Argenx Halts Phase 3 Thyroid Eye Disease Trial, Peers Like Viridian Therapeutics To Benefit

Core Insights - Argenx SE has decided to discontinue the Phase 3 UplighTED studies for efgartigimod in adults with moderate to severe thyroid eye disease (TED) based on an Independent Data Monitoring Committee's recommendation due to futility [1][3] Study Design and Outcomes - The Phase 3 studies aimed to evaluate the efficacy, safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity of efgartigimod PH20 SC in adult participants with TED, with the primary endpoint being the percentage of participants who were proptosis responders at week 24 [4] - Key secondary endpoints included changes in proptosis measurement, total Graves' Orbitopathy Quality of Life (GO-QoL) score, and the percentage of participants with resolution of diplopia at week 24 [5] Safety Profile - Efgartigimod demonstrated a favorable safety and tolerability profile, with no new safety signals identified during the trials [2] Market Implications - The discontinuation of the studies raises questions about the biological differences between TED and related conditions, as noted by analysts [6] - Amgen's Tepezza is currently the only FDA-approved drug for TED, while Viridian Therapeutics' veligrotug is expected to receive FDA approval in 2026 [7] - Analyst projections for peak TED sales for Vyvgart are estimated at $550 million, assuming a 60% probability of success, indicating a secondary opportunity compared to larger programs [7] - Following the news, Argenx shares fell by 4.86% to $835.31 [8]