argenx pays $2.2B for Forte’s early autoimmune promise

Why it matters: The deal turns an exploratory investment into a full takeover within four months. It also shows argenx is willing to pay heavily for early clinical validation as rising VYVGART sales give it more power to expand beyond its flagship franchise.

By the numbers: argenx will pay $77 per Forte share in cash. That represents an 86% premium to Forte’s volume-weighted average share price since its positive vitiligo data on July 9, or about 41% over its July 24 closing price. The acquisition, which will be funded from cash on hand, is expected to close in the third quarter of 2026. Both companies’ boards have approved the transaction.

Backstory: argenx had already taken a strategic position in Forte. An April 8 regulatory filing disclosed that argenx participated in Forte’s $150 million public offering, priced at $26.27 per share, although the size of its investment was not reported.

• This suggests argenx used the investment to gain an early view of FB102 before committing to the full acquisition. The decisive event appears to have been the subsequent vitiligo readout.

Zoom in: FB102 targets CD122, a receptor subunit shared by the IL-2 and IL-15 pathways. The antibody is designed to reduce pathogenic T-cell and natural killer cell activity attacking pigment-producing melanocytes in vitiligo and damaging the intestinal lining in celiac disease, while preserving regulatory T cells. Argenx describes the asset as a potential “pipeline in a product,” with possible applications beyond vitiligo and celiac disease, including alopecia areata.

• In a 43-patient, placebo-controlled Phase 1b vitiligo study, FB102 produced a 29.6% mean improvement in facial repigmentation at Week 24, compared with 7.9% for placebo. The benefit continued to increase for 12 weeks after treatment ended. Adverse events were mild to moderate. Forte’s stock jumped 78% following the announcement and kept climbing for several weeks.
• Last year, a separate 32-patient Phase 1b celiac disease trial also generated an early efficacy signal. Following a controlled gluten challenge, FB102 significantly reduced a composite measure of intestinal damage compared with placebo. Treated patients also had fewer inflammatory T cells and 42% fewer gastrointestinal symptom events.

Between the lines: These are small Phase 1b studies, and their results may not hold up in larger trials. Still, seeing placebo-controlled efficacy in two diseases at this stage helps explain why argenx accepted such a high premium. Phase 2 celiac disease data are expected in the second half of 2026 and will provide the first major test of that valuation.

Competitive context: FB102 is not the industry’s first attempt to target CD122. Incyte acquired Villaris Therapeutics in 2022 to obtain auremolimab, later called INCA034460, an anti-CD122 antibody intended for vitiligo. The deal included $70 million upfront and up to $1.36 billion in milestones.

• Incyte stopped the Phase 1 program in 2025. The company attributed the decision to broader pipeline prioritization and did not identify a safety problem with INCA034460.

Why now: The takeover comes four days after argenx reported $1.5 billion in second-quarter VYVGART sales, up 60% year over year. First-half sales reached $2.8 billion, while cash, cash equivalents and current financial assets totaled $5.2 billion at June 30.

• That financial strength gives argenx room to pursue its Vision 2030 goal of building a multi-asset immunology company but the Forte purchase will still consume more than 40% of its reported liquidity.

What to watch: The upcoming Phase 2 celiac readout will determine whether argenx bought a broadly applicable immunology mechanism or paid a substantial premium for signals that remain too early to reproduce.

The big picture: The deal reinforces a notable trend in biopharma M&A this year of European buyers targeting U.S. companies. Of the 20 transactions involving European-based companies recorded by our internal tracker, 12 involved a European company acquiring a U.S. target. These deals accounted for $26.75 billion (€23.51 billion) in upfront payments, representing 68% of the $39.37 billion (€34.60 billion) committed upfront across all tracked transactions.