Exploring concurrent validity of the CLN2 Clinical Rating Scale: Comparison to PedsQL using cerliponase alfa clinical trial data.

BACKGROUND: The CLN2 Clinical Rating Scale evaluates disease progression in CLN2 disease, an ultra-rare, neurodegenerative disorder with late infantile onset. To validate the Clinical Rating Scale, a comparison with the Pediatric Quality of Life Inventory (PedsQL) was conducted utilising clinical trial data investigating cerliponase alfa use in CLN2 disease. METHODS: Linear regression and mixed effects models were used to investigate the relationship between the Clinical Rating Scale and PedsQL using open-label, single-arm, phase 1/2 (NCT01907087) and ongoing extension study (NCT02485899) data of 23 children with CLN2 disease treated with cerliponase alfa for ≥96 weeks. RESULTS: Correlations between the four Clinical Rating Scale domains were low. Linear mixed effects analyses showed significant correlation between PedsQL and Clinical Rating Scale (Total score or motor-language [ML] score adjusted p-values <0.05), driven by the relationship with the PedsQL Physical domain. A statistically significant relationship was identified between the Clinical Rating Scale motor domain and PedsQL (Total score: adjusted p-value = 0.048, parameter estimate [PE] = 8.10; Physical domain score: adjusted p-value = 0.012; PE = 13.79). CONCLUSIONS: Each domain of the Clinical Rating Scale provides unique information on disease state. Validity of the scale is supported by its relationship with the PedsQL. Among the four domains of the Clinical Rating Scale, motor has the highest correlation to PedsQL, suggesting motor function as a driver of patients' quality of life. The lack of association between the remaining domains of the Clinical Rating Scale and PedsQL suggests that additional disease-specific measures may be needed to fully capture the quality of life impact of CLN2 disease. TRIAL REGISTRATION: NCT01907087, NCT02485899.

Time Trade-Off Utilities for Hereditary Angioedema Health and Caregiver States.

BACKGROUND: Hereditary angioedema (HAE) is an inherited chronic rare disease characterised by recurrent swelling attacks that are associated with significant physical and psychological burden. There is limited understanding of the effect of attack location on this burden and of caregiver burden. OBJECTIVE: Our objective was to capture the relative burden of HAE health and caregiver states, including different attack locations, through a time trade-off (TTO) analysis involving participants from the general public. METHODS: Qualitative interviews were undertaken to inform vignette development for the TTO study, including vignettes for abdominal, facial, hand and laryngeal attack health states, and an attack-free and caregiver state. Members of the general public in England rated vignettes in TTO interviews, which included a visual analogue scale (VAS) component. For the development of the health state vignettes, qualitative interviews with 15 patients, 5 caregivers and 1 clinical expert were performed. TTO analysis was based on vignette valuation completed by 100 members of the general public. RESULTS: The TTO values were as follows: attack-free, 0.783 (standard deviation [SD] 0.316); hand: 0.582 (SD 0.380); facial: 0.483 (SD 0.448); abdominal: 0.345 (SD 0.458); and laryngeal: 0.128 (SD 0.529). The caregiver rating was 0.762 (SD 0.303). V' scores were similar and consistent with TTO values. CONCLUSION: TTO utility values demonstrate that HAE places a significant burden on patients, which is influenced by attack location, and on caregivers. These utility weights can provide important information on quality of life for future economic evaluations of treatments.

Investigating health-related quality of life in rare diseases: a case study in utility value determination for patients with CLN2 disease (neuronal ceroid lipofuscinosis type 2).

