Minimal clinically important differences in six-minute walking distance in late-onset Pompe disease.

BACKGROUND: The minimal clinically important difference (MCID) is the smallest change in outcome that physicians or patients would consider meaningful and is relevant when evaluating disease progression or the efficacy of interventions. Studies of patients with late-onset Pompe disease (LOPD) have used the 6-min walk distance (6MWD) as an endpoint to assess motor function. However, an MCID for 6MWD (% predicted and meters) has yet to be established in LOPD. The objective of the study was to derive 6MWD MCID (% predicted and meters) with different analysis methods and for subgroups of different disease severity for LOPD. METHODS: Data from the PROPEL trial were used to calculate 6MWD MCID in the overall PROPEL population and subgroups of baseline severity as assessed by walking distance and body mass index (BMI), using anchor- and distribution-based approaches. RESULTS: The 6MWD MCIDs varied widely, depending on the method and subgroup, ranging from 2.27%-8.11% predicted for the overall LOPD population (23.7 m-57.2 m). For patients with baseline 6MWD < 150 m, MCIDs ranged from -0.74%-3.37% (-2.1 m-11.3 m). MCIDs increased with distance walked at baseline until a plateau was reached. For BMI subgroups, the MCIDs were generally lowest in obese patients. CONCLUSION: Our analysis shows that MCID depends on the chosen method and disease severity. The findings suggest that applying a single MCID to all patients can be misleading; consequently, a range of possible MCIDs should be considered. This may also be highly relevant for other neuromuscular diseases. This study provides a range of 6MWD MCIDs for LOPD, with lower MCIDs for more severe patients.

Validation of the Patient-Reported Outcomes Measurement Information System (PROMIS®) physical function questionnaire in late-onset Pompe disease using PROPEL phase 3 data.

BACKGROUND: The construct validity and interpretation of the Patient-Reported Outcome Measurement Information System (PROMIS®) Physical Function short form 20a (PF20a) questionnaire were evaluated for patients with late-onset Pompe disease (LOPD), a rare, autosomal recessive, progressive neuromuscular disorder treatable by enzyme replacement therapy (ERT). METHODS: In the phase 3 PROPEL study, adults with LOPD underwent testing of physical functioning and had PRO measurements at baseline and at weeks 12, 26, 38, and 52 while receiving experimental or standard-of-care ERT. All patients were pooled for analyses, without comparisons between treatment groups. Associations and correlations between PROMIS PF20a scores and the 6-minute walk distance (6MWD), % predicted forced vital capacity (FVC), manual muscle test (MMT) of the lower extremities, Gait, Stairs, Gowers' maneuver, Chair (GSGC) score, and Rasch-built Pompe-specific Activity (R-PAct) scale were evaluated by calculating regression coefficients in linear regression models and Pearson correlation coefficients (R); patients' age, sex, race, ERT prior to study, body mass index, and study treatment were included as covariables. The minimal clinically important difference (MCID) of PROMIS PF20a was determined using distribution- and anchor-based methods. RESULTS: 123 patients received at least 1 dose of ERT. In multivariable analyses, PROMIS PF20a scores had strong correlations with R-PAct scores (R = 0.83 at baseline and R = 0.67 when evaluating changes between baseline and 52 weeks) and moderate correlations with the 6MWD (R = 0.57 at baseline and R = 0.48 when evaluating changes between baseline and 52 weeks). Moderate correlations were also observed between PROMIS PF20a and MMT (R = 0.54), GSGC (R=-0.51), and FVC (R = 0.48) at baseline. In multivariable linear regression models, associations were significant between PROMIS PF20a and 6MWD (P = 0.0006), MMT (P = 0.0034), GSGC (P = 0.0278), and R-PAct (P < 0.0001) at baseline, between PROMIS PF20a and 6MWD (P < 0.0001), FVC (P = 0.0490), and R-PAct (P < 0.0001) when combining all measurements, and between PF20a and 6MWD (P = 0.0016) and R-PAct (P = 0.0001) when evaluating changes in scores between baseline and 52 weeks. The anchor-based and distribution-based MCID for a clinically important improvement for PROMIS PF20a were 2.4 and 4.2, respectively. CONCLUSIONS: PROMIS PF20a has validity as an instrument both to measure and to longitudinally follow physical function in patients with LOPD. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03729362. Registered 2 November 2018, https://www. CLINICALTRIALS: gov/search?term=NCT03729362 .

