Forte's FB102 hits Week 24 vitiligo endpoint in placebo-controlled Phase 1b
FB102 produced a 29.6% mean facial-VASI improvement versus 7.9% for placebo at Week 24, with gains still building after the 12-week dosing period ended.
Executive Summary
- Forte Biosciences' Phase 1b vitiligo trial cleared its placebo-controlled primary endpoint, with facial depigmentation improving on FB102 and continuing to improve after dosing stopped.
- The readout gives FB102 a second positive human efficacy signal, following an earlier celiac disease result, both built on the same CD122-targeting mechanism.
- The randomized population behind the finding is small, and the company's own disclosure flagged a responder-rate quirk driven by a single placebo patient, which narrows how much weight the topline responder numbers can carry.
- Forte pointed investors toward its Phase 2 celiac disease trial as the next readout, positioning the vitiligo data as one data point in a broader push across multiple autoimmune indications for the same molecule.
The data
Forte Biosciences said FB102 produced a 29.6% mean improvement in facial vitiligo area scoring index (F-VASI) from baseline at Week 24, against 7.9% for placebo in the efficacy-evaluable population (p=0.020). In the placebo-adjusted intent-to-treat analysis, the company reported a 45.8% benefit for FB102 (p=0.005). The trial, registered as NCT06905873, tests FB102 against placebo in adults with confirmed non-segmental vitiligo, with F-VASI percent change from baseline as a registered primary endpoint alongside treatment-emergent and serious adverse event counts. FB102+1FB102 Achieves Statistically Significant Improvement in Vitiligo at Week 24 After Completion of 12-Week Treatment PeriodJul 9, 2026A Study to Evaluate the Safety and Efficacy of FB102 in Patients With Non-segmental VitiligoNCT06905873
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
Depth of response
Among subjects with more extensive baseline disease (F-VASI of 0.75 or higher, roughly one-quarter of the face depigmented), FB102 produced a 43.2% mean improvement at Week 24 (p=0.006), with 58.8% reaching FVASI50 and 23.5% reaching FVASI75. Overall, 84% of FB102-treated subjects (27 of 32) improved from baseline to Week 24 after the 12-week treatment period ended, and none worsened, while 27% of placebo subjects (3 of 11) worsened over the same 24 weeks. FB102-treated subjects continued to gain an additional 8 percentage points of FVASI improvement between Week 12 and Week 24, after dosing had already stopped, with that continued-gain pattern reaching 14 percentage points in the more severely affected subgroup. FB102FB102 Achieves Statistically Significant Improvement in Vitiligo at Week 24 After Completion of 12-Week Treatment PeriodJul 9, 2026
The responder caveat
Forte disclosed that its overall responder analysis, FVASI50 in 34.4% of FB102-treated subjects and FVASI75 in 12.5%, was affected by a single placebo patient who also reached FVASI75, a dynamic the company said underscores the importance of randomization and baseline severity when reading vitiligo responder endpoints. The trial safety profile was described as favorable, with FB102 compared favorably to placebo on adverse events limited to mild-to-moderate severity. FB102FB102 Achieves Statistically Significant Improvement in Vitiligo at Week 24 After Completion of 12-Week Treatment PeriodJul 9, 2026
Program context
FB102 first showed a positive human signal in celiac disease, where a separate Phase 1b trial met a composite histological endpoint (mean VCIEL change of -1.849 for placebo versus 0.079 for FB102, p=0.0099) with no grade 3 or higher adverse events in the FB102 arm. Forte's chief executive said at the time that the celiac results supported the biology of FB102's other target indications, including vitiligo, alopecia areata and type 1 diabetes. No other industry-sponsored trial currently targets CD122 in vitiligo, leaving FB102 without a direct same-target comparator in this indication; the closest active competitors in vitiligo, including AbbVie's upadacitinib and InnoCare's ICP-332, work through JAK or other unrelated mechanisms. ForteForte Biosciences Announces Positive Data in FB102 Celiac Disease Phase 1B StudyJun 23, 2025
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.