Stelara (ustekinumab) and Humira (adalimumab) are two biological medicines that doctors use to treat immune system conditions. They have different effects on the body and some different benefits and risks.

Biological medicines, or biologics, are a class of drugs composed of naturally occurring molecules, such as sugars and proteins. Some biologics contain living cells or tissues. Manufacturers design these drugs to replicate proteins and other molecules that the body naturally produces. Doctors use ustekinumab and adalimumab to treat a number of autoimmune diseases, including psoriatic arthritis and Crohn's disease. Read on to learn about the similarities and differences of Stelara and Humira as treatments for various conditions.

What is adalimumab?

Humira is a brand name for the biological medicine adalimumab. Doctors use this medicine to treat a number of long-term illnesses that impact the immune system. These include psoriatic arthritis, which affects the joints, and Crohn's disease, which affects the digestive system.

People with these conditions have higher levels of a protein called tumor necrosis factor alpha. This causes inflammation in the body. Adalimumab works by attaching to these proteins and stopping them from working. This can reduce the inflammation that causes many of the conditions' symptoms.

What is ustekinumab?

Stelara is the brand name for the biological medicine ustekinumab. Like adalimumab, doctors use this medicine to treat autoimmune conditions, which are diseases that affect the immune system. Ustekinumab works by targeting two proteins in the body, interleukin-12 (IL-12) and interleukin-23 (IL-23).

In healthy people, IL-12 and IL-23 cause temporary inflammation to help the body fight infection. In people with psoriatic arthritis or Crohn's disease, the body produces too much IL-12 and IL-23, causing excess inflammation when it is not needed. Ustekinumab works by attaching to the proteins and blocking their activity.

How are these medicines different?

The two medicines both impact the immune system, but in different ways. There are similarities and differences in the ways that both drugs work, their side effects, and their risks as treatments for various medical conditions, which we discuss below.

How they work
Both medicines dampen the activity of the immune system. This reduces the inflammation that can cause the symptoms of autoimmune diseases. Also, doctors prescribe both drugs for long-term use.

Crohn's disease
Large studies of adalimumab as a treatment for Crohn's disease have shown that, initially, around 6 in 10 people respond well to the drug. After taking adalimumab for a year, more than 1 in 3 people from this group had not experienced a flare-up of the disease.

Trials of ustekinumab for Crohn's disease found that the drug could benefit around 50% of people with the condition. After starting this treatment, some people no longer need to use steroids to control Crohn's disease symptoms.

Psoriatic arthritis
In clinical trials, 57% of adult participants with psoriatic arthritis who took adalimumab for 6 months experienced at least a 20% improvement in their symptoms.

Studies involving usetkinumab as a treatment for the condition found that 50% of adult participants experienced at least a 20% improvement after 6 months.

Side effects
Like all medicines, adalimumab and ustekinumab can cause side effects, though it is important to note that not everyone experiences them. Common side effects of adalimumab can include:

• Skin reactions around the injection site, such as pain, swelling, or itching
• Respiratory infections, such as a cold, a sinus infection, or pneumonia
• Stomach pain
• A headache
• Feeling nauseous and possibly vomiting
• A rash
• Musculoskeletal pain

People taking adalimumab may also experience infections, dehydration, mood swings, depression, and difficulty sleeping.

Common side effects of ustekinumab are similar to those of adalimumab. They include:

• Upper respiratory infections
• Vomiting
• A headache
• Vaginal yeast infections
• Tiredness
• Urinary tract infections
• Itching

In some people, the drug can cause lung inflammation. Symptoms of this include shortness of breath and a cough that does not go away. People who experience these symptoms should see a doctor right away.

As with many medicines, biologics can trigger allergic reactions. Anyone who notices the following symptoms of a serious allergic reaction should seek urgent medical attention:

• Feeling faint
• Chest tightness
• Swelling of the face, eyelids, tongue, or throat
• Hives

Risks

Both medicines block the activity of the immune system. This can be risky because it reduces the body's natural defenses. It can increase the chances of a person contracting a serious infection, such as tuberculosis (TB) or pneumonia. Health-care professionals tend to closely monitor people taking these drugs, in order to spot any early signs of infection. Doctors advise individuals who take biologics not to receive live vaccines.

How to take them

A person takes either ustekinumab or adalimumab over a long period of time. Individuals receive these medicines by injection. Biologics would not survive in the gut, so people cannot take them as pills. A health-care professional will usually give a person an injection pen so that they can inject themselves. The exact dose depends on individual factors, including the severity of the condition.

Alternatives

Adalimumab and ustekinumab treat mild-to-moderate symptoms of Crohn's disease, psoriatic arthritis, and various other autoimmune diseases. Health-care professionals can recommend a number of other options to people with these conditions. Other treatments include steroids and nonsteroidal anti-inflammatory drugs, such as ibuprofen. Because of the risks associated with taking adalimumab or ustekinumab, doctors tend only to prescribe them when other treatments have failed.

Takeaway

Adalimumab and ustekinumab are biological medications that doctors use to treat autoimmune diseases such as Crohn's disease and psoriatic arthritis. The drugs work by dampening the immune system and reducing the inflammation that leads to many of the symptoms of these long-term conditions. Doctors prescribe them when other forms of treatment have failed. They are effective, but not without risks. These biologics can leave people unable to fight off serious infections, such as TB and pneumonia. A health-care team will closely monitor individuals on these medications to make sure that they notice and treat any infections early.