Therapeutic Role of Pharmacological Chaperones in Lysosomal Storage Disorders: A Review of the Evidence and Informed Approach to Reclassification.

The treatment landscape for lysosomal storage disorders (LSDs) is rapidly evolving. An increase in the number of preclinical and clinical studies in the last decade has demonstrated that pharmacological chaperones are a feasible alternative to enzyme replacement therapy (ERT) for individuals with LSDs. A systematic search was performed to retrieve and critically assess the evidence from preclinical and clinical applications of pharmacological chaperones in the treatment of LSDs and to elucidate the mechanisms by which they could be effective in clinical practice. Publications were screened according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) reporting guidelines. Fifty-two articles evaluating 12 small molecules for the treatment of seven LSDs are included in this review. Overall, a substantial amount of preclinical and clinical data support the potential of pharmacological chaperones as treatments for Fabry disease, Gaucher disease, and Pompe disease. Most of the available clinical evidence evaluated migalastat for the treatment of Fabry disease. There was a lack of consistency in the terminology used to describe pharmacological chaperones in the literature. Therefore, the new small molecule chaperone (SMC) classification system is proposed to inform a standardized approach for new, emerging small molecule therapies in LSDs.

Real-World Outcomes of Selective Laser Trabeculoplasty in the United Kingdom.

PURPOSE: Selective laser trabeculoplasty (SLT) is a common treatment option for managing glaucoma and ocular hypertension. We assessed the real-world effectiveness of SLT and baseline factors associated with treatment success in the United Kingdom. DESIGN: Retrospective observational study of de-identified electronic medical records (Medisoft Glaucoma module [Medisoft Ltd, Leeds, UK]) from 5 UK ophthalmology teaching centers. PARTICIPANTS: Adult patients undergoing their first recorded SLT. For bilateral SLT (same day), analyses included 1 randomly selected eye. METHODS: Patient demographics, procedure details, and clinical outcomes data were extracted. Factors associated with treatment success were assessed using multivariable Cox regression. MAIN OUTCOME MEASURES: Change from baseline in intraocular pressure (IOP) and glaucoma medication use at 12 to 18 and 24 to 36 months post-SLT. A Kaplan-Meier survival analysis was also conducted. Failure of SLT was defined as any further glaucoma procedure post-SLT or any of the following at 2 consecutive visits: IOP >21 mmHg, IOP reduction <20% from baseline, or increase in glaucoma medications from baseline. RESULTS: A total of 831 SLT-treated eyes (mean baseline IOP 22.0 mmHg) of 831 patients were analyzed. At 12 to 18 and 24 to 36 months post-SLT, respectively, significant reductions in IOP (-4.2 [95% confidence interval {CI}, -4.7 to -3.7] and -3.4 [95% CI, -4.1 to -2.7] mmHg; both P < 0.0001) and significant increases in the number of glaucoma medications (0.13 [95% CI, 0.04-0.23], P = 0.007, and 0.20 [95% CI, 0.06-0.33], P = 0.005) were observed. Survival analysis demonstrated treatment success in 70%, 45%, and 27% of eyes at 6, 12, and 24 months post-SLT, respectively. Higher baseline IOP was strongly associated with treatment success (hazard ratio [HR], 0.67 for baseline IOP >21 mmHg vs. ≤21 mmHg, 95% CI, 0.57-0.80; P < 0.001). Selective laser trabeculoplasty success was not significantly associated with age (P = 0.78), baseline visual field mean deviation (P = 1.00), or concurrent use of IOP-lowering medication (P = 0.52). CONCLUSIONS: Most patients initially responded to SLT, but the majority failed within 1 year. Efficacy of SLT was better in patients with higher baseline IOP but did not differ by glaucoma severity or concurrent use of IOP-lowering medication. These findings may help inform which patients are suitable for SLT therapy.

Updated cost-effectiveness analysis of onabotulinumtoxinA for the prevention of headache in adults with chronic migraine who have previously received three or more preventive treatments in the UK.

