88 research outputs found
Genetische Ursachen und Therapie der Osteogenesis imperfecta
No full textZusammenfassung Die Osteogenesis imperfecta (OI) ist die häufigste angeborene Erkrankung, die zu einer erhöhten Fragilität des Skelettsystems führt. Die Variabilität des Phänotyps kann nicht vollständig durch die ursächlichen genetischen Veränderungen erklärt werden. Die meisten Formen werden durch Mutationen in Genen verursacht, die die Kollagen-Synthese/-Prozessierung verändern, wobei die meisten Patientinnen und Patienten von Mutationen in den Genen COL1A1/A2 betroffen sind. Das bessere Verständnis der Pathophysiologie bei seltenen rezessiven Formen der Erkrankung hat bereits in zwei Fällen zu neuen therapeutischen Ansätzen geführt. Bei OI Typ VI, verursacht durch Mutationen in SERPINF1, kommt es zu einer Überaktivierung von Osteoklasten über den OPG/RANKL-pathway. Hier konnte gezeigt werden, dass eine Behandlung mit dem Osteoklasten-Antikörper Denosumab effektiver ist als eine antiresorptive Therapie mit Bisphosphonaten. Bei Patientinnen und Patienten, bei denen die ursächliche Mutation im Gen WNT1 liegt, bietet sich eine osteoanabole Behandlung mit Antisklerostin-Antikörpern an. Neben der medikamentösen Therapie sind die Bereiche der Rehabilitation und Orthopädie unverzichtbare Bestandteile einer interdisziplinären Behandlung
Therapie der Hypophosphatasie
No full textZusammenfassung Die Hypophosphatasie (HPP) als Folge einer genetisch bedingt defizienten Aktivität der gewebeunspezifischen alkalischen Phosphatase (TNAP) ist geprägt durch ein ausgesprochen weites Spektrum möglicher Manifestationen, sowohl hinsichtlich der Art der Symptomatik als auch bzgl. des Schweregrades der assoziierten Einschränkungen. Eine adäquate Behandlung erfordert insofern immer auch eine multimodale Herangehensweise unter spezieller Berücksichtigung der individuellen Ausprägung der Erkrankung. Für Patienten, bei denen die Erkrankung im Kindesalter aufgetreten ist, steht in Europa zur Behandlung der Knochenmanifestation mit Asfotase alfa (Strensiq) eine Enzymersatztherapie zur Verfügung. Sowohl in den Zulassungsstudien als auch in der klinischen Anwendung zeigen sich bei schwer betroffenen Kindern prinzipiell sehr erfreuliche radiologische und funktionelle Verbesserungen und ein verbessertes Gesamtüberleben. Auch bei Erwachsenen mit zulassungsentsprechender Krankheitsausprägung zeigen erste Ergebnisse eine deutliche Verbesserung der krankheitsassoziierten Einschränkungen und funktionelle Verbesserungen. Inzwischen gibt es auch ermutigende Daten zur Sicherheit und Wirksamkeit von Asfotase alfa über mehrere Behandlungsjahre. Während die oftmals als stark belastend empfundenen entzündlichen Schmerzen häufig gut auf eine intermittierende, bedarfsangepasste Behandlung mit NSAR ansprechen, sind im Hinblick auf die muskuloskelettale Gesamtgesundheit nachhaltige, langfristig ausgerichtete supportive Maßnahmen mit spezifischen Trainingskonzepten und einer alters- und bedarfsgerechten orthopädietechnischen Versorgung zu empfehlen. Das Potenzial diätetischer Maßnahmen zur Beeinflussung des Phosphat- und Vitamin-B6-Stoffwechsels bedarf sicher noch weiterer Untersuchungen. Bezüglich spezifisch knochenwirksamer Strategien sind primär antiresorptive Substanzen nach aktueller Datenlage kritisch zu betrachten, wohingegen osteoanabole Konzepte grundsätzlich möglich erscheinen. Sinnvollerweise sollte die Gesamtheit aller therapeutischen Maßnahmen an einem Zentrum mit entsprechender Erfahrung koordiniert und überblickt werden, wobei ein Großteil der konkreten Maßnahmen im aktiven Austausch auch heimatnah umgesetzt werden kann
Supplement: Impaired Physical Performance in X-linked Hypophosphatemia is not caused by depleted muscular phosphate stores
No full textSupplemental Data to "Impaired Physical Performance in X-linked Hypophosphatemia is not caused by depleted muscular phosphate stores
Genetic Diagnostics in Routine Osteological Assessment of Adult Low Bone Mass Disorders
