The Effect of Fabry Disease Therapy on Bone Mineral Density.

Fabry disease (FD) is an X-linked lysosomal storage disorder, characterised by the cellular accumulation of globotriaosylceramide due to impaired alpha-galactosidase A enzyme activity. FD may manifest with multisystem pathology, including reduced bone mineral density (BMD). Registry data suggest that the introduction of Fabry-specific therapies (enzyme replacement therapy or chaperone therapy) has led to significant improvements in overall patient outcomes; however, there are limited data on the impact on bone density. The aim of this study was to describe the effect of Fabry-specific therapies on longitudinal changes in bone mineral density (BMD) in FD. We performed a retrospective observational study analysing bone densitometry (DXA) in patients with genetically confirmed FD. Patients were grouped based on the use of Fabry-specific therapies. The between-group longitudinal change in BMD Z-score was analysed using linear mixed effects models. A total of 88 FD patients were analysed (50 untreated; 38 treated). The mean age at first DXA was 38.5 years in the untreated group (84% female) and 43.7 years in the treated group (34% female). There was no significant longitudinal between-group difference in the BMD Z-score at the lumbar spine. However, the Z-score per year at the total hip (ß = -0.105, p < 0.001) and femoral neck (ß = -0.081, p = 0.001) was significantly lower over time in the treated than the untreated group. This may reflect those receiving therapy having a more severe underlying disease. Nevertheless, this suggests that Fabry-specific therapies do not reverse all disease mechanisms and that the additional management of BMD may be required in this patient population.

Fabry-specific treatment in Australia: time to align eligibility criteria with international best practices.

BACKGROUND: Disease-specific therapy aims to improve symptoms, stabilise current disease and delay progression in patients with Fabry disease. In Australia, treatment access is subject to eligibility criteria initially established in 2004. Patients and their clinicians question why these criteria have remained unchanged despite significant progress in disease understanding. AIMS: Appraise the clinical quality of the Australian treatment access criteria. METHODS: The Fabry Australia Medical Advisory Committee (N = 6) used the Appraisal of Guidelines for REsearch and Evaluation Global Rating Scale (AGREE II GRS) to assess the clinical quality of the current treatment eligibility criteria. They reviewed the literature, developed 17 clinical statements to help guide reforms of the eligibility criteria and achieved consensus (achievement of ≥75% agreement in the range 5-7 on a 7-point Likert scale) through anonymous voting. The findings were applied to develop proposals for revised classification and treatment initiation criteria. RESULTS: The current treatment eligibility criteria underperformed on the AGREE II GRS. They are pragmatic but out-of-step with contemporary data. Consensus was achieved on all 17 proposed clinical statements. There was strong agreement to differentiate classical male Fabry patients to facilitate timelier access to Fabry-specific treatment. There was also agreement on the value of adopting relevant organ involvement criteria in classical female patients and patients with non-classical disease. CONCLUSIONS: Australian access criteria are misaligned with current clinical evidence. The clinical statements and proposed classification and initiation criteria should prompt discussions to support more equitable access to treatment and better align Australian practice with contemporary evidence and international guidelines.

A 15-Year Perspective of the Fabry Outcome Survey

Abstract The Fabry Outcome Survey (FOS) is an international long-term observational registry sponsored by Shire for patients diagnosed with Fabry disease who are receiving or are candidates for therapy with agalsidase alfa (agalα). Established in 2001, FOS provides long-term data on agalα safety/efficacy and collects data on the natural history of Fabry disease, with the aim of improving clinical management. The FOS publications have helped establish prognostic and severity scores, defined the incidence of specific disease variants and implications for clinical management, described clinical manifestations in special populations, confirmed the high prevalence of cardiac morbidity, and demonstrated correlations between ocular changes and Fabry disease severity. These FOS data represent a rich resource with utility not only for description of natural history/therapeutic effects but also for exploratory hypothesis testing and generation of tools for diagnosis/management, with the potential to improve future patient outcomes.