Risedronate, a highly effective oral agent in the treatment of patients with severe Paget's disease

Epidemiology of Paget's disease of bone in South Korea

Paget's disease of bone (PDB) is a chronic disorder characterized by abnormal bone remodeling, leading to enlarged and deformed bones, and commonly affecting older adults. The disease frequently involves the pelvis, skull, spine, and long bones. Despite significant geographical variations in PDB prevalence, data from Asian populations remain sparse. This study evaluates the incidence, skeletal distribution, comorbidities, and bisphosphonate use for PDB in South Korea from 2010 to 2020, using a retrospective analysis of the Korean Health Insurance Review and Assessment database. We identified 4252 patients diagnosed with PDB via ICD-10 codes (M880, M888, and M889) over the study period. The primary outcome measured was the incidence of PDB, stratified by sex and age, with secondary outcomes including anatomical site involvement, associated comorbidities, and bisphosphonate use. The mean age of patients was 56.3 ± 14.8 yr, with a mean prevalence of 1.20 per 100 000 and an age-adjusted incidence ranging from 0.38 to 1.26 per 100 000 person-years. The incidence of PDB decreased in men but showed a significant increase in women, especially after 2015. The spine (23.5%) and pelvis & femur (17.0%) were the most commonly affected sites. Gastritis and gastroesophageal reflux disease (91.6%), upper respiratory infections (78.9%), and endocrine disorders (69.5%) were frequent comorbidities. Despite the established efficacy of bisphosphonates in managing PDB, only 9.8% of patients received these treatments, predominantly etidronate (3.2%) and alendronate (2.2%). This study is the first comprehensive epidemiologic assessment of PDB in South Korea, highlighting a low but increasing incidence, particularly among women. The findings underscore the need for greater clinical awareness and more proactive management strategies, especially regarding the use of bisphosphonates to improve patient outcomes.

Paget's Disease of Bone: A Review of Epidemiology, Pathophysiology and Management

Paget's disease of bone is a common disorder which may affect one or many bones. Although many patients are asymptomatic, a variety of symptoms and complications may occur. Fortunately, effective pharmacologic therapy, primarily with potent bisphosphonates, is now available to treat patients with complications or symptoms. This review of Paget's disease of bone will include epidemiology and pathophysiology, complications and clinical findings, indications for treatment, and the drugs currently available to treat this condition.

New mouse models for metabolic bone diseases generated by genome-wide ENU mutagenesis

Metabolic bone disorders arise as primary diseases or may be secondary due to a multitude of organ malfunctions. Animal models are required to understand the molecular mechanisms responsible for the imbalances of bone metabolism in disturbed bone mineralization diseases. Here we present the isolation of mutant mouse models for metabolic bone diseases by phenotyping blood parameters that target bone turnover within the large-scale genome-wide Munich ENU Mutagenesis Project. A screening panel of three clinical parameters, also commonly used as biochemical markers in patients with metabolic bone diseases, was chosen. Total alkaline phosphatase activity and total calcium and inorganic phosphate levels in plasma samples of F1 offspring produced from ENU-mutagenized C3HeB/FeJ male mice were measured. Screening of 9,540 mice led to the identification of 257 phenodeviants of which 190 were tested by genetic confirmation crosses. Seventy-one new dominant mutant lines showing alterations of at least one of the biochemical parameters of interest were confirmed. Fifteen mutations among three genes (Phex, Casr, and Alpl) have been identified by positional-candidate gene approaches and one mutation of the Asgr1 gene, which was identified by next-generation sequencing. All new mutant mouse lines are offered as a resource for the scientific community.

Radiological features of Paget disease of bone associated with VCP myopathy

OBJECTIVE

Mutations in the Valosin-containing protein (VCP) gene cause a unique disorder characterized by classic Paget disease of bone (PDB), inclusion body myopathy, and frontotemporal dementia (IBMPFD). Our objective was to analyze the radiographic features of PDB associated with VCP mutations since there is a dearth of literature on the PDB component of VCP disease.

MATERIALS AND METHODS

Radiographic bone surveys were examined in 23 individuals with VCP mutation and compared with their unaffected relatives. Laboratory testing relevant for VCP disease was performed in all individuals.

