Generic Name

Cosentyx

Mechanism

Secukinumab binds with high affinity to circulating IL‑17A, preventing its interaction with the IL‑17 receptor (IL‑17RA/IL‑17RC) on target cells.
• Outcome: ↓ keratinocyte proliferation, ↓ pro‑inflammatory cytokines (IL‑6, TNF‑α), ↓ neutrophil recruitment → resolution of psoriatic plaques and joint inflammation.
• Key detail: selective inhibition of IL‑17A (not IL‑17F) preserves mucosal immunity while dampening systemic inflammation.

Pharmacokinetics

• Absorption: Subcutaneous (SC) injection → peak plasma concentration (Cmax) at ~14–17 days post‑dose.
• Distribution: Large volume (~450 mL), high protein binding (≥ 95 %).
• Metabolism & Excretion: Protein‑mediated catabolism; minimal renal/hepatic elimination.
• Half‑life: ~27 days (steady‑state).
• Reduced clearance with higher body weight → dose adjustment for patients > 100 kg (20 % increase).
• Drug interactions: None significant (not a CYP450 substrate).

Indications

• Plaque psoriasis (≥ 12 % body surface area, PASI ≥ 12, DLQI ≥ 10)
• Psoriatic arthritis (active arthritis with ≥ 3 tender & swollen joints)
• Ankylosing spondylitis (active disease)
• Non‑infectious uveitis (off‑label, limited evidence)

Contraindications

• Known hypersensitivity to secukinumab or murine proteins.
• Active, uncontrolled infections (TB, candidiasis, viral hepatitis).
• Immunocompromised states (HIV, chronic steroid use > 20 mg/day).
• Pregnancy & lactation: Category B; avoid if possible.
• Rapidly progressive bacterial infections (e.g., Staphylococcus aureus).

Warnings
• General risk of mucocutaneous candidiasis (0.4–0.9 %).
• IL‑17 blockade may impair mucosal defense → monitor for fungal & bacterial infections.
• Inflammatory bowel disease flare possible; avoid in patients with known IBD.

Dosing

• Premedication: none required.
• Injection site: abdomen, thigh, or upper arm, rotate sites.
• Reconstitution (if prepared as powder): add sterile water, mix gently; do not shake.

Adverse Effects

Common (> 5 %):
• Injection‑site reaction (erythema, pain)
• Upper respiratory tract infection (sinusitis, pharyngitis)
• Diarrhea, abdominal pain
• Headache, fatigue

Serious (≤ 1 %):
• Mucocutaneous candidiasis (especially oral/genital)
• Severe bacterial infections (sepsis, cellulitis)
• Hypersensitivity reactions (angioedema, anaphylaxis)
• Potential IBD flare or exacerbation
• Possible increase in malignancy risk (rare) – monitor.

Monitoring

• Baseline: CBC, CMP, Hepatitis B/C serology, TB IGRA.
• During treatment:
• Infections: evaluate clinically; obtain cultures as needed.
• CBC/CMP: every 3 months (or sooner if clinically indicated).
• Gastrointestinal complaints: assess for IBD flare.
• Immunizations: administer vaccines pre‑treatment; live vaccines contraindicated during therapy.
• Pregnancy: counsel use only if benefits outweigh risks; discontinue if pregnancy confirmed.

Clinical Pearls

• Weight‑adjusted dosing: a one‑size‑fits‑all recommendation belies the pharmacokinetic variability in obese patients; consider a 20 % higher dose for those > 100 kg.
• Candidiasis: Nasal or oral candidiasis are subtle; ask specifically during visits; treat with topical or systemic antifungals promptly.
• Psoriatic arthritis vs. plaque psoriasis: Maintain consistent dosing across indications; no dose reduction based on skin response alone.
• Rapid initiation is feasible: because secukinumab has a fast onset, early improvement (within 2 weeks) can support adherence.
• Safe in combination: Well‑tolerated with methotrexate; no pharmacokinetic interaction; still monitor for additive immunosuppression.
• Patient education: Emphasize the importance of reporting fever, chills, or new ulcers; early infection detection reduces complications.

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• *For detailed prescribing information, consult the FDA label and the manufacturer’s prescribing handbook.*