Biologic Agents

General Types & MOA

1. TNF-Alpha Inhibitors

   • Examples: Etanercept, infliximab, adalimumab

   • MOA: Block TNF-alpha, reducing inflammation

2. Interleukin Inhibitors

   • Targets: IL-1, IL-6, or IL-17 pathways

   • Examples: Tocilizumab, anakinra, secukinumab

3. B/T Cell Inhibitors

   • Examples: Rituximab (CD20), abatacept (T-cell activation inhibitor)

Mechanism

• Monoclonal Antibodies ("mab"): Bind specific proteins (e.g., TNF-alpha, CD20), tagging for immune suppression

• Fusion Proteins ("cept"): Act as receptor decoys (e.g., etanercept binds TNF-alpha)

Applications

1. Autoimmune Diseases

   • Rheumatoid arthritis: TNF-alpha, IL-6 inhibitors, abatacept

   • Psoriatic arthritis, ankylosing spondylitis: TNF-alpha, IL-17 inhibitors

   • Inflammatory bowel disease: TNF-alpha, vedolizumab

2. Haematological Malignancies

   • Rituximab: B-cell lymphomas

3. Other Conditions

   • Severe asthma: IL-5 inhibitors (mepolizumab)

   • Multiple sclerosis: B-cell inhibitors (ocrelizumab)

Side Effects & Monitoring

Common Side Effects

• Infusion reactions (fever, chills)

• Injection site reactions, fatigue, nausea

• Increased infection risk (e.g., TB, hepatitis B reactivation)

Serious Risks

• Opportunistic infections (e.g., fungal infections, PJP pneumonia)

• Malignancy (e.g., skin cancers with prolonged use)

• Demyelinating disorders (TNF-alpha inhibitors may worsen MS)

Monitoring

• Pre-Treatment:

  • Screen for latent TB (Mantoux/IGRA), hepatitis B/C

  • Baseline FBC, LFTs, renal function

• During Treatment:

  • FBC, LFTs, renal function every 3–6 months

  • Monitor for infections and neurological symptoms

  • Dermatology reviews for malignancy

Notes:

• Often combined with DMARDs (e.g., methotrexate) to boost efficacy and reduce immunogenicity

• Avoid live vaccines during therapy due to immunosuppression