Effect of Efgartigimod PH20 SC on Lower Limb Function in Chronic Inflammatory Demyelinating Polyradiculoneuropathy in ADHERE

Topic:

Clinical Trials

Poster Number: 350 T

Author(s):

Richard A. Lewis, MD, Cedars-Sinai Medical Center, Los Angeles, CA, USA, Sharon Reizner, PharmD, argenx, Jeffrey A. Allen, MD, University of Minnesota, Minneapolis, MN, USA, Jie Lin, MD, Huashan Hospital, Fudan University, Shanghai, China, Mark Stettner, MD, PhD, University Medicine Essen, Essen, Germany, Ingemar Merkies, MD PhD, Curaçao Medical Center, Willemstad, Curaçao, Jeffrey T. Guptill, MD, argenx, Ghent, Belgium, Channa Hewamadduma, MBChB, PhD, Sheffield Teaching Hospitals Foundation NHS Trust, Sheffield, UK, Geoffrey Istas, PhD, argenx, Ghent, Belgium, Arne De Roeck, PhD, argenx, Ghent, Belgium, Satoshi Kuwabara, MD, Chiba University, Chiba, Japan, Giuseppe Lauria Pinter, MD, IRCCS Foundation “Carlo Besta” Neurological Institute & University of Milan, Milan, Italy, Luis Querol, MD, PhD, Hospital de La Santa Creu I Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain, Niraja Suresh, MD, Lakeland Regional Health, Lakeland, FL, USA, Chafic Karam, MD, 2University of Pennsylvania, Philadelphia, PA, USA, Thomas Skripuletz, MD, Hannover Medical School, Hanover, Germany, Andoni Echaniz-Laguna, MD, PhD, CERAMIC, Bicêtre University Hospital, Le Kremlin-Bicêtre, France, Benjamin Van Hoorick, MD, argenx, Ghent, Belgium, Ryo Yamasaki, MD, PhD, 8Kyushu University Hospital, Fukuoka, Japan, Richard A. Lewis, MD, Cedars-Sinai Medical Center, Los Angeles, CA, USA, Pieter A. van Doorn, MD, PhD, Erasmus University Medical Center, Rotterdam, the Netherlands

Background: In the ADHERE trial (NCT04281472), subcutaneous (SC) efgartigimod PH20 (coformulated with recombinant human hyaluronidase PH20), a neonatal Fc inhibitor, reduced relapse risk and improved disability scores in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Objectives: This post hoc analysis explores the effect of efgartigimod PH20 SC on lower limb function. Methods: Participants had active CIDP and were off treatment or on standard treatments (withdrawn during ≤12-week run-in). Participants received weekly efgartigimod PH20 SC 1000 mg (stage A). Responders were randomized (1:1) to weekly efgartigimod PH20 SC 1000 mg or placebo for ≤48 weeks (stage B). Outcomes included changes from run-in baseline (after participants withdrew prior treatments) to stage B last assessment in adjusted Inflammatory Neuropathy Cause and Treatment (aINCAT) leg score, selected Inflammatory Rasch-Built Overall Disability Scale (I-RODS) individual items, and Timed Up and Go (TUG) test. Results: 322 participants entered stage A; 221 were randomized and treated in stage B (efgartigimod PH20 SC: 111, placebo: 110). In participants who had an INCAT leg score of ≥2 at run-in baseline, improvement to an INCAT leg score of 0 or 1 was reported in 17/51 (33.3%) efgartigimod PH20 SC-group and 16/57 (28.1%) placebo-group participants at stage B baseline, and 18/51 (35.3%) efgartigimod PH20 SC-treated and 17/56 (30.4%) placebo-treated participants at stage B last assessment. In participants who had a score of 0 or 1 in selected individual I-RODS items at run-in baseline, improvements of ≥1 points in I-RODS individual items at stage B last assessment were reported for run (efgartigimod PH20 SC: 21/94 [22.3%], placebo: 5/90 [5.6%]), walk outdoors (efgartigimod PH20 SC: 27/83 [32.5%], placebo: 16/78 [20.5%]), walk one flight of stairs (efgartigimod PH20 SC: 25/83 [30.1%], placebo: 15/81 [18.5%]), and walk avoiding obstacles (efgartigimod PH20 SC: 19/72 [26.4%], placebo: 14/71 [19.7%]). At stage B last assessment, mean (standard error) TUG test completion time (seconds) in efgartigimod PH20 SC-treated participants decreased by −2.6 (0.66) from 16.5 (1.32) at run-in baseline, while in placebo-treated participants it decreased by −1.4 (1.48) from 19.9 (3.33). Conclusions: Numerically more efgartigimod PH20 SC-treated participants with CIDP in ADHERE stage B experienced improvements from run-in baseline in lower limb function compared with placebo-treated participants.