Forte Biosciences announced positive results from its double-blind, placebo-controlled Phase 1b study of FB102 in patients with vitiligo, reporting statistically significant improvements in disease activity that continued for months after treatment ended.
The company said FB102 demonstrated a 29.6% mean improvement from baseline in Facial Vitiligo Area Scoring Index (FVASI) at Week 24, reaching statistical significance, after patients completed only a 12-week treatment period.
The treatment effect emerged early and continued to build over time, with statistically significant improvement observed as soon as Day 64 and maintained through Week 24.
Forte said the results support FB102’s ability to target key immune pathways involved in vitiligo by modulating both IL-2– and IL-15–dependent pathogenic T-cell biology while preserving regulatory T cells.
Among patients with greater disease involvement — those with baseline FVASI scores of 0.75 or higher, representing approximately one-quarter facial depigmentation — FB102 produced a 43.2% mean FVASI improvement at Week 24 compared with placebo, achieving statistical significance.
In this more advanced patient group: 58.8% achieved FVASI50, representing at least 50% improvement; 23.5% achieved FVASI75, representing at least 75% improvement.
Forte highlighted that improvement continued even after dosing stopped. FB102-treated patients recorded an additional 8 percentage point improvement between Week 12 and Week 24, while patients with higher baseline disease severity improved an additional 14 percentage points during the same period.
The company reported that 84% (27/32) of FB102-treated patients improved from baseline through Week 24, and none worsened, compared with 27% (3/11) of placebo patients who experienced disease worsening.
Safety results remained favorable, with adverse events reported as mild to moderate and FB102 continuing to compare favorably with placebo.
"With statistically significant placebo-controlled activity now demonstrated in vitiligo and the prior Phase 1b activity demonstrated in celiac disease, we look forward to the imminent readout from our ongoing Phase 2 celiac disease trial as the next important clinical catalyst for FB102,” said Paul Wagner, Chairman and CEO of Forte Biosciences.
“Forte’s optimized FB102 blockade of CD122 was designed to modulate both IL-2– and IL-15–dependent pathogenic T-cell biology while preserving regulatory T cells, and clinical data to date support this profile.
"This may enable broader immune pathway modulation than IL-15 blockade alone and may avoid the regulatory T-cell modulation that can occur with overly potent CD122 inhibition. Data from this Phase 1b vitiligo study and from the previously reported Phase 1b trial in celiac disease reinforce the activity and broad potential for FB102.”
