ICANS AFTER CAR-T:
NEUROTOXICITY, GRADING & MANAGEMENT
ICANS is a distinct neurological toxicity that follows CAR-T infusion โ understanding its symptoms, grading, and treatment helps patients and families prepare for what to monitor during recovery.
analyticsAt a Glance
- check_circleICANS causes confusion, aphasia, tremor, agitation, or seizure โ distinct from CRS fever and hypotension
- check_circleTypically follows CRS by 1โ3 days; onset usually within the first 2 weeks post-infusion
- check_circleDexamethasone 10mg IV is the frontline treatment โ NOT tocilizumab (which treats CRS, not ICANS)
- check_circleMost ICANS cases resolve within 1โ4 weeks; long-term cognitive effects are rare
What Is ICANS?
ICANS (immune effector cell-associated neurotoxicity syndrome) is a neurological complication of CAR-T therapy caused by cytokine-mediated disruption of the blood-brain barrier, allowing cytokines and activated immune cells to enter the central nervous system.
โICANS is not a sign of disease progression โ it is an immune-mediated neurological response that is treatable at experienced centres.โ
How It Develops
High systemic cytokine levels (especially IL-6 and IFN-ฮณ) during CRS increase blood-brain barrier permeability. Cytokines and CAR-T cells enter the CNS, triggering neuroinflammation and endothelial activation.
Symptoms to Watch For
Early ICANS: handwriting deterioration, word-finding difficulty, mild confusion. Severe ICANS: aphasia, somnolence, tremor, agitation, focal seizures, cerebral oedema (grade 4).
ICANS Grading โ ASTCT 2019 Consensus
ICANS grading uses the ICE (Immune Effector Cell-Associated Encephalopathy) score (0โ10 points) combined with level of consciousness, seizure, and motor findings. CARTOX-10 is an earlier scoring tool still in use at many centres.
| Grade | ICE Score | Level of Consciousness | Seizure / Motor / Cerebral Oedema |
|---|---|---|---|
| Grade 1 | 7โ9 | Spontaneously awake | No seizure, no motor findings |
| Grade 2 | 3โ6 | Arousable to voice | No life-threatening seizure |
| Grade 3 | 0โ2 | Arousable only to tactile stimulus | Any clinical seizure (brief); focal/generalised; papilloedema or raised ICP |
| Grade 4 | 0 (patient untestable) | Unarousable / stupor or coma | Life-threatening prolonged seizure; motor weakness; cerebral oedema on imaging |
ICANS Management by Grade
Management escalates with grade. The critical distinction from CRS management: ICANS requires dexamethasone (a corticosteroid), not tocilizumab.
- 1
Grade 1 โ Monitor and Protect Airway
Neurological assessment every 8 hours using ICE score. Levetiracetam 500โ750mg twice daily started as seizure prophylaxis. No corticosteroids yet.
- 2
Grade 2 โ Dexamethasone
Dexamethasone 10mg IV every 6 hours initiated. Continue levetiracetam. Brain MRI to exclude alternative diagnoses. EEG if subclinical seizures suspected.
- 3
Grade 3 โ ICU + Higher-Dose Steroids
ICU admission. Methylprednisolone 1โ2mg/kg/day IV if dexamethasone response is insufficient. Non-convulsive status epilepticus excluded by continuous EEG. Intracranial pressure monitoring considered.
- 4
Grade 4 โ Cerebral Oedema Protocol
Intensive care with intubation if GCS falling. High-dose methylprednisolone 1g/day. Mannitol or hypertonic saline for raised ICP. Neurosurgical consultation for refractory cerebral oedema.
ICANS Rates: Axicabtagene vs Tisagenlecleucel
ICANS incidence varies significantly between approved CAR-T products, likely due to differences in construct design, co-stimulatory domains, and patient populations studied.
Axicabtagene (Yescarta) โ CD28 co-stimulation
- Any-grade ICANS: ~64%Higher neurotoxicity rates associated with the CD28 co-stimulatory domain driving more rapid, intense T-cell expansion.
