Secukinumab: 6 Indications, Efficacy, Side Effects & Dosage
Comprehensive guide to secukinumab, the IL-17A inhibitor for psoriasis, psoriatic arthritis, and related inflammatory conditions.
Authoritative facts about secukinumab (Cosentyx®), what secukinumab is, and what secukinumab is used for and its properties.
What is secukinumab?
Secukinumab is a fully human monoclonal immunoglobulin G1 (IgG1) κ antibody that selectively binds to interleukin-17A (IL-17A), a key cytokine driving chronic inflammation in immune-mediated diseases. By neutralizing IL-17A, secukinumab prevents its interaction with the IL-17 receptor on target cells such as keratinocytes and synoviocytes, interrupting downstream inflammatory signaling pathways. This mechanism inhibits pro-inflammatory processes including epidermal hyperproliferation, neutrophil recruitment, and angiogenesis, which are hallmarks of conditions like plaque psoriasis.
Developed by Novartis, secukinumab is marketed as Cosentyx® and represents the first-in-class IL-17A inhibitor approved for multiple dermatologic and rheumatologic indications. It acts downstream of other cytokines like TNF-α and IL-23, providing targeted blockade irrespective of the cytokine’s origin from adaptive or innate immune cells. At therapeutic doses, secukinumab fully neutralizes IL-17A without affecting IL-17F or other Th17 cell functions, leading to normalization of skin histology and joint function.
What is secukinumab used for?
Secukinumab is FDA-approved and indicated for the following conditions:
- Moderate-to-severe plaque psoriasis (PsO) in adults and children/adolescents aged ≥6 years who are candidates for systemic therapy or phototherapy.
- Active psoriatic arthritis (PsA) in adults and pediatric patients ≥2 years, alone or with methotrexate, after inadequate response to conventional DMARD therapy.
- Active ankylosing spondylitis (AS) in adults with inadequate response to conventional therapy.
- Active non-radiographic axial spondyloarthritis (nr-axSpA) with objective inflammation (elevated CRP or MRI evidence) in adults failing NSAIDs.
- Moderate-to-severe hidradenitis suppurativa (HS) in adults with inadequate response to conventional systemic therapy.
- Enthesitis-related arthritis (ERA) in pediatric patients ≥2 years.
Clinical trials demonstrate secukinumab’s superiority over TNF inhibitors like etanercept in achieving PASI 75/90/100 responses and clear/almost clear skin (IGA 0/1) in psoriasis, with sustained efficacy up to 5 years. In PsA, it reduces signs/symptoms, inhibits radiographic progression, and improves physical function.
Mechanism of action of secukinumab
In psoriasis pathogenesis, IL-17A—produced primarily by Th17 cells—binds to IL-17 receptors on keratinocytes, inducing chemokine/cytokine release (e.g., TNF-α, IL-6, IL-8), antimicrobial peptide production, and epidermal hyperplasia. Secukinumab selectively inhibits IL-17A, blocking this cascade and restoring skin barrier function without impacting Th1 pathways or IL-17F.
Pharmacologically, secukinumab exhibits high affinity for IL-17A (KD = 0.2 pM), rapid absorption post-subcutaneous injection (Tmax 5-6 days), and a half-life of 27 days, supporting monthly maintenance dosing. It reduces psoriatic plaque erythema, induration, desquamation, acanthosis, and parakeratosis, as evidenced by biopsy-confirmed histologic normalization.
Pharmacokinetics of secukinumab
Following subcutaneous administration (150-300 mg), secukinumab achieves bioavailability of ~55-77%, with steady-state concentrations after 4-5 doses. Mean Cmax and AUC increase proportionally with dose. In plaque psoriasis patients, a 150 mg dose yields mean Cmax of 13.5 µg/mL. Clearance is ~0.31 L/day, predominantly via catabolism, with minimal CYP450 impact despite inflammation-modulated cytokines.
| Parameter | Value |
|---|---|
| Bioavailability (SC) | 55-77% |
| Tmax (SC) | 5-6 days |
| Half-life | 27 days |
| Clearance | 0.31 L/day |
| Volume of distribution | 7.1 L |
No dose adjustments needed for renal/hepatic impairment, but body weight influences exposure (higher weight = lower exposure).
