FLUDARABINE PHOSPHATE- fludarabine phosphate injection, powder, lyophilized, for solution
Hospira Worldwide, Inc.
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WARNING: Fludarabine Phosphate for Injection, USP should be administered under the supervision of a qualified physician experienced in the use of antineoplastic therapy. Fludarabine Phosphate for Injection, USP can severely suppress bone marrow function. When used at high doses in dose-ranging studies in patients with acute leukemia, Fludarabine Phosphate for Injection, USP was associated with severe neurologic effects, including blindness, coma, and death. This severe central nervous system toxicity occurred in 36% of patients treated with doses approximately four times greater (96 mg/m2 /day for 5 to 7 days) than the recommended dose. Similar severe central nervous system toxicity, including coma, seizures, agitation and confusion, has been reported in patients treated at doses in the range of the dose recommended for chronic lymphocytic leukemia.
Instances of life-threatening and sometimes fatal autoimmune phenomena such as hemolytic anemia, autoimmune thrombocytopenia/thrombocytopenic purpura (ITP), Evan's syndrome, and acquired hemophilia have been reported to occur after one or more cycles of treatment with Fludarabine Phosphate for Injection, USP. Patients undergoing treatment with Fludarabine Phosphate for Injection, USP should be evaluated and closely monitored for hemolysis.
In a clinical investigation using Fludarabine Phosphate for Injection, USP in combination with pentostatin (deoxycoformycin) for the treatment of refractory chronic lymphocytic leukemia (CLL), there was an unacceptably high incidence of fatal pulmonary toxicity. Therefore, the use of Fludarabine Phosphate for Injection, USP in combination with pentostatin is not recommended.
DESCRIPTION
Fludarabine Phosphate for Injection, USP contains fludarabine phosphate, USP, a fluorinated nucleotide analog of the antiviral agent vidarabine, 9-?-D-arabinofuranosyladenine (ara-A) that is relatively resistant to deamination by adenosine deaminase. Each vial of sterile lyophilized solid cake contains 50 mg of the active ingredient fludarabine phosphate, USP, 50 mg of mannitol, and sodium hydroxide to adjust pH to 7.7. The pH range for the final product is 7.2 to 8.2. Reconstitution with 2 mL of Sterile Water for Injection, USP results in a solution containing 25 mg/mL of fludarabine phosphate, USP intended for intravenous administration.
The chemical name for fludarabine phosphate, USP is 9H -Purin-6-amine, 2-fluoro-9-(5-O -phosphono- ? - D-arabinofuranosyl)(2-fluoro-ara-AMP). The molecular formula of fludarabine phosphate, USP is C10 H13 FN5 O7 P (MW 365.2) and the structure is:
Fludarabine Phosphate structural formula
CLINICAL PHARMACOLOGY
Fludarabine phosphate, USP is rapidly dephosphorylated to 2-fluoro-ara-A and then phosphorylated intracellularly by deoxycytidine kinase to the active triphosphate, 2-fluoro-ara-ATP. This metabolite appears to act by inhibiting DNA polymerase alpha, ribonucleotide reductase and DNA primase, thus inhibiting DNA synthesis. The mechanism of action of this antimetabolite is not completely characterized and may be multi-faceted.
Phase I studies in humans have demonstrated that fludarabine phosphate, USP is rapidly converted to the active metabolite, 2-fluoro-ara-A, within minutes after intravenous infusion. Consequently, clinical pharmacology studies have focused on 2-fluoro-ara-A pharmacokinetics. After the five daily doses of 25 mg 2-fluoro-ara-AMP/m2 to cancer patients infused over 30 minutes, 2-fluoro-ara-A concentrations show a moderate accumulation. During a 5-day treatment schedule, 2-fluoro-ara-A plasma trough levels increased by a factor of about 2. The terminal half-life of 2-fluoro-ara-A was estimated as approximately 20 hours. In vitro , plasma protein binding of fludarabine ranged between 19% and 29%.
A correlation was noted between the degree of absolute granulocyte count nadir and increased area under the concentration x time curve (AUC).
