Efgartigimod improved health-related quality of life in generalized myasthenia gravis: results from a randomized, double-blind, placebo-controlled, phase 3 study (ADAPT)

Abstract

There are substantial disease and health-related quality-of-life (HRQoL) burdens for many patients with myasthenia gravis (MG), especially for those whose disease symptoms are not well controlled. HRQoL measures such as the Myasthenia Gravis Quality of Life 15-item revised (MG-QOL15r) and EuroQoL 5-Dimensions 5-Levels (EQ-5D-5L) are vital for evaluating the clinical benefit of therapeutic interventions in patients with MG, as they assess the burden of disease and the effectiveness of treatment, as perceived by patients. The phase 3 ADAPT study (NCT03669588) demonstrated that efgartigimod-a novel neonatal Fc receptor inhibitor-was well tolerated and that acetylcholine receptor antibody-positive (AChR-Ab+) participants who received efgartigimod had statistically significant improvements in MG-specific clinical scale scores. The ancillary data reported here, which cover an additional treatment cycle, show that these participants had similar significant improvements in HRQoL measures, the MG-QOL15r and EQ-5D-5L utility and visual analog scales, and that these improvements were maintained in the second treatment cycle. Positive effects on HRQoL were rapid, seen as early as the first week of treatment in both treatment cycles, and maintained for up to 4 weeks in the follow-up-only portion of treatment cycles. The pattern of improvements in HRQoL paralleled changes in immunoglobulin G level, and correlational analyses show that improvements were consistent across HRQoL measures and with clinical efficacy measures in the ADAPT study. The substantial and durable improvements in HRQoL end points in this study demonstrate the broader benefit of treatment with efgartigimod beyond relief of immediate signs and symptoms of gMG.

Keywords: Efgartigimod; Generalized myasthenia gravis; HRQoL; Patient-reported outcomes; Quality of life; gMG.

Fig. 1

Mean change from baseline in MG-QOL15r score, by treatment cycle (AChR-Ab+ participants). AChR-Ab+ acetylcholine receptor antibody receptor–positive, LSMD least squares mean difference, MG-QOL15r Myasthenia Gravis-Quality of Life 15-item revised, SE standard error. *indicates treatment administration (efgartigimod or matching placebo) timepoints (weeks 0, 1, 2, and 3)

Fig. 2

MG-QOL15r and total IgG for TC 1 in AChR-Ab+ participants. AChR-Ab+ acetylcholine receptor antibody receptor–positive, IgG immunoglobulin G, MG-QOL Myasthenia Gravis-Quality of Life, MG-QOL15r Myasthenia Gravis-Quality of Life 15-item revised, TC treatment cycle. *indicates treatment administration (efgartigimod or matching placebo) timepoints (weeks 0, 1, 2, and 3)

Fig. 3

Mean change from baseline in EQ-5D-5L UK utility score, by treatment cycle (AChR-Ab+ participants). AChR-Ab+ acetylcholine receptor antibody receptor–positive, EQ-5D-5L EuroQoL 5-Dimensions 5-Levels, LSMD least squares mean difference, SE standard error. *indicates treatment administration (efgartigimod or matching placebo) timepoints (weeks 0, 1, 2, and 3)

Fig. 4

Mean change from baseline in EQ-5D-5L VAS score, by treatment cycle (AChR-Ab+ participants). AChR-Ab+ acetylcholine receptor antibody receptor–positive, EQ-5D-5L EuroQoL 5-Dimensions 5-Levels, LSMD least squares mean difference, SE standard error, VAS visual analog scale. *indicates treatment administration (efgartigimod or matching placebo) timepoints (weeks 0, 1, 2, and 3)

Fig. 5

EQ-5D-5L domain responses, by treatment cycle (AChR-Ab+ participants). 4Wk week 4, AChR-Ab+ acetylcholine receptor antibody receptor–positive; BL baseline, EQ-5D-5L EuroQoL 5-Dimensions 5-Levels. Efgartigimod BL (n = 65), efgartigimod 4Wk (n = 63), placebo BL (n = 64), placebo 4Wk (n = 60)

Fig. 6

Correlations between MG-QOL15r scores and other assessment scores for efgartigimod group (TC 1; AChR-Ab+ population). AChR-Ab+ acetylcholine receptor antibody receptor–positive, EQ-5D-5L EuroQol 5-Dimensions 5-Levels, EQ VAS EuroQol visual analog scale, MG-ADL Myasthenia Gravis Activities of Daily Living, MG-QOL15r Myasthenia Gravis Quality of Life 15-item revised, TC treatment cycle. Lower scores equate to better outcomes for both MG-QOL15r and the MG-ADL; higher scores equate to better outcomes for both the EQ-5D-5L VAS and utility values