Common Symptoms of CRS
- High fever
- Low or high blood pressure
- Shortness of breath
- Fatigue
CRS: The Most Common Side Effect
The most common side effect of CAR T-cell therapy is called cytokine release syndrome (CRS). CRS occurs when the activated T cells recognize the cancer cell antigen they're designed to attack. "The T cells actually recruit more T cells to come to the environment. They do this by creating chemicals called cytokines to get into the blood and say the equivalent of 'Bring the cavalry, bring everybody to this area, let's go kill this thing now!'" explains Dr. Martin.
Read MoreHow To Treat CRS
Most people who develop CRS will have mild to moderate symptoms, but sometimes CRS can be serious and even life-threatening. When symptoms occur, doctors follow their patients closely to make sure they are effectively managed."If the symptoms are mildmeaning that the temperature might rise but the blood pressure is fine and there's no change in the oxygen saturation in the bloodthen we can usually just give acetaminophen (Tylenol) to control the fever," says Dr. Martin. "But if the oxygen level gets a little bit low in the blood, some people will need oxygen support by either a nasal cannular or face mask. Or if the blood pressure gets a little low we give fluids or medication for that.”
The medication most often used to battle moderate to severe CRS is called tocilizumab, or "toci" for short. "Toci is a medicine that tries to turn off this really high cytokine storm, and it's pretty effective in most people," says Dr. Martin. The CRS symptoms generally last from four to seven days.
The Benefits Outweigh the Risks
CRS isn't the only side effect associated with CAR T-cell therapy. Patients may have neurologic events that can include brain injury or malfunction, confusion, aphasia (difficulty understanding or speaking), drowsiness, agitation, seizures, loss of balance and altered consciousness. The treatment can also lower white or red blood cell count. Most of these side effects will resolve on their own or can be managed with medication. But patients should always let their physician or care team know immediately if they are experiencing side effects of treatment.
While CRS can be severe, it is manageable. "We see it in 70 to 90 percent of patients with CAR T-cell therapy, but we know it's coming, and we know how to manage it," says Dr. Martin. And when it's over, he says, "what we're hoping is that you've had a good anti-cancer effect."
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