Highlights
- Bimekizumab, a dual IL-17A and IL-17F inhibitor, provides deep and sustained clinical responses in moderate to severe hidradenitis suppurativa (HS) through 96 weeks of treatment.
- The BE HEARD extension data shows that over 85% of patients achieved HiSCR50 by Year 2, with significant proportions reaching the rigorous HiSCR90 and HiSCR100 benchmarks.
- Safety outcomes remained stable over the long term, with exposure-adjusted incidence rates of adverse events actually decreasing between Year 1 and Year 2.
- Long-term treatment resulted in sustained improvements in skin pain and health-related quality of life (HRQoL), addressing critical patient-reported unmet needs in HS management.
Background
Hidradenitis suppurativa (HS) is a debilitating, chronic inflammatory skin disease characterized by recurrent, painful nodules, abscesses, and draining tunnels, typically in intertriginous areas. The pathophysiology of HS is complex, involving follicular occlusion and immune-mediated inflammation. For decades, therapeutic options for moderate-to-severe disease were limited, with adalimumab (an anti-TNF agent) serving as the primary biologic standard of care. However, many patients fail to achieve or maintain an adequate response to TNF inhibition, highlighting a substantial unmet need for therapies with different mechanisms of action and higher durability.
Recent research has identified the IL-23/IL-17 axis as a central driver of HS inflammation. While IL-17A has been the primary target of earlier inhibitors like secukinumab, IL-17F is also highly expressed in HS lesions and shares structural homology with IL-17A. Bimekizumab is a humanized IgG1 monoclonal antibody that selectively inhibits both IL-17A and IL-17F. By neutralizing both isoforms, bimekizumab aims to suppress the inflammatory cascade more comprehensively than agents targeting IL-17A alone. The BE HEARD I and II trials were designed to evaluate the efficacy and safety of this dual inhibition over a short-term period, while the BE HEARD Extension provides the crucial long-term evidence needed for chronic management.
Key Content
Study Design and Clinical Program Overview
**Refining the Framework**
I am now focusing on structuring the article, incorporating the data on Bimekizumab’s efficacy and safety from BE HEARD I & II and the extension study. I plan to flesh out the introduction with the pathology of Hidradenitis Suppurativa, the impact on QoL, and include the specifics of the trial design (320mg Q2W/Q4W). I will specifically break down the HiSCR data and patient-reported outcomes.
The evidence base for bimekizumab in HS stems from two identical, randomized, double-blind, placebo-controlled phase 3 trials: BE HEARD I and BE HEARD II. These trials enrolled adults with moderate-to-severe HS (defined by total abscess and inflammatory nodule [AN] count ≥5 and Hurley stage II or III). Patients were randomized to receive bimekizumab 320 mg every 2 weeks (Q2W), every 4 weeks (Q4W), or placebo. After the initial 16-week and 48-week periods, eligible patients entered the BE HEARD Extension, an open-label extension (OLE) study designed to evaluate the long-term safety and efficacy profile up to Year 2 (Week 96).
The pooled analysis included 556 patients who entered the OLE, with 446 patients completing the treatment through Year 2. The primary efficacy endpoint across these trials was the Hidradenitis Suppurativa Clinical Response (HiSCR), with a focus on higher thresholds of response (HiSCR75, 90, and 100) to measure the depth of clinical improvement.
Safety and Tolerability Profile over 2 Years
In chronic inflammatory conditions like HS, long-term safety and the potential for cumulative toxicity are paramount. The pooled results from the BE HEARD program indicated a favorable and consistent safety profile. Exposure-adjusted incidence rates (EAIRs) of treatment-emergent adverse events (TEAEs) per 100 patient-years (PY) showed a downward trend: 261.6/100 PY during Year 1 compared to 235.7/100 PY during Year 2. This suggests that longer exposure to bimekizumab does not lead to an accumulation of safety signals.