No full textAbstract Context Many different inherited and acquired conditions can result in premature bone fragility / low bone mass disorders (LBMD). Objective We aimed at elucidating the impact of genetic testing on differential diagnosis of adult LBMD and at defining clinical criteria for predicting monogenic forms. Methods Four clinical centers broadly recruited a cohort of 394 unrelated adult women before menopause and men younger than 55 years with a bone mineral density (BMD) Z-score <-2.0, and/or pathological fractures. After exclusion of secondary causes or unequivocal clinical/biochemical hallmarks of monogenic LBMD all participants were genotyped by targeted next-generation sequencing Results In total 20.8% of the participants carried rare disease-causing variants (DCV) in genes known to cause osteogenesis imperfecta (COL1A1, COL1A2), hypophosphatasia (ALPL), and early-onset osteoporosis (LRP5, PLS3, and WNT1). In addition, we identified rare DCV in ENPP1, LMNA, NOTCH2, and ZNF469. Three individuals had autosomal recessive, 75 autosomal dominant, and four X-linked disorders. 9.7% of the participants harbored variants of unknown significance. A regression analysis revealed that the likelihood of detecting a DCV correlated with a positive family history of osteoporosis, peripheral fractures (>2), and a high normal BMI. In contrast, mutation frequencies did not correlate with age, prevalent vertebral fractures, BMD, or biochemical parameters. In individuals without monogenic disease-causing rare variants, common variants predisposing for low BMD, e.g. in LRP5, were overrepresented. Conclusion The overlapping spectra of monogenic adult LBMD can be easily disentangled by genetic testing and the proposed clinical criteria can help to maximize the diagnostic yield
A randomised Phase 3 study comparing the efficacy and safety of proposed denosumab biosimilar RGB-14-P and reference denosumab in women with postmenopausal osteoporosis
No full textUnlabelled: • In women with postmenopausal osteoporosis, proposed denosumab biosimilar RGB-14-P demonstrated equivalent efficacy and pharmacodynamics, and similar immunogenicity and safety to reference denosumab. • RGB-14-P comprehensively replicates the therapeutic benefit of denosumab in a clinical setting. • Denosumab biosimilars, such as RGB-14, have potential to provide lower-cost alternatives to denosumab with comparable efficacy and safety. Purpose: To demonstrate the equivalence of the proposed denosumab biosimilar RGB-14-P and the reference denosumab (hereafter denosumab) in women with postmenopausal osteoporosis. Methods: In this multicentre, double-blind, Phase 3 study (EudraCT 2020-006017-38; NCT05087030), participants were randomised 1:1 to subcutaneous RGB-14-P or denosumab 60 mg every 6 months, on Day 1 and Week 26, with follow-up to Week 52. Primary endpoints were percentage change from baseline (ÏB) in lumbar spine bone mineral density (BMD) at Week 52 and area under the effective curve (AUEC) of ÏB serum C-terminal telopeptide of type 1 collagen (CTX) to Week 26. Secondary endpoints included ÏB in total hip and femoral neck BMD, vertebral and non-vertebral fragility fractures, immunogenicity, and safety to Week 52. Results: Overall, 473 participants were randomised and received study drug (RGB-14-P, n = 242; denosumab, n = 231). Both primary endpoints demonstrated equivalence of RGB-14-P and denosumab. Adjusted mean (95% CI) ÏB in lumbar spine BMD at Week 52 was 4.89 (3.55, 6.24) for RGB-14-P and 4.55 (3.22, 5.87) for denosumab (estimated difference, 0.34; 95% CI, - 0.40, 1.09). Geometric mean ratio in AUEC of ÏB in CTX concentration was 1.01 (95% CI, 0.98, 1.05; P = 0.494). There were no statistical differences in ÏB in total hip and femoral neck BMD. Incidence of vertebral or non-vertebral fragility fractures was comparable between treatments. Anti-drug antibody incidence was < 1% in both arms. Safety was comparable between groups. Conclusion: In women with postmenopausal osteoporosis, RGB-14-P demonstrated equivalent efficacy and pharmacodynamics, and similar immunogenicity and safety to denosumab
Journal of Bone and Mineral Research / Novel therapeutic options for hypophosphatasia
No full textCommentary to: Amadeu, de Oliveira F Kazuko Tokuhara C, Mohamed FF, et al. Preclinical evaluation of the efficacy and safety of AAV8-TNAP-D10 in Alpl-/- and AlplPrx1/Prx1 mouse models for the treatment of early and late-onset hypophosphatasia . J Bone Miner Res. 2025; zjaf005. 10.1093/jbmr/zjaf005.Accepted versio
Bone mineral density and fracture risk in adult patients with hypophosphatasia
No full textSummary
In adult hypophosphatasia (HPP) patients, elevated lumbar spine dual X-ray absorptiometry (DXA) values are associated with markers of disease severity and disease-specific fracture risk while femoral bone mineral density (BMD), being largely unaffected by the disease severity, may still be useful to monitor other causes of increased fracture risk due to low BMD.
