Bimekizumab Maintains Clinical Response in HS Across Subgroups at 3 Years

Data from the BE HEARD EXT open-label extension have now extended the phase 3 record for bimekizumab in hidradenitis suppurativa (HS) to 3 years, and the picture that emerges is one of deepening, durable response — across diverse patient subgroups, disease severities, and disease durations.^1-3 Three posters presented at the 2026 American Academy of Dermatology Annual Meeting synthesized these findings, each approaching the long-term dataset from a distinct clinical angle.

Consistent Responses Across Patient Subgroups

The first analysis, led by Sayed and colleagues, examined whether bimekizumab's efficacy held up across the kinds of demographic and clinical heterogeneity that characterize real-world HS populations.¹ Using pooled data from BE HEARD I&II and BE HEARD EXT, the investigators reported HiSCR50 and HiSCR90 outcomes at years 1, 2, and 3 for subgroups defined by age, sex, body weight, BMI, Hurley stage, prior biologic exposure, and disease duration.

The overall bimekizumab total population (N=556) achieved HiSCR50 rates of 79.9%, 84.6%, and 90.2% at years 1, 2, and 3, respectively — a trajectory that ran broadly parallel across all subgroups examined. At year 3, HiSCR50 achievement was at or above 87.2% in every subgroup reported, including those with Hurley stage III disease (88.5%), BMI ≥35 kg/m² (87.2%), and prior biologic exposure (89.7%).

The deeper response threshold, HiSCR90, followed a similarly consistent pattern, though — as expected — at lower absolute rates. Overall HiSCR90 reached 42.3% at year 1, rising to 56.8% at year 2 and 64.3% at year 3. Notably, the data suggest that deeper responses continue to accumulate over time: patients who had not yet achieved HiSCR90 at one year were still gaining ground by year 3, regardless of subgroup. Even among patients with prior biologic exposure — historically a more challenging population — HiSCR90 at year 3 reached 65.4%. The authors concluded that bimekizumab provides consistent long-term efficacy regardless of patient demographics or disease characteristics.

Sustained Flare-Free Status Through 3 Years

A second analysis from Daveluy and colleagues focused specifically on flare outcomes — a clinically meaningful endpoint given the significant morbidity that acute exacerbations impose on HS patients.² A flare was defined as a ≥25% increase in abscess and inflammatory nodule (AN) count from baseline, with an absolute AN increase of ≥2.

In the bimekizumab total group, the cumulative proportion of patients remaining flare-free was 88.0% at week 16, and remained substantial through the 3-year period, reported at 83.8% at year 1, 83.7% at year 2, and 86.1% at year 3. The proportion experiencing a flare at any given clinic visit — a point-in-time measure — declined markedly over the treatment course, dropping from 5.3% at week 16 to 2.2% at year 1 and 0.9% at year 2, reaching 0% at year 3 among patients who remained in the study.

When stratified by baseline Hurley stage, patients with stage II disease demonstrated numerically lower flare rates through year 1 compared to those with stage III. By year 3, however, flare rates were comparably low across both subgroups among patients who continued treatment — 0% for both Hurley II and III at the final timepoint. The authors note that this convergence over time may reflect the progressive anti-inflammatory effect of sustained dual IL-17A/F inhibition, and suggest that initiating bimekizumab in stage II patients may allow for more rapid control of inflammatory flares early in the treatment course.

Earlier Treatment Yields Greater Response Depth

The third poster, presented by Chovatiya and colleagues, examined the influence of disease duration and baseline severity on response depth — a question with direct clinical relevance given the longstanding underdiagnosis problem in HS.³ The investigators compared outcomes in 2 contrasting subgroups: patients in the lowest disease duration quartile with moderate (Hurley stage II) disease at baseline (duration <2.38 years; n=85), and patients in the highest disease duration quartile with severe (Hurley stage III) disease (duration ≥10.74 years; n=52).

Both groups demonstrated clinically meaningful responses by year 1 that continued to improve through year 3. However, the differences were most pronounced at the deeper response thresholds. At year 3, patients with shorter, moderate disease achieved HiSCR50 in 91.4%, HiSCR75 in 87.9%, HiSCR90 in 74.1%, and HiSCR100 in 62.1% of cases. In the longer-duration, severe disease group, corresponding figures were 84.8%, 78.8%, 51.5%, and 33.3%. The gradient widened progressively from HiSCR50 to HiSCR100, suggesting that disease burden accrued over time specifically constrains the achievability of complete or near-complete lesion clearance.

The authors frame these findings within the concept of a "window of opportunity" in HS — a period early in the disease course when inflammation may be most amenable to control and when fibrotic, structural changes have not yet permanently altered the tissue architecture. Their data are consistent with emerging evidence that delayed treatment start, common in HS due to diagnostic lag, may constrain the ceiling of biologic response even when therapy is eventually initiated.

Clinical Takeaways

Taken together, these 3 analyses reinforce bimekizumab's profile as a durable, broadly effective treatment for moderate to severe HS. The subgroup consistency data should provide reassurance that response rates are not substantially driven by patient selection, and the flare data add a dimension — acute exacerbation prevention — that is often underweighted in pivotal trial endpoints but highly relevant to patients. Perhaps most clinically actionable is the disease duration analysis, which strengthens the case for early biologic intervention and may help practitioners and payers alike reframe the rationale for not waiting until Hurley stage III before escalating therapy.

References

1. Sayed C, Porter M, Molina-Leyva A, et al. Bimekizumab efficacy by patient subgroups in moderate to severe hidradenitis suppurativa: 3-year phase 3 results from BE HEARD EXT. Poster presented at the 2026 American Academy of Dermatology Annual Meeting. Denver, Colorado. March 27-31, 2026. https://eposters.aad.org/s3/AM2026/poster/73230/Bimekizumab+efficacy+by+patient+subgroups+in+moderate+to+severe+hidradenitis+suppurativa+3-year+phase+3+results+from+BE+HEARD+EXT.pdf
2. Daveluy S, Naik H, Reguiai Z, et al. Bimekizumab leads to sustained flare-free status in moderate to severe hidradenitis suppurativa: 3-year data from BE HEARD EXT. Poster presented at the 2026 American Academy of Dermatology Annual Meeting. Denver, Colorado. March 27-31, 2026. https://eposters.aad.org/s3/AM2026/poster/73493/Bimekizumab+leads+to+sustained+flare-free+status+in+moderate+to+severe+hidradenitis+suppurativa+3-year+data+from+BE+HEARD+EXT.pdf
3. Chovatiya R, Alavi A, Shi V, et al. Bimekizumab efficacy by disease duration and severity in moderate to severe hidradenitis suppurativa: 3-year phase 3 results from BE HEARD EXT. Poster presented at the 2026 American Academy of Dermatology Annual Meeting. Denver, Colorado. March 27-31, 2026. https://eposters.aad.org/s3/AM2026/poster/73498/Bimekizumab+efficacy+by+disease+duration+and+severity+in+moderate+to+severe+hidradenitis+suppurativa+3-year+phase+3+results+from+BE+HEARD+EXT.pdf