Common brand names

• Nipent

How it is administered

Pentostatin is given as an intravenous (IV) infusion. It is supplied as a powder that is mixed with sterile water and then further diluted before being administered. The recommended dose for blood cancers like hairy cell leukemia is 4 mg/m² every other week. The infusion can be given as a quick injection or over 20 to 30 minutes. Patients are usually given fluids before and after the infusion to help protect the kidneys.

How it works

Pentostatin works by blocking an enzyme called adenosine deaminase (ADA), which is found in high amounts in certain white blood cells, especially T-cells. By inhibiting ADA, pentostatin causes a buildup of substances inside the cancerous cells that eventually leads to their death. This effect is particularly strong in blood cancers where these cells are abnormal and multiplying uncontrollably.

The medication interferes with both DNA and RNA synthesis, which are essential for cell growth and division. By blocking these processes, pentostatin helps stop the growth of cancerous cells and allows normal blood cell production to recover. The exact way it works in hairy cell leukemia is not fully understood, but its ability to target and kill abnormal lymphocytes is key to its effectiveness.

Who should take it

Pentostatin is approved for adults with hairy cell leukemia, especially those who have not been treated before or whose disease did not respond to alpha-interferon therapy. It is used when the disease is active, which means there are symptoms like anemia (low red blood cells), neutropenia (low white blood cells), thrombocytopenia (low platelets), or other disease-related symptoms.

While there is limited direct data for large granular lymphocytic leukemia, pentostatin may be considered in some blood cancers where similar abnormal lymphocytes are present, but this should be discussed with your doctor.

Who should not take it

Pentostatin should not be used in people who have had a severe allergic reaction (hypersensitivity) to it in the past. It should also be avoided in patients with active, uncontrolled infections unless the potential benefit outweighs the risk.

Caution is needed in patients with poor kidney function, as the drug is cleared through the kidneys and can build up in the body if the kidneys are not working well. Pregnant women should not take pentostatin, as it can harm the unborn baby. It is also not recommended for nursing mothers, as it is unknown if the drug passes into breast milk.

Commonly used with

Pentostatin is usually used alone for the treatment of hairy cell leukemia. It is not commonly combined with other chemotherapy drugs for this indication, as combining with certain drugs (like fludarabine) can increase the risk of serious lung problems.

In some cases, supportive medications such as anti-nausea drugs, antibiotics, or growth factors may be used alongside pentostatin to help manage side effects or prevent infections.

Commonly tested with

Pentostatin has been studied in combination with other chemotherapy agents in clinical trials, especially for bone marrow transplant regimens. However, combining pentostatin with drugs like fludarabine, carmustine, etoposide, and high-dose cyclophosphamide has been associated with severe side effects and is not routinely recommended.

In clinical studies for hairy cell leukemia, pentostatin has mainly been compared to interferon-alpha, and not typically tested in combination with other chemotherapy drugs for this disease.