Health-Related Quality-of-Life Utility Values in Adults With Late-Onset Pompe Disease: Analyses of EQ-5D Data From the PROPEL Clinical Trial.

Background: Pompe disease is a rare lysosomal storage disorder, leading to accumulation of glycogen characterized by muscle weakness, fatigue, pain, and, in the longer term, a requirement for ventilatory and ambulatory support, and early mortality if untreated. Clinical evidence suggests that enzyme replacement therapy improves health outcomes for adults with late-onset Pompe disease (LOPD). PROPEL was a Phase 3, double-blind, randomized controlled trial, which evaluated cipaglucosidase alfa plus miglustat, vs alglucosidase alfa plus placebo in 123 adult patients with LOPD (clinicaltrials.gov: NCT03729362). Objectives: To analyze EQ-5D health-related quality of life (HRQoL) utility data from PROPEL. Methods: Multilevel modeling techniques (mixed regression methods) were used to analyze PROPEL EQ-5D-3L estimates and predict utility values for 7 health states previously identified in an economic evaluation for LOPD. In PROPEL, EQ-5D-5L values were assessed at screening and at weeks 12, 26, 38, and 52. EQ-5D-5L utility values were mapped to EQ-5D-3L values using the van Hout algorithm as recommended by the EuroQoL and the National Institute of Health and Care Excellence position statement at time of analysis. UK population tariffs were applied for all EQ-5D utility valuations. Utility values were predicted according to 6-minute walk distance (6MWD) and percent predicted sitting forced vital capacity. Results: The mixed model predicted that EQ-5D-3L utility values for patients who could walk >75 m with LOPD ranged between 0.55 and 0.67 according to patient 6MWD and respiratory function. In this analysis, patients with a 6MWD ≤75 m, consistent with a health state requiring wheelchair support in the economic analysis, had a predicted utility value of 0.49. There were few patients in PROPEL who could walk ≤75 m at any time point in the study, hence, these utility estimates should be interpreted with caution. EQ-5D-3L utility estimates from PROPEL were consistent with previously reported EQ-5D-3L values in LOPD. Conclusions: Overall, the results from our analysis indicate that important HRQoL losses are associated with reductions in mobility and respiratory function for patients with Pompe disease. The study provides important evidence of HRQoL utility values for patients with advanced LOPD, a population for whom published data are limited.