Safety and clinical activity of atacicept in the long-term extension of the phase 2b ADDRESS II study in systemic lupus erythematosus.

Daniel J Wallace, David A Isenberg, Eric F Morand, Cristina Vazquez-Mateo, Amy H Kao, Aida Aydemir, Kishore Pudota, Victor Ona, Cynthia Aranow, Joan T Merrill

Rheumatology (Oxford, England) 2021 Nov 03

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Atacicept reduced SLE disease activity in the phase 2b ADDRESS II study, particularly in patients with high disease activity (HDA; SLEDAI-2K ≥10) at screening. We assessed long-term safety and efficacy of atacicept in the long-term extension (LTE) of ADDRESS II. In the 24-week, randomized, double-blind, placebo-controlled ADDRESS II study, patients received weekly atacicept (75 or 150 mg) or placebo. Atacicept was continued at the same dose in atacicept-treated patients in the LTE; placebo-treated patients switched to atacicept 150 mg. Long-term safety was the primary endpoint. Secondary endpoints included SLE responder index (SRI)-4 and SRI-6 response rates and flares. In total, 253 patients entered the ADDRESS II LTE; 88 received atacicept 150 mg, 82 atacicept 75 mg and 83 placebo/atacicept 150 mg. Median active treatment duration in the LTE was 83.8 weeks. Frequencies of treatment-emergent adverse events (TEAEs) were similar across groups (90.4-93.2%), and 12.5%, 14.6% and 21.7% of patients in the atacicept 150 mg, atacicept 75 mg and placebo/atacicept 150 mg groups reported serious TEAEs during the treatment period. The proportions of patients with TEAEs leading to discontinuation were 5.7%, 4.9% and 10.8%, respectively. SRI-4 and SRI-6 response rates were maintained with atacicept in the modified intent-to-treat and HDA populations and those on continuous 150 mg had a reduced risk of first severe flare and longer time to first severe flare vs those who initially received placebo. Long-term treatment with atacicept 150 mg in SLE patients had an acceptable safety profile, with durable efficacy. ClinicalTrials.gov, http://clinicaltrials.gov, NCT02070978. © The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology.

Citation

Daniel J Wallace, David A Isenberg, Eric F Morand, Cristina Vazquez-Mateo, Amy H Kao, Aida Aydemir, Kishore Pudota, Victor Ona, Cynthia Aranow, Joan T Merrill. Safety and clinical activity of atacicept in the long-term extension of the phase 2b ADDRESS II study in systemic lupus erythematosus. Rheumatology (Oxford, England). 2021 Nov 03;60(11):5379-5389