OBJECTIVES: UCB are investigating zilucoplan for the treatment of adult AChR positive generalized myasthenia gravis. To understand the relationship between disease status and health-related quality of life as expressed via the EQ-5D-5L instrument, data from RAISE- a P3 RCT comparing zilucoplan to placebo- was utilized.

METHODS: RAISE collected EQ-5D-5L and MG-ADL data at baseline and weeks 1, 2, 4, 8 and 12. Using the van Hout (2012) UK crosswalk, EQ-5D-5L responses were assigned utility weights. The subsequent data set of observed MG-ADL values and utility weights was examined to determine if statistical relationships existed between activities of daily living as measured by MG-ADL and utility scores.

RESULTS: The observed distribution of MG-ADL and utility scores displayed the expected relationship of higher MG-ADL scores (higher impact on activities of daily living) aligning to lower utility values. Patients randomized to zilucoplan had a mean CFB utility of 0.10, compared to 0.08 for placebo patients which aligned to a greater change in MG-ADL score in zilucoplan patients. A MMRM regression model was fitted to the data, where a 1-point improvement in MG-ADL estimated a 0.02 (p <0.0001) improvement in utility. Similar results were obtained when assessing QMG (disease severity). The HRQoL impact of better MG-ADL response was confirmed when considering minimal symptom expression (an MG-ADL score of 0 or 1) with a mean utility score of 0.85 in patients who achieved MSE at week 12 vs. 0.60 in patients that did not achieve MSE at week 12.

CONCLUSIONS: Results demonstrated that disease status in generalized myasthenia gravis as measured by MG-ADL is related to utility weights derived from EQ-5D-5L; which is of relevance to HTA and payers. The value of a higher MG-ADL response and minimal symptom expression as treatment goals that have a meaningful impact on patient quality of life are supported by these analyzes.