Psoriasis is a life-long chronic inflammatory skin condition affecting approximately 2% of the general population.  There are many clinical variants of psoriasis. Most patients have plaques with silver-white scale and an erythematous base.   Some patients have joint involvement. There is strong evidence in favour of psoriasis being an immune-mediated disease with T-cells playing a central role. However, the pathogenesis of psoriasis is complex and likely includes mediators of both the innate and adaptive immune systems. To date, there is no consensus as to the antigens involved in the autoreactive immune response that is responsible for psoriasis. However, the cytokine secretion profile of the T-cells has been well characterized and both Th1 and Th17 cells have been found to play a role in the pathogenesis of psoriasis. 

Biological therapy is the use of agents that can specifically target an immune or genetic mediator of a pathophysiological process. The introduction of biological-based therapies has greatly improved treatment of psoriasis.

What is a biologic drug (biologics)? 

A biologic drug (biologics) is a product that is produced from living organisms or contains components of living organisms. Biologic drugs are sometimes referred to as biologic response modifiers because they change the manner of operation of natural biologic intracellular and cellular actions.

What are the medical uses for biologics?

 Biologic drugs are used for the treatment of numerous diseases and conditions and are the most advanced therapies available. Some biologic drugs are used for the treatment of Crohn's disease, ulcerative, rheumatoid arthritis, and other autoimmune diseases. Available biologics have revolutionized cancer treatment, delayed or reversed the course of immune-related conditions, changed the lives of people with rare diseases, and have offered hope for many patients who previously had no effective treatment options for their condition

What are the side effects of biologics?

Side effects of a biologic drug depend on the specific biologic drug, and method of introduction into the body and are rarely seen 

What are preparations available for biologics?

Biologic drugs are administered by injection or infusion because they are proteins that are quickly digested and inactivated if given by mouth. Therefore, biologic drugs are supplied as powders for infusion or solutions for injection.

Are biologics safe to use during pregnancy or while breastfeeding?

Most biologic drugs have not been adequately studied in pregnant women or women who are breastfeeding.

What are FDA-approved biologics for psoriasis?

The currently approved biologic agents for the treatment of either psoriasis or PsA include alefacept, infliximab, etanercept, adalimumab, golimumab, secukinumab, ustekinumab, with alefacept and ustekinumab FDA approved for psoriasis only and golimumab FDA approved for PsA only.

Management of psoriasis

It may involve topical and systemic medication, phototherapy, stress reduction, climatotherapy, and various adjuncts such as sunshine, moisturizers, salicylic acid, and other keratolytics such as urea. Expert dermatologists from across the globe released a consensus report on treatment optimization and transitioning for moderate-to-severe plaque psoriasis. Recommendations of the 2013 consensus report include the following:

  • Methotrexate may be used for as long as it remains effective and well-tolerated.
  • Cyclosporine is generally used intermittently for inducing a clinical response with one or several courses over a 3–6 month period. The transition from conventional systemic therapy to a biological agent may be done directly or with an overlap if transitioning is needed because of lack of efficacy, or with a treatment-free interval if transitioning is needed for safety reasons.
  • Combination therapy may be helpful.
  • Continuous therapy for patients receiving biologicals is recommended.
  • Switching biologicals because of lack of efficacy should be performed without a washout period while switching biologicals for safety reasons may require a treatment-free interval.
  • Interleukin-17A (IL-17 or IL-17A) has now emerged as a major factor in the pathogenesis of psoriasis vulgaris. It is produced by Th17 cells, a class of T helper cells that act outside the established Th1/Th2 paradigm for regulation of innate and adaptive immunity.

Hence, drugs targeting this cytokine are being widely researched. Currently, there are three different IL-17 antagonists under clinical evaluation for psoriasis. The monoclonal antibodies ixekizumab and secukinumab both target IL-17A, while brodalumab blocks the IL-17 receptor IL-17RA.1.