How it is administered

Pentostatin is administered as an intravenous (IV) infusion. It comes as a sterile, lyophilized powder that is reconstituted and then either injected as a bolus or infused over 20 to 30 minutes. The recommended dose for hairy cell leukemia is 4 mg/m² every other week. Hydration with IV fluids is recommended before and after administration to help protect the kidneys.

How it works

Pentostatin works by inhibiting an enzyme called adenosine deaminase (ADA), which is especially active in cells of the lymphoid system, including certain cancerous white blood cells. By blocking ADA, pentostatin leads to the buildup of substances inside the cell that are toxic to the cancer cells, particularly by increasing levels of dATP. This buildup interferes with DNA synthesis and can also affect RNA synthesis, ultimately leading to cell death.

The drug is especially effective in blood cancers where ADA activity is high, such as hairy cell leukemia. While the exact mechanism in these cancers is not fully understood, the inhibition of DNA and RNA synthesis is thought to be the main way pentostatin kills cancer cells.

Who Should take it

Pentostatin is indicated for adults with hairy cell leukemia, including those who have not been treated before and those who did not respond to or could not tolerate alpha-interferon therapy. It is used in patients with active disease, which means they have symptoms like anemia, low white blood cell counts, low platelets, or other disease-related issues.

While pentostatin is not specifically approved for chronic lymphocytic leukemia (CLL), it is sometimes considered for other blood cancers in clinical settings. The decision to use pentostatin should be made by a hematologist or oncologist familiar with your specific diagnosis and health situation.

Who should not take it

Pentostatin should not be used in patients who have shown hypersensitivity to pentostatin or any of its components. It should also be avoided in patients with severe infections unless the potential benefit outweighs the risk, as treatment can worsen infections.

Caution is needed in patients with impaired kidney function, as the drug is cleared by the kidneys and can accumulate, increasing the risk of side effects. Pentostatin should not be used in pregnant women, as it can cause harm to the unborn baby. Safety and effectiveness in children have not been established.

Commonly used with

Pentostatin is generally used as a single agent for hairy cell leukemia. However, in some clinical situations, it may be used alongside supportive medications such as anti-nausea drugs, antibiotics for infection prevention, or medications to manage low blood counts.

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

Commonly tested with

Pentostatin has been tested in combination with other chemotherapy agents in research settings, such as carmustine, etoposide, and high-dose cyclophosphamide, particularly as part of conditioning regimens for bone marrow transplantation. However, such combinations can increase the risk of severe side effects, including fatal pulmonary edema and hypotension.

It has also been studied in patients who were refractory to or intolerant of interferon therapy.