Argenx Expands Immunology Portfolio with $2.2B Buyout of Forte Biosciences

Argenx has agreed to acquire Forte Biosciences for $2.2 billion, the companies said, in a deal intended to expand the buyer’s immunology portfolio with an early clinical stage candidate that has shown promising data.

Earlier this month Forte announced positive results for its lead candidate FB102, from a Phase Ib trial assessing the anti-CD122 monoclonal antibody in vitiligo. FB102 achieved a 29.6% mean Facial Vitiligo Area Scoring Index (FVASI) improvement from baseline at week 24 (p-value = 0.020), with statistically significant improvements seen as early as Day 64 after dosing (p=0.023), continuing through week 24 after completion of the 12-week treatment period.

FB102 also achieved 43.2% mean FVASI improvement from baseline at week 24 (p-value = 0.006) in subjects with greater disease involvement having baseline FVASI ≥0.75 (approximately one-quarter of face depigmented). That percentage increased at 58.8% at FVASI50 but fell to 23.5% at FVASI75.

Forte announced positive Phase Ib data for FB102 last year in celiac disease, with Phase II data expected to be released in the second half of this year.

The celiac disease and vitiligo studies were key drivers, Argenx said, of its decision to go from being a strategic investor in Forte to acquiring the company, since the clinical data covers indications with significant unmet need and limited treatment options. Argenx was among investors in Forte’s $150 million public offering (5,709,936 shares priced at $26.27), which closed in April.

Pipeline-in-a-product

As with Forte, Argenx reasons that FB102 is a pipeline-in-a-product because of its potential to treat alopecia areata and additional autoimmune diseases. FB102 adds to Forte’s pipeline a mechanism focused on pathogenic T-cell and NK-cell activity, which according to the company broadens its ability to pursue diseases driven by different dimensions of the immune system.

“The addition of FB102 to our portfolio aligns perfectly with the Argenx playbook: compelling biology, strong clinical validation and broad potential to address patient need,” Argenx CEO Karen Massey said in a statement.

Argenx says FB102 complements its antibody-based portfolio, which is led by marketed drugs Vyvgart^® (efgartigimod alfa-fcab) injection, indicated to treat adults with generalized myasthenia gravis (gMG); and Vyvgart Hytrulo^® (efgartigimod alfa and hyaluronidase-qvfc), a subcutaneous treatment combination of the neonatal Fc receptor blocker and endoglycosidase that is indicated for gMG and chronic inflammatory demyelinating polyneuropathy (CIDP).

Vyvgart and Vyvgart Hytrulo comprise a blockbuster franchise, having generated $2.813 billion in the first half of this year, up 62% from $1.739 billion in January-June 2025. The franchise racked up $4.151 billion in all of 2025, up 90% from $2.186 billion in 2024.

“The company is setting itself up for continued growth beyond the Vyvgart peak that is anticipated in the first half of the 2030s,” analysts at Van Lanschot Kempen wrote in a research note, as reported by Bloomberg News. “All in all, the right deal at the right time.”

40% surge

Forte’s investors appeared to share that upbeat sentiment, as the company’s shares traded on Nasdaq surged about 40% Monday on news of the deal, to $76.50 from $54.78 at Friday’s close. Argenx’s ordinary shares traded on Euronext Brussels slid 1.8%, to €789.80 ($895.67) from €804.40 ($913.24), while American Depositary Shares (ADSs) traded on Nasdaq fell 3%, to $888.82 from $918.22.

Under its generic name, efgartigimod is also being developed for ocular myasthenia gravis (oMG), primary immune thrombocytopenia (ITP), Graves’ disease, myositis and related diseases (Immune-mediated necrotizing myopathy or IMNM; Antisynthetase syndrome or ASyS; and diabetic myositis); Sjogren’s disease (partnered with IQVIA); systemic sclerosis; and antibody mediated rejection or AMR.

Also in Argenx’s pipeline is:

• Empasiprubart (formerly ARGX-117), designed to be a humanized sweeping antibody that binds specifically to C2 in a pH- and Ca²⁺-dependent manner. Empasiprubart is in registrational studies for CIDP and multifocal motor neuropathy (MMN), and in proof-of-concept studies for delayed graft function (DGF).
• Adimanebart, a MuSK-targeting candidate in proof-of-concept studies for congenital myasthenic syndromes (CMS) and spinal muscular atrophy (SMA).
• Four Phase I candidates, all with undisclosed indications: ARGX-109 targeting IL-6, ARGX-121 targeting IgA, ARGX-124 targeting FcRn and ARGX-213, which also targets FcRn.
• Three preclinical candidates: ARGX-118, a Galectin-10 targeting candidate for airway inflammation; ARGX-125, undisclosed target and indication; and TSP-101, also undisclosed target and indication.

Acquiring Forte will build upon Argenx’s Vision 2030 strategy, which sets goals of treating 50,000 patients globally with its treatments, securing 10 labeled indications across its approved medicines, and progressing five pipeline candidates into Phase III development, all by 2030.

“Our Vision 2030 strategy is well-defined and on track, and our discovery, development and commercialization engines are delivering real value for patients,” Massey added. “The acquisition of Forte Biosciences builds on the strength of that foundation and advances our ambition to be the leading immunology innovator of the future.”

The boards of Argenx and Forte have approved the transaction, which is expected to close in the third quarter.

Through a wholly owned subsidiary, Argenx plans to launch a cash tender offer to acquire all outstanding shares of Forte’s common stock at $77 per share cash. The deal price represents an approximately 86% premium to Forte Biosciences’ volume-weighted average price (VWAP) since reporting positive Phase Ib data in vitiligo on July 9.

The tender offer is subject to the tender of at least a majority of the outstanding shares of Forte Biosciences, the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, and other customary closing conditions.

Upon successful completion of the tender offer, a wholly owned subsidiary of Argenx will merge with Forte Biosciences, and the outstanding Forte Biosciences shares not tendered in the tender offer will be converted into the right to receive the same $77 per share in cash paid in the tender offer.

“We are incredibly proud of what we have achieved in advancing FB102 through clinical development and firmly believe that Argenx is the ideal strategic partner to unlock the full potential of this novel anti-CD122 antibody across a broad range of autoimmune diseases,” stated Paul A. Wagner, PhD, Forte’s CEO and chairperson.

“By combining FB102’s promising clinical profile with Argenx’s proven development expertise, global reach and commercial capabilities, we have a unique opportunity to accelerate its development and maximize its impact for patients living with vitiligo, celiac disease, alopecia areata and other autoimmune conditions,” Wagner added. “We are excited about the future of FB102 and the potential to bring this innovative therapy to many more patients worldwide.”

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