Argenx SE has commenced a tender offer to acquire Forte Biosciences, Inc., the clinical-stage biopharmaceutical company advancing FB102, a proprietary anti-CD122 monoclonal antibody. The move adds a second mechanism—complementary to argenx's FcRn-blocking platform—into what is already a $12 billion market capitalization autoimmune franchise.
Forte's FB102 targets CD122, the beta subunit of the IL-2 and IL-15 receptor complex, implicating pathways distinct from argenx's flagship Vyvgart (efgartigimod). The asset has completed Phase 1 safety studies and is positioned for expansion into moderate-to-severe atopic dermatitis and potentially alopecia areata. Forte's enterprise value at last close was approximately $48 million, with $22 million in cash on the balance sheet as of Q2 2025. The tender represents a modest bolt-on acquisition in absolute terms, but the strategic aperture is wider—argenx is now building a dual-pronged immunology toolkit that can be layered or sequenced in IL-2/IL-15-driven indications.
The significance is in the optionality. Efgartigimod works by degrading pathogenic IgG; FB102 interrupts T-cell and NK-cell signaling upstream. For myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, and pemphigus, argenx already holds FDA approvals or late-stage readouts. Adding CD122 blockade opens a second vector into T-cell-mediated dermatology and potentially solid-organ transplant rejection, where IL-15 biology is implicated. The company is not disclosing deal consideration in the initial tender filing, but given Forte's run-rate burn of roughly $18 million annually and limited competitive tension, the headline multiple is likely modest—1.5x to 2.5x book, or $70 million to $120 million all-in. For argenx, that is less than two quarters of R&D spend and preserves optionality on a mechanism that pairs cleanly with its existing sales force and KOL network in neurology and dermatology.
Allocators should track three events. First, the tender acceptance threshold and close timeline—likely 30 to 45 days from commencement—will reveal whether argenx negotiated a go-shop or no-shop period and whether competing bids emerge from dermatology-focused acquirers like Incyte or Galderma. Second, any disclosure of combination trial plans pairing FB102 with efgartigimod in autoimmune dermatoses would signal accelerated capital deployment and validate the dual-mechanism thesis. Third, argenx's next quarterly call—expected mid-November 2025—will clarify whether this tender is the opening move in a broader tuck-in M&A campaign or a one-off opportunistic buy.
The tender is live. Forte's board has not yet filed a formal recommendation, which means argenx either has a pre-negotiated support agreement or is moving hostile. Given Forte's cash position and lack of near-term catalysts, the former is more probable. The clock on acceptance runs through early September.