Secukinumab

• Plaque Psoriasis
• Psoriatic Arthritis
• Ankylosing Spondylitis
• Axial Spondyloarthritis

Secukinumab is a human monoclonal antibody that selectively binds to interleukin-17A (IL-17A), neutralizing its activity. It is used to treat moderate-to-severe plaque psoriasis, psoriatic arthritis, ankylosing spondylitis, and non-radiographic axial spondyloarthritis.

Mechanism of Action

Secukinumab targets the IL-17A cytokine pathway:

• IL-17A neutralization: Binds to IL-17A with high affinity and specificity
• Blocks receptor binding: Prevents IL-17A from interacting with IL-17 receptor
• Reduces inflammation: IL-17A promotes keratinocyte proliferation and recruitment of inflammatory cells
• Decreases downstream mediators: Reduces chemokines, cytokines, and tissue-damaging molecules

IL-17A is overexpressed in psoriatic skin lesions and inflamed joints.

Available Formulations

Secukinumab is available as:

• Prefilled syringe: 75 mg/0.5 mL, 150 mg/mL
• Prefilled pen (Sensoready): 150 mg/mL, 300 mg/2 mL
• Lyophilized powder: 150 mg vial (for reconstitution)

Medical Uses

FDA-Approved Indications:

• Moderate-to-severe plaque psoriasis in adults and pediatric patients ≥6 years
• Active psoriatic arthritis in adults
• Active ankylosing spondylitis in adults
• Active non-radiographic axial spondyloarthritis with objective signs of inflammation
• Active enthesitis-related arthritis in patients ≥4 years

Dosing Guidelines

Plaque Psoriasis (Adults):

• Induction: 300 mg at weeks 0, 1, 2, 3, and 4
• Maintenance: 300 mg every 4 weeks
• Some patients may use 150 mg

Psoriatic Arthritis:

• With coexistent psoriasis: 300 mg at weeks 0, 1, 2, 3, 4, then every 4 weeks
• Without coexistent psoriasis: 150 mg at weeks 0, 1, 2, 3, 4, then every 4 weeks; may increase to 300 mg
• With TNF inhibitor: May use loading dose or start with maintenance dosing

Ankylosing Spondylitis / nr-axSpA:

• With loading: 150 mg at weeks 0, 1, 2, 3, 4, then every 4 weeks
• Without loading: 150 mg every 4 weeks
• May increase to 300 mg for AS

Important Safety Information

Contraindications:

• Previous serious hypersensitivity reaction to secukinumab

Warnings and Precautions:

• Infections: Increased risk; evaluate for TB before initiating
• Tuberculosis: Test for latent TB; treat before starting
• Inflammatory bowel disease: New onset or exacerbations reported; use with caution if history of IBD
• Hypersensitivity reactions: Anaphylaxis and urticaria reported
• Latex sensitivity: Needle cap of prefilled syringe contains latex

Drug Interactions

No formal drug interaction studies conducted. IL-17A inhibition may reverse cytokine-mediated suppression of CYP450 enzymes.

Considerations:

• Live vaccines: Avoid during treatment
• CYP450 substrates with narrow therapeutic index (e.g., warfarin, cyclosporine): Monitor when initiating or discontinuing secukinumab

Special Populations

• Hepatic Impairment: Not specifically studied
• Renal Impairment: Not expected to affect pharmacokinetics
• Pregnancy: Limited data; use only if benefit outweighs risk
• Lactation: Unknown if excreted in milk
• Pediatric: Approved for plaque psoriasis ≥6 years; enthesitis-related arthritis ≥4 years
• Elderly: No dose adjustment