BACKGROUND: Utility studies enable preference-based quantification of a disease's impact on patients' health-related quality of life (HRQoL). It is often difficult to obtain utility values for rare, neurodegenerative conditions due to cognitive burden of direct elicitation methods, and the limited size of patient/caregiver populations. CLN2 disease (neuronal ceroid lipofuscinosis type 2) is an ultra-rare, progressive condition, for which there are no published utility data fully capturing all disease stages. This case study demonstrates how utility values can be estimated for ultra-rare paediatric diseases by asking clinicians to complete EQ-5D-5L questionnaires based on vignettes describing the stages of CLN2 disease. METHODS: An indirect elicitation method using proxy-reporting by clinical experts was adopted. Eighteen vignettes were developed, describing nine progressive disease stages as defined by motor and language domain scores of the CLN2 Clinical Rating Scale, in individuals treated with cerliponase alfa or standard care. Eight clinical experts with experience of treating CLN2 disease with cerliponase alfa and current standard care completed the proxy version 2 EQ-5D-5L online after reading these vignettes. Resulting scores were converted to EQ-5D-5L utility values for each disease stage, using UK, German and Spanish value sets. RESULTS: Utility values, which are typically anchored by 0 (equivalent to death) and 1 (full health), decreased with CLN2 disease progression (results spanned the maximum range of the utility scale). Assigned utility values were consistently higher for patients receiving cerliponase alfa than standard care; differences were statistically significant for the 6 most severe disease stages (p < 0.05). Analysis of the individual dimensions of the EQ-5D-5L showed that greatest differences between patients treated with cerliponase alfa and standard care occurred in the pain dimension (differences in mean scores ranged between no difference and 1.8), with notable differences also observed in the anxiety/depression dimension (differences in mean scores ranged between 0.1 and 1.0). CONCLUSIONS: This study demonstrates a feasible methodology for eliciting utility values in CLN2 disease, indicating HRQoL declines with disease progression. Vignettes describing patients receiving cerliponase alfa were consistently assigned higher utility values for the same disease state, suggesting this treatment improves HRQoL compared with standard care. Trial registration NCT01907087, NCT02485899.

Enzyme replacement therapy initiated in adulthood: Findings from the mucopolysaccharidosis VI Clinical Surveillance Program.

OBJECTIVE: To evaluate the impact of galsulfase enzyme replacement therapy (ERT) when initiated in adulthood for patients with mucopolysaccharidosis (MPS) VI. METHODS: In 2005, the multi-national, MPS VI Clinical Surveillance Program (CSP) was established to collect long-term observational data from routine clinical and laboratory assessments. A sub-analysis was performed in patients who started ERT at ≥16 years of age and had received galsulfase for ≥6 months. Urinary glycosaminoglycans (uGAG), 6-min walk test (6MWT), 3-min stair climb test (3MSCT), pulmonary function measures, cardiac function, ophthalmology measures, liver and spleen sizes, and safety were evaluated. RESULTS: Of 223 patients enrolled in the CSP, 51 were included in the sub-analysis. Patients were between 16 and 63 years of age at first infusion. From pre-treatment baseline, uGAG level decreased by a mean (±standard deviation [SD]) of 66 (±45)% (N = 29) after a median follow-up of 7.2 years. 6MWT distance decreased slightly by a mean of 17 (±107) meters (N = 23) after 6.6 years. Stairs/min in the 3MSCT increased by a mean of 26 (±33) (N = 14) after 2.8 years. Pulmonary function measures, forced expiratory volume in 1 second and forced vital capacity, increased by a mean of 0.06 (±0.21) L after 7.3 years and 0.05 (±0.28) L after 7.2 years, respectively (N = 19 for both measures). Overall, galsulfase was well tolerated, with most adverse events reported being MPS-related clinical manifestations and not related to galsulfase. CONCLUSIONS: Results of this sub-analysis of the CSP suggest that initiation of galsulfase in adulthood is well tolerated and can possibly stabilize MPS VI in the long term.

Enzyme replacement therapy outcomes across the disease spectrum: Findings from the mucopolysaccharidosis VI Clinical Surveillance Program.

