A phase 2 celiac disease trial of argenx’s FB102 has hit its primary endpoint, delivering a boost to a drug candidate that the biotech acquired in its $2.2 billion takeover of Forte Biosciences.
Amsterdam-based argenx agreed to buy Forte in July to acquire FB102, an anti-CD122 antibody that hit the mark in a phase 1b vitiligo trial weeks before the deal. Forte already had phase 1 data in celiac disease by then. With Teva’s rival drug candidate, TEV'408, clearing the bar in a phase 2a celiac disease clinical trial last month, analysts had high hopes that FB102 would pass its midstage test.
The phase 2 trial linked FB102 to statistically significant improvement in villus height–to–crypt depth (Vh:Cd) compared to placebo at Day 78. The biotech generated the data in 126 adults with celiac disease undergoing an oral gluten challenge, providing evidence that blocking CD122 can prevent gluten-induced intestinal damage.
Argenx named Vh:Cd, a measure of gut health, as the primary endpoint. Teva also used Vh:Cd as its primary endpoint. In addition, Argenx said the VCIEL result—which combines Vh:Cd with a measure of inflammation—was “consistent with the primary endpoint” in this morning's readout.
VCIEL was one of a clutch of measures that argenx said were consistent with the primary endpoint. The results provided additional evidence of FB102’s histologic, inflammatory and clinical effects, the biotech said. However, argenx has yet to share data beyond the 0.0176 p value for the Vh:Cd analysis. Safety was consistent with prior studies, the company said.
Based on the data, argenx plans to advance FB102 into phase 3 development. The plan keeps argenx at the forefront of efforts to treat celiac disease by inhibiting IL-15 signaling pathways.
FB102 targets CD122 to inhibit IL-2 and IL-15 pathways. Teva’s TEV'408 is an anti-IL-15 antibody, while Amgen and Novartis were studying IL-15 drugs in celiac disease but discontinued development.
With Teva planning (PDF) to run another phase 2 trial before entering pivotal development, argenx has a shot at beating its rival to a blockbuster opportunity. In July and September notes to investors, TD Cowen analysts predicted that FB102 could launch in celiac disease in 2031, followed by TEV'408 in 2034. The analysts see celiac disease as a blockbuster market.
Argenx is also testing FB102 in vitiligo and alopecia.
Bringing FB102—which argenx is also testing in vitiligo and alopecia—to market could lessen the company’s reliance on efgartigimod, the FcRn drug that the biotech sells as Vyvgart and Vyvgart Hytrulo. Argenx published details of FB102’s success alongside news that efgartigimod has flunked a phase 3 Sjögren’s disease trial. TD Cowen analysts expected positive data in the indication in mid-2027. However, argenx stopped the trial early because it was destined to fail.
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