Aims: OnabotulinumtoxinA is recommended by NICE for the treatment of chronic migraine. This economic evaluation provides updated estimates of the cost-effectiveness of onabotulinumtoxinA for chronic migraine using new utility estimates in an existing model structure.Methods: A previously published model was revised to include EQ-5D utility estimates from a large observational study (REPOSE; n = 633). Efficacy data were taken from the pooled phase III PREEMPT clinical trial program, while resource utilization estimates were obtained from the International Burden of Migraine Study (IBMS). The model estimated costs and quality-adjusted life years (QALYs) gained over 2 years from the UK NHS perspective.Results: OnabotulinumtoxinA treatment resulted in total discounted incremental costs of £1,204 and an incremental discounted QALY gain of 0.07 compared with placebo in patients with chronic migraine who have previously failed three or more preventive treatments, corresponding to an incremental cost-effectiveness ratio (ICER) of £16,306 per QALY gained. Scenario analysis showed that the administration of onabotulinumtoxinA by a specialist nurse rather than a neurology consultant reduced the ICER from £16,306 to £13,832 per QALY gained. Removal of the positive stopping rule recommended in current NICE guidance increased the ICER to £20,768 per QALY for onabotulinumtoxinA vs. placebo. Combining these two scenarios produced an ICER of £17,686 per QALY gained.Conclusion: NICE recommended onabotulinumtoxinA for the prevention of chronic migraine in 2012 amid concerns about the uncertainty of ICER estimates, with a positive stopping rule used to manage some of these uncertainties. Since the publication of the NICE guidance, the REPOSE study provides a more recent source of utility data based on real-world evidence. The results of analyses including these utilities suggest that the application of the positive stopping rule may not be necessary to ensure cost-effectiveness and that this aspect of the current NICE guidance for onabotulinumtoxinA may merit reconsideration.

A UK-based cost-utility analysis of indacaterol, a once-daily maintenance bronchodilator for patients with COPD, using real world evidence on resource use.

INTRODUCTION: Chronic Obstructive Pulmonary Disease (COPD) is a chronic, progressive disease that is not curable. However, there are effective treatments available. In the UK, long-acting bronchodilators are first-line treatments for COPD patients requiring maintenance therapy, and there are several options available. The aim of this study is to establish, from the UK National Health Service (NHS) perspective, the cost-effectiveness profile of indacaterol, the first once-daily long-acting beta2-agonist (LABA), compared with tiotropium and salmeterol, in patients with moderate to severe COPD. In assessing the cost-effectiveness of COPD therapies, this study has the advantage of using real world evidence on the resource use associated with COPD management across the spectrum of the disease. METHODS: A Markov model was developed with four health states following the GOLD classification for severity of airflow limitation. The model time horizon was 3 years, and the cycle length was 3 months. From each state, patients could experience a severe or non-severe exacerbation, move to a different COPD state, remain in the current state or die. Transition probabilities were based on data from the indacaterol clinical trials. The majority of the resource use data was taken from the Optimum Patient Care Research Database (OPCRD), which contains data from over 20,000 COPD patients in England and Scotland. Cost data were taken from UK-based sources and published literature and presented for the cost year 2011. Health-related quality of life was the main outcome of interest and utility data for the COPD states were based on data from the indacaterol clinical trials and disutility due to exacerbations were taken from the literature. Both one way and probabilistic sensitivity analyses were performed to test the robustness of the results. RESULTS: Indacaterol dominated in the comparison with salmeterol producing an incremental QALY gain of 0.008 and cost savings of £110 per patient over a 3-year time horizon. In the comparison with tiotropium over the same time horizon, indacaterol remained the dominant strategy, producing an incremental QALY gain of 0.008 and cost savings of £248 per patient. The one-way sensitivity analysis indicates that the proportion of patients in each of the COPD stages and the mortality rate associated with Very Severe COPD are the variables with the largest impact on the results. The probabilistic sensitivity analyses showed that over 72 % and 89 % of the iterations when compared with salmeterol and tiotropium, respectively, produced dominant results for indacaterol. CONCLUSION: The analyses demonstrate that indacaterol dominates both tiotropium and salmeterol in the base case and is likely to remain cost-effective under a range of assumptions.