The Biologic Revolution in Dermatology: How Targeted Therapies Are Transforming the Treatment of Psoriasis and Atopic Dermatitis
Biologic therapies targeting IL-17, IL-23, and IL-4/13 pathways have transformed the treatment of psoriasis and atopic dermatitis. With PASI 90 clearance achievable for most psoriasis patients and significant eczema improvements with dupilumab and JAK inhibitors, the therapeutic goals in dermatology have been fundamentally redefined.
Introduction
Psoriasis and atopic dermatitis (eczema) are among the most prevalent chronic inflammatory skin diseases worldwide, collectively affecting hundreds of millions of people. Psoriasis alone impacts approximately 125 million individuals globally, while atopic dermatitis affects up to 20% of children and 10% of adults in many countries. For patients in the Gulf Cooperation Council (GCC) region, where environmental factors such as extreme heat, low humidity, and indoor air conditioning can exacerbate skin conditions, access to advanced dermatological treatment is particularly important.
The past decade has witnessed a revolution in the treatment of these conditions through the development of biologic therapies — precision-engineered monoclonal antibodies that target specific molecules in the inflammatory cascade. Unlike traditional systemic treatments such as methotrexate, ciclosporin, and oral corticosteroids, which broadly suppress the immune system, biologics act with remarkable specificity, blocking the exact cytokines and signalling pathways that drive skin inflammation. This targeted approach delivers unprecedented efficacy with a significantly improved safety profile.
Understanding the Science: Targeted Cytokine Blockade
The development of biologic therapies for skin diseases is grounded in decades of immunological research that has identified the specific molecular pathways driving chronic skin inflammation.
The IL-23/IL-17 Axis in Psoriasis: Psoriasis is driven primarily by the interleukin-23 (IL-23) and interleukin-17 (IL-17) signalling axis. Inflammatory dendritic cells in the skin release IL-23, which activates T-helper 17 (Th17) cells to produce IL-17A, IL-17F, and IL-22. These cytokines stimulate keratinocyte proliferation and recruit neutrophils, creating the characteristic red, scaly plaques of psoriasis. By blocking either IL-23 or IL-17, biologic therapies can effectively interrupt this inflammatory cycle.
The Type 2 Inflammatory Pathway in Atopic Dermatitis: Atopic dermatitis is driven by a different immunological pathway — the type 2 (Th2) inflammatory response. Key cytokines include interleukin-4 (IL-4), interleukin-13 (IL-13), and interleukin-31 (IL-31), which drive skin barrier dysfunction, inflammation, and the intense itch that characterises eczema. Targeting these specific cytokines has opened new therapeutic avenues for patients with moderate to severe atopic dermatitis.
The Biologic Landscape: Current Treatment Options
The range of biologic therapies available for inflammatory skin diseases has expanded dramatically, offering clinicians and patients an unprecedented choice of effective treatments.
Biologics for Psoriasis
| Drug Class | Examples | Target | Dosing Frequency | PASI 90 Response |
|---|---|---|---|---|
| IL-17A inhibitors | Secukinumab, Ixekizumab | IL-17A | Every 4 weeks (maintenance) | 65–75% |
| IL-17A/F inhibitor | Bimekizumab | IL-17A and IL-17F | Every 8 weeks (maintenance) | 75–85% |
| IL-23 inhibitors | Guselkumab, Risankizumab, Tildrakizumab | IL-23 p19 subunit | Every 8–12 weeks | 70–80% |
| IL-12/23 inhibitor | Ustekinumab | IL-12 and IL-23 p40 subunit | Every 12 weeks | 45–55% |
| TNF-alpha inhibitors | Adalimumab, Etanercept | TNF-alpha | Every 1–2 weeks | 30–50% |
The IL-23 inhibitors have emerged as particularly attractive options due to their combination of high efficacy and infrequent dosing. Risankizumab and guselkumab, for example, require injections only every eight to twelve weeks during maintenance therapy, offering patients significant convenience. Real-world drug survival studies from the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR) have confirmed that IL-23 inhibitors demonstrate excellent treatment persistence, reflecting both their efficacy and tolerability in clinical practice.
