argenx acquires Forte Biosciences, adding anti-CD122 antibody
argenx has completed the acquisition of Forte Biosciences, adding FB102, a clinical-stage anti-CD122 monoclonal antibody, to its immunology pipeline. The deal closed on 27 August 2026, with argenx paying $77.00 per share in cash through a subsidiary tender offer. As of expiry, approximately 87% of Forte's outstanding shares had been tendered, and a subsequent merger converted the remainder at the same price. Forte's stock has been delisted from the Nasdaq Capital Market.
FB102 targets CD122, a receptor subunit involved in signalling for interleukin-2 and interleukin-15, pathways that drive pathogenic T-cell and natural killer cell activity. The antibody has generated clinical proof-of-concept data in vitiligo, with results reported in July 2026, and in coeliac disease, where positive Phase 1 data were announced in June 2025. A Phase 2 coeliac disease study is ongoing with a readout expected in the second half of 2026, and a Phase 1b trial in alopecia areata is also running with data due in the same window.
Karen Massey, chief executive of argenx, said FB102 "does exactly that with a potential first-in-class molecule targeting diseases with few treatment options today", adding that the deal is a step toward the company's Vision 2030 ambition to become the leading immunology innovation company.
Strategic fit
FB102 adds a distinct mechanism to argenx's existing antibody portfolio, which includes efgartigimod, its commercialised neonatal Fc receptor blocker, alongside empasiprubart, adimanebart, and ARGX-121. Where efgartigimod reduces pathogenic IgG antibody levels, FB102 acts upstream on lymphocyte activity, giving argenx a broader toolkit across autoimmune disease subtypes. The company has characterised the acquisition as consistent with its "disciplined" business development approach, though it has not disclosed a total transaction value beyond the per-share price.
The anti-CD122 mechanism is not unique in concept. IL-15 pathway targeting has attracted interest from several other developers in autoimmune and inflammatory settings, meaning argenx will need strong Phase 2 data across FB102's indications to establish durable differentiation. The coeliac disease readout, expected before year-end, will be a near-term test of that thesis given the limited approved systemic options in that indication.
Market context
argenx has built one of the most closely watched immunology pipelines in European biotech, driven by efgartigimod's commercial rollout across myasthenia gravis and expanding indications. Bolt-on acquisitions of clinical-stage assets are a predictable lever as the company looks to sustain pipeline density beyond its existing programmes. The Forte deal is relatively modest in scale for a company of argenx's capitalisation, but the breadth of indications FB102 is being evaluated in, spanning vitiligo, coeliac disease, and alopecia areata, gives argenx optionality across conditions where patient advocacy is strong and regulatory precedent for novel mechanisms is growing. Upcoming clinical data across all three indications by the end of 2026 will be the primary near-term value inflection point investors will monitor.