argenx SE (ARGX) Down 14.1% — Should I Take Profits and Move On?
argenx SE (ARGX) is under heavy pressure this Thursday, last changing hands at $797.99 on the NASDAQ — a $130.45 drop from the prior close of $928.44. The decline erases a large share of the stock's recent strength. ARGX now trades roughly 25.6% below its 52-week high of $1,072.75, reached on September 2, 2026, so a little more than a month has been enough to undo a quarter of the stock's peak value. The shares still sit about 20.6% above the 52-week low of $661.85, but today's move pushes them meaningfully closer to the bottom of that range.
Volume is running at 894,123 shares, nearly 2.9 times the 90-day average of 313,667. That level of turnover on a double-digit decline points to decisive repositioning in the name.
Why argenx SE Price is Moving Lower
The selloff is a direct result of a late-stage clinical setback. argenx announced on October 8 that it will stop the Phase 3 UNITY trial of subcutaneous efgartigimod in adults with moderate-to-severe Sjögren's disease. An independent monitoring committee recommended halting the study for futility after an interim review concluded it was unlikely to meet its primary endpoint, which was change in systemic disease activity at Week 48. The company reported no new safety signals, so the problem is efficacy rather than tolerability. Even so, losing Sjögren's removes a sizable potential indication from efgartigimod's expansion path, and investors are repricing the franchise's long-term reach accordingly. The reaction was similar overseas, where the shares were down 15.7% to €707.40 in European trading.
argenx paired the UNITY news with a positive update that did little to offset it. The company's 126-patient Phase 2 study of FB102 in celiac disease met its primary endpoint with a statistically significant result (p=0.0176), and argenx plans to advance the drug into Phase 3. That result widens the pipeline. Still, FB102 is an earlier-stage asset, while efgartigimod is the engine behind the company's commercial growth, and the market weighted the setback for its lead molecule far more heavily.
Valuation sharpened the reaction. ARGX entered the session at a forward P/E of 60.71, a multiple that assumes efgartigimod keeps adding indications on top of an already rapidly growing commercial base. That base remains strong. Revenue reached $1.52 billion in the quarter ended June 30, up 17.8% from $1.29 billion in the prior reported quarter ended December 31, 2025, and trailing revenue growth stands at 59.36%. But a premium multiple leaves little cushion when a Phase 3 program fails. The broad Health Care group was also soft today, with Thermo Fisher Scientific Inc. (TMO) down 3.41% and Merck & Co., Inc. (MRK) off 2.12%. Those moves are a fraction of ARGX's decline, which confirms that today's damage is company-specific.
What is the argenx SE Rating - Should I Sell?
Weiss Ratings assigns ARGX a C rating. The rating was downgraded on 7/23/2026. Current recommendation is Hold. The downgrade came more than two months before today's trial news, which suggests Weiss's framework had already flagged a less favorable risk/reward balance while the stock was still climbing toward its September high. A C rating is not a sell signal. It does indicate that the case for holding rests on fundamentals strong enough to offset meaningful price risk.
Those fundamentals hold up well. The Excellent rating on the Solvency Index stands out for a biotech still expanding its commercial footprint, because it means argenx can absorb a failed Phase 3 program and fund the FB102 advance without straining its finances. The Good Growth Index rating reflects 59.36% revenue growth and the jump to $1.52 billion in quarterly sales, figures that show VYVGART's adoption is still accelerating. The Good rating on the Efficiency Index is supported by EPS of $15.33, an uncommon level of profitability for a company that was still building its commercial operation only a few years ago. The Total Return Index is also rated Good. Despite today's drop, the stock remains about 20.6% above its 52-week low, so longer-term holders are still ahead over the measurement period.
Where the picture becomes more cautious is the Fair rating on the Volatility Index. A 14% one-day decline driven by a single trial readout is exactly the kind of binary event risk that keeps this dimension from scoring higher. The stock's valuation depends heavily on pipeline milestones, and the UNITY outcome shows how quickly that dependence can cut the other way. This volatility, combined with a premium forward multiple, is the main reason the overall rating stays at C rather than moving into Buy territory.
Within the Health Care sector, argenx sits alongside Merck & Co., Inc. (MRK, C), Gilead Sciences, Inc. (GILD, C), and Pfizer Inc. (PFE, C). It trails Thermo Fisher Scientific Inc. (TMO, C+), which carries a modestly better risk/reward profile in Weiss's framework. ARGX stands apart from those large-cap peers mainly in its higher growth and its greater exposure to clinical outcomes.
About argenx SE
argenx SE (ARGX) is a commercial-stage biopharmaceutical company in the Health Care sector. Incorporated in 2008 and based in Amsterdam, the Netherlands, the company develops therapies for autoimmune diseases. It sells them in the United States, Japan, China, the Netherlands, and other international markets. Its commercial franchise is built on efgartigimod, a neonatal Fc receptor (FcRn) blocker. VYVGART is approved for generalized myasthenia gravis (gMG) and immune thrombocytopenia (ITP), while VYVGART HYTRULO, the subcutaneous formulation, treats gMG and chronic inflammatory demyelinating polyneuropathy (CIDP).
The company's strategy is to extend efgartigimod across a broad set of IgG-driven autoimmune conditions, with development work in seronegative gMG, ocular myasthenia gravis, primary ITP, Graves' disease, myositis, systemic sclerosis, and antibody-mediated rejection. Beyond efgartigimod, the pipeline includes empasiprubart for multifocal motor neuropathy, delayed graft function, and CIDP, and adimanebart for congenital myasthenic syndrome and spinal muscular atrophy. ARGX-213 is a next-generation FcRn antibody engineered for half-life extension and sustained IgG reduction, and ARGX-124 is another FcRn candidate. Earlier programs include ARGX-109 targeting IL-6, ARGX-121 targeting immunoglobulin A, and ARGX-118 directed against Galectin-10.
argenx's competitive position rests on its early lead in the FcRn class and on partnerships that extend its reach. Zai Lab co-develops and commercializes efgartigimod in its territories. Halozyme Therapeutics' ENHANZE technology enables the subcutaneous VYVGART HYTRULO formulation. OncoVerity, Inc. holds rights to cusatuzumab, and AbbVie, Inc. is partnered on ARGX-115. Together, the commercial products, the multi-indication strategy, and the next-generation FcRn candidates give argenx several ways to build on its lead in autoimmune immunology.
Investor Outlook
argenx SE (ARGX) carries a Weiss Rating of C (Hold). The UNITY futility stop is a real blow to efgartigimod's expansion story, even though the commercial business underneath it remains strong. Investors should watch whether VYVGART revenue keeps growing from the $1.52 billion quarterly level, how quickly FB102 moves into Phase 3, and whether the remaining efgartigimod indications deliver cleaner readouts that can support the stock's premium valuation. See full rankings of all C-rated Health Care stocks inside the Weiss Stock Screener.
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