- Grade 3โ4 ICANS: ~28%From ZUMA-1 pivotal trial in r/r large B-cell lymphoma.
- Earlier onsetICANS onset typically 4โ5 days post-infusion, overlapping with or immediately following CRS.
Tisagenlecleucel (Kymriah) โ 4-1BB co-stimulation
- Any-grade ICANS: ~21%Lower neurotoxicity rates; 4-1BB co-stimulatory domain associated with more gradual, sustained T-cell expansion.
- Grade 3โ4 ICANS: ~13%From JULIET trial in r/r DLBCL; lower rates also seen in ELIANA paediatric ALL data.
- Typically later onsetICANS may appear up to day 10โ14, sometimes after CRS has already resolved.
ICANS Recovery Outcomes
The majority of ICANS cases are reversible with appropriate management. Long-term neurological sequelae are uncommon.
- ~85%ICANS resolution within 4 weeksMost patients recover fully from grade 1โ3 ICANS with dexamethasone and supportive care.
- 1โ4 wksMedian recovery durationGrade 1โ2 typically resolves within 1โ2 weeks; grade 3โ4 may take 2โ4 weeks.
- <5%Long-term cognitive effectsRare with grade 1โ3 ICANS; more common after grade 4 cerebral oedema events.
ICANS Incidence by Trial and Product
Pooled trial data showing any-grade and severe (grade 3โ4) ICANS rates across approved and investigational CAR-T products.
Any-Grade ICANS by Product
Source: ZUMA-1 (axi-cel), JULIET (tisa-cel), TRANSCEND (liso-cel) pivotal trials
- Axicabtagene (ZUMA-1)64%
- Lisocabtagene (TRANSCEND)30%
- Tisagenlecleucel (JULIET)21%
Grade 3โ4 ICANS by Product
Severe ICANS requiring ICU management; dexamethasone used in all cases
- Axicabtagene (ZUMA-1)28%
- Lisocabtagene (TRANSCEND)10%
- Tisagenlecleucel (JULIET)13%
More from the CAR-T Cell Therapy Resource Library
Continue reading about CAR-T access, toxicity management, and treatment planning in China.
Frequently Asked Questions About ICANS
Key questions from patients and families about neurological side effects after CAR-T therapy.
Understanding ICANS
How is ICANS different from CRS?
CRS is a systemic response (fever, low blood pressure, low oxygen) caused by cytokines in the bloodstream. ICANS is a neurological response caused by cytokine-mediated disruption of the blood-brain barrier โ symptoms are neurological: confusion, speech difficulty, tremor, seizure. They can occur simultaneously but require different treatments: CRS uses tocilizumab; ICANS uses dexamethasone.
Should my family member know what ICANS looks like?
Yes โ this is strongly encouraged. Early ICANS warning signs include handwriting becoming untidy, difficulty finding words mid-conversation, mild confusion about time or place, and uncharacteristic agitation. Families who can recognise these signs early enable faster escalation to the medical team, which improves outcomes.
Will ICANS damage my brain permanently?
Permanent neurological damage from ICANS is uncommon. The vast majority of grade 1โ3 ICANS cases resolve fully within 1โ4 weeks. Grade 4 cerebral oedema carries a higher risk of lasting effects, but this is the rarest form. Experienced centres with early dexamethasone protocols have significantly reduced severe ICANS rates over time.
Does using dexamethasone for ICANS cancel out the CAR-T therapy?
Not significantly when used reactively rather than prophylactically. Short courses of dexamethasone used to treat established ICANS (typically days 5โ14) are given after the initial CAR-T cell expansion has already occurred. While prolonged high-dose steroids can reduce CAR-T persistence, the clinical priority is always patient safety first.
How CancerFax Helps
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Preparing for CAR-T? Know the Neurological Risks Before You Go.
CancerFax provides pre-treatment briefings on CRS and ICANS management protocols at the specific Chinese centre you are considering, and supports families with real-time interpretation and guidance during the hospital stay.
This content is for informational purposes only and does not constitute medical advice. Always consult a qualified oncologist before making treatment decisions.