Pentostatin

Pronunciation: PEN-toe-STAT-in
Class: Purine antimetabolite

Trade Names

Nipent
- Powder for injection 10 mg/vial

Pharmacology

Pentostatin is a potent transition state inhibitor of the enzyme adenosine deaminase (ADA) that leads to cytotoxicity because of elevated intracellular levels of dATP that can block DNA synthesis through inhibition of ribonucleotide reductase. Pentostatin can also inhibit RNA synthesis as well as cause increased DNA damage.

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Pharmacokinetics

Distribution

Concentrations are highest in the kidneys with little CNS penetration. Protein binding is approximately 4%. The distribution t ½ half-life is 11 minutes. Pentostatin crosses the blood brain barrier. CSF concentrations are 10% to 12.5% of serum concentrations within 24 h after a single dose.

Metabolism

Hepatic; only small amounts are metabolized.

Elimination

Urine (90% as unchanged or metabolites). Distribution t ½ is 11 minutes and terminal t ½ is 5.7 h (single dose) and increases to 18 h with renal function impairment. Plasma Cl is 68 mL/min/m 2 .

Onset

Time to achieve response is approximately 4.7 mo.

Duration

More than 1 wk after a single dose.

Special Populations

Renal Function Impairment

The t ½ increased to 18 h (CrCl less than 50 mL/min).

Indications and Usage

Treatment for both untreated and alpha-interferon refractory hairy cell leukemia.

Unlabeled Uses

Palliative therapy of chronic lymphocytic leukemia, prolymphocytic leukemia, cutaneous T-cell lymphoma.

Contraindications

Standard considerations.

Dosage and Administration

Refractory Hairy Cell Leukemia
Adults

IV For patients with a CrCl at least 60 mL/min, give 4 mg/m 2 every other wk until complete response is achieved, then give 2 additional doses. Administer by IV bolus injection or diluted in a larger volume and give over 20 to 30 minutes. Assess patient response after 6 mo of therapy. If no response occurs, discontinue therapy. If a partial response occurs, continue therapy for no more than 6 mo then discontinue. Give 2 additional doses after achieving a complete response. Delay further therapy in patients whose absolute neutrophil count falls less than 200 cells/mm 3 from a baseline value greater than 500 cells/mm 3 and in patients with active infections, severe rash, or nervous system toxicity. Therapy may be resumed when infection is controlled.

Hydration

It is recommended that patients receive hydration with 500 to 1,000 mL of dextrose 5% in 0.5 mL normal saline before pentostatin administration. An additional 500 mL of dextrose 5% or equivalent should be administered after pentostatin is given.

Renal function impairment (CrCl greater than 60 mL/min)

Patients who have elevated serum creatinine should have their dose withheld and a CrCl determined.

General Advice

  • For IV bolus or infusion only. Not for intradermal, subcutaneous, IM, intra-arterial, or oral administration.
  • Diligently follow institutional and NIH procedures for handling, administration, and disposal of anticancer drugs. Wear appropriate protective equipment when preparing and administering pentostatin. Avoid exposure by inhalation or by direct contact of the skin, mucous membranes, and eyes. Treat spills and wastes with a sodium hypochlorite 5% solution prior to disposal.
  • If accidental skin or mucus membrane contact occurs, wash thoroughly with soap and water. If accidental eye contact occurs, immediately institute copious irrigation with plain water.
  • Reconstitute powder for injection with 5 mL sterile water for injection. Mix thoroughly to obtain complete dissolution. Resulting solution contains 2 mg/mL of pentostatin.
  • Do not administer if particulate matter, cloudiness, or discoloration is noted.
  • May administer reconstituted solution as bolus injection or may further dilute reconstituted solution with 25 to 50 mL of dextrose 5% in water or sodium chloride 0.9% injection for IV infusion over 20 to 30 minutes.

Storage/Stability

Store unopened vials in refrigerator (36° to 46°F). Reconstituted solution or reconstituted solution further diluted contains no preservatives and may be stored at room temperature and ambient light but should be used within 8 h of reconstitution.

Drug Interactions

Allopurinol

May enhance toxicity of pentostatin.

Carmustine, cyclophosphamide, etoposide

Acute pulmonary edema, hypotension, and death have been reported when coadministered with pentostatin.

Fludarabine

Coadministration can result in severe pulmonary toxicity; coadministration is not recommended.

Vidarabine

Pentostatin may increase toxicity of vidarabine.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Hemorrhage, hypotension (3% to 10%); angina pectoris, arrhythmia, AV block, bradycardia, ventricular extrasystoles; heart arrest, heart failure, hypertension, pericardial effusion, phlebitis, pulmonary embolus, sinus arrest, tachycardia, thrombophlebitis, vasculitis (less than 3%).

