Safety, tolerability, and efficacy of subcutaneous efgartigimod in patients with chronic inflammatory demyelinating polyradiculoneuropathy (ADHERE): a multicentre, randomised-withdrawal, double-blind, placebo-controlled, phase 2 trial.

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system that can lead to severe disability from muscle weakness and sensory disturbances. Around a third of patients do not respond to currently available treatments, and many patients with a partial response have residual neurological impairment, highlighting the need for effective alternatives. Efgartigimod alfa, a human IgG1 antibody Fc fragment, has demonstrated efficacy and safety in patients with generalised myasthenia gravis. We evaluated the safety, tolerability, and efficacy of subcutaneous efgartigimod PH20 in adults with CIDP.

METHODS

ADHERE, a multistage, double-blind, placebo-controlled trial, enrolled participants with CIDP from 146 clinical sites from Asia-Pacific, Europe, and North America. Participants with evidence of clinically meaningful deterioration entered an open-label phase of weekly 1000 mg subcutaneous efgartigimod PH20 for no longer than 12 weeks (stage A). Those with confirmed evidence of clinical improvement (ECI; treatment responders) entered a randomised-withdrawal phase of 1000 mg subcutaneous efgartigimod PH20 weekly treatment versus placebo for a maximum of 48 weeks (stage B). Participants were randomised (1:1) through interactive response technology and stratified by their adjusted Inflammatory Neuropathy Cause and Treatment (aINCAT) score change during stage A and their most recent CIDP medication within 6 months before screening. Investigators, the clinical research organisation, and participants were masked to the treatment. The primary endpoint in stage A, evaluated in the stage A safety population, was confirmed ECI (≥1 points aINCAT decrease, ≥4 points [centile metric] Inflammatory Rasch-built Overall Disability Scale increase, or ≥8 kPa grip strength increase after four injections and two consecutive visits). The primary endpoint in stage B, evaluated in the modified intention-to-treat population, was the risk of relapse (time to first aINCAT increase of ≥1 points). ADHERE is registered with ClinicalTrials.gov (NCT04281472) and EudraCT (2019-003076-39) and is completed.

FINDINGS

Between April 15, 2020, and May 11, 2023, 629 participants were screened; 322 (114 female, 208 male) entered stage A, of whom 214 (66%, 95% CI 61·0-71·6) had confirmed ECI. In stage B, 221 participants were randomised (79 female, 142 male; 111 to subcutaneous efgartigimod PH20, 110 to placebo). Subcutaneous efgartigimod PH20 significantly reduced the risk of relapse versus placebo (hazard ratio 0·39 [95% CI 0·25-0·61]; p<0·0001). 31 (27·9% [19·6-36·3]) participants given subcutaneous efgartigimod PH20 had a relapse versus 59 (53·6% [44·3-63·0]) given placebo. In stage A, treatment-emergent adverse events (TEAEs) occurred in 204 (63%) participants and serious TEAEs in 21 (7%). In stage B, TEAEs occurred in 71 (64%) participants on subcutaneous efgartigimod PH20 and 62 (56%) participants on placebo, and serious TEAEs in six (5%) on subcutaneous efgartigimod PH20 and six (5%) on placebo. Three deaths occurred: two in stage A (one non-related and one unlikely related to treatment) and one in stage B (placebo group).

INTERPRETATION

ADHERE showed the efficacy of subcutaneous efgartigimod PH20 in reducing the risk of relapse versus placebo in people with CIDP who responded to treatment. Further studies are needed to provide data on the longer-term effects of efgartigimod alfa and how it compares with currently available treatment options.

FUNDING

argenx.

Informations de copyright

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Déclaration de conflit d'intérêts

Declaration of interests JAA reports consulting fees from Akcea Therapeutics, Alexion, Alnylam, Annexon Biosciences, argenx, CSL Behring, Grifols, Immunovant, ImmuPharma, Johnson & Johnson, and Takeda, and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Alnylam, Annexon Biosciences, argenx, CSL Behring, and Takeda. TD reports participation on a data safety monitoring board or advisory board for Dianthus Therapeutics. CE reports grants or contracts from argenx; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from argenx; support for attending meetings and travel from argenx; and stock or stock options from argenx. AT was an employee of argenx, and reports stock or stock options at the time of the study completion. JTG is an employee of argenx; reports support for attending meetings and travel from argenx; and reports stock or stock options from argenx. BVH is an employee of argenx. PU is an employee of argenx; reports patents planned, issued, or pending from argenx; reports stock or stock options from argenx; and reports other financial or non-financial interests from argenx. EH is an employee of argenx; reports patents planned, issued, or pending from argenx; and reports stock or stock options from argenx. KGG reports consulting fees from Alexion, and UCB; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Alexion, argenx, and Xeris Pharmaceuticals; and leadership or fiduciary role in other board, society, committee, or advocacy group, paid or unpaid for Myasthenia Gravis Foundation of America. FL reports grants or contracts from German Ministry of Education and Research, German Research Society DFG, HORIZON MSCA 2022 Doctoral Network, and Stiftung Pathobiochemie of the German Society for Laboratory Medicine; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Bayer, Biogen, Fresenius, Grifols, Novartis, Roche, and Teva Pharmaceuticals; support for attending meetings and travel from Bayer, Grifols, and Merck; and participation on a data safety monitoring board or advisory board for argenx, Alexion, Biogen, and Roche. MLi reports grants or contracts from Kedrion Biopharma; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from CSL Behring, Kedrion Biopharma, and Takeda; support for attending meetings and travel from CSL Behring, Kedrion Biopharma, and Takeda; and other financial or non-financial interests from argenx. MLo was an employee of argenx at the time of the study completion. LQ reports grants or contracts from argenx, CIBERER, Instituto de Salud Carlos III–Ministry of Economy and Innovation (Spain), and UCB; consulting fees from Annexon Biosciences, Alnylam, argenx, Avilar Therapeutics, CSL Behring, Dianthus Therapeutics, Janssen, LFB, Novartis, Nuvig Therapeutics, Roche, Sanofi, and Takeda; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Alnylam, argenx, CSL Behring, Novartis, Roche, and Sanofi; support for attending meetings and travel from Alnylam and Sanofi; participation on a data safety monitoring board or advisory board for argenx, CSL Behring, Sanofi, and UCB; and a leadership or fiduciary role in other board, society, committee, or advocacy group, paid or unpaid, for Inflammatory Neuropathy Consortium and Peripheral Nerve Society. NS reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Alnylam, and participation on a data safety monitoring board or advisory board for Takeda. RY reports consulting fees from Japan Tobacco and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Alnylam Japan, CSL Behring, FP Pharm, Kyowa Kirin, Ono Pharmaceutical, and Takeda Pharmaceutical. RAL reports royalties or licenses from UpToDate; consulting fees from Annexon Biosciences, argenx, CSL Behring, Dianthus Therapeutics, Grifols, Immunovant, Janssen, Nuvig Therapeutics, Sanofi, and Takeda; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from argenx, CSL Behring, Medscape, and Sanofi; participation on a data safety monitoring board or advisory board for Boehringer Ingelheim and Novartis; and leadership or fiduciary role in other board, society, committee, or advocacy group, paid or unpaid, for Peripheral Nerve Society and GBS-CIDP Foundation International. PAvD reports support for attending meetings and travel from argenx and participation on a data safety monitoring board or advisory board for argenx. All other authors declare no competing interests.