SKIN ATLAS · ACTIVE INGREDIENT · 4 MIN. READING TIME

Sonelokimab: Targeted Biologic Therapy for Hidradenitis Suppurativa in the Beard Area

Sonelokimab is a bispecific nanobody that selectively neutralizes Interleukin-17A and Interleukin-17F, thereby interfering with the central inflammatory pathway of hidradenitis suppurativa (HS). In the beard area – an anatomically and mechanically exposed zone – razor-triggered folliculitis represents an independent pathogenetic factor that can be addressed by biologic therapy. As a prescription drug, sonelokimab is exclusively subject to medical indication and does not fall within the scope of cosmetic skin care.

Term and Origin

The name "Sonelokimab" follows the INN nomenclature for monoclonal antibodies: The suffix -mab (monoclonal antibody) indicates the drug class, while the stem refers to the interleukin target area. Developed by MoonLake Immunotherapeutics, it is a so-called nanobody – an antibody fragment from the variable region of heavy chains, originally derived from the immunobiology of camelids (dromedaries, llamas). This nanobody architecture is more compact than conventional IgG antibodies, allows for deeper tissue penetration, and can simultaneously block two related target structures: IL-17A and IL-17F.

Acne inversa – predominantly referred to as hidradenitis suppurativa (HS) in clinical literature – is a chronic-recurrent, neutrophil-dominated inflammatory disease of the apocrine gland follicles. The term "acne inversa" was coined in German-speaking countries to emphasize the pathophysiological proximity to acne: Both begin with follicular occlusion but differ in anatomical pattern (intertriginous zones, beard region, axillary area) and inflammatory profile. The IL-17 axis plays a quantitatively more significant role in HS than in acne vulgaris.

Clinical data for sonelokimab are available from the Phase II MIRA study (2022, The Lancet), which showed significant response rates compared to placebo in patients with moderate to severe HS. Phase III development is ongoing at the time of this publication; EMA approval has not yet been granted.

Characteristics & Mechanism of Action

The mechanism of action of sonelokimab is aimed at the simultaneous neutralization of interleukin-17A and interleukin-17F. Both cytokines are secreted by Th17 lymphocytes, γδ-T cells, and mast cells and activate keratinocytes, fibroblasts, and neutrophils in the skin. The result is a self-reinforcing inflammatory cascade: Neutrophils accumulate in perifollicular tissue, leading to abscess formation, sinus tracts, and cicatricial fibrosis – the complete clinical picture of HS. The simultaneous blockade of both isoforms by a single bispecific nanobody is considered an advantage over active ingredients that only inhibit IL-17A (e.g., secukinumab).

In the beard area, a mechanical cofactor is added: Shaving creates micro-traumatic entry points for keratin plugs into perifollicular tissue, stimulates sebaceous gland secretion, and promotes occlusive conditions due to beard shadow and tight hair follicle architecture. In HS-predisposed individuals, this triggering mechanism can cause or prolong flares. The dermatitis-like hypersensitization of the perifollicular milieu, combined with sensitive skin and impaired follicular integrity, forms the local correlate to the systemic IL-17 excess.

Biochemically, sonelokimab differs from conventional biologics due to its molecular size (~15 kDa per domain versus ~150 kDa for IgG1 antibodies). This compactness results in faster tissue distribution and potentially higher tissue penetration into chronically inflamed, fibrotic tissue – clinically relevant, as HS lesions are often surrounded by thickened, scarred dermis. In addition, the Fc fragment is modified to prolong the half-life of subcutaneously administered doses.

Skincare Approach

Sonelokimab is not a cosmetic active ingredient, but a prescription biologic. Its use requires a dermatological diagnosis according to ICD-10 L73.2 (Hidradenitis suppurativa), therapy escalation according to the DDG S1 guideline, and close monitoring for infections, tuberculosis reactivation, and laboratory parameters.

