Standardising clinical outcomes measures for adult clinical trials in Fabry disease: A global Delphi consensus

Fabry Disease Nephropathy: Histological Changes With Nonclassical Mutations and Genetic Variants of Unknown Significance

RATIONALE & OBJECTIVE

Fabry disease (FD) is an X-linked genetic disorder that causes lysosomal storage of glycosphingolipids, primarily globotriaosylceramide (Gb3) and its derivative globotriaosylsphingosine (lyso-Gb3), with multiorgan dysfunction including chronic kidney disease. Affected individuals may be carriers of gene variants that are of uncertain significance (GVUS). We describe kidney pathology at the early stages of FD-related kidney disease to gain insights into its association with GVUS and sex.

STUDY DESIGN

Single-center, case series.

SETTING & PARTICIPANTS

Thirty-five consecutively biopsied patients (aged 48.1±15.4 years, 22 females) from among 64 patients with genetically diagnosed FD. Biopsies were retrospectively screened using the International Study Group of Fabry Nephropathy Scoring System.

OBSERVATIONS

Genetic mutation type, p.N215S and D313Y, sex, age, estimated glomerular filtration rate (eGFR), plasma lyso-Gb3 (pLyso-Gb3) levels, and histological parameters, including Gb3 deposits were recorded. Genetic analyses showed mostly missense mutations, p.N215S variant in 15, and the "benign polymorphism" D313Y in 4 of the biopsied patients. Morphological lesions were similar for men and women except for interstitial fibrosis and arteriolar hyalinosis being more common in men. Early in their clinical course, patients with normal/mild albuminuria had podocyte, tubular, and peritubular capillary vacuoles/inclusions, and evidence of chronicity, i.e., glomerulosclerosis, interstitial fibrosis, tubular atrophy. These findings appeared to be associated with pLyso-Gb3, eGFR, and age.

LIMITATIONS

Retrospective design and inclusion of outpatients partially based on family pedigree.

CONCLUSIONS

In early stages of kidney disease in the setting of FD, numerous histological abnormalities are present. These observations suggest that kidney biopsies early in FD may reveal activity of kidney involvement that may inform clinical management.

Long-term multisystemic efficacy of migalastat on Fabry-associated clinical events, including renal, cardiac and cerebrovascular outcomes

BACKGROUND

Fabry disease is a rare, multisystemic disorder caused by GLA gene variants that lead to alpha galactosidase A deficiency, resulting in accumulation of glycosphingolipids and cellular dysfunction. Fabry-associated clinical events (FACEs) cause significant morbidity and mortality, yet the long-term effect of Fabry therapies on FACE incidence remains unclear.

METHODS

This posthoc analysis evaluated incidence of FACEs (as a composite outcome and separately for renal, cardiac and cerebrovascular events) in 97 enzyme replacement therapy (ERT)-naïve and ERT-experienced adults with Fabry disease and amenable GLA variants who were treated with migalastat for up to 8.6 years (median: 5 years) in Phase III clinical trials of migalastat. Associations between baseline characteristics and incidence of FACEs were also evaluated.

RESULTS

During long-term migalastat treatment, 17 patients (17.5%) experienced 22 FACEs and there were no deaths. The incidence rate of FACEs was 48.3 events per 1000 patient-years overall. Numerically higher incidence rates were observed in men versus women, patients aged >40 years versus younger patients, ERT-naïve versus ERT-experienced patients and men with the classic phenotype versus men and women with all other phenotypes. There was no statistically significant difference in time to first FACE when analysed by patient sex, phenotype, prior treatment status or age. Lower baseline estimated glomerular filtration rate (eGFR) was associated with an increased risk of FACEs across patient populations.

CONCLUSIONS

The overall incidence of FACEs for patients during long-term treatment with migalastat compared favourably with historic reports involving ERT. Lower baseline eGFR was a significant predictor of FACEs.

Epidemiology of Fabry disease in patients in hemodialysis in the Madrid community

This study screened for Fabry disease (FD) in patients in hemodialysis (HD) in the region of Madrid (CAM) with a cross-sectional design to evaluate HD-prevalent patients, followed by a three-year period prospective design to analyze HD-incident patients.

INCLUSION CRITERIA

patients older than 18 years on HD in the CAM, excluding patients diagnosed with any other hereditary disease with renal involvement different from FD, that sign the Informed Consent (IC).

EXCLUSION CRITERIA

underaged patients or not agreeing or not being capable of signing the IC.

RESULTS

3470 patients were included, 63% males and with an average age of 67.9±9.7 years. 2357 were HD-prevalent patients and 1113 HD-incident patients. For HD-prevalent patients, average time in HD was 45.2 months (SD 51.3), in HD-incident patients proteinuria was present in 28.4%. There were no statistical differences in plasmatic alpha-galactosidase A (α-GAL-A) activity or Lyso-GL-3 values when comparing HD-prevalent and HD-incident populations and neither between males and females. A genetic study was performed in 87 patients (2.5% of patients): 60 male patients with decreased enzymatic activity and 27 female patients either with a decreased GLA activity, increased Lyso-Gl3 levels or both. The genetic variants identified were: p.Asp313Tyr (4 patients), p.Arg220Gln (3 patients) and M290I (1 patient). None of the identified variants is pathogenic.

