for patients with Paget's disease of bone in the central part of Japan

Although Paget's disease of bone (PDB) is common in western countries, it is extremely rare in Asian ones including Japan. Recently, oral risedronate (17.5 mg once daily) was approved in Japan as a treatment of PDB besides calcitonin and etidronate. However, there are few data regarding the efficacy of this agent, dose for patients with PDB in Japan, or the durability of its effect. The purpose of this study was to evaluate the midterm outcome of oral risedronate (17.5 mg once daily) for patients with PDB in Japan. Seventeen patients with PDB were treated with risedronate (17.5 mg once daily) for 8 weeks. Efficacy and its durability were accessed based on serum total alkaline phosphatase (ALP) and symptoms. Risedronate effectively suppressed bone turnover evaluated with serum total ALP in all patients. In 8 of 10 patients with bone pain, risedronate reduced the pain. On the other hand, tinnitus and hearing loss did not disappear but somewhat improved. None of the patients suffered severe complications. Seven of 17 patients required readministration of oral bisphosphonate (risedronate, six; alendronate, one) due to elevated total ALP at 27 months (mean ranging from 9 to 39 months) after the initial administration of risedronate. Treatment of oral risedronate (17.5 mg once daily) for 8 weeks is safe and effective for patients with PDB in Japan. However, the durability of its effect is limited in some patients.

Thirteen Chinese patients with sporadic Paget's disease of bone: clinical features, SQSTM1 mutation identification, and functional analysis

To increase awareness of the rarity of Paget's disease of bone (PDB) in the Chinese population, we characterized the clinical manifestations and features of 13 Chinese sporadic PDB patients. The clinical features of our Chinese PDB patients show similarities with cases reported in Western countries. The most common lesion sites were the pelvis, femur, and tibia; the next most common lesion sites were the spine and skull. Most patients had a higher serum alkaline phosphatase (ALP) level. Treatment with bisphosphonates was effective. In addition, we screened for PDB-causing mutations and performed a functional analysis in an attempt to elucidate the molecular pathogenesis of PDB. A total of 216 persons, including 13 sporadic PDB patients, three unaffected relatives of 1 patient, and 200 healthy donors, were recruited. All eight exons and exon-intron boundaries of the SQSTM1 gene were amplified by polymerase chain reaction (PCR) and directly sequenced. We identified a 53-year-old man who harbored a heterozygous T-to-C transversion at position 1250 in exon 8 (1250T > C), which resulted in a methionine-to-threonine (ATG > ACG) substitution at codon 404 (M404T). The M404T mutant SQSTM1 protein exhibited increased NF-κB activation and drove a significantly increased number of osteoclast-like cells (OLCs) that formed in response to RANKL and an increased number of OLC nuclei. This is the first report of an SQSTM1 genetic mutation that contributes to the pathogenesis of PDB in Chinese patients. These results may partially explain the mechanism by which this SQSTM1 mutation contributes to the pathogenesis of sporadic PDB in Chinese patients.

Pathogenesis of Paget disease of bone

Paget disease of bone (PDB) is a common disease characterized by focal areas of increased and disorganized bone turnover. Some patients are asymptomatic, whereas others develop complications such as pain, osteoarthritis, fracture, deformity, deafness, and nerve compression syndromes. PDB is primarily caused by dysregulation of osteoclast differentiation and function, and there is increasing evidence that this is due, in part, to genetic factors. One of the most important predisposing genes is SQSTM1, which harbors mutations that cause osteoclast activation in 5-20 % of PDB patients. Seven additional susceptibility loci for PDB have been identified by genomewide association studies on chromosomes 1p13, 7q33, 8q22, 10p13, 14q32, 15q24, and 18q21. Although the causal variants remain to be discovered, three of these loci contain CSF1, TNFRSF11A, and TM7SF4, genes that are known to play a critical role in osteoclast differentiation and function. Environmental factors are also important in the pathogenesis of PDB, as reflected by the fact that in many countries the disease has become less common and less severe over recent years. The most widely studied environmental trigger is paramyxovirus infection, but attempts to detect viral transcripts in tissues from patients with PDB have yielded mixed results. Although our understanding of the pathophysiology of PDB has advanced tremendously over the past 10 years, many questions remain unanswered, such as the mechanisms responsible for the focal nature of the disease and the recent changes in prevalence and severity.