Biologics and Targeted Therapies for Atopic Dermatitis
| Drug | Target | Route | Key Efficacy Data |
|---|---|---|---|
| Dupilumab | IL-4Ralpha (blocks IL-4 and IL-13) | Subcutaneous injection | EASI-75 in 40–50% at 16 weeks |
| Tralokinumab | IL-13 | Subcutaneous injection | EASI-75 in 25–35% at 16 weeks |
| Lebrikizumab | IL-13 | Subcutaneous injection | EASI-75 in 40–50% at 16 weeks |
| Nemolizumab | IL-31 receptor | Subcutaneous injection | Significant itch reduction |
| Upadacitinib | JAK1 | Oral tablet | EASI-75 in 60–70% at 16 weeks |
| Abrocitinib | JAK1 | Oral tablet | EASI-75 in 55–65% at 16 weeks |
Dupilumab, the first biologic approved for moderate to severe atopic dermatitis, has transformed the treatment landscape since its introduction. By blocking the IL-4 receptor alpha subunit, it simultaneously inhibits both IL-4 and IL-13 signalling, addressing multiple aspects of the disease pathology. The Janus kinase (JAK) inhibitors upadacitinib and abrocitinib offer the convenience of oral administration with rapid onset of action, though they require careful monitoring due to their broader immunological effects.
2025–2026 Breakthroughs
The pace of innovation in dermatological therapeutics shows no signs of slowing. Several significant advances have emerged in 2025 and early 2026.
Rocatinlimab (OX40 Pathway): Clinical trial data published in early 2026 demonstrated that rocatinlimab, targeting the OX40 pathway, shows significant efficacy in moderate to severe atopic dermatitis. This represents an entirely new therapeutic class, offering hope for patients who have not responded adequately to existing biologics.
Cardiovascular Risk Reduction: A landmark study published in Dermatology Times in 2025 demonstrated that IL-23 and IL-17 inhibitors significantly reduce cardiovascular outcomes in statin-treated psoriasis patients. This finding highlights the systemic benefits of controlling skin inflammation, as psoriasis is associated with an increased risk of cardiovascular disease.
Redefining Corticosteroid Use: Due to the growing availability of advanced therapies, 2025 has seen a trend towards redefining the role of corticosteroids in dermatological practice. With effective targeted therapies available, the reliance on long-term topical and systemic corticosteroids — with their well-known side effects — is diminishing.
Biologic Therapy in Hong Kong
Hong Kong's dermatology services have embraced the biologic revolution, with both public and private healthcare sectors offering access to the full range of modern biologic therapies. The Hong Kong Society of Dermatology and Venereology maintains active engagement with international guidelines and clinical evidence, ensuring that treatment protocols reflect the latest advances.
For GCC patients seeking dermatological care in Hong Kong, the city offers several advantages. Hong Kong's dermatologists are trained to international standards and have extensive experience with biologic therapies across diverse patient populations. The availability of comprehensive allergy testing, skin biopsy services, and phototherapy alongside biologic treatments ensures that patients receive a holistic approach to their skin condition. The city's pharmacy infrastructure ensures reliable access to all approved biologic agents, with cold-chain logistics that maintain drug integrity.
Who Is a Candidate for Biologic Therapy?
Biologic therapies are generally indicated for patients with moderate to severe psoriasis or atopic dermatitis who have not responded adequately to conventional systemic treatments, or who have contraindications to such treatments. The assessment of disease severity uses validated scoring systems — the Psoriasis Area and Severity Index (PASI) for psoriasis and the Eczema Area and Severity Index (EASI) for atopic dermatitis.
Before initiating biologic therapy, patients undergo screening for latent tuberculosis, hepatitis B and C, and other infections. Baseline blood tests and, in some cases, chest radiography are performed to establish a safety profile. Once treatment begins, regular monitoring ensures ongoing safety and allows dose adjustments if needed.
Conclusion
The biologic revolution in dermatology has transformed the treatment of psoriasis and atopic dermatitis from a paradigm of broad immunosuppression to one of precision-targeted therapy. With PASI 90 and even PASI 100 (complete clearance) now achievable for many psoriasis patients, and significant improvements in eczema severity and quality of life for atopic dermatitis patients, the therapeutic goals in dermatology have been fundamentally redefined. For patients seeking access to the full spectrum of modern biologic therapies, Hong Kong's dermatology services offer world-class expertise in a patient-centred, multilingual healthcare environment.
