Table 2

American Society for Transplantation and Cellular Therapy (ASTCT) ICANS consensus grading for adults16

Overall ICANS gradeGrade 1Grade 2Grade 3Grade 4
ICE score*7–93–60–20 (Patient is unarousable and unable to perform the test)
Depressed level of consciousness†Awakens spontaneouslyAwakens to voiceAwakens only to tactile stimulusPatient is unarousable or requires vigorous or repetitive tactile stimuli to arouse. Stupor or coma
SeizureN/AN/AAny clinical seizure focal or generalised that resolves rapidly or non-convulsive seizures on EEG that resolve with interventionLife-threatening prolonged seizure (>5 min); or repetitive clinical or electrical seizures without return to baseline in between
Motor findings‡N/AN/AN/ADeep focal motor weakness such as hemiparesis or paraparesis
Elevated intracranial pressure/cerebral oedemaN/AN/AFocal/local oedema on neuroimaging§Diffuse cerebral oedema on neuroimaging; decerebrate or decorticate posturing; or sixth cranial nerve palsy; or papilledema; or Cushing’s triad
  • ICANS grade is determined by the most severe event (ICE score, level of consciousness, seizure, motor findings, raised intracranial pressure/cerebral oedema) not attributable to any other cause; for example, a patient with an ICE score of 3 who has a generalised seizure is classified as grade 3 ICANS.

  • N/A indicates not applicable.

  • *A patient with an ICE score of 0 may be classified as grade 3 ICANS if awake with global aphasia, but a patient with an ICE score of 0 may be classified as grade 4 ICANS if unarousable.

  • †Depressed level of consciousness should be attributable to no other cause (eg, no sedating medication).

  • ‡Tremors and myoclonus associated with immune effector cell therapies may be graded according to CTCAE v5.0, but they do not influence ICANS grading.

  • §Intracranial haemorrhage with or without associated oedema is not considered a neurotoxicity feature and is excluded from ICANS grading. It may be graded according to CTCAE v5.0.

  • CTCAE, Common Terminology Criteria for Adverse Events; EEG, electroencephalogram; ICANS, immune effector cell-associated neurotoxicity syndrome; ICE, immune effector cell-associated encephalopathy; N/A indicates not applicable.