Highlights
- Secukinumab 300 mg Q2W achieves approximately 2-fold higher mean trough concentrations compared to the Q4W regimen, with sustained levels through 52 weeks.
- Body weight, baseline disease severity, and high-sensitivity C-reactive protein (hsCRP) are significant covariates influencing secukinumab serum concentrations.
- Secukinumab significantly reduces systemic inflammation, as measured by hsCRP, with reductions maintained over 1 year of treatment.
- The long-term safety profile is consistent with other approved indications, with a remarkably low immunogenicity rate (<1%).
Background
Hidradenitis suppurativa (HS) is a chronic, debilitating inflammatory skin disease characterized by recurrent, painful nodules, abscesses, and draining tunnels. The pathophysiology of HS involves the follicular occlusion of the pilosebaceous unit, leading to immune dysregulation where the interleukin (IL)-17A pathway plays a central role. For years, therapeutic options for moderate-to-severe HS were limited, primarily relying on adalimumab.
Secukinumab, a fully human monoclonal antibody that selectively neutralizes IL-17A, has recently emerged as a pivotal treatment option. Following the success of the SUNSHINE and SUNRISE Phase 3 trials, it became essential for clinicians to understand the nuances of its pharmacokinetic (PK) profile, the impact of patient-specific covariates on drug exposure, and the long-term safety in the HS population, which often presents with higher body weight and significant systemic inflammatory burdens.
Key Content
Methodological Framework of the Pooled Analysis
The data presented stems from an exploratory analysis of pooled results from the SUNSHINE (NCT03713619) and SUNRISE (NCT03713632) trials. These were multicenter, randomized, double-blind, placebo-controlled Phase 3 studies. Patients with moderate-to-severe HS were randomized to receive secukinumab 300 mg every 2 weeks (SECQ2W), every 4 weeks (SECQ4W), or placebo. This pooled analysis utilized a population PK (PopPK) model to evaluate how specific factors such as weight and inflammatory markers affect the drug’s behavior in the body and assessed the relationship between serum concentrations and clinical response, primarily measured by the Hidradenitis Suppurativa Clinical Response (HiSCR).
Pharmacokinetic Dynamics and Regimen Comparison
The study revealed a clear dose-proportionality in systemic exposure. The mean serum trough concentration for the SECQ2W regimen was approximately double that of the SECQ4W regimen at all major time points (Weeks 16, 24, and 52).
At Week 16, a significant overlap in exposure was observed between the two dosing frequencies; however, the SECQ2W regimen was associated with an estimated numerical increase in the probability of achieving HiSCR by approximately 3% over the SECQ4W regimen. By Week 52, clinical response levels reached a plateau, suggesting that for many patients, the higher frequency of dosing ensures a more stable therapeutic window, especially during the maintenance phase.
The Impact of Patient Covariates: Weight and hsCRP
A critical finding of the PopPK model was the influence of baseline characteristics on secukinumab concentrations. Higher body weight was strongly associated with lower serum concentrations, a common challenge in HS where obesity is a frequent comorbidity. Furthermore, higher baseline disease severity (Hurley stage) and elevated baseline hsCRP were linked to reduced secukinumab exposure. This suggests that patients with the highest inflammatory burden and higher BMI may necessitate the Q2W regimen to maintain optimal therapeutic drug levels.
Systemic Inflammation and Biomarker Response
High-sensitivity C-reactive protein (hsCRP) served as a key systemic biomarker. At baseline, the mean hsCRP levels were elevated (18.6 mg/L in the SECQ2W group). By Week 16, both secukinumab regimens induced a significant reduction in hsCRP (to 12.8 mg/L for Q2W and 11.5 mg/L for Q4W), while the placebo group remained unchanged (14.4 mg/L to 14.7 mg/L). These reductions were sustained through 52 weeks, confirming that secukinumab successfully modulates the systemic inflammatory state associated with HS.
Long-term Safety and Immunogenicity
Over the 52-week period, secukinumab demonstrated a safety profile consistent with its established use in psoriasis and psoriatic arthritis. No new safety signals were identified. Notably, the incidence of anti-drug antibodies (ADAs) was extremely low, occurring in less than 1% of the pooled population. This low immunogenicity is vital for long-term efficacy, as it reduces the risk of loss of response over time due to neutralizing antibodies.
Expert Commentary
The analysis of SUNSHINE and SUNRISE data provides essential guidance for clinical practice. The finding that SECQ2W provides a 2-fold higher trough concentration is clinically significant. While both regimens are effective, the Q2W dosing may be particularly beneficial for “difficult-to-treat” sub-populations, such as those with high body mass index or severe Hurley Stage III disease, where drug clearance might be faster due to higher inflammatory turnover.
One area of ongoing discussion is whether hsCRP can be used as a predictor for treatment success. The data shows that while secukinumab reduces hsCRP, the initial high levels of the protein actually lower the drug’s concentration. This suggests that clinicians should be aggressive with the Q2W regimen in patients with high baseline markers to “overcome” the initial inflammatory sink. The lack of a dose-response relationship for adverse events between Q2W and Q4W provides further reassurance that the more frequent dosing does not compromise patient safety.
Conclusion
The pooled analysis of the SUNSHINE and SUNRISE trials confirms that secukinumab is a robust and safe long-term treatment for moderate-to-severe HS. The variability in serum concentrations based on weight and inflammation emphasizes the need for a tailored approach to dosing. Moving forward, the SECQ2W regimen stands as a vital tool for achieving and maintaining clinical response in patients with high disease burdens. Future research should focus on whether even more personalized dosing strategies based on real-time PK monitoring could further improve outcomes in HS.
References
- Alavi A, et al. Secukinumab in the Treatment of Moderate-to-Severe Hidradenitis Suppurativa: Pooled Pharmacokinetics and Safety Results From the SUNSHINE and SUNRISE Phase 3 Studies. Int J Dermatol. 2026;65(2):289-298. PMID: 40839197.
- Kimball AB, et al. Secukinumab in moderate-to-severe hidradenitis suppurativa (SUNSHINE and SUNRISE): week 16 and week 52 results of two identical, multicentre, randomised, placebo-controlled, double-blind phase 3 trials. Lancet. 2023.
