In short
Pentostatin is a chemotherapy drug used mainly for hairy cell leukaemia, a rare blood cancer. It is also being studied as one of several possible treatments for chronic graft-versus-host disease in a Phase 3 trial with 464 participants. The trial is authorised but not yet reporting results.
Key points
- Pentostatin is a chemotherapy medicine that blocks an enzyme called adenosine deaminase.
- It is used mainly to treat hairy cell leukaemia, a rare cancer of the blood.
- One Phase 3 trial is investigating pentostatin as part of best available therapy for chronic graft-versus-host disease.
- The trial plans to enrol 464 participants aged 12 years or older.
- The main measure in the trial is overall response rate at 24 weeks.
- The trial is currently authorised, meaning it has not yet started recruiting.
What is pentostatin?
Pentostatin is a chemotherapy drug that belongs to a group of medicines called antineoplastic agents. It is also known by the names deoxycoformycin and NSC218321, and is sold under the brand name Nipent. The substance is described as a potent inhibitor of the enzyme adenosine deaminase, and it induces apoptosis, or programmed cell death, of lymphocytes. Pentostatin is used in the treatment of many lymphoproliferative malignancies, particularly hairy cell leukaemia.
How does pentostatin work?
Pentostatin works by blocking an enzyme called adenosine deaminase. This enzyme is important for the survival of certain white blood cells called lymphocytes. By inhibiting this enzyme, pentostatin causes lymphocytes to undergo apoptosis, which is a form of controlled cell death. This effect is useful in treating cancers that arise from lymphocytes, such as hairy cell leukaemia and some types of lymphoma. In the clinical trial for chronic graft-versus-host disease, pentostatin appears as one of the drugs that make up the best available therapy comparison arm.
Which conditions is it used or studied for?
- Hairy cell leukaemia — a rare, slow-growing cancer of the blood in which the bone marrow makes too many abnormal lymphocytes. Pentostatin is used in its treatment.
- Low-grade B-cell lymphomas — a group of slow-growing cancers affecting B lymphocytes. Pentostatin has been studied in combination with other drugs for previously untreated advanced stage disease.
- Chronic graft-versus-host disease — a condition that can occur after a stem cell transplant, where donated immune cells attack the recipient's body. Pentostatin is included as one of the possible treatments in a Phase 3 trial comparing belumosudil with best available therapy.
How is pentostatin given?
In the clinical trial record, pentostatin is listed with the pharmaceutical form "00 DF dosage form" and the route of administration "oral use". The Leeds Formulary lists pentostatin under the category of other antineoplastic drugs, and it is restricted to hospital use only. The trial record does not give a specific dose for pentostatin, as it is one of several drugs that may be used as part of the best available therapy arm.
What do the clinical trials show?
One clinical trial involving pentostatin is registered in the EU Clinical Trials Information System. It is a Phase 3 study that aims to compare the efficacy and safety of belumosudil with best available therapy in participants aged 12 years or older with chronic graft-versus-host disease. The trial plans to enrol 464 participants.
Pentostatin is not the main drug being tested in this trial. Instead, it is listed as one of the possible drugs that make up the best available therapy arm, alongside sirolimus, bortezomib, mycophenolic acid, ibrutinib, imatinib, ixazomib, methotrexate, rituximab, everolimus and carfilzomib. The main measure of the trial is the overall response rate, which is the proportion of participants whose disease shows a meaningful improvement, assessed at 24 weeks.
The trial is currently authorised, which means it has received approval to proceed but has not yet started recruiting participants. People aged 12 years or older with chronic graft-versus-host disease are the intended participants.
What side effects are known?
The provided sources do not contain a detailed list of side effects for pentostatin. The Leeds Formulary notes that treatment with cytotoxic medicines such as pentostatin must be started by an experienced and specifically trained prescriber, which reflects the potential risks associated with chemotherapy. The DrugCentral record states that pentostatin induces apoptosis of lymphocytes, which can affect normal lymphocytes as well as cancer cells. No specific common or serious side effect frequencies are given in the available sources.