The impact of galsulfase enzyme replacement therapy in patients with mucopolysaccharidosis (MPS) VI with phenotypes at either end of the disease spectrum was evaluated. The MPS VI Clinical Surveillance Program (CSP) was established to collect long-term observational data from routine clinical and laboratory assessments. A subanalysis of the CSP was performed in patients with pretreatment urinary glycosaminoglycan (uGAG) levels <100 µg/mg and ≥200 µg/mg creatinine (low- and high-uGAG) who had received galsulfase for ≥6 months. uGAG, 6-minute walk test (6MWT), 3-minute stair climb test (3MSCT), pulmonary function measures, height/growth, cardiac function, and safety were evaluated. Patients with a high-uGAG level at pre-treatment baseline (N = 68) showed greater impairments in endurance and pulmonary function than those with low-baseline uGAG levels (N = 39). From pre-treatment baseline, the distance walked on the 6MWT in the low- and high-uGAG groups increased by a mean (±SD) of 49 (±151) meters and 42 (±165) meters (median follow-up 5.5 and 7.7 years), respectively. The number of stairs/min climbed in the 3MSCT in the low- and high-uGAG groups increased by a mean of 18 (±33) and 30 (±45) (median follow-up 2.8 and 3.5 years), respectively. Overall, pulmonary function remained unchanged for both groups. No impact was seen on cardiac function. Galsulfase was generally well tolerated in both groups, with most adverse events being MPS-related complications unrelated to galsulfase. Results of this CSP sub-analysis suggest that galsulfase stabilizes MPS VI in the long-term and has an acceptable safety profile, regardless of baseline disease severity.

Acetylator Status Impacts Amifampridine Phosphate (Firdapse™) Pharmacokinetics and Exposure to a Greater Extent Than Renal Function.

PURPOSE: The purpose of this study is to evaluate safety, tolerability, and pharmacokinetic (PK) properties of amifampridine phosphate (Firdapse™) and its major inactive 3-N-acetyl metabolite in renally impaired and healthy individuals with slow acetylator (SA) and rapid acetylator (RA) phenotypes. METHODS: This was a Phase I, multicenter, open-label study of the PK properties and safety profile of amifampridine phosphate in individuals with normal, mild, moderate, or severely impaired renal function. Amifampridine phosphate was given as a single 10 mg (base equivalent) dose, and the plasma and urine PK properties of amifampridine and its 3-N-acetyl metabolite were determined. The safety profile was evaluated by monitoring adverse events (AEs), clinical laboratory tests, and physical examinations. FINDINGS: Amifampridine clearance was predominantly metabolic through N-acetylation, regardless of renal function in both acetylator phenotypes. In individuals with normal renal function, mean renal clearance represented approximately 3% and 18% of the total clearance of amifampridine in RA and SA, respectively. Large differences in amifampridine exposure were observed between acetylation phenotypes across renal function levels. Mean amifampridine exposure values of AUC0-∞ and Cmax were up to 8.8-fold higher in the SA group compared with the RA group across renal function levels. By comparison, mean AUC0-∞ was less affected by renal function within an acetylator group, only 2- to 3-fold higher in individuals with severe renal impairment (RI) compared with those with normal renal function. Exposure to amifampridine in the SA group with normal renal function was higher (AUC0-∞, approximately 1.8-fold; Cmax, approximately 4.1-fold) than the RA group with severe RI. Exposure to the inactive 3-N-acetyl metabolite was higher than amifampridine in both acetylator groups, independent of renal function level. The metabolite is cleared by renal excretion, and exposure was clearly dependent on renal function with 4.0- to 6.8-fold increases in AUC0-∞ from normal to severe RI. No new tolerability findings were observed. IMPLICATIONS: A single dose of 10 mg of amifampridine phosphate was well tolerated, independent of renal function and acetylator status. The results indicate that the PK profile of amifampridine is affected by metabolic acetylator phenotype to a greater extent than by renal function level, supporting Firdapse™ administration in individuals with RI in line with current labeling recommendations. Amifampridine should be dosed to effect per the individual patient need, altering administration frequency and dose in normal through severe RI. The therapeutic dose of amifampridine phosphate should be tailored to the individual patient needs by gradual dose titration up to the present maximum recommended dose (60-80 mg/day) or until dose-limiting AEs intervene to avoid overdosing and underdosing. EudraCT identifier: 2013-005349-35.