RESULTS

Of the 17 affected individuals with clinical manifestations of VCP disease, 16 of whom had myopathy, radiographic analysis revealed classic PDB in 11 individuals (65%). The mean age of diagnosis for myopathy was 43.8 years and for PDB was 38.1 years of age. Radiological evidence of PDB was seen in one individual (16%) amongst six clinically asymptomatic VCP mutation carriers. Alkaline phosphatase was a useful marker for diagnosing PDB in VCP disease.

CONCLUSIONS

Radiographic findings of classic PDB are seen in 52% of individuals carrying VCP mutations at a significantly younger age than conventional PDB. Screening for PDB is warranted in at-risk individuals because of the benefit of early treatment with the new powerful bisphosphonates that hold the potential for prevention of disease.

Effect of renal function on risedronate pharmacokinetics after a single oral dose

AIMS

To determine the relationship between risedronate pharmacokinetics and renal function.

METHODS

Risedronate was administered to adult men and women (n=21) with various degrees of renal function (creatinine clearance 15-126 ml min-1 ) as a single oral dose of 30 mg. Serum samples were obtained for 72 h after dosing, and urine samples were collected for 72 h after dosing and then periodically for 6 weeks. Risedronate concentrations were determined using an enzyme-linked immunosorbent assay (ELISA). Risedronate serum concentration-time and urinary excretion rate-time profiles were analysed simultaneously using nonlinear regression.

RESULTS

Renal clearance and volume of distribution were linearly related to creatinine clearance (r2=0.854, P<0.001; and r2=0.317, P<0.01, respectively). Decreases in predicted renal clearance and volume of distribution of 82 and 69%, respectively, were observed when creatinine clearance decreased from 120 to 20 ml min-1. A 64% decrease in predicted oral clearance was observed when creatinine clearance decreased from 120 to 20 ml min-1 (P=0.064). Iohexol clearance, a predictor of renal function, produced similar results to those observed with creatinine clearance. Risedronate was well tolerated by the study population.

CONCLUSIONS

Risedronate renal clearance was significantly related to a decrease in renal function. There was a consistent reduction in oral clearance with a decrease in creatinine clearance. However, based on the regression analysis, generally no dosage adjustment appears to be necessary for most patients with mild or moderate renal impairment (creatinine clearance >20 ml min-1 ).

The effect of dosing regimen on the pharmacokinetics of risedronate

AIMS

To examine the effect of timing of a risedronate dose relative to food intake on the rate and extent of risedronate absorption following single-dose, oral administration to healthy male and female volunteers.

METHODS

A single-dose, randomized, parallel study design was conducted with volunteers assigned to four treatment groups (31 or 32 subjects per group, 127 subjects total). Each subject was orally administered 30 mg risedronate. Group 1 was fasted for 10 h prior to and 4 h after dosing (fasted group); Groups 2 and 3 were fasted for 10 h and were dosed 1 and 0.5 h, respectively, before a high-fat breakfast; and Group 4 was dosed 2 h after a standard dinner. Blood and urine samples were collected for 168 h after dosing. Pharmacokinetic parameters were estimated by simultaneous analysis of risedronate serum concentration and urinary excretion rate-time data.

RESULTS

Extent of risedronate absorption (AUC and Ae ) was comparable (P=0.4) in subjects dosed 2 h after dinner and 0.5 h before breakfast; however, a significantly greater extent of absorption occurred when risedronate was given 1 or 4 h prior to a meal (1.4- to 2.3-fold greater). Administration 0.5, 1, or 4 h prior to a meal resulted in a significantly greater rate of absorption (Cmax 2.8-, 3.5-, and 4.1-fold greater, respectively) when compared with 2 h after dinner.

CONCLUSIONS

The comparable extent of risedronate absorption when administered either 0.5-1 h before breakfast or 2 h after an evening meal support previous clinical studies where risedronate was found to have similar effectiveness using these dosing regimens. This flexibility in the timing of risedronate administration may provide patients an alternative means to achieve the desired efficacy while maintaining their normal daily routine.