II. Indications
- 
                          Non-Small Cell Lung Cancer
                          - Atezolizumab
 
- Urothelial Cancer- Atezolizumab
- Avelumab
 
- 
                          Merkel Cell Carcinoma- Avelumab
 
III. Mechanism
- See Immune Checkpoint Inhibitor
- Immune Checkpoint Inhibitors are a subtype of Monoclonal Antibody-Mediated Chemotherapy
- 
                          Antigen Presenting Cells (APC) can inhibit T Cells via several "Checkpoints"- In healthy patients, this T-Cell suppression prevents Autoimmune Disease
- However, cancer cells may exploit this mechanism to allow for their own propagation
 
- Programmed Cell Death Receptor 1 (PD-1) and its Ligand (PDL-1) are among factors that suppress T-Cell function- PD-1 is expressed on T Cell surface and APC-B7 Binding (PD Ligand 1) inhibits the T cells
- Checkpoint Inhibitors that target the PDL-1 Ligand are described here- Also see PD-1 Monoclonal Antibody
 
 
IV. Medications
- Atezolizumab (Tecentriq)
- Avelumab (Bavencio)
- Durvalumab (Imfinzi)
V. Dosing
- See other references for disease specific dosing protocols
VI. Adverse Effects: PDL-1 Monoclonal Antibody
- See Immune Checkpoint Inhibitors
- Precautions- Immune Checkpoint Inhibitors counter mechanisms to prevent Autoimmunity (i.e. risking autoimmune reactions)
- Toxicity may be severe or even life threatening
- Reactions may be delayed for even a year after medication is discontinued
- Initially may be unclear that presentation is related to Immunotherapy adverse effects- Keep a broad differential diagnosis with careful history and examination
- Consult the patient's oncologist
 
 
- 
                          General Immunotherapy related adverse effects- Ipilimumab (CTLA-4 inhibitor) is associated with up to 65% adverse effect rate
- Increased adverse effects with combination of Ipilimumab  (CTLA-4 agent) and PD-1 or PDL-1 agents- Adverse effects with combination therapy occur in nearly all patients and tend to be more severe
 
- Reactions are classified on a 4 grade scale from low grade or high grade reactions (simplified into 2 groups below)- Low grade Immunotherapy related adverse effects- Supportive and symptomatic care
- Localized Corticosteroids (e.g. rash, colitis) or oral Prednisone (0.5 to 1 mg/kg/day)
 
- High grade Immunotherapy related adverse effects (severe or life threatening)- Hospitalization
- High dose Corticosteroids (1 to 2 mg/kg up to 4 mg/kg/day)
- Infliximab (tnf-alpha agent) or Mycophenolate have been used in steroid refractory cases- Consider if no Corticosteroid response in 2 to 3 days
 
- Corticosteroids tapering over 4 to 6 weeks is started after symptoms improve- Start Pneumocystis jirovecii prophylaxis if longterm Corticosteroids are used
 
 
 
- Low grade Immunotherapy related adverse effects
 
- Immune- Graft Versus Host Disease- Occurs in recipients of Hematopoietic Stem Cell Transplant
 
- Immune Mediated Reactions may affect any system- Immune-Mediated Colitis
- Immune-Mediated Hepatitis
- Immune-Mediated Dermatitis
- Immune-Mediated Endocrinopathy (e.g. Thyroiditis)
- Immune-Mediated Pneumonitis
- Immune-Mediated Nephritis
 
 
- Graft Versus Host Disease
- Skin reactions (34-62%)- Pruritus
- CTLA-4 inhibitor (Ipilimumab) with onset of rash 3-6 weeks after treatment- Morbilliform Rash
 
- PD-1 Inhibitor (e.g. Atezolizumab) with onset of rash at 4-10 months after treatment- Lichenoid Dermatitis
- Eczematous Dermatitis
- Vitiligo
 
 
- 
                          Diarrhea or colitis (up to 44-46% of cases, esp. combination therapy)- Exclude Clostridium difficile and CMV-Associated Diarrhea (and obtain CT Abdomen if significant Abdominal Pain)
- Onset typically 5-8 weeks after treatment
- Earlier onset and worse with CTLA-4 inhibitor than with PD-1 Inhibitors
- Treat symptomatically- Loperamide may be used if infection has been excluded (e.g. Clostridium difficile, CMV-Associated Diarrhea)
 
 
- Hepatotoxicity- Evaluate for Viral Hepatitis and Alcoholic Hepatitis
- Occurs in <2% of monotherapy but 17% of combination therapy (CTLA-4 inhibitor with PD-1 Inhibitor)
- Onset 6 weeks after starting CTLA-4 inhibitor and 12 weeks after starting PD-1 Inhibitor
- Mycophenolate Mofetil has been used in severe hepatotoxicity
 
- Endocrine Effects- Autoimmune Thyroid Dysfunction resulting in Thyroiditis, Hypothyroidism or Hyperthyroidism (24%)
- Hypophysitis with anterior pituitary deficiency (esp. Hypothyroidism)
- Type I Diabetes Mellitus
- Adrenalitis and Adrenal Insufficiency
 
- Pneumonitis- Life threatening condition, occurs in 3% of monotherapy but 10% of combination therapy (CTLA-4 with PD-1)
- Often treated initially as Pneumonia until able to distinguish from pneumonitis
- Presents as cough, fever, Hypoxemia and in some cases Respiratory Failure
- Start with Chest XRay, but best diagnosed on CT Chest
- Onset 2.5 months after starting treatment
 
- 
                          Myocarditis
                          - Presents with Chest Pain, Dysrhythmia and in some cases Cardiogenic Shock
- Obtain EKG, Troponin and ntBNP (MRI heart with biopsy may be needed for diagnosis)
 
- 
                          Hypersensitivity
                          - Older monoclonal antibodies were produced in mice and resulted in Hypersensitivity
- Newer drugs use a greater percentage of human antibodies (65-100%)
- Corticosteroids tapered over a 4-6 week course may be needed
 
- Other reactions- Nephritis and Renal Insufficiency
- Neurologic adverse effects (e.g. Encephalitis)
- Ophthalmic adverse effects
- Vasculitis
- Myositis
- Arthritis
 
- References
VII. Safety
- Avoid in Lactation
- Avoid in pregnancy (all trimesters, Pregnancy category X)- Use reliable Contraception
 
VIII. Resources
- Atezolizumab (DailyMed)
- Avelumab (DailyMed)
- Durvalumab (DailyMed)
- American Cancer Society
IX. References
- (2024) Presc Lett 31(3): 17
- Jansson and Pallin (2020) Crit Dec Emerg Med 34(4): 19-28
- Dine (2017) Asia Pac J Oncol Nurs 4(2): 127–135 [PubMed]
- Smith (2021) Am Fam Physician 103(3): 155-63\ [PubMed]
