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

BACKGROUND

Recent years have witnessed a considerable increase in clinical trials of new investigational agents for Fabry disease (FD). Several trials investigating different agents are currently in progress; however, lack of standardisation results in challenges to interpretation and comparison. To facilitate the standardisation of investigational programs, we have developed a common framework for future clinical trials in FD.

METHODS AND FINDINGS

A broad consensus regarding clinical outcomes and ways to measure them was obtained via the Delphi methodology. 35 FD clinical experts from 4 continents, representing 3389 FD patients, participated in 3 rounds of Delphi procedure. The aim was to reach a consensus regarding clinical trial design, best treatment comparator, clinical outcomes, measurement of those clinical outcomes and inclusion and exclusion criteria. Consensus results of this initiative included: the selection of the adaptative clinical trial as the ideal study design and agalsidase beta as ideal comparator treatment due to its longstanding use in FD. Renal and cardiac outcomes, such as glomerular filtration rate, proteinuria and left ventricular mass index, were prioritised, whereas neurological outcomes including cerebrovascular and white matter lesions were dismissed as a primary or secondary outcome measure. Besides, there was a consensus regarding the importance of patient-related outcomes such as general quality of life, pain, and gastrointestinal symptoms. Also, unity about lysoGb3 and Gb3 tissue deposits as useful surrogate markers of the disease was obtained. The group recognised that cardiac T1 mapping still has potential but requires further development before its widespread introduction in clinical trials. Finally, patients with end-stage renal disease or renal transplant should be excluded unless a particular group for them is created inside the clinical trial.

CONCLUSION

This consensus will help to shape the future of clinical trials in FD. We note that the FDA has, coincidentally, recently published draft guidelines on clinical trials in FD and welcome this contribution.

Fabry disease in Spain: description of Spanish patients and a comparison with other European countries using data from the Fabry Outcome Survey (FOS)

AIMS

Fabry disease (FD) is an X-chromosome-linked transmitted lysosomal storage disorder as a result of the deficient activity of enzyme α-galactosidase A. This leads to accumulation of neutral glycosphingolipids associated with organ involvement and premature death. We report the clinical characteristics of Spanish patients enrolled on the Fabry Outcome Survey (FOS; an international multicentre registry for the disease) and also compare these data with those from the rest of Europe.

METHODS

Baseline clinical data of 92 patients (41 males and 51 females) are described and analysed globally and according to gender. We compare the data of Spanish patients with those previously published from the rest of Europe patients in FOS.

RESULTS

Mean age of onset of symptoms in men was 20, and 24 years in women, with a mean delay of 11 years to the diagnosis in both genders. The predominant clinical involvement in male patients was renal (69%), cardiac (66%) and neurological (60%), and for female patients, it was neurological (42%), cardiac (33%), keratopathy (30%) and nephropathy (28%). Disease severity was significantly higher in male patients. Compared to the rest of European FOS-patients, Spanish patients were diagnosed at an earlier age with a smaller proportion of disease-related involvement for most organ irrespective of gender, though not its global severity in male patients.

CONCLUSIONS

We present the largest cohort of Spanish patients diagnosed with FD. The pattern of involvement (though not its global severity) could be different in Spanish patients in comparison with others from Europe. Expanding the knowledge of FD will permit early diagnosis as well as the possibility of starting the specific treatment.

First experience of enzyme replacement therapy with idursulfase in Spanish patients with Hunter syndrome under 5 years of age: case observations from the Hunter Outcome Survey (HOS)

