Long‐term effects of migalastat therapy in clinical practice are currently unknown. We evaluated migalastat efficacy and biomarker changes in a prospective, single‐center study on 14 patients with Fabry disease (55 ± 14 years; 11 men). After 1 year of open‐label migalastat therapy, patients showed significant changes in alpha‐galactosidase‐A activity (0.06–0.2 nmol/minute/mg protein; P = 0.001), left ventricular myocardial mass index (137–130 g/m 2 ; P = 0.037), and serum creatinine (0.94–1.0 mg/ dL ; P = 0.021), accounting for deterioration in estimated glomerular filtration rate (87–78 mL/minute/1.73 m 2 ; P = 0.012). The enzymatic increase correlated with myocardial mass reduction ( r = −0.546; P = 0.044) but not with renal function ( r = −0.086; P = 0.770). Plasma globotriaosylsphingosine was reduced in therapy‐naive patients (10.9–6.0 ng/mL; P = 0.021) and stable (9.6–12.1 ng/mL; P = 0.607) in patients switched from prior enzyme‐replacement therapy. These first real‐world data show that migalastat substantially increases alpha‐galactosidase‐A activity, stabilizes related serum biomarkers, and improves cardiac integrity in male and female patients with amenable Fabry disease mutations.

Fabry's disease (FD) is an X‐linked lysosomal storage disorder caused by the deficient activity of the lysosomal enzyme α‐galactosidase A (α‐Gal A) leading to intracellular accumulation of globotriaosylceramide (Gb3). Patients with amenable mutations can be treated with migalastat, a recently approved oral pharmacologic chaperone to increase endogenous α‐Gal A activity. We assessed safety along with cardiovascular, renal, and patient‐reported outcomes and disease biomarkers in a prospective observational multicenter study after 12 months of migalastat treatment under “real‐world” conditions. Fifty‐nine (28 females) patients (34 (57.6%) pretreated with enzyme replacement therapy) with amenable mutations were recruited. Migalastat was generally safe and well tolerated. Females and males presented with a reduction of left ventricular mass index (primary end point) (−7.2 and −13.7 g/m2, P = 0.0050 and P = 0.0061). FD‐specific manifestations and symptoms remained stable (all P > 0.05). Both sexes presented with a reduction of estimated glomerular filtration rate (secondary end point) (−6.9 and −5.0 mL/minute/1.73 m2; P = 0.0020 and P = 0.0004, respectively), which was most prominent in patients with low blood pressure (P = 0.0271). α‐Gal A activity increased in male patients by 15% from 29% to 44% of the normal wild‐type activity (P = 0.0106) and plasma lyso‐Gb3 levels were stable in females and males (P = 0.3490 and P = 0.2009). Reevaluation of mutations with poor biochemical response revealed no marked activity increase in a zero activity background. We conclude that therapy with migalastat was generally safe and resulted in an amelioration of left ventricular mass. In terms of impaired renal function, blood pressure control seems to be an unattended important goal.

α-Galactosidase A genotype N215S does not lead to the development of a classical Fabry phenotype but induces a specific cardiac variant of Fabry disease mimicking nonobstructive hypertrophic cardiomyopathy. The lack of prominent noncardiac impairment leads to a significant delay in diagnosis and Fabry-specific therapy.