Asymptomatic Paget's bone disease in ethnic Thais: a series of four case reports and a review of the literature

Paget's bone disease is quite common in some parts of Europe and countries inhabited by European emigrants, but it is rare in Asia. There have been only 13 reported cases in Southeast Asia, including one reported case from Thailand. Half of the previously reported cases had bone symptoms and the other half were asymptomatic, but were incidentally discovered when patients were being investigated for other medical problems. Here are reported cases of four asymptomatic patients who presented elevation of serum alkaline phosphatase during routine annual medical checkups. All patients were of Chinese descent and all cases were proven by biopsy. Based on this experience, we are of the opinion that a substantial number of unrecognized cases of Paget's disease exist among ethnic Thais. We feel that they would be revealed if clinicians were alerted of its presence and if they included it as a possible diagnosis together with metastasis and osteoporosis when examining bone lesions or when results for elevated serum alkaline phosphatase are detected during routine checkups. We also anticipate that a higher prevalence of this disease may occur in future Thai generations due to the addition of offspring from Asian-European intermarriages to offspring of Chinese descent in the ethnic Thai population.

Paget's disease of the bone after treatment with Denosumab: a case report

Bone affection in Paget's disease is characterized by increased bone turnover localised at one or more sites of the skeleton. Bisphosphonates are the drugs of choice when treating the increased bone turnover in Paget's disease. However, in cases of decreased kidney function only less effective treatments that are available as bisphosphonates are contraindicated in these patients. We present a case of a male patient aged 86 years with GFR of 11 mL/min and Paget's disease successfully treated by Denosumab. The bone turnover and pain decreased upon treatment.

Treatment of Paget's disease of bone

Paget's disease of bone is the paradigm of bone focal distortion with accelerated bone turnover. Over the years, a number of different drugs have been used to control its activity but, since biphosphonates were introduced for the treatment of the disease, they have become the preferred treatment. This review will update the therapeutic indications, available drugs and therapeutic response monitoring.

Paget's disease of bone resembling bone metastasis from gastric cancer

A 74-year-old man had an endoscopic type 0'-IIc tumor in the upper gastric body on the greater curvature and biopsy showed the tumor to be a well-differentiated adenocarcinoma (Group 5). He was referred to us for endoscopic submucosal dissection (ESD). Endoscopy revealed fold convergency, fold swelling, and fusion of the fold, indicating tumor invasion into the submucosa, which was outside the indications for ESD. In addition, there was an increase of serum bone-type alkaline phosphatase (ALP-III and ALP-IV) and urinary cross-linked N-terminal telopeptide of type I collagen (a bone metabolism marker), while (18)F-fluorodeoxyglucose positron emission tomography showed increased uptake in the left pelvis and Th10, suggesting bone metastases. We first diagnosed gastric cancer with bone metastases; however, the symptoms suggested pathological bone fracture and no bone pain. Therefore, a computed tomography-guided aspiration bone biopsy was performed to exclude the possibility of Paget's disease of bone. Biopsy specimens revealed no tumor and a mosaic pattern. No increased uptake of (18)F-FAMT (L-[3-(18)F] α-methyltyrosine) supported a diagnosis of no bone metastases from gastric cancer. We finally diagnosed gastric cancer accompanied by Paget's disease of bone and performed a laparoscopy-assisted proximal gastrectomy. The pathological diagnosis was U less 0-IIb, and U post 0-IIc ypT1a (M) N0H0P0M0 yp stage IA. In gastric cancer patients with suspected bone metastasis, we also need to consider Paget's disease of bone.

Paget disease of the bone: does it exist in Saudi Arabia?