In the context of adjunctive skin care for HS – especially in the beard area – supportive measures play a documented role: astringent and soothing care, reduction of mechanical irritation (shaving technique, blade quality, shaving direction), and care of the skin barrier. As both practitioners and affected individuals seek complementary concepts, the chronobiological dimension of skincare routines is relevant: The rationale for aligning care temporally with the body's own regeneration phases is extensively described under Chronobiology of the Skin.

For daily complementary care in the beard area – regardless of medical therapy – the following applies: less irritating formulations, no exfoliation on acutely inflamed areas, preferably fragrance-free and dermatologically tested products. The topic of HS-specific inflammatory dynamics and their overlap with silent inflammaging is covered separately in NATURFACTOR® Field Notes.

NATURFACTOR® develops products according to a day-night rhythm principle. Since sonelokimab and the inflammatory biology of hidradenitis suppurativa have no relation to the active ingredients of the Porcelain Skin Serum (day care) or the Blue Crystal Drops (face oil, night care), no active ingredient bridge is drawn here. The rhythm logic behind both products is described under Chronobiology of the Skin.

Realistic Expectations

Clinical studies show that biologic therapies for HS – including sonelokimab – generally demonstrate an initial objective response after 12 to 16 weeks, as measured by the HiSCR score (Hidradenitis Suppurativa Clinical Response), which defines a ≥50% reduction in abscessing and inflammatory lesions. Some patients do not respond or respond inadequately; predictors of non-response include long-standing disease duration, pronounced fibrosis, and smoking.

In the beard area, the prognosis is further influenced by the continuous mechanical stress of shaving. Even with a good biological response, shaving microtraumas can trigger flares; affected individuals report sustained improvement only after a combination of medical therapy and modified shaving routine. Individual variations in IL-17 axis activation, microbiome composition in the beard area, and genetic polymorphisms in the follicular keratinization pathway influence treatment outcome.

Cosmetic skin care cannot replace inflammation reduction, but it can complementarily support subjective skin feel, barrier function between flares, and skin tolerance to shaving irritation. Expectations for skincare products for active HS lesions should be calibrated accordingly.

Frequently Asked Questions

Is Sonelokimab already approved in Germany?

As of the current publication, sonelokimab has not received EMA or national approval in Germany for the indication of hidradenitis suppurativa. Clinical development is in Phase III. Therapy is therefore exclusively available within the framework of clinical studies or under named-patient programs. Initial positive Phase II data were published in The Lancet in 2022.

How does Sonelokimab differ from Adalimumab (Humira) for hidradenitis suppurativa?

Adalimumab (anti-TNF-α) was the first approved biologic for HS and addresses the TNF-α signaling pathway. Sonelokimab acts further downstream in the IL-17A/F axis, which is pathophysiologically considered a direct driver of neutrophilic infiltration. Both mechanisms are not equivalent: A portion of adalimumab non-responders show an IL-17-dominated inflammatory profile and could theoretically benefit from IL-17 blockade. Comparative studies are not yet available.

What role does shaving technique play in hidradenitis suppurativa in the beard area?

Shaving, through blade traction, follicular opening, and keratin displacement into the perifollicular space, creates a mechanical cofactor that can trigger inflammatory flares in genetically predisposed individuals. Recommended measures include: shaving with the grain (not against the direction of hair growth), sharp disposable blades or electric shavers with a protective guard, avoiding aggressive astringent alcohol-based aftershave products on lesional skin, and – in between flares – gentle soothing care. These measures do not replace medical therapy.

Conclusion

Sonelokimab represents a mechanistically precise therapeutic approach to hidradenitis suppurativa through simultaneous IL-17A/F neutralization via a bispecific nanobody. The beard area is particularly relevant as an anatomically and mechanically exposed zone, as shaving triggers have independent pathogenetic significance. As a biologic, sonelokimab is exclusively subject to medical prescription and is still in the approval phase. Adjunctive skin care – timed to the skin rhythm, barrier-supporting, and formulated to be low-irritant – can complement the medical therapy course but not substitute it. The precision medicine of biologics and evidence-based care routines follow different but complementary logics.

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