How it is administered

Pentostatin is administered as an intravenous (IV) infusion. It comes as a sterile powder that must be reconstituted and diluted before being given through a vein. The usual dose for blood cancers is 4 mg/m² every other week, either as a bolus injection or infused over 20 to 30 minutes. Patients typically receive fluids before and after the infusion to help protect the kidneys.

How it works

Pentostatin is a type of chemotherapy that works by inhibiting an enzyme called adenosine deaminase (ADA). This enzyme is especially active in lymphoid cells, including T-cells and B-cells. By blocking ADA, pentostatin causes a build-up of certain molecules inside the cancer cells, which interferes with their ability to make DNA and RNA. This leads to the death of these abnormal cells.

The drug is particularly effective in blood cancers where the malignant cells have high ADA activity, such as hairy cell leukemia and some T-cell malignancies. By targeting this enzyme, pentostatin helps reduce the number of cancerous cells in the blood and bone marrow, allowing normal blood cell production to recover.

Who Should take it

Pentostatin is approved for the treatment of patients with hairy cell leukemia, including those who have not been treated before and those who did not respond to alpha-interferon therapy. While its main use is in hairy cell leukemia, pentostatin may sometimes be considered in other blood cancers, such as T-cell prolymphocytic leukemia, especially if other treatments are not effective or suitable.

Patients with active disease—meaning they have symptoms or low blood counts due to the leukemia—are the ones who benefit most from this medication. Your doctor will determine if pentostatin is appropriate based on your specific diagnosis and health status.

Who should not take it

Pentostatin should not be used in patients who have had a hypersensitivity (allergic) reaction to the medication. It should also be used with caution in people with active, uncontrolled infections, as it can further suppress the immune system and worsen infections.

Pregnant women should avoid pentostatin because it can cause harm to the unborn baby. It is not known if pentostatin passes into breast milk, so nursing mothers should discuss with their doctor whether to stop breastfeeding or discontinue the medication. The safety and effectiveness of pentostatin in children have not been established.

Commonly used with

Pentostatin is usually used alone for the treatment of hairy cell leukemia and similar blood cancers. However, in some cases, it may be combined with other chemotherapy drugs as part of a treatment regimen, especially in clinical trials or for bone marrow transplant preparation. Your doctor will decide if combination therapy is appropriate for your situation.

Commonly tested with

Pentostatin has been tested in combination with other chemotherapy agents such as carmustine, etoposide, and high-dose cyclophosphamide, particularly in the setting of bone marrow transplantation. It has also been studied with interferon-alpha and, less commonly, with drugs like fludarabine (though this combination is not recommended due to increased risk of lung toxicity).