Paget disease of the bone is a chronic disease characterized by accelerated bone turnover with abnormal repair leading to expansion, pain and deformities. The disease is common in the West, but little if any information is available on its existence in the Arab world, including Saudi Arabia. We present four cases of Saudi patients with Paget disease with variable presentations. The first case, a 63-year-old woman with a history of papillary thyroid cancer, presented with bone, shoulder and chest wall pain and foci of uptake in the ribs and skull that were thought to be metastases, indicating the possibility of diagnostic difficulty in a patient with history of malignancy. Bone biopsy confirmed the diagnosis of Paget disease. The second case was a 47-year-old asymptomatic woman with an elevated alkaline phosphatase of 427 U/L, a common presentation but at an unusual age. Plain x-rays and bone scan confirmed the diagnosis. The third case was a 43-year-old man who presented with hearing impairment and right knee osteoarthritis, unusual presentations at a young age leading to a delay in diagnosis. The fourth case was a 45-year-old man who presented with sacroiliac pain and normal biochemical values, including a normal alkaline phosphatase. Bone biopsy unexpectedly revealed features of Paget disease, which evolved over time into a classical form. A common feature in all except the first case was the relatively young age. Paget disease does exist in Saudi Arabia, and it should be considered in the differential diagnosis of similar cases.

Emerging strategies and therapies for treatment of Paget's disease of bone

Paget's disease of bone (PDB) is a progressive monostotic or polyostotic metabolic bone disease characterized by focal abnormal bone remodeling, with increased bone resorption and excessive, disorganized, new bone formation. PDB rarely occurs before middle age, and it is the second most frequent metabolic bone disorder after osteoporosis, affecting up to 3% of adults over 55 years of age. One of the most striking and intriguing clinical features is the focal nature of the disorder, in that once the disease is established within a bone, there is only local spread within that bone and no systemic dissemination. Despite many years of intense research, the etiology of PDB has still to be conclusively determined. Based on a detailed review of genetic and viral factors incriminated in PDB, we propose a unifying hypothesis from which we can suggest emerging strategies and therapies. PDB results in weakened bone strength and abnormal bone architecture, leading to pain, deformity or, depending on the bone involved, fracture in the affected bone. The diagnostic assessment includes serum total alkaline phosphatase, total body bone scintigraphy, skull and enlarged view pelvis x-rays, and if needed, additional x-rays. The ideal therapeutic option would eliminate bone pain, normalize serum total alkaline phosphatase with prolonged remission, heal radiographic osteolytic lesions, restore normal lamellar bone, and prevent recurrence and complications. With the development of increasingly potent bisphosphonates, culminating in the introduction of a single intravenous infusion of zoledronic acid 5 mg, these goals of treatment are close to being achieved, together with long-term remission in almost all patients. Based on the recent pathophysiological findings, emerging strategies and therapies are reviewed: ie, pulse treatment with zoledronic acid; denosumab, a fully human monoclonal antibody directed against RANK ligand; tocilizumab, an interleukin-6 receptor inhibitor; odanacatib, a cathepsin K inhibitor; and proteasome and Dickkopf-1 inhibitors.

Efficacy, tolerability, and safety of risedronate in Japanese patients with Paget's disease of bone

This study evaluated the clinical efficacy of treatment with oral risedronate (17.5 mg once daily) for 8 weeks in 11 Japanese patients with Paget's disease of bone (PDB). Risedronate suppressed the excessive bone turnover associated with PDB and improved several biochemical markers, including serum alkaline phosphatase (ALP), serum bone-specific ALP (BALP), urinary deoxypyridinoline (DPD), and urinary cross-linked N-telopeptide of type 1 collagen (NTX). These markers began to decrease within about 2 weeks after the initiation of treatment in most patients, and the response persisted for up to 40 weeks after the cessation of treatment. Risedronate reduced pain by week 24 in most patients. According to quantitative bone scintigraphy, the lesion with the highest radioisotope (RI) uptake showed a decrease of uptake from 12.7 +/- 6.8 to 6.0 +/- 2.3 (mean +/- SD) in week 24, although each lesion of patients with polyostotic disease had a different scintigraphic response. Overall, risedronate at a dose of 17.5 mg once daily was well tolerated by patients with PDB, even though the dosage was seven times higher than that approved for the treatment of osteoporosis in Japan (2.5 mg once daily). In conclusion, treatment with high-dose risedronate for 8 weeks resulted in clinically significant and sustained improvement of biochemical markers of bone turnover for 48 weeks in patients with PDB, and this improvement was associated with a decrease of RI uptake by Paget's bone lesions and with reduced pain.

