How Is Capillary Leak Syndrome Managed During Tagraxofusp?

If you start rapidly gaining weight, developing swelling (edema), experiencing drops in blood pressure, or having trouble breathing during tagraxofusp therapy, your medical team will act quickly to manage a potential complication called Capillary Leak Syndrome (CLS) ^[1]. CLS is a severe condition where fluid and proteins leak from your blood vessels into surrounding tissues ^[1]. Because CLS can be life-threatening and carries a boxed warning on the tagraxofusp label, it is treated as a medical emergency requiring strict monitoring ^[2][3]. While most cases occur during the first cycle of treatment, CLS can happen during any cycle, so vigilance is always required ^[1].

What to Do If You Notice Symptoms at Home

Do not wait for your next scheduled appointment or the next day’s weight check if you suspect CLS.

• Immediate Action: Call your oncology team’s 24/7 emergency number immediately if you experience sudden or rapidly worsening swelling, unexpected rapid weight gain, dizziness, fainting, or significantly reduced urine output ^[2].
• Call Emergency Services (911): If you experience severe symptoms like shortness of breath, chest pain, or confusion, seek emergency medical care immediately ^[4].
• Never Self-Treat: Do not attempt to manage swelling with extra fluids or by taking over-the-counter water pills (diuretics) without explicit instruction from your care team ^[5].

How the Hospital Manages CLS

If CLS is suspected, the immediate response is to hold or stop your tagraxofusp infusions ^[6]. You will be closely monitored; while mild cases might be managed in a standard oncology ward, severe cases or patients with breathing and kidney complications may require transfer to an Intensive Care Unit (ICU) ^[5][3].

Treatment is highly individualized based on your blood pressure, circulating fluid volume, and kidney function. There is no one-size-fits-all package, but the hospital may use specific therapies to stabilize you:

• Albumin Infusions: Because CLS causes your body to lose albumin (a key blood protein) into the tissues, doctors may provide IV albumin to help pull fluid back into your blood vessels and stabilize your blood volume ^[7][5].
• Cautious Fluid Replacement: Doctors must be very careful with standard IV fluids. Giving too much can worsen tissue swelling and cause fluid to build up in your lungs (pulmonary edema) ^[5][8].
• Vasopressors: If your blood pressure remains dangerously low, you may be given vasopressors—medications that tighten your blood vessels to help safely raise your blood pressure ^[9][10].
• Intravenous Steroids: In some cases, corticosteroids may be administered through an IV to help reduce the inflammation associated with the leaky blood vessels ^[11][12].
• Diuretics (Water Pills): Once your blood pressure is stabilized and the leaking stops, the fluid trapped in your tissues will return to your bloodstream. At this specific stage, doctors may use diuretics to help your kidneys flush the extra fluid out as urine, preventing fluid overload ^[13]. Diuretics are only used when clinically indicated, as using them too early can dangerously worsen low blood pressure ^[4].
• Advanced Support: In severe cases where fluid buildup heavily impacts lung or kidney function, patients may require oxygen, breathing assistance, or renal replacement therapy (a form of dialysis that may or may not be temporary) to clear the fluid safely ^[4][14].

When Can Treatment Resume?

Stopping the drug is only the first step. Tagraxofusp will not automatically be restarted just because you feel better ^[6]. The decision to resume therapy depends on strict, label-based criteria and requires that your CLS symptoms have resolved and your weight, blood pressure, and serum albumin levels have returned to safe baselines ^[15][6].

Before any future doses, your care team will continue to rigorously check your serum albumin, weight, and other health markers ^[7]. Depending on the severity of the CLS episode, your doctor may decide to permanently discontinue tagraxofusp to ensure your safety ^[15].