Forte Biosciences surges 55% on positive phase 1b vitiligo trial data

Forte Biosciences shares surged about 55% after FB102 showed a 29.6% mean FVASI improvement in vitiligo, beating placebo by 21.7 percentage points.

"These independently centrally-reviewed, placebo-controlled data demonstrate statistically significant FB102 mean FVASI improvements from baseline, with progressive improvement through week 24," Paul Wagner, chairman and chief executive officer of Forte Biosciences, said.

The 43-subject Phase 1b trial randomized patients 3-to-1 to FB102 or placebo over 12 weeks. In the protocol-defined efficacy-evaluable population, FB102 achieved a 29.6% mean FVASI improvement from baseline at week 24 versus 7.9% for placebo (p=0.020). Response was observed early, with statistically significant separation by day 64 (p=0.023). Among subjects with greater disease involvement — baseline FVASI of 0.75 or higher, representing roughly one-quarter facial depigmentation — FB102 produced a 43.2% mean improvement versus 0.5% for placebo (p=0.006), with 58.8% achieving at least a 50% improvement and 23.5% reaching a 75% improvement.

FB102-treated subjects continued to improve after completing the 12-week dosing period, with an additional 8 percentage point FVASI improvement between week 12 and week 24. Among those with baseline FVASI of 0.75 or higher, the improvement accelerated to an additional 14 percentage points. Overall, 84% of FB102-treated subjects improved from baseline, and none worsened, compared with 27% of placebo subjects who deteriorated. All adverse events were mild to moderate, with FB102 comparing favorably to placebo.

The results position FB102 as a potential competitor in the vitiligo treatment market, which currently has only one FDA-approved therapy, Incyte's Opzelura. FB102 is a proprietary anti-CD122 monoclonal antibody designed to modulate IL-2- and IL-15-dependent pathogenic T-cell biology while preserving regulatory T cells, according to the company. Forte has previously reported Phase 1b activity in celiac disease.

The 55% surge reflects strong investor optimism for a company targeting an underserved dermatology market affecting an estimated 1% to 2% of the global population. The positive data could attract partnership or acquisition interest from larger dermatology-focused pharmaceutical companies. Forte's next catalyst is the imminent readout from its ongoing Phase 2 celiac disease trial.

This article is for informational purposes only and does not constitute investment advice.