Five-year follow-up of Japanese patients with Paget's disease of the bone after treatment with low-dose oral alendronate: a case series

INTRODUCTION

Paget's disease of the bone is characterized by focal abnormalities of increased bone turnover affecting one or more sites throughout the skeleton. Although this disease is rare in Japan, it is common in western and southern Europe, and among British migrants in Australia and New Zealand. Bisphosphonates have been widely used for the treatment of Paget's disease of the bone and are considered to be the treatment of choice. However, there have been few reports on the long-term follow-up examination of patients after their treatment with bisphosphonates.

CASE PRESENTATION

We report the treatment with a low dose of oral alendronate (5 mg per day) which was effective in reducing bone turnover and pain over the five-year follow-up period in two Japanese patients, a 66-year-old man and a 68-year-old woman, with Paget's disease of the bone. Furthermore, in one patient, no clinical symptoms, such as bone pain or increases in serum total alkaline phosphatase and urinary N-terminal telopeptide of type I collagen as markers of bone turnover, were observed over the patient's five-year follow-up period.

CONCLUSIONS

To the best of our knowledge, this is the first report of a long-term follow-up of patients with Paget's disease of the bone after a six-month treatment with low-dose oral alendronate (5 mg per day).

Functional bracing for delayed union of a femur fracture associated with Paget's disease of the bone in an Asian patient: a case report

Paget's disease of the bone is a common metabolic bone disease in most European countries, Australia, New Zealand, and North America. Conversely, this disease is rare in Scandinavia, Asia, and Africa. In Japan, it is extremely rare, with a prevalence of 0.15/100000. Paget's disease is a localized disorder of bone remodeling. Excessive bone resorption and abnormal bone formation result in biomechanically weakened bone and predispose patients to fracture. Delayed union and non-union of fractures have been reported in patients with Paget's disease. Therefore, open reduction and internal fixation of fractures has been recommended to prevent such complications. Here we report an unusual case of a 63-year-old Asian woman with delayed union of a femur fracture secondary to Paget's disease, which was treated successfully by functional bracing.

Serum homocysteine, folate and vitamin B12 in patients with Paget's disease of bone: the effect of zoledronic acid

High serum homocysteine (HCY) and indirectly deficiency of folate and/or vitamin B(12) stimulate bone resorption and adversely affect collagen cross-linking. The aim of this study was the evaluation of serum levels of HCY, folate and vitamin B(12) in patients with Paget's disease of bone (PDB) and the effect of zoledronic acid (ZOL) on their serum levels. Nine consecutive patients with polyostotic PDB (median age 66 years) received a single 5-mg ZOL infusion. Blood samples for HCY, folate, vitamin B(12), 25-hydroxyvitamin D (25-OH-D), total serum alkaline phosphatase (TSAP), bone-specific serum alkaline phosphatase (BSAP) and C-terminal cross-linking telopeptide of type I collagen (CTX) were obtained at baseline and 3, 6 and 12 months after ZOL infusion. Twelve age-, gender- and BMI-matched healthy individuals were recruited for the control group at baseline assessment. Patients with PDB had significantly higher serum HCY (p = 0.028), folate (p < 0.001) and bone markers [TSAP (p < 0.001), BSAP (p < 0.001) and CTX (p < 0.001)] compared with the control group at baseline. In the pagetic group, serum HCY significantly decreased 3 months after ZOL infusion and remained essentially unchanged up to the end of the study (p = 0.005). Serum vitamin B(12) and folate remained unaffected throughout the study. Our data suggest that serum HCY levels are increased in patients with PDB. A single ZOL infusion results in a decrease in HCY levels that might represent another mechanism for the reduction of the activity of PDB achieved by ZOL.

