How it is administered

Pentostatin is administered as an intravenous (IV) infusion. It comes as a sterile, lyophilized powder that is reconstituted with sterile water and then further diluted for IV administration. The recommended dose for treating hairy cell leukemia is 4 mg/m² every other week. The infusion can be given as a bolus injection or over 20 to 30 minutes. Patients are usually hydrated with IV fluids before and after receiving pentostatin.

How it works

Pentostatin is a potent inhibitor of the enzyme adenosine deaminase (ADA). ADA is found in high amounts in cells of the lymphoid system, especially in T-cells and some cancerous cells. By blocking ADA, pentostatin causes a buildup of certain molecules (like dATP) inside cells. This buildup interferes with DNA synthesis and can also affect RNA synthesis, leading to cell death. These effects are particularly strong in lymphoid cells, which are the type of cells involved in hairy cell leukemia.

While the exact way pentostatin works against hairy cell leukemia is not fully understood, its ability to disrupt DNA and RNA synthesis in these cancer cells is believed to be the main reason for its effectiveness.

Who Should take it

Pentostatin is indicated for adults with hairy cell leukemia who have active disease. This includes patients who have not been treated before, as well as those whose disease has not responded to or has come back after treatment with alpha-interferon. Active disease is defined by symptoms such as significant anemia, low white blood cell or platelet counts, or other disease-related symptoms.

Pentostatin is not typically used for other types of blood cancers unless specifically recommended by a healthcare provider.

Who should not take it

Pentostatin should not be taken by anyone who has had a hypersensitivity (allergic) reaction to pentostatin. It should also be used with caution in patients with active infections, as treatment can worsen infections or suppress the immune system further. Patients with severe kidney problems should only receive pentostatin if the potential benefits outweigh the risks, as the drug is cleared by the kidneys and can accumulate in those with impaired kidney function.

Pentostatin can cause harm to an unborn baby and should not be used during pregnancy. Women of childbearing potential should avoid becoming pregnant while receiving this medication. It is also not recommended for use in children, as safety and effectiveness have not been established.

Commonly used with

Pentostatin is usually used as a single agent for the treatment of hairy cell leukemia. It is not commonly combined with other chemotherapy drugs for this specific disease. However, in some cases, it may be used with supportive medications such as anti-nausea drugs, antibiotics, or growth factors to manage side effects or complications.

Commonly tested with

Pentostatin has been studied in comparison with and after treatment with alpha-interferon in clinical trials for hairy cell leukemia. It has also been tested in combination with other chemotherapy agents (such as carmustine, etoposide, and cyclophosphamide) in bone marrow transplant regimens, but this is not common for hairy cell leukemia and may carry significant risks.

It is not recommended to use pentostatin in combination with fludarabine due to an increased risk of serious lung toxicity.