[Fabry disease in Spain: first analysis of the response to enzyme replacement therapy]

Enzyme replacement therapy for Anderson-Fabry disease: A complementary overview of a Cochrane publication through a linear regression and a pooled analysis of proportions from cohort studies

BACKGROUND

Anderson-Fabry disease (AFD) is an X-linked recessive inborn error of glycosphingolipid metabolism caused by a deficiency of alpha-galactosidase A. Renal failure, heart and cerebrovascular involvement reduce survival. A Cochrane review provided little evidence on the use of enzyme replacement therapy (ERT). We now complement this review through a linear regression and a pooled analysis of proportions from cohort studies.

OBJECTIVES

To evaluate the efficacy and safety of ERT for AFD.

MATERIALS AND METHODS

For the systematic review, a literature search was performed, from inception to March 2016, using Medline, EMBASE and LILACS. Inclusion criteria were cohort studies, patients with AFD on ERT or natural history, and at least one patient-important outcome (all-cause mortality, renal, cardiovascular or cerebrovascular events, and adverse events) reported. The pooled proportion and the confidence interval (CI) are shown for each outcome. Simple linear regressions for composite endpoints were performed.

RESULTS

77 cohort studies involving 15,305 participants proved eligible. The pooled proportions were as follows: a) for renal complications, agalsidase alfa 15.3% [95% CI 0.048, 0.303; I2 = 77.2%, p = 0.0005]; agalsidase beta 6% [95% CI 0.04, 0.07; I2 = not applicable]; and untreated patients 21.4% [95% CI 0.1522, 0.2835; I2 = 89.6%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; b) for cardiovascular complications, agalsidase alfa 28% [95% CI 0.07, 0.55; I2 = 96.7%, p<0.0001]; agalsidase beta 7% [95% CI 0.05, 0.08; I2 = not applicable]; and untreated patients 26.2% [95% CI 0.149, 0.394; I2 = 98.8%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; and c) for cerebrovascular complications, agalsidase alfa 11.1% [95% CI 0.058, 0.179; I2 = 70.5%, p = 0.0024]; agalsidase beta 3.5% [95% CI 0.024, 0.046; I2 = 0%, p = 0.4209]; and untreated patients 18.3% [95% CI 0.129, 0.245; I2 = 95% p < 0.0001]. Effect differences favored agalsidase beta over agalsidase alfa or untreated patients. A linear regression showed that Fabry patients receiving agalsidase alfa are more likely to have higher rates of composite endpoints compared to those receiving agalsidase beta.

CONCLUSIONS

Agalsidase beta is associated to a significantly lower incidence of renal, cardiovascular and cerebrovascular events than no ERT, and to a significantly lower incidence of cerebrovascular events than agalsidase alfa. In view of these results, the use of agalsidase beta for preventing major organ complications related to AFD can be recommended.

[Comparison of patients from a Spanish Registry of Fabry disease in two periods]

BACKGROUND AND OBJECTIVE

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by a deficiency of the enzyme alpha-galactosidase A, that leads to multiorgan dysfunction and premature death. Data from the first 24 Spanish patients enrolled on the Fabry Outcome Survey (FOS) were published in 2004, with a significant increase in the number of patients since then. This manuscript analyzes whether the clinical profile or diagnosis of these patients between the 2 periods has changed.

PATIENTS AND METHODS

In 2009 the FOS included data from 92 patients. Patients included up to 2003 and those included after that year (68) were compared by sex, regarding age at onset of symptoms and diagnosis, severity and previous misdiagnoses. Similar analysis was performed between the index cases (31) and the other patients.

RESULTS

Mean delay in diagnosis was 10 years for both sexes. Male had a classic phenotype, and up to 40% of the females reported symptoms. In females, the enzyme activity seemed to determine disease severity. No differences were observed in any parameter when comparing the patients included in the first period to those included afterwards, nor when comparing index cases with the rest of the patients.

CONCLUSIONS

Registries like FOS have a great value to deepen our understanding of rare diseases. We confirm that women are not just carriers of the disease. There is still a lack of education and awareness in order to include FD in the differential diagnosis of other processes. Complete family studies would allow early diagnosis of this disorder.

[Role of cardiac magnetic resonance in cardiac involvement of Fabry disease]

BACKGROUND AND OBJECTIVES

Fabry disease is a hereditary disorder. Clinical manifestations are multisystemic. The majority of the patients remain undiagnosed until late in life, when alterations could be irreversible. Early detection of cardiac symptoms is of major interest in Fabry's disease (FD) in order to gain access to enzyme replacement therapy. Echo-Doppler tissular imaging (TDI) has been used as a cardiologic early marker in FD.

OBJECTIVES

This study is intended to determine whether the cardiac magnetic resonance is as useful tool as TDI for the early detection of cardiac affectation in FD.

PATIENTS AND METHODS

Echocardiography, tissue Doppler and Cardio magnetic resonance was performed in 20 patients with confirmed Fabry Disease. Left ventricular hypertrophy was defined as septum and left ventricular posterior wall thickness ≥12 mm. An abnormal TDI velocity was defined as (Sa), (Ea) and/or (Aa) velocities <8 cm/s at either the septal or lateral corner. Late phase gadolinium-enhanced images sequences were obtained using magnetic resonance.

RESULTS

Twenty patients included in the study were divided into three groups: 1. Those without left ventricular hypertrophy nor tissue Doppler impairment 2. Those without left ventricular hypertrophy and tissue Doppler impairment 3. Those with left ventricular hypertrophy and Tissue Doppler impairment. Late gadolinium enhancement was found in only one patient, who has already altered DTI and LVH.

CONCLUSION

Tissue Doppler imaging (TDI) is the only diagnostic tool able to provide early detection of cardiac affectation in patients with FD. Magnetic resonance provides information of the disease severity in patients with LVH, but can not be used as an early marker of cardiac disease in patients with FD. However MRI could be of great value for diagnostic stratification.

[Utility of enzyme replacement therapy in Fabry disease]

BACKGROUND AND OBJECTIVE

The lysosomal deposit of sphingolipids secondary to alpha-galactosidase-A deficiency causes Fabry disease. The deposit in the endothelial cells of the vasa nervorum and the small caliber axons, among other structures, results in the characteristic painful neuropathy. It is our objective to present the findings of the neuropathy evaluation before and after 18 months of agalsidase beta enzyme replacement therapy.

MATERIALS AND METHOD

A neurological exam, a neurophysiological study measuring sensory and motor conduction velocities and amplitudes and a quantitative sensory testing were performed on 5 patients with confirmed Fabry disease; quantification on pain measurement scales was also done.

RESULTS

Prior to treatment, no anomalies were found in the conduction velocities or the compound muscular action potential amplitudes; the quantitative sensory test was abnormal in all patients. After treatment, improvement was seen in the pain scales and the quantitative sensory test.

CONCLUSIONS

Enzyme replacement therapy with agalsidase beta demonstrated subjective and objective benefits related to the painful neuropathy of Fabry disease.