Generic Name

Stelara

Brand Names

with labeling nuances regarding pediatric use and biosimilars.

Mechanism

• Selective IL‑12/IL‑23 inhibition: Binds the common p40 subunit, preventing IL‑12 from stimulating Th1 differentiation and IL‑23 from maintaining Th17 cells.
• Downstream effects: ↓ production of IFN‑γ, IL‑17, IL‑22, and other pro‑inflammatory cytokines, leading to reduced keratinocyte hyperproliferation, T‑cell migration, and inflammatory cell recruitment.
• Result: Rapid control of cutaneous lesions, joint inflammation, and gut mucosal immune dysregulation.

Pharmacokinetics

Indications

• Plaque Psoriasis: Moderate‑to‑severe disease refractory to topical therapy or phototherapy.
• Psoriatic Arthritis: Active peripheral arthritis in pts ≥18 yrs.
• Crohn’s Disease: Moderate‑to‑severe disease requiring biologic therapy.
• Ulcerative Colitis: Moderate‑to‑severe disease refractory to conventional therapy.

*Note*: Approved in several regions under different brand names (e.g., Cosentyx, Stelara) with labeling nuances regarding pediatric use and biosimilars.

Contraindications

• Active serious bacterial, mycobacterial, or opportunistic infections (e.g., TB).
• Known hypersensitivity to ustekinumab or any excipients.
• History of hypersensitivity to other IgG monoclonal antibodies may warrant caution.
• Caution in patients with:
• Chronic viral infections (HBV, HCV).
• Severe uncontrolled asthma.
• Active malignancy (unless evaluated individually).

Warnings
• Increased risk of serious infections (including opportunistic infections).
• Possible reactivation of latent TB; screening mandatory.
• Potential for reactivation of hepatitis B; baseline HBsAg and HBcAb testing recommended.
• Mild elevations in liver enzymes may occur; monitor hepatic function.

Dosing

• Psoriasis / Psoriatic Arthritis
• *Initial*: 45 mg SC for pts ≤100 kg; 90 mg for >100 kg.
• *Maintenance*: 45 mg every 12 weeks (age 20 kg: weight‑based).
• *Maintenance*: 90 mg every 8 weeks, adjusted to 90–120 mg for weight >100 kg.
• Ulcerative Colitis
• *Initial*: 6 mg/kg SC (≤20 kg: 90 mg; >20 kg: weight‑based).
• *Maintenance*: 90 mg every 8 weeks (up to 120 mg for >100 kg).

Administration Tips
• Administer SC into abdomen, thigh, or upper arm; rotate sites.
• Premedicate with antihistamine for injection site reactions if history of pruritus.
• No need for blood level monitoring; therapeutic drug monitoring not routinely indicated.

Adverse Effects

• Common (≥5% pts)
• Upper respiratory tract infections, nasopharyngitis.
• Injection site reactions (pain, erythema, pruritus).
• Headache, arthralgia.
• Serious
• Opportunistic infections: tuberculosis, histoplasmosis, candidiasis, pneumocystis jirovecii.
• Herpes zoster reactivation (~1–2% pts).
• Hepatic enzyme elevations (>3× ULN).
• Malignancies reported at low rates; surveillance recommended.

Monitoring

Clinical Pearls

• Weight‑based dosing is critical for Crohn’s disease; under‑dosing can lead to treatment failure.
• Age‑adjusted maintenance intervals: Elderly pts ≥55 yrs shift from 12‑week to 8‑week intervals for psoriasis to achieve early maximal effect.
• TB screening is non‑negotiable: Use IGRA or TST plus chest X‑ray; treat latent TB before initiating therapy.
• Herpes zoster prophylaxis: Consider acyclovir for pts with a history of shingles, especially if they’re immunosuppressed.
• Drug–drug interactions: Minimal; no CYP450 involvement → safe when combined with most systemic agents.
• Biosimilars: Abatacept‑like product "Stelara‑b" offers cost‑effective alternatives; monitor for antibody formation.
• Pregnancy category: Category B; placenta cross‑s, but safety data limited—use only if benefits outweigh risks.

Keep these pearls in mind to optimize Stelara therapy while minimizing complications.