Introduction
Hypophosphatasia (HPP) is a rare inherited metabolic disorder due to deficient activity of the tissue-nonspecific alkaline phosphatase (TNAP). Clinical manifestation in adult HPP patients is manifold including an increased risk for fractures, but data regarding clinical significance of DXA measurement and associations with fracture risk and disease severity is scarce.
Methods
Retrospective single-center analysis of DXA scans in patients with confirmed HPP (documented mutation, clinical symptoms, low alkaline phosphatase activity). Further data evaluation included disease-related fractures, laboratory results (alkaline phosphatase, pyridoxalphosphate, phosphoethanolamine), and medical history.
Results
Analysis included 110 patients (84 female, mean age of 46.2 years) of whom 37.3% (n = 41) were harboring two mutations. Average T-Score level at the lumbar spine was − 0.1 (SD 1.9), and mean total hip T-Score was − 1.07 (SD 0.15). Both lower ALP activity and higher substrate levels (pyridoxalphosphate and phosphoethanolamine) were significantly correlated with increased lumbar spine T-Score levels (p < 0.001) while BMD at the hip was not affected by indicators of disease severity. Increased lumbar spine BMD was significantly associated with an increased risk for HPP-related fractures, prevalent in 22 (20%) patients (p < 0.001) with 21 of them having biallelic mutations.
Conclusion
BMD in adult HPP patients is not systematically reduced. Conversely, increased lumbar spine BMD appears to be associated with severely compromised mineralization and increased risk for HPP-related fractures while BMD at the hip appears unaffected by indicators of disease severity, suggesting suitability of this anatomic location for assessing and discerning disorders with increased fracture risk owing to reduced BMD like osteoporosis.
Trial registration number
German register for clinical studies (DRKS00014022)
Date of registration
02/10/2018 – retrospectively registere
Bone turnover and mineral metabolism in adult patients with hypophosphatasia treated with asfotase alfa
No full textSummary
There is limited understanding of how asfotase alfa affects mineral metabolism and bone turnover in adults with pediatric-onset hypophosphatasia. This study showed that adults with hypophosphatasia treated with asfotase alfa experienced significant changes in biochemical markers of bone and mineral metabolism, possibly reflecting enhanced bone remodeling of previously osteomalacic bone.
Introduction
Hypophosphatasia (HPP), due to a tissue nonspecific alkaline phosphatase (TNSALP) deficiency, can cause impaired bone mineralization and turnover. Although HPP may be treated with asfotase alfa, an enzyme replacement therapy, limited data are available on how treatment with asfotase alfa affects mineral metabolism and bone turnover in adults with HPP.
Methods
ALP substrates, bone turnover and mineral metabolism markers, and bone mineral density (BMD) data from EmPATHY, a single-center, observational study of adults (≥ 18 years) with pediatric-onset HPP treated with asfotase alfa (NCT03418389), were collected during routine clinical care and analyzed from baseline through 24 months of treatment.
Results
Data from 21 patients showed significantly increased ALP activity and reduced urine phosphoethanolamine (PEA)/creatinine (Cr) ratios after baseline through 24 months of asfotase alfa treatment. There were significant transient increases in parathyroid hormone 1-84 (PTH), osteocalcin, and procollagen type 1 N-propeptide (P1NP) levels at 3 and 6 months and in tartrate-resistant acid phosphatase 5b (TRAP5b) levels at 3 months, with a significant decrease in N-terminal telopeptide of type 1 collagen (NTX) levels at 24 months. Lumbar spine BMD T scores continuously increased during treatment.
Conclusion
Significant changes in bone turnover and mineral metabolism markers after asfotase alfa treatment suggest that treatment-mediated mineralization may enable remodeling and bone turnover on previously unmineralized surfaces. Urine PEA/Cr ratios may be a useful parameter in monitoring treatment during routine care
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