Biologic Response Modifiers

  • Definition: Agents that modify the immune response.

Mechanisms of Action

  • Direct Immune Response Alteration
    • Modify immune system to enhance the response against cancer.
    • Direct cytotoxic effects on tumor cells.
  • Hematopoiesis Stimulation
    • Enhance blood cell production in bone marrow.
  • Tumor Biology Changes
    • Adverse effects on tumor biology and inhibition of metastases.
  • Clinical Applications: Used for treating autoimmune diseases, certain cancers, and in response to chemotherapy.

Hematopoietic Drugs

  • Purpose: Promote synthesis of blood components (RBCs, platelets, WBCs).
  • Types:
    • Colony-Stimulating Drugs: Stimulate the production of neutrophils to prevent nadir.
    • Impact:
    • Allow higher chemotherapy doses by mitigating myelosuppression.
    • Reduce recovery time, avoiding transfusions.
  • Examples:
    • Epoetin alfa: Synthetic erythropoietin for RBC stimulation.
    • Filgrastim (Neupogen): Administered before infections, not within 24 hrs post-myelosuppressive drugs; discontinue once ANC > 10,000 cells.
  • Adverse Effects:
    • Fever, muscle aches, bone pain.
    • Continuous monitoring of baseline and ongoing cell counts required.

Interferons

  • Properties: Antiviral, antitumor, and immunomodulating.
  • Types: Three groups - alfa, beta, gamma.
  • Cautions:
    • Not to be used with immunosuppressants or in severe liver disease.
  • Adverse Effects:
    • Flu-like symptoms and primarily dose-limiting fatigue.
    • Black Box Warning: May cause or aggravate autoimmune disorders.
  • Monitoring:
    • CBC for neutropenia or thrombocytopenia.

Monoclonal Antibodies

  • Use Cases: In rheumatoid arthritis (RA), multiple sclerosis (MS), cancers, inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), and organ transplants.
    • Minimal effects on healthy cells, reducing adverse effects.
  • Naming: Often end in -mab, indicating monoclonal antibodies.
  • Immunosuppressive Risks: Not for use during active infections; high risk for severe infections.
  • Adverse Effects:
    • Flu-like symptoms and potential severe allergic reactions. Premedication may be needed.
    • Long half-life can result in persistent presence in tissues, increasing toxicity risk.

Interleukins (Lymphokines)

  • Mechanism: Activate natural killer cells that have antitumor actions.
  • Most Common: Aldesleukin.
  • Severe Toxicities:
    • Capillary Leak Syndrome: Leads to weight gain (20-30 lbs), respiratory distress, heart failure, dysrhythmias, hypotension, and potential myocardial infarction.
  • Monitoring: Daily weights; watch for early symptoms like runny nose or cough.

Rheumatoid Arthritis Treatment

  • DMARDs: Disease-modifying antirheumatic drugs, including -nibs and -mabs.
  • Characteristics:
    • Effects take weeks to manifest.
    • Not for use during active bacterial infections or certain viral infections.
    • Risk of serious infections and malignancies.
  • Example: Methotrexate (MTX) reduces folic acid to its active form; not used during pregnancy or lactation, administered weekly.
  • Adverse Effects: Immunosuppressive, anti-inflammatory; significant risk of bone marrow suppression.

Assessment, Implementation, and Education

  • Laboratory Monitoring: Specific parts of the CBC must be monitored.
  • Dosing: Accurate weight necessary; daily monitoring recommended.
  • Pre-medications: High incidence of drug reactions requires premedication.
  • Safety: Follow dilation directions from manufacturers; advise against hazardous tasks due to CNS effects and fatigue.
  • Infection Awareness: Education on signs and symptoms of infection is crucial.
  • Contraceptive Measures: Use of contraception is advised for up to 2 years post-treatment.