Special Populations

Dose Dependent Neurologic Toxicities

There are clear dose dependent toxic effects seen with fludarabine phosphate for injection. Dose levels approximately 4 times greater (96 mg/m 2/day for 5 to 7 days) than that recommended for CLL (25 mg/m 2/day for 5 days) were associated with a syndrome characterized by delayed blindness, coma and death. Symptoms appeared from 21 to 60 days following the last dose. Thirteen of 36 patients (36%) who received fludarabine phosphate for injection at high doses (96 mg/m 2/day for 5 to 7 days) developed this severe neurotoxicity. 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.

In postmarketing experience neurotoxicity has been reported to occur either earlier or later than in clinical trials (range 7 to 225 days).  

The effect of chronic administration of fludarabine phosphate for injection on the central nervous system is unknown; however, patients have received the recommended dose for up to 15 courses of therapy.

Bone Marrow Suppression

Severe bone marrow suppression, notably anemia, thrombocytopenia and neutropenia, has been reported in patients treated with fludarabine phosphate for injection. In a Phase I study in adult solid tumor patients, the median time to nadir counts was 13 days (range, 3 to 25 days) for granulocytes and 16 days (range, 2 to 32) for platelets. Most patients had hematologic impairment at baseline either as a result of disease or as a result of prior myelosuppressive therapy. Cumulative myelosuppression may be seen. While chemotherapy-induced myelosuppression is often reversible, administration of fludarabine phosphate for injection requires careful hematologic monitoring.

Several instances of trilineage bone marrow hypoplasia or aplasia resulting in pancytopenia, sometimes resulting in death, have been reported in adult patients. The duration of clinically significant cytopenia in the reported cases has ranged from approximately 2 months to approximately 1 year. These episodes have occurred both in previously treated or untreated patients.

Autoimmune Reactions

Instances of life-threatening and sometimes fatal autoimmune phenomena such as hemolytic anemia, autoimmune thrombocytopenia/thrombocytopenic purpura (ITP), Evans syndrome, and acquired hemophilia have been reported to occur after one or more cycles of treatment with fludarabine phosphate for injection in patients with or without a previous history of autoimmune hemolytic anemia or a positive Coombs' test and who may or may not be in remission from their disease. Steroids may or may not be effective in controlling these hemolytic episodes. The majority of patients rechallenged with fludarabine phosphate for injection developed a recurrence in the hemolytic process. The mechanism(s) which predispose patients to the development of this complication has not been identified. Patients undergoing treatment with fludarabine phosphate for injection should be evaluated and closely monitored for hemolysis. Discontinuation of therapy with fludarabine is recommended in case of hemolysis.

Transfusion Associated Graft-Versus-Host Disease

Transfusion-associated graft-versus-host disease has been observed after transfusion of nonirradiated blood in fludarabine phosphate for injection treated patients. Fatal outcome as a consequence of this disease has been reported. Therefore, to minimize the risk of transfusion-associated graft-versus-host disease, patients who require blood transfusion and who are undergoing, or who have received, treatment with fludarabine phosphate for injection should receive irradiated blood only.

Pulmonary Toxicity

In a clinical investigation using fludarabine phosphate for injection in combination with pentostatin (deoxycoformycin) for the treatment of refractory chronic lymphocytic leukemia (CLL) in adults, there was an unacceptably high incidence of fatal pulmonary toxicity. Therefore, the use of fludarabine phosphate for injection in combination with pentostatin is not recommended.

Pregnancy Category D

Based on its mechanism of action, fludarabine phosphate can cause fetal harm when administered to a pregnant woman. There are no adequate and well-controlled studies of fludarabine phosphate for injection in pregnant women. Fludarabine administered to rats and rabbits during organogenesis caused an increase in resorptions, skeletal and visceral malformations and decreased fetal body weights. If fludarabine phosphate for injection is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus. Women of childbearing potential should be advised to avoid becoming pregnant.