CONCLUSIONS

76% of HD Centers of the CAM participated in the study. This is the first publication to describe the prevalence of FD in the HD-population of a region of Spain as well as its average α-GAL-A-activity and plasmatic Lyso-Gl3 levels. It is also the first study that combines a cross-sectional design with a prospective follow-up design. This study has not identified any FD patient.

COVID-19 in Fabry disease: a reference center prospective study

Background

During the coronavirus disease-19 (COVID-19) pandemic, vulnerable populations must be identified to prevent increased mortality. Fabry disease (FD) is a rare X-linked lysosomal storage disorder leading to chronic kidney disease (CKD), cardiomyopathy, pneumonopathy and premature strokes. Little is known whether SARS-CoV-2 infection bears a particular risk for FD patients.

Methods

During pandemic (02.2020–03.2021) we have regularly followed 104 unvaccinated FD patients. In 61/104, titre of serum antibodies against SARS-CoV-2 were measured and SARS-CoV-2 PCR test was performed in symptomatic patients or in case of positivity of other family members. The symptoms and duration of COVID-19 were reported by the patients or the treating physician.

Results

No deaths or intensive care unit hospitalizations occurred. 13/104 (12.5%) were diagnosed with SARS-CoV-2 infection (16.7% (4/24) men 12.2% (6/49) women of classic phenotype, 25% (3/12) of the men and 0% (0/8) of the women of later- onset phenotype). Of those, 2/13 (15.4%) patients—both kidney transplant recipients—developed severe COVID-19, were hospitalized, and required a high-flow oxygen mask. The rest either developed mild COVID-19 manifestations (8/13, 61.5%) or were asymptomatic (3/13, 23.1%). 2/13 (15.4%) of the patients experienced Fabry pain crisis and 3/13 (23.1%) long COVID-19 like symptoms.

Conclusions

Similar to the general population, in FD patients the risk for severe COVID-19 seems to be driven by the immune system rather than by FD itself. Immunosuppression in kidney transplant recipients represented the highest risk in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02386-7.

Fabry Disease in Slovakia: How the Situation Has Changed over 20 Years of Treatment

Fabry disease (FD, OMIM#301500) is a rare inborn error of the lysosomal enzyme α-galactosidase (α-Gal A, EC 3.2.1.22) and results in progressive substrate accumulation in tissues with a wide range of clinical presentations. Despite the X-linked inheritance, heterozygous females may also be affected. Hemizygous males are usually affected more severely, with an earlier manifestation of the symptoms. Rising awareness among health care professionals and more accessible diagnostics have positioned FD among the most-common inherited metabolic diseases in adults. An early and correct diagnosis of FD is crucial with a focus on personalised therapy. Preventing irreversible destruction of vital organs is the main goal of modern medicine. The aim of this study was to offer a complex report mapping the situation surrounding FD patients in Slovakia. A total of 48 patients (21 males, 27 females) with FD are registered in the Centre for Inborn Errors of Metabolism in Bratislava, Slovakia. In our cohort, we have identified three novel pathogenic variants in five patients. Three patients presented with the frameshift mutation c.736delA, and two others presented with the missense mutations c.203T>C, c.157A>C. Moreover, we present a new clinical picture of the pathogenic variant c.801+1G>A, which was previously described and associated with the renal phenotype.

Long-term follow-up of renal function in patients treated with migalastat for Fabry disease

The effect of migalastat on long-term renal outcomes in enzyme replacement therapy (ERT)-naive and ERT-experienced patients with Fabry disease is not well defined. An integrated posthoc analysis of the phase 3 clinical trials and open-label extension studies was conducted to evaluate long-term changes in renal function in patients with Fabry disease and amenable GLA variants who were treated with migalastat for ≥2 years during these studies. The analysis included ERT-naive (n = 36 [23 females]; mean age 45 years; mean baseline estimated glomerular filtration rate (eGFR), 91.4 mL/min/mL/1.73 m²) and ERT-experienced (n = 42 [24 females]; mean age, 50 years; mean baseline eGFR, 89.2 mL/min/1.73m²) patients with amenable variants who received migalastat 123 mg every other day for ≥2 years. The annualized rate of change from baseline to last observation in estimated glomerular filtration rate using the Chronic Kidney Disease Epidemiology Collaboration equation (eGFR_CKD-EPI) was calculated by both simple linear regression and a random coefficient model. In ERT-naive patients, mean annualized rates of change from baseline in eGFR_CKD-EPI were - 1.6 mL/min/1.73 m² overall and - 1.8 mL/min/1.73 m² and - 1.4 mL/min/1.73 m² in male and female patients, respectively, as estimated by simple linear regression. In ERT-experienced patients, mean annualized rates of change from baseline in eGFR_CKD-EPI were - 1.6 mL/min/1.73 m² overall and - 2.6 mL/min/1.73 m² and - 0.8 mL/min/1.73 m² in male and female patients, respectively. Mean annualized rate of change in eGFR_CKD-EPI in ERT-naive patients with the classic phenotype (defined by white blood cell alpha galactosidase A [α-Gal A] activity of <3% of normal and multiorgan system involvement) was -1.7 mL/min/1.73 m². When calculated using the random coefficient model, which adjusted for sex, age, and baseline renal function, the annualized eGFR_CKD-EPI change was minimal (mean: -0.1 and 0.1 mL/min/1.73 m² in ERT-naive and ERT-experienced patients, respectively). In conclusion, patients with Fabry disease and amenable GLA variants receiving long-term migalastat treatment (≤8.6 years) maintained renal function irrespective of treatment status, sex, or phenotype.