Impact of elosulfase alfa in patients with morquio A syndrome who have limited ambulation: An open-label, phase 2 study.

Efficacy and safety of elosulfase alfa enzyme replacement therapy (ERT) were assessed in an open-label, phase 2, multi-national study in Morquio A patients aged ≥5 years unable to walk ≥30 meters in the 6-min walk test. Patients received elosulfase alfa 2.0 mg/kg/week intravenously for 48 weeks. Efficacy measures were functional dexterity, pinch/grip strength, mobility in a modified timed 25-foot walk, pain, quality of life, respiratory function, and urine keratan sulfate (KS). Safety/tolerability was also assessed. Fifteen patients received elosulfase alfa, three patients discontinued ERT due to adverse events (two were grade 3 drug-related adverse events, the other was not drug-related), and two patients missed >20% of planned infusions; 10 completed treatment through 48 weeks and received ≥80% of planned infusions (Modified Per Protocol [MPP] population). The study population had more advanced disease than that enrolled in other trials. From baseline to week 48, MPP data showed biochemical efficacy (urine KS decreased 52.4%). The remaining efficacy results were highly variable due to challenges in test execution because of severe skeletal and joint abnormalities, small sample sizes, and clinical heterogeneity among patients. Eight patients showed improvements in one or more outcome measures; several patients indicated improvements not captured by the study assessments (e.g., increased energy, functional ability). The nature of adverse events was similar to other elosulfase alfa studies. This study illustrates the considerable challenges in objectively measuring impact of ERT in very disabled Morquio A patients and highlights the need to examine results on an individual basis. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

Estimation of EuroQol 5-Dimensions health status utility values in hereditary angioedema.

OBJECTIVE: To estimate health status utility (preference) weights for hereditary angioedema (HAE) during an attack and between attacks using data from the Hereditary Angioedema Burden of Illness Study in Europe (HAE-BOIS-Europe) survey. Utility measures quantitatively describe the net impact of a condition on a patient's life; a score of 0.0 reflects death and 1.0 reflects full health. STUDY DESIGN AND METHODS: The HAE-BOIS-Europe was a cross-sectional survey conducted in Spain, Germany, and Denmark to assess the real-world experience of HAE from the patient perspective. Survey items that overlapped conceptually with the EuroQol 5-Dimensions (EQ-5D) domains (pain/discomfort, mobility, self-care, usual activities, and anxiety/depression) were manually crosswalked to the corresponding UK population-based EQ-5D utility weights. EQ-5D utilities were computed for each respondent in the HAE-BOIS-Europe survey for acute attacks and between attacks. RESULTS: Overall, a total of 111 HAE-BOIS-Europe participants completed all selected survey items and thus allowed for computation of EQ-5D-based utilities. The mean utilities for an HAE attack and between attacks were 0.44 and 0.72, respectively. Utilities for an acute attack were dependent on the severity of pain of the last attack (0.61 for no pain or mild pain, 0.47 for moderate pain, and 0.08 for severe pain). There were no significant differences across countries. Mean utilities derived from the study approach compare sensibly with other disease states for both acute attacks and between attacks. CONCLUSION: The impacts of HAE translate into substantial health status disutilities associated with acute attacks as well as between attacks, documenting that the detrimental effects of HAE are meaningful from the patient perspective. Results were consistent across countries with regard to pain severity and in comparison to similar disease states. The results can be used to raise awareness of HAE as a serious disease with wide-ranging personal and social impacts.

Pregnancy in patients with mucopolysaccharidosis: a case series.

