Definition
CRS is a potentially life-threatening systemic inflammatory response caused by massive cytokine release, often following immunotherapies like:
- CAR-T cell therapy (e.g., tisagenlecleucel, axicabtagene)
- Bispecific T-cell engagers (e.g., blinatumomab)
- Some monoclonal antibodies and immune checkpoint inhibitors
Pathophysiology
- Activation of immune effector cells (e.g., T cells, macrophages) → release of cytokines like IL-6, IFN-γ, TNF-α → systemic inflammation
- Resembles sepsis or HLH/MAS
Onset and Duration
- Typically within 1–14 days of therapy (often earlier with bispecifics or CAR-T)
- Can last hours to several days
Grading (ASTCT Criteria)
- Grade 1: Fever ≥38°C
- Grade 2: Fever + hypotension responsive to fluids or low-flow oxygen
- Grade 3: Hypotension requiring vasopressors or higher-flow oxygen
- Grade 4: Life-threatening (ventilation, multiple vasopressors)
- Grade 5: Death
Clinical Features
- Fever, chills
- Hypotension, tachycardia
- Hypoxia, dyspnea
- Fatigue, myalgias, rash
- Severe cases: organ dysfunction, coagulopathy, encephalopathy
Management
Supportive Care
- IV fluids, oxygen, vasopressors as needed
- ICU support in severe cases
- Rule out sepsis (can mimic)
Pharmacologic
- Tocilizumab (IL-6 receptor antagonist):
- First-line treatment (especially Grade ≥2)
- 8 mg/kg IV (max 800 mg); can repeat every 8 hours (max 4 doses)
- Corticosteroids (e.g., dexamethasone, methylprednisolone):
- For Grade ≥2 not responsive to tocilizumab
- Especially important in CAR-T–associated neurotoxicity
Monitoring
- Vital signs: continuous in at-risk patients
- CBC, CRP, ferritin, IL-6 (if available)
- Liver and renal function, coags
- Neurologic assessment (due to risk of immune effector cell-associated neurotoxicity syndrome [ICANS])
Prevention/Prophylaxis
- Premedication: acetaminophen, antihistamines ± corticosteroids before therapy (especially with bispecifics)
- Use of step-up dosing (e.g., with blinatumomab) to reduce risk
- CRS risk stratification protocols for CAR-T patients
Key Notes for Oncology Pharmacist
- Ensure tocilizumab is available and accessible in centers giving CAR-T or bispecifics
- Educate staff on early recognition
- Coordinate care closely with ICU/critical care teams in high-grade CRS
- Do not delay tocilizumab if CRS is suspected