The most common TEAEs reported during Year 2 were:
- Hidradenitis (worsening or flare of the underlying condition): 26.6/100 PY
- Coronavirus infection: 23.1/100 PY
- Oral candidiasis: 12.5/100 PY
Oral candidiasis is a known mechanism-related effect of IL-17 inhibition, as IL-17 plays a role in mucocutaneous defense against fungi. However, most cases were mild to moderate in severity and rarely led to treatment discontinuation. No new safety signals regarding inflammatory bowel disease (IBD), major adverse cardiovascular events (MACE), or suicidal ideation/behavior were identified, confirming the results seen in bimekizumab trials for psoriasis and psoriatic arthritis.
Sustained Clinical Efficacy and Depth of Response
Efficacy outcomes at Year 2 demonstrated remarkable durability. Among patients receiving bimekizumab, the proportion achieving HiSCR50 at Year 2 was 85.4%. More importantly, the data revealed a significant “depth of response” that is often difficult to achieve in HS:
- HiSCR75: 77.1% of patients
- HiSCR90: 57.6% of patients
- HiSCR100 (Total clearance of inflammatory lesions): 44.2% of patients
These figures represent an improvement from the outcomes observed at Year 1, suggesting that some patients continue to improve well into the second year of therapy. The ability of nearly half the study population to achieve HiSCR100 is particularly noteworthy, as this level of clearance was previously considered unattainable for many with moderate-to-severe disease.
Patient-Reported Outcomes and Quality of Life
Beyond the reduction of physical lesions, the BE HEARD program assessed the impact of bimekizumab on the daily lives of patients. Skin pain is often cited as the most burdensome symptom of HS. Improvements in skin pain (assessed via the Numeric Rating Scale) that were achieved by the end of the first year were sustained throughout Year 2. Similarly, health-related quality of life (HRQoL), measured by the Dermatology Life Quality Index (DLQI), showed persistent benefit. A significant proportion of patients reached a DLQI score of 0 or 1, indicating that the disease no longer had a negative impact on their life. These results underscore the translational impact of dual IL-17A/F inhibition on the holistic well-being of the patient.
Expert Commentary
The 2-year pooled data for bimekizumab represent a milestone in the management of Hidradenitis Suppurativa. From a mechanistic standpoint, the success of bimekizumab reinforces the hypothesis that IL-17F contributes significantly to the inflammatory milieu of HS, independently of IL-17A. By targeting both, bimekizumab appears to achieve a more profound suppression of tissue inflammation, which likely explains the high rates of HiSCR90 and HiSCR100 observed compared to historical data from IL-17A-only or TNF-alpha inhibitors.
Clinicians should note the transition in safety data. While fungal infections remain the primary clinical consideration with IL-17 inhibitors, the lack of increasing TEAE rates over time is reassuring for long-term maintenance. However, it is essential to consider the limitations of these trials. Clinical trial populations are often more adherent and have fewer comorbidities than the general “real-world” HS population. For instance, the exclusion of patients with active IBD in many biologic trials may limit the generalizability to patients with these specific comorbidities. Furthermore, while the pooled analysis is robust, future studies should focus on head-to-head comparisons between bimekizumab and other emerging biologics (such as IL-23 inhibitors or JAK inhibitors) to better define the optimal treatment algorithm.
The durability of response is particularly impressive. In HS, “treatment fatigue” or secondary loss of response is a frequent challenge with adalimumab. The BE HEARD data suggest that bimekizumab maintains its efficacy through 96 weeks, which may reduce the need for frequent switching of biologics.
Conclusion
The pooled 2-year results from the BE HEARD I, BE HEARD II, and BE HEARD Extension trials establish bimekizumab as a highly effective and well-tolerated long-term treatment option for moderate-to-severe hidradenitis suppurativa. With a safety profile that remains stable over 100 patient-years of exposure and efficacy rates that include nearly 45% of patients achieving total lesion clearance (HiSCR100) at two years, bimekizumab addresses the core clinical and quality-of-life needs of this patient population. Future research will likely explore its use in earlier stages of the disease to prevent the development of irreversible scarring and tunnels, further shifting the treatment paradigm toward early, aggressive, and durable intervention.
