Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Filtros adicionais











Intervalo de ano
1.
Calcif Tissue Int ; 2018 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-30343436

RESUMO

The phase 3 teriparatide Fracture Prevention Trial showed significant reductions in vertebral (VF) and nonvertebral (NVF) fractures; however, patient exposure was insufficient for full analysis of low-incidence fractures, including hip. We assessed fracture results in pooled data from four prospective, observational teriparatide studies. Ambulatory women and men with osteoporosis received subcutaneous teriparatide 20 µg/day for up to 24 months per routine clinical practice. Fracture rates were compared between 6-month periods, using 0 to 6 months of treatment as the reference period. Analyses used a piecewise exponential model for first fracture. Hip, NVF, clinical VF (CVF), any clinical, and wrist fractures were assessed. For 8828 patients analyzed, mean age was 71 years; mean (SD) treatment duration was 17.4 (8.6) months. The rate of hip fracture decreased significantly for the > 12 to 18-month (- 47.7%) and > 18-month periods (-85.2%) versus the first 6 months of therapy, and for the > 18 versus the > 6 to 12-month period. NVF, CVF, and all clinical fractures were all significantly decreased in each post-reference period, with maximum decreases (> 18-month period) of 52.7%, 69.4%, and 61.2%, respectively, versus 0 to 6 months. No significant reduction was seen for rates of wrist fracture. Teriparatide treatment was associated with statistically significant decreases in hip fracture rate, particularly for > 18 months of treatment, and in NVF, CVF, and all clinical fracture rate in real-world patients. These results should be interpreted in the context of the non-controlled design of the source studies.

2.
Bone ; 116: 58-66, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30021126

RESUMO

INTRODUCTION: Teriparatide significantly reduces fracture rates in clinical trials; however, those study populations were relatively restricted and included too few patients to analyze fracture outcomes within clinically important patient subgroups. We assessed fracture outcomes in subgroups of osteoporosis patients from 4 real-world teriparatide observational studies. METHODS: Patients received teriparatide 20 µg/day for up to 24 months. Fracture rates were compared between 0 to 6 months versus >6 months using a piecewise exponential model for first fracture. Analyses included incident clinical vertebral fractures (CVF) and nonvertebral fractures (NVF), and clinical fractures (CVF and NVF) by subgroups of gender, age <75 or ≥75 years, diabetes, prior bisphosphonates use, rheumatoid arthritis (RA), glucocorticoid use, prior hip, and prior vertebral fracture. RESULTS: The population included 8828 patients (8117 women, 92%) with mean (SD) age 71 (10.6) years and teriparatide treatment duration 17.4 (8.6) months. Overall, CVF, NVF, clinical fracture, and hip fracture rates decreased by 62%, 43%, 50%, and 56%, respectively (all p < .005) for >6 months versus 0 to 6 months. Subgroup analyses all showed significantly decreased rates after >6 months except for NVF reduction in males (n = 710, fracture rate low during months 0 to 6) and in patients using glucocorticoids, and CVF in patients with prior hip fracture. The effects of teriparatide on CVF, NVF, and clinical fractures over time were statistically consistent in all subgroups except age for CVF (p = .074, patients <75 years of age responded better), and diabetes for clinical fractures (p = .046, patients with diabetes responded better), although all of these subgroups experienced significant reductions over time. Glucocorticoids, prior bisphosphonate, and prior vertebral fracture were associated with increased CVF, NVF, and clinical fracture rates; RA, prior hip fracture and female gender were associated with higher NVF and clinical fracture rates; increased age was associated with higher CVF and clinical fracture rates. CONCLUSIONS: Data from 4 real-world observational studies showed statistically significant reductions during teriparatide treatment in rates of CVF, NVF, and clinical fractures in clinically relevant patient subgroups. These results should be interpreted in the context of the non-controlled design of the source studies.

3.
J Bone Miner Res ; 33(4): 627-633, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29194749

RESUMO

Previously, we reported on bone histomorphometry, biochemical markers, and bone mineral density distribution after 6 and 24 months of treatment with teriparatide (TPTD) or zoledronic acid (ZOL) in the SHOTZ study. The study included a 12-month primary study period, with treatment (TPTD 20 µg/d by subcutaneous injection or ZOL 5 mg/yr by intravenous infusion) randomized and double-blind until the month 6 biopsy (TPTD, n = 28; ZOL, n = 30 evaluable), then open-label, with an optional 12-month extension receiving the original treatment. A second biopsy (TPTD, n = 10; ZOL, n = 9) was collected from the contralateral side at month 24. Here we present data on remodeling-based bone formation (RBF), modeling-based bone formation (MBF), and overflow modeling-based bone formation (oMBF, modeling overflow adjacent to RBF sites) in the cancellous, endocortical, and periosteal envelopes. RBF was significantly greater after TPTD versus ZOL in all envelopes at 6 and 24 months, except the periosteal envelope at 24 months. MBF was significantly greater with TPTD in all envelopes at 6 months but not at 24 months. oMBF was significantly greater at 6 months in the cancellous and endocortical envelopes with TPTD, with no significant differences at 24 months. At 6 months, total bone formation surface was also significantly greater in each envelope with TPTD treatment (all p < 0.001). For within-group comparisons from 6 to 24 months, no statistically significant changes were observed in RBF, MBF, or oMBF in any envelope for either the TPTD or ZOL treatment groups. Overall, TPTD treatment was associated with greater bone formation than ZOL. Taken together the data support the view that ZOL is a traditional antiremodeling agent, wheareas TPTD is a proremodeling anabolic agent that increases bone formation, especially that associated with bone remodeling, including related overflow modeling, with substantial modeling-based bone formation early in the course of treatment. © 2017 American Society for Bone and Mineral Research.

