Biologics are injectable medications made from living cells in a lab or through a biological process. They change or stop specific cytokine activities inside immune cells that cause inflammation in psoriasis.

As biologics target specific parts of the immune system, they can be safer than broad-spectrum medications that suppress the entire immune system.

In a person with psoriasis, biologics modulate or block the activity of specific cytokines inside immune cells that cause the inflammation associated with the condition.

As we continue to gain knowledge about the specific causes of psoriasis, better and safer biologics will continue to come onto the market.

Four classes of biologics are currently available:

  • blockers of tumor necrosis factor-alpha (TNF-alpha)
  • interleukin 12 and 23 (IL-12/23) inhibitors
  • IL-17 inhibitors
  • IL-23 inhibitors

Each of these molecules are specific messengers in the immune system involved in the development of psoriasis. The dosing regimen and side effects differ, depending on the drug.

TNF-alpha blockers include adalimumab (Humira), etanercept (Enbrel), and certolizumab pegol (Cimzia).

They are all approved to treat both psoriasis and psoriatic arthritis. Depending on the drug, people will need a dose every week or every other week.

Also, these biologics are the most broad-acting medications, as TNF-alpha is an upstream mediator of inflammation. The further downstream the target, the more specific the biologic is, and — potentially — the fewer side effects it has.

The only IL-12/23 inhibitor available is ustekinumab (Stelara). It can treat both psoriasis and psoriatic arthritis, and a person receives a dose every 12 weeks.

The IL-17 inhibitors include secukinumab (Cosentyx), ixekizumab (Taltz), and brodalumab (Siliq). They treat both psoriasis and psoriatic arthritis, and the dosing schedule is every 2–4 weeks.

The IL-23 inhibitors are the newest class of biologics to come onto the market. They include risankizumab-rzaa (Skyrizi), guselkumab (Tremfya), and tildrakizumab-asmn (Ilumya). Each is approved to treat psoriasis. Depending on the drug, a person receives a dose every 8–12 weeks.

We know that psoriasis is caused by overactivity of the immune system with resulting skin inflammation.

By blocking specific steps in the immune pathway that cause this inflammation, biologics can minimize the inflammation and stop the immune attack on the skin and joints.

Without inflammation, the skin can return to its original healthy state, but joint damage can be permanent. This is why it is so important to receive a diagnosis and start treatment as early in the course of the disease as possible.

Biologics are appropriate for people with moderate to severe psoriasis. In some cases, this refers to psoriasis that affects more than 10% of the body’s surface area.

People with psoriasis that affects less of the skin may still receive biologics. The affected areas may be unique and significant — for example, psoriasis affecting the hands can be debilitating, even though it only covers a small percent of the total body surface area.

People who should not receive biologics include those with active cancer, an active infection (including untreated tuberculosis), and individuals who are systemically unwell, in general.

The main side effects that biologics can cause include infections and malignancies.

While reducing inflammation in the skin is good for psoriasis, blocking the immune system — which defends the body from infections and combats cancerous cells — can potentially lead to adverse effects.

If the immune system does not protect the body from infections and cannot recognize and fight off abnormal cells as well as usual, a person may have a greater risk of infections and malignancies.

Besides these risks, TNF blockers have been associated with the development of multiple sclerosis, or MS.

Also, IL-17 blockers have an additional warning about a potential increased risk of inflammatory bowel disease, or IBD.

While the potential adverse effects may be worrisome, they are extremely rare. With regular follow-up visits to a dermatologist, these drugs are safe to use.

The dermatologist will examine the person’s skin, assess their medical history for any potentially concerning symptoms, and perform blood monitoring.

Many people experience benefits from biologics for several years. But in some cases, the response lessens over time.

This may result from the person’s body developing antibodies against the medication, neutralizing its effect. In some cases, a particular class of biologics may not be effective at all.

While psoriasis on any two people may look the same, various genetic mutations can cause the condition. Depending on the particular type of mutation, or genotype, a person may respond better to a certain class of biologic.

Currently, medical professionals have yet to identify all of the genetic mutations that cause psoriasis, and they have no way of predicting which drug will lead to the best response.

However, many of these medications have been evaluated — both in people new to biologics and those who have previously used other types. So, we do have some guidance when making decisions for our patients.

If an individual does not respond to a biologic after several weeks of continuous use, or if someone is no longer responding to one, the dermatologist may change the medication to another in the same class or to one in a different class.

A person can self-inject nearly every biologic on the market in the comfort of their own home. Many companies also provide nursing support, which involves a nurse visiting the person’s home to teach them to self-administer injections.

Most of the medications are administered through auto-injector pens, rather than traditional syringes, to ease the process. In some cases, people can still go to their doctor’s office for the injections, if they are not comfortable administering them at home.

The first step is to thoroughly clean the hands and the site of the injection. An injection should only take place in an area that is not affected by psoriasis.

Place the auto-injector flush to the skin, then press the releaser to deliver the medication. Do not lift the auto-injector from the skin until the dose has been fully administered.

Then, clean the skin again if there is a drop of blood, and apply an adhesive bandage.

While researchers are currently evaluating new biologics, it will be several years before they become available.

The good news is that the options available are providing safe and effective results. We can confidently say that the current medications can lead to 90–100% clearance of symptoms in people with psoriasis.

Joshua Zeichner, MD, is the Director of Cosmetic and Clinical Research in Dermatology at Mount Sinai Hospital in New York City. He actively lectures to international audiences and is involved in daily teaching of residents and medical students. His expert opinion is commonly called upon by the media, and he is regularly quoted in national newspapers and magazines, such as The New York Times, Allure, Women’s Health, Cosmopolitan, Marie Claire, and more. Dr. Zeichner has been consistently voted by his peers to the Castle Connolly list of New York City’s best doctors.