Hunter syndrome (mucopolysaccharidosis type II [MPS II], OMIM309900) is a rare X-linked lysosomal storage disorder caused by deficiency of the enzyme iduronate-2-sulphatase, resulting in accumulation of glycosaminoglycans (GAGs), multisystem organ failure and early death. Enzyme replacement therapy (ERT) with idursulfase is commercially available since 2007. Early access programs were established since 2005. However, limited information on the effects of ERT in young children is available to date. The aim of this analysis was therefore to determine the effects of ERT on patients younger than 5 years of age. We report data from six Spanish patients with confirmed Hunter syndrome who were younger than 5 years at the start of ERT, and had been treated with weekly intravenous infusions of idursulfase between 6 and 14 months. Baseline and treatment data were obtained from the Hunter Outcome Survey (HOS). HOS is an international database of MPS II patients on ERT or candidates to be treated, that collects data in a registry manner. HOS is supported by Shire Human Genetic Therapies, Inc. (Cambridge, MA, USA). At baseline, all patients showed neurological abnormalities, including ventriculomegaly, hydrocephaly, cerebral atrophy, perivascular changes and white matter lesions. Other signs and symptoms included thoracic deformity, otitis media, joint stiffness and hepatosplenomegaly, demonstrating that children under 5 years old can also be severely affected. ERT reduced urinary GAG levels, and reduced spleen (n = 2) and liver size (n = 1) after only 8 months. Height growth was maintained within the normal range during ERT. Joint mobility either stabilized or improved during ERT. In conclusion, this case series confirms the early onset of signs and symptoms of Hunter syndrome and provides the first evidence of ERT beneficial effects in patients less than 5 years of age. Similar efficacy and safety profiles to those seen in older children can be suggested, although further studies including a direct comparison with older patients would still be required.

Severe cardiac phenotype of Berardinelli-Seip congenital lipodystrophy in an infant with homozygous E189X BSCL2 mutation

Berardinelli-Seip congenital lipodystrophy (BSCL) is a rare autosomal recessive condition associating insulin resistance, absence of subcutaneous fat and muscular hypertrophy. Disease-causing mutations have been described in AGPAT2 and BSCL2 genes. Hypertrophic cardiomyopathy is a classical late (third decade) complication which has only been occasionally described in childhood. We report on a 4-month-old Chinese male infant who presented with a severe BSCL "cardiac" phenotype comprising heart failure, hypertension and hypertrophic cardiomyopathy.

Fabry disease and the skin: data from FOS, the Fabry outcome survey

BACKGROUND

Fabry disease (also known as Anderson-Fabry disease) is a rare, X-linked lysosomal storage disorder that is characterized by accumulation of globotriaosylceramide throughout a range of tissues in the body.

OBJECTIVES

To ascertain the prevalence and nature of cutaneous manifestations in patients with Fabry disease and to relate these to the severity of systemic manifestations of the disease.

METHODS

We have documented the dermatological features of this disease with reference to data from 714 patients (345 males, 369 females) registered on the Fabry Outcome Survey (FOS), a multicentre European database.

RESULTS

We confirm that the commonest disease manifestation is angiokeratoma. Overall, 78% of males and 50% of females had one or more dermatological abnormality, the commonest being angiokeratoma (66% males, 36% females), hypohidrosis (53% males, 28% females), telangiectasia (23% males, 9% females) and lymphoedema (16% males, 6% females). We demonstrate for the first time that the presence of cutaneous vascular lesions correlates with the severity of the systemic manifestations of the disease (pain, renal failure, cardiac disease, premature cerebrovascular disease) as assessed by a severity scoring system. Although the condition is X linked, there is a surprisingly high prevalence of abnormalities in females.

CONCLUSIONS

The FOS database is a useful epidemiological tool in establishing the variety and relevance of cutaneous manifestations in Fabry disease. The present study confirms that the presence of dermatological manifestations appears to be a marker of greater severity of systemic disease, which emphasizes the importance of the dermatological assessment of these patients.

Enzyme replacement therapy with agalsidase alfa in children with Fabry disease

AIM

To assess the effects of enzyme replacement therapy (ERT) in children with Fabry disease.

METHODS

Safety and efficacy of ERT with agalsidase alfa, 0.2 mg/kg infused over 40 minutes every 2 weeks for 23 weeks, were studied in a multicentre open-label trial in nine boys and four girls. Median age at the start of the study was 11.0 years (range 3.5-18 years).

