Ustekinumab for psoriasis
What is ustekinumab?
Ustekinumab (brand name STELARA™) is a biological treatment used to treat moderate to severe psoriasis. It is a human monoclonal antibody that antagonises interleukin-12 (IL-12) and IL-23. Good to excellent responses are seen in more than two-thirds of patients with chronic plaque psoriasis treated with ustekinumab.
Ustekinumab has been shown in small studies to be useful in other forms of psoriasis, including nail psoriasis, erythrodermic psoriasis, generalised pustular psoriasis and palmoplantar pustulosis and blah. It is under investigation in the treatment of psoriatic arthritis and Crohn disease.
How does ustekinumab work in psoriasis?
Psoriasis is caused by an increase in the production of T-cells and is influenced by cytokines, the chemical messengers produced by cells. Certain cytokines cause skin cells to grow rapidly, producing plaques of psoriasis. Ustekinumab is a monoclonal antibody that targets the p40 subunit of the cytokines IL-12 and IL-23, preventing them from binding and activating T-lymphocytes.
Dosing of ustekinumab
Ustekinumab is given by subcutaneous injection. The second dose is given 4 weeks after the first injection, and further doses are delivered every 12 weeks. It reaches its peak effect at around 28 weeks.
- The dose for patients weighing less than 100 kg is 45 mg
- The dose for patients weighing more than 100 kg is 90 mg
- Each injection is best administered at a different location (such as upper arms, buttocks, thighs, or abdomen)
Adverse events due to ustekinumab
To date adverse infections are consistent with that seen with other biologics.
- Infections – ustekinumab may increase the risk of infections and reactivation of latent infections. Serious bacterial, fungal, and viral infections have been observed in subjects receiving the drug.
- Malignancies – ustekinumab is an immunosuppressant and may increase the risk of malignancy (cancer) including skin cancers.
- Immune system disorders have been reported during post-approval use with ustekinumab. These have included serious allergic reactions (including angioedema, breathlessness and low blood pressure) and hypersensitivity (allergy) reactions (including rash and urticaria).
- Injection site reactions include pain, swelling, itch, thickening, bleeding, and bruising.
Precautions when considering ustekinumab
- Chronic infection or a history of recurrent infection. Ustekinumab should not be administered until the infection resolves or is adequately treated.
- Patients treated with ustekinumab may be susceptible to infection (including tuberculosis, atypical mycobacteria), salmonella (including nontyphi strains), and Bacillus Calmette-Guerin (BCG) vaccinations.
- Ustekinumab should not be administered to patients with active tuberculosis. Prior to biologic treatment, chest X-ray, Mantoux and/or QuantiFERON gold indirect testing should be performed. Consider anti-tuberculosis therapy prior to initiation of ustekinumab in patients with a past history of latent or active tuberculosis. Patients receiving ustekinumab should be monitored closely for signs and symptoms of active tuberculosis during and after treatment.
Vaccinations and ustekinumab
Immunisation status should be reviewed prior to starting ustekinumab. If necessary, vaccines should be updated prior to treatment with a biologic agent. Annual influenza vaccination is recommended.
As they may induce illness in immunodeficient individuals, live vaccines should not be used during treatment with ustekinumab. Currently available live attenuated viral vaccines include measles, mumps, rubella, varicella, yellow fever, influenza (intranasal vaccine) and oral polio vaccine. Live attenuated bacterial vaccines include BCG and oral typhoid vaccine.
Drug interactions with ustekinumab
- No formal drug-drug interaction studies have been conducted with ustekinumab.
- The safety of ustekinumab in combination with immunosuppressive agents or phototherapy has not been evaluated.
Use of ustekinumab in specific populations
Pregnancy Category B
There are no studies of ustekinumab in pregnant women. Ustekinumab should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Caution should be exercised when ustekinumab is administered to a nursing woman. The unknown risks to the infant from gastrointestinal or systemic exposure to ustekinumab should be weighed against the known benefits of breast-feeding.
Safety and effectiveness of ustekinumab in children have not been evaluated.
Hepatic and renal impairment
No pharmacokinetic data are available in patients with liver or kidney disease treated with ustekinumab.
Monitoring while on ustekinumab
It is recommended that patients on biologic medications have routine blood tests every 6 months or so, including full blood count and liver function tests. TB testing should be repeated from time to time.