Chemotherapy uses cytotoxic drugs to destroy cancer. These drugs do not only alter the way in which cancer cells grow and divide, but they may also affect normal cells.

Chemotherapy is usually given during as part of a treatment session. Usually, after each session you will have a two-week rest period, which will allow your body to recover from the side effects.

The treatment and rest period make up one treatment cycle. Your specialist will decide how many cycles you will have.

The most commonly used chemotherapy regimen for CLL is:

• The alkylating agents à chlorambucil and cyclophosphamide

Chlorambucil is considered standard treatment because 40-80% of all cases respond to the treatment. It is used with or without corticosteroid treatment and most often in older patients who have comorbidities. It is commonly given in combination with an anti-CD20 monoclonal antibody (e.g., rituximab, ofatumumab, or obinutuzumab).

Younger patients often receive cyclophosphamide alongside fludarabine and rituximab.

• Purine analogs à fludarabine

This drug was originally used to treat recurrent CLL, although when compared to chlorambucil as first-line treatment it was shown to be more effective. It is usually given in combination with other cytotoxic agents and monoclonal antibodies for increased efficacy. The primary toxicity associated with this drug is hematological since it is a power suppressor of cellular immune response, thus increasing the risk of infection. It is not recommended for older patients or those who have renal conditions. It is usually given alongside chemotherapy and monoclonal antibodies. The most commonly used regimen is FCR.

• Bendamustine àThis drug is usually administered to patients who are not candidates for treatment with fludarabine. It is often used in combination with an anti-CD20 monoclonal antibody (e.g., rituximab, ofatumumab).