RESULTS

Fifty-four adverse events were reported in 11 patients. No serious adverse events related to ERT were reported. Twelve of the 54 adverse events were considered possibly or probably related to ERT. Infusion reactions (8 mild, 3 moderate) occurred in four boys, in seven infusions. One boy developed IgG antibodies, although he continued to make good clinical progress. At the end of the study, two of the four boys and the one girl on regular pain medication at baseline had stopped taking analgesics. Brief Pain Inventory (BPI) scores decreased in most patients by week 12 and were sustained until the end of the study. This change was greater in the boys, who had higher (worse) BPI scores at baseline. Pain-related quality of life (QoL) scores also decreased during the study. Plasma globotriaosylceramide concentrations and urinary globotriaosylceramide:sphingomyelin ratios decreased after 12 and 23 weeks of therapy, particularly in the boys. Increases in sweat volume were recorded in three out of five of the boys and in one of two girls tested after 23 weeks of treatment.

CONCLUSION

ERT with agalsidase alfa in children with Fabry disease is well tolerated and, in the short term, appears to decrease pain and to improve pain-related QoL.

[Diagnostic strategy for mitochondrial diseases]

OBJECTIVE

The variability of both phenotypic and genotypic expression in mitochondrial diseases makes clinical diagnosis difficult, which is essential to establish therapy, aid in genetic counselling or for performing prenatal diagnosis. We have therefore proposed a strategy to help determine correct diagnosis of these alterations, in an attempt to rationalize the number of tests and, whenever possible, avoid tissue biopsy and minimize the size of the biopsy when indicated.

DEVELOPMENT

Based on mitochondrial metabolism and molecular bases, as well as their alterations, a preliminary metabolic examination is carried out including at least one study of cytoplasmatic (lactate/pyruvate) and mitochondrial oxide reduction (hydroxibutirate/acetoacetate) in basal conditions or, if required, following glucose overload or an effort test. Metabolic study, in addition to clinical exploration, are the screening tests used to determine the need for tissue biopsy in which biochemical (pyruvate dehydrogenase, free and total carnitine, beta oxidation enzymes and respiratory chain complexes), genetic (mitochondrial DNA or nuclear alterations) and histologic tests are carried out to confirm diagnosis.

CONCLUSIONS

a) Metabolic exploration may discard mitochondrial disease and many cases, avoid the use of an invasive procedure such as tissue biopsy. b) Biochemical study of tissue biopsy is the only useful key in the confirming of the diagnosis when no mitochondrial and/or nuclear DNA are observed.

Altered leukotriene generation in leukocytes from cystinotic children

Upon in vitro stimulation with 10 microM ionophore A 23187 for 5 min at 37 degrees C, the generation of leukotriene (LT) C4 in polymorphonuclear leukocytes (PMNL) from nine untreated cystinotic children was significantly increased compared with that in eight control children (p < 0.01) and 25 normal adults (p < 0.001) (417.4 +/- 70.0 versus 177.0 +/- 30.9 and 164.9 +/- 19.5 pmol/l x 10(7) cells, respectively). Concomitantly with the increased generation of LTC4, LTB4 production in PMNL from untreated cystinotic children was decreased compared with controls, whereas the total amount of LTA4 derivatives was similar in the three groups. The increase in LTC4 production was not related to the number of eosinophils present in the PMNL preparations from cystinotic children, which was similar to that of control subjects. PMNL from cystinotic children treated with cysteamine, an aminothiol compound that decreases the intracellular cystine content, generated smaller amounts of LTC4 upon ionophore A 23187 stimulation than PMNL from untreated cystinotic children. In addition, abrogation of the cysteamine treatment for 3 or 4 d led to an increase in LTC4 production. These findings suggest that the metabolic abnormalities taking place in infantile cystinosis may favor the biosynthesis of LTC4 from PMNL.

Anti-neutrophil cytoplasmic auto-antibodies-associated vasculitis with pulmonary and renal involvement

We present a 13-year-old boy with a rapidly progressive glomerulonephritis and pulmonary haemorrhage with perinuclear anti-neutrophil cytoplasmic auto-antibodies (pANCA) corresponding to anti-myeloperoxidase antibodies. The diagnosis of microscopic polyarteritis was made on the basis of the clinical features, the positivity of pANCA, and the histological finding of a pauci-immune crescentic glomerulonephritis. He responded excellently to corticosteroids and cyclophosphamide therapy and complete clinical remission persists 1 year after withdrawal of treatment. We emphasize the usefulness of ANCA antibody assays to establish a prompt diagnosis and adequate treatment in systemic vasculitis in children.