The mucopolysaccharidoses (MPS disorders) are rare inherited diseases associated with multi-organ accumulation of glycosaminoglycans, leading to musculoskeletal, respiratory, cardiac, neurological, ophthalmological, otolaryngological, and gastrointestinal abnormalities. As a result of improvements in diagnosis, multi-disciplinary care, and therapies such as enzyme replacement therapy and hematopoietic stem cell transplantation, an increasing number of patients with MPS are reaching adulthood and are involved in family planning. Data on fertility and pregnancy outcome in MPS is sparse and comprises primarily isolated case reports. To address this evidence gap, we present a case series on fertility and pregnancy in eight mothers and five fathers with MPS. This case series demonstrates that women with MPS have high-risk pregnancies and deliveries secondary to their underlying disease. However, with appropriate pre-conceptual multi-disciplinary evaluation, optimization and discussion regarding potential risks, combined with regular multi-disciplinary maternal and fetal surveillance in a tertiary center, the outcome of most pregnancies in this case series seems to be favorable with all babies developing normally. Partners of fathers with MPS had uncomplicated pregnancies and deliveries. All children were healthy, with normal growth and development.

Cervical cord compression in mucopolysaccharidosis VI (MPS VI): Findings from the MPS VI Clinical Surveillance Program (CSP).

OBJECTIVES: To gain insight into the frequency, age of onset, and management of cervical cord compression in mucopolysaccharidosis VI (MPS VI). METHODS: Cervical spine magnetic resonance imaging (MRI) data and/or cervical decompression surgery data collected between 30 June 2005 and 1 September 2015 were analyzed from subjects enrolled in the MPS VI Clinical Surveillance Program (CSP) (ClinicalTrials.gov: NCT00214773), an ongoing multicenter, observational, retrospective and prospective registry. RESULTS: Of 213 subjects enrolled in the CSP, 134 (62.9%) had at least one documented cervical spine MRI assessment. An additional four subjects were identified through surgery records alone to yield a study population comprising 138 subjects (mean age at enrollment =15.1years; age range=0.80-65.0years). Cervical cord compression was documented in 101 (75.4%) of the 134 subjects with ≥1 MRI assessment, the majority (95.0%) by the time of the first recorded MRI. In general, subjects with cervical cord compression had significantly lower height Z-scores compared to those without cervical cord compression (p<0.0001); nevertheless, a few subjects of taller stature had documented cervical cord compression at a young age. Most subjects >20years of age (31/33, 93.9%) presented with cervical cord compression. There was an insufficient number of subjects with both pre- and post-enzyme replacement therapy (ERT) MRI data to determine any association between ERT and cervical cord compression. Surgical decompression was performed on 58 subjects (42.0%), with mean age at first surgery of 13.1years. Decompression plus stabilization procedures accounted for 12.1% of surgeries. Eight subjects (13.8%) underwent reoperation. Complications during or following surgery were reported in 3 subjects, with anesthesia-related complications resulting in two deaths. CONCLUSIONS: All individuals with MPS VI are at high risk of developing cervical cord compression at an early age. Routine MRI assessments should be initiated from the time of MPS VI diagnosis. The perioperative management of MPS VI patients can be challenging. This study contributes to the understanding of the natural history of MPS VI.

Expert Opinions on Managing Fertility and Pregnancy in Patients With Mucopolysaccharidosis

Abstract The mucopolysaccharidosis (MPS) disorders are rare genetic diseases caused by deficiencies in lysosomal enzymes involved in the degradation of glycosaminoglycans, leading to pulmonary, cardiac and neurological dysfunctions, skeletal anomalies, impaired vision, and/or hearing and shortened life spans. Whereas in the past, few individuals with MPS reached adulthood, better diagnosis, multidisciplinary care, and new therapies have led to an increasing number of adult patients with MPS. Therefore, fertility and pregnancy questions in this patient population are becoming more important. Management of fertility issues and pregnancy in patients with MPS is challenging due to the lack of documented cases and a dearth in the literature on this topic. This review presents multidisciplinary expert opinions on managing fertility and pregnancy based on case studies and clinical experience presented at a meeting of MPS specialists held in Berlin, Germany, in April 2015. An overview of the existing literature on this subject is also included.