4.
J Bone Miner Res ; 33(2): 298-306, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29024120

RESUMO

There has been renewed interest of late in the role of modeling-based formation (MBF) during osteoporosis therapy. Here we describe early effects of an established anabolic (teriparatide) versus antiresorptive (denosumab) agent on remodeling-based formation (RBF), MBF, and overflow MBF (oMBF) in human transiliac bone biopsies. Postmenopausal women with osteoporosis received subcutaneous teriparatide (n = 33, 20 µg/d) or denosumab (n = 36, 60 mg once/6 months), open-label for 6 months at 7 US and Canadian sites. Subjects received double fluorochrome labeling at baseline and before biopsy at 3 months. Sites of bone formation were designated as MBF if the underlying cement line was smooth, RBF if scalloped, and oMBF if formed over smooth cement lines adjacent to scalloped reversal lines. At baseline, mean RBF/bone surface (BS), MBF/BS, and oMBF/BS were similar between the teriparatide and denosumab groups in each bone envelope assessed (cancellous, endocortical, periosteal). All types of formation significantly increased from baseline in the cancellous and endocortical envelopes (differences p < 0.001) with teriparatide (range of changes 2.9- to 21.9-fold), as did MBF in the periosteum (p < 0.001). In contrast, all types of formation were decreased or not significantly changed with denosumab, except MBF/BS in the cancellous envelope, which increased 2.5-fold (difference p = 0.048). These data highlight mechanistic differences between these agents: all 3 types of bone formation increased significantly with teriparatide, whereas formation was predominantly decreased or not significantly changed with denosumab, except for a slight increase in MBF/BS in the cancellous envelope. © 2017 American Society for Bone and Mineral Research.

5.
Biochemistry ; 47(25): 6662-70, 2008 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-18507398

RESUMO

Enfuvirtide (ENF), the first human immunodeficiency virus type 1 (HIV-1) fusion inhibitor approved for clinical use, acts by binding to gp41 heptad repeat 1 (HR1) and preventing its interaction with the viral HR2 region. Treatment-emergent resistance to ENF has been mapped to residues within HR1, and these mutations decrease its susceptibility to ENF and may reduce viral fitness and pathogenesis, although the mechanism for these effects is not clear. N43D, a common ENF resistance mutation, was found in in vitro assays to cause a 5-50-fold in antiviral activity. We introduced this mutation into peptide models and determined the impact of this mutation by circular dichroism and X-ray crystallography. We find that the mutation results in a decrease in the thermal stability of the six-helix bundle and causes a significant change in the HR1-HR2 interface, including a loss of HR2 helicity. These data form a mechanistic basis for the decrease in ENF sensitivity and six-helix bundle stability. The E137K polymorphism, generally present at baseline in patients who develop N43D, partially compensates for the loss of stability, and we show that these residues likely form an ion pair. These data form a framework for understanding the impact of resistance mutations on viral fitness and pathogenesis and provide a pathway for the development of novel fusion inhibitor peptides.


Assuntos
Farmacorresistência Viral/genética , Proteína gp41 do Envelope de HIV/farmacologia , HIV-1/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Sítios de Ligação , Dicroísmo Circular , Cristalografia por Raios X , Enfuvirtida , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/genética , Inibidores da Fusão de HIV/farmacologia , HIV-1/genética , Humanos , Ligações de Hidrogênio , Concentração Inibidora 50 , Modelos Moleculares , Mutação , Polimorfismo Genético , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína
6.
AIDS ; 21(18): 2537-9, 2007 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-18025893

RESUMO

Analysis of CD4 cell responses during 48 weeks of enfuvirtide therapy after virological failure (analysis of covariance) demonstrated significant associations between V38 mutations (n = 58 subjects) and continued CD4 cell increases and between Q40 mutations (n = 8) and loss of CD4 cell benefit (+34 versus -95 cells/mul, P < 0.001). Subjects with N43 (n = 20) or other mutations (n = 48) had intermediate CD4 cell responses. These data suggest that key enfuvirtide resistance mutations may be associated with reduced viral pathogenicity in vivo.


Assuntos
Farmacorresistência Viral/genética , Proteína gp41 do Envelope de HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1/genética , Mutação , Fragmentos de Peptídeos/uso terapêutico , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/imunologia , Enfuvirtida , Inibidores da Fusão de HIV/uso terapêutico , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , Humanos , Estudos Retrospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA