Lymphodepletion chemotherapy is the short course of chemotherapy given just before CAR-T infusion. Its role is to reduce the patient’s existing lymphocytes and create a better “space” for the CAR-T cells to expand and persist. It also helps lower immune competition and immunosuppressive signals, which can improve CAR-T engraftment and early activity.

Why it is done

The main purpose is to prepare the immune system for the incoming CAR-T cells so they can multiply more effectively after infusion. In simple terms, it reduces existing immune cells, conditions the environment, and supports the persistence of the CAR-T cells.

Is lymphodepletion strong chemotherapy?

No. This is not the same as full-dose chemotherapy used to treat cancer.
It is considered mild to moderate in intensity and is usually given over a short period of about three days. The most common drugs used are Fludarabine and Cyclophosphamide, at doses lower than standard chemotherapy regimens. Most patients tolerate this phase relatively well compared to traditional chemotherapy.

Does lymphodepleting chemotherapy cause hair loss?

In most cases, no.
This is one of the most common concerns patients have. Hair loss is not typical with lymphodepletion. Some patients may notice mild thinning, but complete hair loss is very unlikely. This is very different from stronger chemotherapy regimens, where hair loss is common.

What are the side effects?

Because this is still chemotherapy, some side effects can occur, but they are usually manageable and temporary. Patients may experience fatigue, a temporary drop in blood counts, a short-term increased risk of infection, and sometimes mild nausea. These effects typically resolve as the body recovers after the CAR-T infusion.

Are there differences between lymphoma, myeloma, and autoimmune CAR-T?

The general approach is similar, but there are some differences:

  • Lymphoma: standard protocol, moderate intensity, well established
  • Multiple myeloma: very similar regimen, sometimes adjusted dosing
  • Autoimmune diseases (e.g., lupus, Sjögren’s): often lower or more tailored doses, as the goal is immune “reset” rather than cancer treatment

Publication date: March 2026