Dosing regimen of secukinumab
Dosing varies by indication, administered subcutaneously via pre-filled syringe or autoinjector:
- Plaque PsO (adults): 300 mg (two 150 mg injections) at weeks 0,1,2,3, then every 4 weeks; may reduce to 150 mg for maintenance if adequate.
- Plaque PsO (pediatric ≥6y): 75-300 mg based on weight, same schedule.
- PsA/AS/nr-axSpA: 150 mg (some 300 mg) loading, then monthly.
- HS: 300 mg weekly x4, then monthly.
Store refrigerated; allow to reach room temperature before injection. Rotate sites (thigh, abdomen, upper arm).
Efficacy of secukinumab
Pivotal trials (ERASURE/FIXTURE/SCULPTURE) showed 71-87% PASI 75 at week 12 vs. 0-44% placebo/etanercept; 44-59% PASI 90, 20-33% PASI 100. CLEAR trial: superior to ustekinumab (IGA 0/1: 79% vs. 58%). Long-term: 75% maintain PASI 90 at 5 years. In PsA (FUTURE studies), ACR20/50/70 responses 51/28/15% at week 24; radiographic non-progression in 84%.
Side effects and risks of secukinumab
Common adverse events (≥5%): upper respiratory infections, oral herpes, diarrhea, influenza. Serious risks include infections (TB screening required), IBD exacerbation, hypersensitivity, neutropenia. Candida infections elevated (3.9% vs. 1.6% placebo) due to IL-17’s antifungal role. No increased malignancy risk in trials.
| Adverse Event | Incidence (Secukinumab vs. Placebo) |
|---|---|
| Upper RTI | 11% vs. 9% |
| Candida infections | 3.9% vs. 1.6% |
| IBD (new/exacerbation) | 0.4% vs. 0.1% |
Contraindicated in active infection/IBD. Monitor for infections; live vaccines discouraged.
Special situations when using secukinumab
- Pregnancy/Lactation: Limited data; weighs risks/benefits (category B animal studies).
- Hepatic/Renal impairment: No adjustment needed.
- Immunosuppression: Avoid concurrent live vaccines; TB screening pre-treatment.
- Pediatrics: Approved ≥6y PsO, ≥2y PsA/ERA; weight-based dosing.
Psoriasis treatment algorithm incorporating secukinumab
First-line biologic for moderate-severe psoriasis due to high PASI 90/100 rates and skin clearance. Positioned after topicals/phototherapy failure; preferred over TNF/IL-12/23 inhibitors based on head-to-head data.
Frequently asked questions (FAQs) about secukinumab
Q: How quickly does secukinumab work for psoriasis?
A: Significant improvement (PASI 50) by week 2-3; PASI 75 by week 4, peak at 12.
Q: Is secukinumab safe for long-term use?
A: Yes, 5-year data show sustained efficacy/safety; no new signals.
Q: Can secukinumab be used with methotrexate?
A: Yes, approved in PsA combination; no formal interaction studies.
Q: Does secukinumab cause weight gain?
A: No clinically significant weight gain reported.
Q: What if I miss a dose?
A: Administer ASAP, resume schedule; do not double dose.
References
- Cosentyx® (secukinumab): Mechanism of action — Novartis Pharmaceuticals UK Ltd. 2023. https://www.pro.novartis.com/uk-en/medicines/dermatology/cosentyx/mechanism-of-action
- Secukinumab Therapeutic Cheat Sheet — Next Steps in Dermatology. 2023. https://nextstepsinderm.com/derm-topics/secukinumab-therapeutic-cheat-sheet/
- Secukinumab: Uses, Interactions, Mechanism of Action — DrugBank Online. 2024-01-15. https://go.drugbank.com/drugs/DB09029
- Secukinumab – First in Class Interleukin-17A Inhibitor — NIH PMC. 2017-03-15. https://pmc.ncbi.nlm.nih.gov/articles/PMC5363145/
- Secukinumab – StatPearls — NCBI Bookshelf. 2023-08-07. https://www.ncbi.nlm.nih.gov/books/NBK537091/
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