Forte Biosciences Reports Positive Phase Ib Results for FB102 Vitiligo Treatment

The anti-CD122 monoclonal antibody demonstrated significant improvements in facial vitiligo scores, with results supporting further clinical development in autoimmune dermatology. Forte Biosciences has reported positive Phase Ib clinical data for FB102, an investigational anti-CD122 monoclonal antibody being developed as a potential treatment for vitiligo.

The company said the therapy demonstrated significant improvements in facial vitiligo severity compared with placebo, while maintaining a favourable safety profile.

Following the data announcement, shares in Forte Biosciences rose more than 55%, reflecting investor optimism around FB102’s potential to become a new treatment option for patients with autoimmune skin disease.

How FB102 Works

FB102 is designed to block CD122, a receptor involved in signalling pathways associated with interleukin-2 (IL-2) and interleukin-15 (IL-15).

These immune pathways play an important role in regulating pathogenic T-cell activity linked to autoimmune diseases.

Unlike approaches that exclusively target IL-15 signalling, Forte believes selective CD122 modulation may provide broader immune pathway control while preserving regulatory T-cell activity.

Phase Ib Trial Shows Improvement in Vitiligo Symptoms

In the Phase Ib study, FB102 demonstrated improvements across multiple measures of facial vitiligo severity.

In the intent-to-treat population, patients receiving FB102 achieved a 29.6% mean improvement in Facial Vitiligo Area Scoring Index (FVASI) from baseline to week 24.

This compared with a 16.2% worsening among placebo patients, representing a placebo-adjusted benefit of 45.8% in favour of FB102.

Among patients with more extensive facial disease, FB102 produced a 43.2% mean improvement at week 24 compared with 0.5% for placebo.

Nearly 59% of these patients achieved FVASI50, representing at least a 50% improvement in facial vitiligo, while 23.5% achieved FVASI75.

Treatment Effects Continued After Dosing Ended

Forte reported that FB102 demonstrated an early onset of activity, with statistically significant improvements observed by day 64.

Importantly, improvements continued after treatment ended, with an additional eight percentage point improvement in FVASI scores between weeks 12 and 24 despite dosing stopping after 12 weeks.

The company said FB102 was generally well tolerated, with adverse events described as mild-to-moderate and a safety profile comparable with placebo.

Vitiligo Treatment Landscape

Vitiligo is a chronic autoimmune condition where immune-mediated destruction of melanocytes causes loss of skin pigmentation.

The disease affects millions of people worldwide and can significantly impact quality of life.

Currently, Incyte’s Opzelura (ruxolitinib) cream remains the only FDA-approved therapy specifically indicated for repigmentation in non-segmental vitiligo.

Competition in the space is increasing, with Incyte also advancing oral povorcitinib, a JAK1 inhibitor that recently achieved positive Phase III results in vitiligo trials.

Next Steps for FB102

Forte Biosciences is continuing development of FB102 across autoimmune diseases.

The company is also evaluating the therapy in coeliac disease, where Phase II data could provide another important clinical milestone.

Positive results in vitiligo could position FB102 as a differentiated immunology approach targeting underlying disease biology rather than only treating symptoms.

Why This Matters

The latest results add to growing interest in immune-modulating therapies for dermatology and autoimmune disease.

While existing treatments such as JAK inhibitors have demonstrated clinical benefit, new approaches targeting specific immune pathways could expand treatment options for patients with moderate-to-severe vitiligo.

FB102 now moves forward as one of several emerging therapies aiming to reshape the future of autoimmune dermatology.

Summary

Forte Biosciences has reported positive Phase Ib results for FB102, an investigational anti-CD122 monoclonal antibody being developed as a potential treatment for vitiligo.

The therapy demonstrated significant improvements in facial vitiligo scores compared with placebo, with continued benefit observed after dosing ended and a favourable safety profile.

The results position FB102 as an emerging candidate in the growing vitiligo treatment landscape, where pharmaceutical companies are increasingly developing targeted immune therapies to improve repigmentation and address the underlying autoimmune drivers of the disease.

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