What type of drug is ustekinumab?

October 11, 2025 •

3 min read

According to the National Institutes of Health, ustekinumab is a human monoclonal antibody belonging to the class of interleukin inhibitors. This advanced biologic medication, commonly known as Stelara, targets specific proteins in the immune system to treat a variety of inflammatory and autoimmune diseases.

Quick Summary

Ustekinumab, a biologic monoclonal antibody and interleukin inhibitor, targets the inflammatory proteins IL-12 and IL-23. It treats conditions including plaque psoriasis, psoriatic arthritis, Crohn's disease, and ulcerative colitis.

Key Points

Biologic Monoclonal Antibody: Ustekinumab (Stelara) is a biologic drug, specifically a human monoclonal antibody, produced using living cells.
Targets IL-12 and IL-23: Its unique mechanism involves binding to the p40 protein subunit shared by the pro-inflammatory cytokines interleukin-12 and interleukin-23.
Treats Autoimmune Diseases: It is an approved treatment for moderate to severe plaque psoriasis, active psoriatic arthritis, and moderately to severely active Crohn's disease and ulcerative colitis.
Administered via Injection: The medication is delivered via either subcutaneous injection or intravenous infusion, depending on the specific condition and treatment phase.
Immunosuppressive Risk: Due to its immunosuppressant properties, it carries risks such as increased susceptibility to infections, potential malignancies, and rare neurological conditions.
Requires Pre-screening: Patients must be screened for infections like tuberculosis and hepatitis before beginning ustekinumab treatment.

Understanding the classification of ustekinumab

Ustekinumab is a biologic drug, derived from living organisms, differing from conventional small-molecule drugs. It is classified as a human monoclonal antibody, designed to target specific antigens in the body's immune system. Ustekinumab specifically targets the p40 protein subunit, shared by the inflammatory cytokines interleukin (IL)-12 and interleukin (IL)-23. By blocking this subunit, it disrupts the signaling of both IL-12 and IL-23, reducing inflammation in chronic autoimmune diseases. This makes it an interleukin inhibitor.

The mechanism of action: Blocking the IL-12 and IL-23 pathway

Inflammatory conditions such as psoriasis and inflammatory bowel disease are driven by an overactive immune response involving pro-inflammatory cytokines like IL-12 and IL-23. Ustekinumab works by specifically binding to the p40 subunit of IL-12 and IL-23, preventing them from interacting with their receptors and disrupting the inflammatory cascade. This reduces T-cell activation and the production of other inflammatory proteins, helping to alleviate symptoms of autoimmune conditions.

Conditions treated with ustekinumab

Ustekinumab, known by the brand name Stelara, is approved for treating several moderate to severe autoimmune and inflammatory conditions. These include plaque psoriasis (in adults and pediatric patients 6 years and older requiring systemic therapy or phototherapy), psoriatic arthritis (in adults and pediatric patients 6 years and older, used alone or with methotrexate), Crohn's disease (in adults with moderately to severely active disease), and ulcerative colitis (in adults with moderately to severely active disease).

Administration and dosage

Administration and dosage of ustekinumab vary based on the treated condition and patient weight. For plaque psoriasis and psoriatic arthritis, it's typically a subcutaneous injection. For Crohn's disease and ulcerative colitis, treatment often starts with an intravenous infusion followed by subcutaneous injections.

Safety profile and risks

Ustekinumab has immunosuppressant properties, leading to potential safety considerations. Common side effects can include headache, upper respiratory tract infections, and injection site reactions. Serious risks include an increased chance of serious infections, potential for malignancy, and rare conditions like Posterior Reversible Encephalopathy Syndrome (PRES) or noninfectious pneumonia. Patients require screening for conditions such as latent tuberculosis before treatment.

Comparison with other biologic drugs

Ustekinumab targets IL-12 and IL-23, distinguishing it from biologics like TNF-alpha inhibitors. The choice of treatment depends on individual factors.


Feature	Ustekinumab (Stelara)	TNF-alpha Inhibitors (e.g., Infliximab, Adalimumab)
Drug Class	Monoclonal Antibody, Interleukin Inhibitor	Monoclonal Antibody, Tumor Necrosis Factor (TNF) Inhibitor
Mechanism	Binds to the p40 subunit of IL-12 and IL-23	Binds to TNF-alpha to inhibit its pro-inflammatory action
Primary Targets	Cytokines IL-12 and IL-23	Cytokine TNF-alpha
Common Uses	Psoriasis, PsA, Crohn's, Ulcerative Colitis	Psoriasis, PsA, Crohn's, Ulcerative Colitis, Rheumatoid Arthritis, Ankylosing Spondylitis
Administration	SC Injection, IV Infusion	SC Injection, IV Infusion (varies by drug)
Efficacy	Effective for several inflammatory conditions. Clinical comparisons suggest varying efficacy against different TNF-alpha inhibitors depending on the specific condition.	Effective for various inflammatory conditions. Some trials suggest different efficacy profiles when compared to ustekinumab.

Conclusion

Ustekinumab is a targeted biologic drug effective for certain autoimmune diseases by blocking key inflammatory pathways involving IL-12 and IL-23. It is a valuable treatment option for moderate to severe psoriasis, psoriatic arthritis, Crohn's disease, and ulcerative colitis requiring systemic or targeted therapy. Careful consideration of potential side effects, such as increased infection risk, and ongoing medical monitoring are necessary. Its efficacy and safety profile make it an important tool in managing chronic inflammatory conditions. Additional information on ustekinumab for psoriatic disease is available from {Link: the National Psoriasis Foundation https://rheumatology.org/patients/ustekinumab-stelara}.

Frequently Asked Questions

The most common brand name for ustekinumab is Stelara. It is also available under several biosimilar brand names, such as Wezlana, Imuldosa, and Pyzchiva.

Ustekinumab works by binding to a specific protein subunit (p40) that is a part of the inflammatory cytokines IL-12 and IL-23. This prevents these cytokines from signaling, which in turn disrupts the inflammatory immune response.

Ustekinumab is approved to treat moderate to severe plaque psoriasis, active psoriatic arthritis, moderately to severely active Crohn's disease, and moderately to severely active ulcerative colitis.

Depending on the condition, ustekinumab is administered as either a subcutaneous injection or an intravenous infusion. For psoriasis and psoriatic arthritis, it is typically a subcutaneous injection, while an initial intravenous infusion is often used for inflammatory bowel diseases.

Common side effects can include headache, upper respiratory tract infections, and reactions at the injection site. Serious side effects, though less common, involve increased risk of infections, certain cancers, and rare neurological conditions like PRES.

Ustekinumab can be used with some other medications, such as methotrexate for psoriatic arthritis, but it should not be taken with other biologic drugs like TNF-alpha inhibitors. You should inform your doctor of all medications you are taking.

Patients taking ustekinumab should avoid live vaccines, such as the BCG vaccine, for a certain period before, during, and after treatment. Non-live vaccines may not produce an adequate immune response.