Researchers say they have created guidelines for managing the unique toxicities associated with chimeric antigen receptor (CAR) T-cell therapy.

The guidelines focus on cytokine release syndrome (CRS); neurological toxicity, which the researchers have dubbed “CAR-T-cell-related encephalopathy syndrome (CRES);” and adverse effects related to these syndromes.

“The toxicities are unique, and every member of the care team needs to be trained to recognize them and act accordingly,” said Sattva Neelapu, MD, of University of Texas MD Anderson Cancer Center in Houston.

Dr Neelapu and his colleagues described the toxicities and related recommendations in Nature Reviews Clinical Oncology.

The team’s guidelines include supportive-care considerations for patients receiving CAR T‑cell therapy. For example, they recommend:

Baseline brain MRI to rule out central nervous system disease

Cardiac monitoring starting on the day of CAR T‑cell infusion

Assessing a patient’s vital signs every 4 hours after CAR T-cell infusion

Assessing and grading CRS at least twice daily and whenever the patient’s status changes

Assessing and grading CRES at least every 8 hours.

CRS

One section of the guidelines is dedicated to CRS, with subsections on pathophysiology, precautions and supportive care, the use of corticosteroids and IL‑6/IL‑6R antagonists, and grading CRS.

The researchers noted that CRS typically manifests with constitutional symptoms, such as fever, malaise, anorexia, and myalgias. However, CRS can affect any organ system in the body.

The team recommends managing CRS according to grade. For example, patients with grade 1 CRS should typically receive supportive care. However, physicians should consider giving tocilizumab or siltuximab to grade 1 patients who have a refractory fever lasting more than 3 days.

The researchers also noted that CRS can evolve into fulminant hemophagocytic lymphohistiocytosis (HLH), also known as macrophage-activation syndrome (MAS).

The team said HLH/MAS encompasses a group of severe immunological disorders characterized by hyperactivation of macrophages and lymphocytes, proinflammatory cytokine production, lymphohistiocytic tissue infiltration, and immune-mediated multi-organ failure.

The guidelines include diagnostic criteria for CAR T‑cell-related HLH/MAS and recommendations for managing the condition.

CRES

One section of the guidelines is dedicated to the grading and treatment of CRES, which typically manifests as a toxic encephalopathy.

The researchers said the earliest signs of CRES are diminished attention, language disturbance, and impaired handwriting. Other symptoms include confusion, disorientation, agitation, aphasia, somnolence, and tremors.

Patients with severe CRES (grade >2) may experience seizures, motor weakness, incontinence, mental obtundation, increased intracranial pressure, papilledema, and cerebral edema.

Therefore, the guidelines include recommendations for the management of status epilepticus and raised intracranial pressure after CAR T‑cell therapy.

The researchers also devised an algorithm, known as CARTOX-10, for identifying neurotoxicity. (An existing general method didn’t effectively quantify the neurological effects caused by CAR T-cell therapies.)

CARTOX-10 is a 10-point test in which patients are asked to do the following:

Name the current month (1 point) and year (1 point)

Name the city (1 point) and hospital they are in (1 point)

Name the president/prime minister of their home country (1 point)

Name 3 nearby objects (3 points)

Write a standard sentence (1 point)

Count backward from 100 by tens (1 point).

A perfect score indicates normal cognitive function. A patient has mild to severe impairment depending on the number of questions or activities missed.

Dr Neelapu and his colleagues believe their recommendations will be applicable to other types of cell-based immunotherapy as well, including CAR natural killer cells, T-cell receptor engineered T cells, and combination drugs that use an antibody to connect T cells to targets on cancer cells.

Researchers involved in this work have received funding from companies developing/marketing CAR T-cell therapies.

Team creates guidelines on CAR T-cell-related toxicity