CNS

Fatigue (42%); headache (17%); neurologic disorder, asthenia (12%); anxiety, confusion, depression, dizziness, insomnia, nervousness, paresthesia, somnolence (3% to 10%); abnormal thinking and dreaming, amnesia, ataxia, convulsions, dysarthria, emotional lability, encephalitis, hallucination, hostility, hyperkinesias, meningism, neuralgia, neuritis, neuropathy, neurosis, paralysis, syncope, twitching, vertigo (less than 3%); CNS toxicity (1%).

Dermatologic

Rash (43%); pruritus (21%); sweating (8%); skin disorder (4%); dry skin, urticaria (3% to 10%); acne alopecia, eczema, petechial rash, photosensitivity (less than 3%).

EENT

Abnormal vision, amblyopia, deafness, dry eyes, earache, labyrinthitis, lacrimation disorder, nonreactive eye, photophobia, retinopathy, tinnitus, watery eyes (less than 3%).

GI

Nausea/vomiting (63%); diarrhea (17%); abdominal pain (16%); anorexia (13%); stomatitis (12%); dental abnormalities, dyspepsia, flatulence, gingivitis (3% to 10%); constipation, dysphagia, glossitis, ileus, unusual taste (less than 3%).

Genitourinary

Abnormal kidney function, amenorrhea, breast lump, decreased libido, gout, impotence, nephropathy, renal failure, renal insufficiency, renal stone (less than 3%).

Hematologic-Lymphatic

Leukopenia (22%); anemia (8%); thrombocytopenia (6%); agranulocytosis (3% to 10%); acute leukemia, aplastic anemia, hemolytic anemia (less than 3%).

Hepatic

Hepatic disorder/elevated LFTs (2%).

Hypersensitivity

Allergic reaction (2%).

Lab Tests

Elevated creatinine (3% to 10%); hypercalcemia, hyponatremia (less than 3%).

Musculoskeletal

Myalgia (19%); arthralgia (6%); arthritis (less than 3%).

Respiratory

Coughing/increased cough (20%); upper respiratory tract infection (13%); dyspnea, rhinitis, pharyngitis (11%); asthma (3% to 10%); bronchospasm, laryngeal edema (less than 3%).

Miscellaneous

Fever (46%); chills (19%); pain, viral infection (8%); infection (7%); chest pain, death, face edema, peripheral edema (3% to 10%); flu-like symptoms, hangover effect, neoplasm (less than 3%).

Precautions

Warnings

Do not exceed recommended doses. Nephrotoxicity, hepatotoxicity, CNS, and pulmonary toxicity occurred in phase 1 studies that used higher doses than recommended.


Monitor

CBC

Assess CBC with differential and platelet count and renal function before each dose of pentostatin and at other intervals as clinically indicted.


Pregnancy

Category D .

Lactation

Undetermined.

Children

Safety and efficacy not established.

Renal Function

Dosage reduction may be required in patients with impaired renal failure (CrCl less than 60 mL/min).

CNS toxicity

Withhold or discontinue therapy in those with evidence of CNS toxicity.

Myelosuppression

Patients may experience myelosuppression, primarily during the first few courses of treatment.

Hyperuricemia

Ensure that risk of developing hyperuricemia is evaluated before starting therapy and that hypouricemic therapy (including adequate fluid intake) and monitoring of uric acid is initiated before starting treatment in patient determined to be at risk for developing hyperuricemia and urate precipitation.

Neutropenia

Worsening of neutropenia may occur.

Rashes

Rashes, occasionally severe, were commonly reported and may worsen with continued treatment. Withholding of treatment may be required.

Renal toxicity

In patients treated at the recommended dose, elevations in serum creatinine were usually minor and reversible. Some patients who began treatment with healthy renal function had evidence of mild to moderate toxicity at a final assessment.

Overdosage

Symptoms

Severe renal, hepatic, pulmonary, and CNS toxicity.

Patient Information

  • Explain name, action, and potential side effects of the treatment regimen. Review the treatment regimen including dosing schedule, duration of treatment, and monitoring that will be required.
  • Advise patient, family, or caregiver that medication will be prepared and administered by health care providers in a health care setting.
  • Advise patient, family, or caregiver that medication may be used in combination with other agents to achieve max benefit possible.
  • Advise patient, family, or caregiver to immediately report any of the following to health care provider: rash; hives; difficulty breathing; fever, chills, or other signs of infection; bleeding or unusual bruising; sores in mouth; dark urine; yellowing of skin or eyes; pain, redness, or swelling at injection site.
  • Advise patient, family, or caregiver to report any of the following to health care provider: persistent nausea, vomiting, diarrhea, or appetite loss; persistent or worsening general body weakness.
  • Advise women of childbearing potential to avoid becoming pregnant during therapy.

Copyright © 2009 Wolters Kluwer Health.

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