Pathogenesis of Paget's disease of bone

Paget's disease of bone is a common condition characterised by increased and disorganised bone turnover which can affect one or several bones throughout the skeleton. These abnormalities disrupt normal bone architecture and lead to various complications such as bone pain osteoarthritis, pathological fracture, bone deformity, deafness, and nerve compression syndromes. Genetic factors play an important role in PDB and mutations or polymorphisms have been identified in four genes that cause classical Paget's disease and related syndromes. These include TNFRSF11A, which encodes RANK, TNFRSF11B which encodes osteoprotegerin, VCP which encodes p97, and SQSTM1 which encodes p62. All of these genes play a role in the RANK-NFkappaB signalling pathway and it is likely that the mutations predispose to PDB by disrupting normal signalling, leading to osteoclast activation. Although Paget's has traditionally be considered a disease of the osteoclast there is evidence that stromal cell function and osteoblast function are also abnormal, which might account for the fact that the disease is associated with increased bone formation as well as resorption. Environmental factors also contribute to Paget's disease. Most research has focused on paramyxovirus infection as a possible environmental trigger but evidence in favour of the involvement of viruses in the disease remains conflicting. Other factors which have been implicated as possible disease triggers include mechanical loading, dietary calcium and environmental toxins. Further work will be required to identify additional genetic variants that predispose to Paget's disease and to determine how the causal mutations and predisposing polymorphisms interact with environmental factors to influence bone cell function and cause the focal bone lesions that are characteristic of the disease.

Pathogenesis and management of Paget's disease of bone

Paget's disease of bone is a common disease characterised by focal areas of increased bone turnover, affecting one or several bones throughout the skeleton. Paget's disease is often asymptomatic but can be associated with bone pain and other complications such as osteoarthritis, pathological fracture, bone deformity, deafness, and nerve compression syndromes. Genetic factors have an important role in this disease, and mutations have been identified in four genes that cause Paget's disease and related syndromes. The most important of these is Sequestosome 1 (SQSTM1), which is a scaffold protein in the nuclear factor kappaB (NFkappaB) signalling pathway. Patients with SQSTM1 mutations have severe Paget's disease of bone and a high degree of penetrance with increasing age. Environmental factors also contribute. Most research has focused on paramyxovirus infection as a possible trigger, but evidence for this notion is conflicting. Other potential triggers include deficiency of dietary calcium and repetitive mechanical loading of the skeleton. Medical management of Paget's disease of bone is based on giving inhibitors of osteoclastic bone resorption, and bisphosphonates are the treatment of first choice. Bisphosphonate therapy is primarily indicated for patients who have bone pain arising from increased metabolic activity in affected bones. Bisphosphonate therapy is highly effective at reducing bone turnover, and it has been shown to heal radiological lesions and restore normal histology; however, the long-term effects of bisphosphonates on disease progression have not been adequately studied. No firm evidence as yet exists to show that bisphosphonates can prevent the development of complications of Paget's disease of bone, and further work is needed to address the effects of treatment on long-term clinical outcome.

Scintigraphic, biochemical, and clinical response to zoledronic acid treatment in patients with Paget's disease of bone

Bisphosphonates have long been used with success in the treatment of Paget's disease of bone (PDB). The aim of this study was to evaluate the early (up to 3 months) and late (at 12 months) scintigraphic, biochemical, and clinical response to a single intravenous infusion of zoledronic acid (ZOL) in patients with PDB serially assessed for 1 year. Nine patients with 30 bone lesions caused by PDB were prospectively evaluated. Total serum alkaline phosphatase (SAP) was serially measured. Scintigraphy was performed before and at 3 and 12 months after ZOL administration, and bone lesions were assessed quantitatively. After treatment, pain was alleviated in five of six patients starting from the first month. At 3 months, a significant decrease of SAP levels compared to baseline values was found (322 +/- 211 IU/l before vs. 101 +/- 36 IU/l 3 months after; P < 0.05), with normal values attained in all except one patient. The scintigraphic index of involvement (SII), a marker for the per-patient activity of the disease, was reduced from 14.4 +/- 7.6 to 7.2 +/- 1.8 (P = 0.01). The scintigraphic ratio (SR), a marker for the per-lesion activity of the disease, was reduced from 12.8 +/- 7.7 to 7.0 +/- 2.9 (P < 0.001). The values of markers of disease activity remained unchanged up to 12 months. A single intravenous administration of ZOL leads to a favorable clinical, biochemical, and scintigraphic response in patients with PDB starting as early as 3 months after treatment and lasting no less than 12 months (i.e., considerably longer than the other existing therapies).