Trichorhinophalangeal syndrome, type I, with avascular necrosis of the femoral head

We report the case of a seven-year-old girl with peculiar facial traits who presented for right coxalgia of six weeks' duration. The phenotypic findings corresponded to a trichorhinophalangeal syndrome, type I, and the clinical, radiological and gammagraphic characteristics were indicative of avascular necrosis of the right femoral head, Legg-Perthes-Calvé disease.

Increased monocyte-dependent suppression of polyclonal activation of B lymphocytes from cystinotic children

In infantile cystinosis the amino acid cystine preferentially accumulates in phagocytic cells, polymorphonuclear leucocytes (PMN) and monocytes, rather than in lymphocytes. We previously described functional abnormalities in the oxidative metabolism and locomotion of cystinotic PMN and monocytes. The present study shows an abnormal lymphocyte polyclonal activation as evidenced by a decreased immunoglobulin (Ig) production and generation of Ig-containing cells (ICC) in cultures of peripheral blood mononuclear cells (PBMC) from cystinotic children upon stimulation with pokeweed mitogen and Staphylococcus aureus Cowan I. However, monocyte depletion from cystinotic PBMC fully reconstituted Ig production and ICC generation, indicating: (1) the presence of an increased monocyte-dependent suppression on lymphocyte polyclonal activation, and (2) that the intrinsic ability of cystinotic lymphocytes to respond to polyclonal stimulation was preserved. The increased cystinotic monocyte-dependent suppressive effect was not mediated by prostaglandin E2 (PGE2) since its production by cystinotic PBMC upon polyclonal activation was not different from that of controls. In addition, the sensitivity of cystinotic lymphocytes to the immunosuppressive effect of varying concentrations of exogenous PGE2 was similar to that of controls. Finally, indomethacin and 2-mercaptoethanol, two agents able to scavenge hydroxyl (.OH) radicals, restored Ig production by cystinotic PBMC, suggesting a role for reactive oxygen species in the increased cystinotic monocyte-dependent suppression.

Cytochrome c oxidase deficiency in muscle with dicarboxylic aciduria and renal tubular acidosis

A patient with deficient activity of cytochrome c oxidase in muscle presented at 1 year of age with extreme failure to thrive. He was found to have dicarboxylic aciduria, renal tubular acidosis, and deficiency of carnitine. Treatment with sodium bicarbonate, riboflavin, and carnitine led to considerable improvement in growth and a significant reduction in the dicarboxylic aciduria.

Renal anaphylaxis. I. Antigen-initiated responses from isolated perfused rat kidney

Isolated perfused rat kidneys were passively sensitized by addition of either mouse ascitic fluid containing monoclonal IgE against dinitrophenol (DNP) or DNP-specific purified IgE. After washing the organ, defined doses of DNP-bovine serum albumin were given as bolus injection via the kidney artery. Antigen challenge of IgE-sensitized kidneys resulted in a dose-dependent increase of perfusion pressure starting with 5 micrograms antigen (2.46 +/- 0.2 mm Hg) and reaching a maximum at dose higher than 100 micrograms (10.3 +/- 1.6 mm Hg) (N = 4, means +/- 1 SD). A decrease of glomerular filtration rate was also observed which reached a plateau at 100 micrograms antigen (-68.5 +/- 2.9%) (N = 4). Regardless of the dose of antigen used, the urinary protein excretion markedly increased for the first five minutes following antigen injection and returned to basal values after 10 minutes. The total amounts of histamine, PGE2 and paf-acether (platelet-activating factor) released upon antigen challenge (1 mg) for 15 minutes reached maximal values of 405 +/- 21.1 ng, 286 +/- 19.4 pg and 12.3 +/- 3.2 ng (N = 5), respectively. None of these hemodynamic and biochemical effects were observed using IgG1 monoclonal antibodies or when the ascitic fluid containing monoclonal IgE used to sensitize the organ was heated at 56 degrees C for two hours. Thus, we have described a pure IgE-dependent rat kidney anaphylaxis. Antigen challenge markedly altered renal parameters and triggered the release of various mediators from the organ, suggesting that type I-hypersensitivity reactions may play a role in renal pathophysiology.