OBJECTIVES: The phase 3 COMET study (NCT02782741) included multiple PROs that assessed patient’s experience in adults with Pompe disease (PD). Three PROs: Pompe Disease Symptom Scale (PDSS), Pompe Disease Impact Scale (PDIS), Rasch-Built Pompe-Specific Activity (R-PAct) scale specifically measure PD associated symptoms and impacts. These post-hoc analyses were conducted to further illustrate clinical benefits of AVA (n=50) vs. ALG (n=49).

METHODS: The percentage of multi-PDSS domain responders (on ≥ 1, ≥ 2, ≥ 3, and ≥ 4 domains), PDIS domains (responders on both domains), and patients who switched from “unable to do” at baseline to “able to do” a daily activity at Week 49 on key R-PAct scale items were assessed.

RESULTS: In multi-PDSS domain responder analysis, AVA was numerically superior (domain ≥ 1 [39% vs. 18%], ≥ 2 [24% vs. 4%], ≥ 3 [20% vs. 2%], ≥ 4 [14% vs. 0%]) and statistically significant, at nominal p-value (except ≥ 4 PDSS domains) vs. ALG at Week 49. A similar proportion of responders to both PDIS domains (18% vs. 16%) was observed in each treatment group. A numerically greater percentage of patients receiving AVA (n=21) vs. ALG (n=25) was able to complete selected R-PAct activities (bend over [83% vs. 25%], stand up [75% vs. 50%], walk [at a rapid rate: 55% vs. 27%; more than 1 Km: 50% vs. 33%], stairs up and down [33% vs. 20%], bend at knee and stand up [25% vs. 9%], run [17% vs. 6%]) at Week 49 that they could not perform at baseline.

CONCLUSIONS: The PDSS, PDIS, and R-PAct measure symptoms and functional limitations that are specific and important to PD. These post-hoc analyses extend the findings from exploratory endpoint analyses, showing positive, consistent trends throughout LOPD-specific PROs in favour of AVA over ALG on aspects of PD relevant to patients’ daily lives.