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

Argenx SE (NASDAQ:ARGX) on Monday announced it would discontinue the Phase 3 UplighTED studies evaluating efgartigimod subcutaneous (SC) (efgartigimod alfa and hyaluronidase-qvfc) in adults with moderate to severe thyroid eye disease (TED).

The decision is based on the recommendation from an Independent Data Monitoring Committee (IDMC) to stop the trials for futility following its review of data from a pre-specified interim analysis.

Efgartigimod showed a favorable safety and tolerability profile, and no new safety signals were identified.

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"We are disappointed the studies did not meet our desired outcome…," said Luc Truyen, Chief Medical Officer at argenx.

The IDMC conducted a futility evaluation of unblinded data from patients completing 24 weeks in the Phase 3 studies.

Following the closeout and database lock, Argenx will conduct a comprehensive analysis of the data.

Data from the studies will be shared at a future medical meeting.

UplighTED Study Design

The Phase 3 studies are designed to evaluate the efficacy, safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity of efgartigimod PH20 SC administered by prefilled syringe in adult participants with thyroid eye disease.

The primary endpoint is measured as the percentage of participants who were proptosis (bulging eyes) responders at week 24.

Key secondary endpoints include change in proptosis measurement in the study eye from baseline up to week 24, change in the total Graves' Orbitopathy Quality of Life (GO-QoL) score from baseline up to week 24, and percentage of participants with resolution of diplopia at week 24.

Analyst Take

William Blair on Monday, "The news came as a bit of a surprise, given external data in the clinically related Graves' disease showing ability of FcRn inhibition to drive strong response rates, clearly raising additional questions on the biological differences between the two diseases."

Analyst Phipps highlights that the announcement comes as a positive for the IGF-1R antibody class, which remains the most effective treatment for TED.

Amgen Inc.'s (NASDAQ:AMGN) Tepezza is the only FDA-approved drug for TED, but analyst Matt Phipps expects Viridian Therapeutics Inc.'s (NASDAQ:VRDN) veligrotug to receive FDA approval in 2026.

William Blair had modeled peak TED sales for Vyvgart at $550 million, assuming a 60% probability of success, viewing the indication as a meaningful but secondary opportunity compared with larger programs in myositis and Sjögren's disease.

Citing the strong Vyvgart launch—especially uptake of the prefilled syringe—and additional commercial expansion opportunities, analyst Phipps maintains the Outperform rating.

ARGX Price Action: argenx shares were down 4.86% at $835.31 at the time of publication on Monday, according to Benzinga Pro data.

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