Burden of Illness in Hereditary Angioedema: A Conceptual Model.

The objective of the Hereditary Angioedema Burden of Illness Study in Europe was to assess the real-world experience of hereditary angioedema (HAE) from the patient perspective. Based on open-ended qualitative interviews with 30 patients from Spain, Germany and Denmark, 5 key themes emerged characterizing the impact of HAE on health-related quality of life (HRQoL): (i) unnecessary treatments and procedures, (ii) symptom triggers, (iii) attack impacts, (iv) caregiver impacts, and (v) long-term impacts. Patients for example experience unnecessary medical procedures due to diagnostic delays; anxiety and fear about attacks, and passing HAE to children; reduced work/school productivity; and limited career/educational achievement. Patient caregivers also experience worry and work/activity interruption during the attacks. In conclusion, a conceptual model was developed illustrating the hypothesized relationships among the wide-ranging short- and long-term HRQoL impacts of HAE. These findings can be used to highlight important issues in clinical management, raise awareness of the patients' experience among policymakers and help guide measurement of HRQoL outcomes in future studies in HAE.

Socioeconomic burden of hereditary angioedema: results from the hereditary angioedema burden of illness study in Europe.

BACKGROUND: Hereditary angioedema (HAE) due to C1 inhibitor deficiency is a rare but serious and potentially life-threatening disease marked by spontaneous, recurrent attacks of swelling. The study objective was to characterize direct and indirect resource utilization associated with HAE from the patient perspective in Europe. METHODS: The study was conducted in Spain, Germany, and Denmark to assess the real-world experience of HAE via a cross-sectional survey of HAE patients, including direct and indirect resource utilization during and between attacks for patients and their caregivers over the past 6 months. A regression model examined predictors of medical resource utilization. RESULTS: Overall, 164 patients had an attack in the past 6 months and were included in the analysis. The most significant predictor of medical resource utilization was the severity of the last attack (OR 2.6; p < 0.001). Among patients who sought medical care during the last attack (23%), more than half utilized the emergency department. The last attack prevented patients from their normal activities an average of 4-12 hours. Patient and caregiver absenteeism increased with attack severity and frequency. Among patients who were working or in school (n = 120), 72 provided work/school absenteeism data, resulting in an estimated 20 days missing from work/school on average per year; 51% (n = 84) indicated that HAE has hindered their career/educational advancement. CONCLUSION: HAE poses a considerable burden on patients and their families in terms of direct medical costs and indirect costs related to lost productivity. This burden is substantial at the time of attacks and in between attacks.

The humanistic burden of hereditary angioedema: results from the Burden of Illness Study in Europe.

Hereditary angioedema (HAE) is a rare but potentially life-threatening disease marked by spontaneous, recurrent attacks of swelling. The broad range of consequences of HAE on patients' lives is not well understood. The study objective was to comprehensively characterize the burden of illness and impact of HAE types I and II from the patient perspective. The HAE Burden of Illness Study in Europe was conducted in Spain, Germany, and Denmark to assess the real-world experience of HAE from the patient perspective via a one-time survey, which included items on clinical characteristics and physical and emotional impacts. One hundred eighty-six patients participated; 59% reported having an attack at least once a month, 67% reported moderate-to-severe pain during their last attack, and 74% reported moderate-to-severe swelling. The most common sites of the last attack were the abdomen and extremities; 24% experienced an attack in more than one site. The impact of HAE on daily activities was high during attacks and did not vary significantly by body site affected; patients also reported that HAE impacted their daily activities between attacks. Patients reported substantial anxiety about future attacks, traveling, and passing HAE to their children. Based on Hospital Anxiety and Depression Scale scores, 38 and 14% had clinically meaningful anxiety and depression, respectively. Despite standard of care, HAE patients still have frequent and painful attacks. Patients experience substantial impairment physically and emotionally both during and between attacks. A better understanding of these effects may help in the clinical management of HAE patients.