Biologics are medications made from human or animal proteins. They are designed to specifically target biologic pathways that cause inflammation in the skin and other organs.
Biologics have been used in many people worldwide to treat severe psoriasis, psoriatic arthritis, other types of arthritis and inflammatory bowel diseases (e.g. Crohn’s disease). Biologic medications are given as injections.
A condition such as psoriasis develops in people who are genetically predisposed. Immune cells are triggered and become overactive, creating inflammation in the skin (which we recognise as psoriasis) and, in some cases, the joints (psoriatic arthritis). Biologics work in different ways to traditional treatments by blocking the activation and behaviour of immune cells that play a role in a disease such as psoriasis. Examples of biologic drugs currently used in Australia to treat psoriasis include etanercept (enbrel), adalimumab (humira), infliximab (remicade), ustekinumab (stelara) and secukinumab (cosentyx).
It is important to remember that all systemic medications, whether traditional or the newer biologics, have broad effects and people undergoing treatment have to be carefully monitored.
Biologics are very expensive. In Australia they are available on the Pharmaceutical Benefits Scheme (PBS) only after all the more commonly prescribed treatments have been tried and shown to be ineffective or cannot be used in in a particular person due to side effects.
Biologic drugs may be prescribed by a dermatologist for a person with severe and extensive psoriasis that has not responded to topical treatments and adequate trials of phototherapy (NBUVB or PUVA), acitretin or other immunosuppressive drugs such as methotrexate or cyclosporine.
If a person has significant psoriatic arthritis but limited skin involvement, a rheumatologist will need to be involved.
Biologics are associated with an increased risk of new infections or reactivation of old infections. With long-term treatment there may be an increased risk of lymphoma.
Prior to starting on a biologic drug, your dermatologist will carefully review your medical history and examine or test you for evidence of tuberculosis, HIV and other chronic infections, significant heart disease or significant evidence of atherosclerosis and past history of cancer.
Your vaccination status will be reviewed. It may be necessary to have a booster for some childhood diseases such as whooping cough, diphtheria or polio. You should be immunised against hepatitis A and B as well. Necessary live vaccines will be given prior to commencing treatment.
A number of blood tests, a chest X-ray and other investigations will be required.
Biologic drugs are rated category B or C in pregnancy, and planned pregnancy needs to be discussed with the treating doctor.
Live or attenuated vaccines should not be given while taking biologics. These include vaccines such as herpes zoster, influenza (including nasal form), measles, mumps, rubella rotavirus, oral polio vaccine, smallpox, varicella, yellow fever, typhoid (oral form) and BCG injection.
Because the immune system is suppressed, extra care will be needed when travelling to parts of the world where you may be exposed to infectious diseases that are not prevalent in Australia.
While we have a greater understanding of how the immune system works in maintaining health and the steps involved in the development and persistence of disease, it is by no means complete. There is a theoretical risk that biologic drugs may interfere with our body’s defenses in unexpected ways leading to secondary diseases such as infection, cancer or autoimmune disease. Reported safety data on these drugs has been reassuring but it is important that people on biologic medications are monitored regularly for response to treatment and any associated complications.
This information has been written by Dr Pam Brown