What is a biological drug and what are they used for in rheumatology?

Biological drugs, also known as biologics, are a class of medications derived from living organisms or their components, often produced using biotechnological processes. These drugs are typically large and complex molecules, such as proteins, antibodies, or nucleic acids. Unlike small-molecule drugs, which are chemically synthesized, biologics are usually produced through living cells, such as bacteria, yeast, or mammalian cells.

In rheumatology, biological drugs have revolutionized the treatment of autoimmune and inflammatory diseases.

Biological drugs target specific components of the immune system or inflammatory pathways. Many of them work by inhibiting pro-inflammatory cytokines or blocking immune cells involved in the pathogenesis of autoimmune diseases.


Types of Biological Drugs in Rheumatology:

  • Biologics Targeting Tumor Necrosis Factor (TNF) Inhibitors: Examples include etanercept, adalimumab, infliximab. They block the action of TNF and are used in conditions like rheumatoid arthritis and ankylosing spondylitis.
  • Interleukin-6 (IL-6) Inhibitors: Tocilizumab targets the IL-6 receptor and is used in rheumatoid arthritis.
  • B-cell Depleting Agents Biologics: Rituximab depletes B cells and is used in diseases like rheumatoid arthritis.
  • Interleukin-17 (IL-17) Inhibitors: Secukinumab and ixekizumab target IL-17 and are used in conditions like psoriatic arthritis.
  • Interleukin-12/23 Inhibitors: Ustekinumab is a monoclonal antibody that inhibits the activity of both IL-12 and IL-23. Guselkumab is another biologic that specifically targets IL-23. They are used in the treatment of conditions such as psoriasis, psoriatic arthritis, and Crohn's disease.

Biological drugs are typically administered by injection (subcutaneous or intravenous). The route of administration depends on the specific drug.

Biologics are used to treat autoimmune and inflammatory diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and lupus. They are often prescribed when traditional disease-modifying antirheumatic drugs (DMARDs) have not provided sufficient benefit.

Regular monitoring is essential due to the potential for side effects, including increased susceptibility to infections and infusion reactions. The safety profile varies among different biologics.

Biological drugs in rheumatology have significantly improved patient outcomes, offering targeted therapies that help control inflammation, prevent joint damage, and improve overall quality of life. However, their use requires careful consideration of individual patient factors, disease characteristics, and potential risks and benefits.