Male Fertility and Reproductive Outcomes  

Males with female sexual partners of childbearing potential should use contraception during and after cessation of fludarabine phosphate for injection therapy. Fludarabine may damage testicular tissue and spermatozoa. Possible sperm DNA damage raises concerns about loss of fertility and genetic abnormalities in fetuses. The duration of this effect is uncertain. (See PRECAUTIONS, Impairment of Fertility. )

General

Fludarabine phosphate for injection is a potent antineoplastic agent with potentially significant toxic side effects. Patients undergoing therapy should be closely observed for signs of hematologic and nonhematologic toxicity. Periodic assessment of peripheral blood counts is recommended to detect the development of anemia, neutropenia and thrombocytopenia.

In patients with impaired state of health, fludarabine phosphate for injection should be given with caution and after careful risk/benefit consideration. This applies especially for patients with severe impairment of bone marrow function (thrombocytopenia, anemia, and/or granulocytopenia), immunodeficiency or with a history of opportunistic infection. Prophylactic treatment should be considered in patients at increased risk of developing opportunistic infections.

Fludarabine phosphate for injection may reduce the ability to drive or use machines, since fatigue, weakness, visual disturbances, confusion, agitation and seizures have been observed.

Tumor Cell Lysis

Tumor lysis syndrome has been associated with fludarabine phosphate for injection treatment. This syndrome has been reported in CLL patients with large tumor burden. Since fludarabine phosphate for injection can induce a response as early as the first week of treatment, precautions should be taken in those patients at risk of developing this complication.

Renal Impairment

Fludarabine phosphate for injection must be administered cautiously in patients with renal impairment. The total body clearance of 2-fluoro-ara-A has been shown to be directly correlated with creatinine clearance.  Patients with creatinine clearance 30 to 79 mL/min should have their fludarabine phosphate for injection dose reduced and be monitored closely for excessive toxicity. Fludarabine phosphate for injection should not be administered to patients with creatinine clearance less than 30 mL/min. (See DOSAGE AND ADMINISTRATION section.)

In patients aged 65 years or older, creatinine clearance should be measured before start of treatment.

Laboratory Tests

During treatment, the patient's hematologic profile (particularly neutrophils and platelets) should be monitored regularly to determine the degree of hematopoietic suppression.

Drug Interactions

The use of fludarabine phosphate for injection in combination with pentostatin is not recommended due to the risk of fatal pulmonary toxicity (see WARNINGS section).

Carcinogenesis

No animal carcinogenicity studies with fludarabine phosphate for injection have been conducted.

Mutagenesis

Fludarabine phosphate was not mutagenic to bacteria (Ames test) or mammalian cells (HGRPT assay in Chinese hamster ovary cells) either in the presence or absence of metabolic activation. Fludarabine phosphate was clastogenic in vitro to Chinese hamster ovary cells (chromosome aberrations in the presence of metabolic activation) and induced sister chromatid exchanges both with and without metabolic activation. In addition, fludarabine phosphate was clastogenic in vivo (mouse micronucleus assay) but was not mutagenic to germ cells (dominant lethal test in male mice).

Impairment of Fertility

Studies in mice, rats and dogs have demonstrated dose-related adverse effects on the male reproductive system. Observations consisted of a decrease in mean testicular weights in mice and rats with a trend toward decreased testicular weights in dogs and degeneration and necrosis of spermatogenic epithelium of the testes in mice, rats and dogs. The possible adverse effects on fertility in humans have not been adequately evaluated.

Pregnancy

Nursing Mothers

It is not known whether fludarabine phosphate is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions including tumorigenicity in nursing infants, a decision should be made to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Data submitted to the FDA was insufficient to establish efficacy in any childhood malignancy. Fludarabine phosphate for injection was evaluated in 62 pediatric patients (median age 10, range 1 to 21) with refractory acute leukemia (45 patients) or solid tumors (17 patients). The fludarabine phosphate for injection regimen tested for pediatric acute lymphocytic leukemia (ALL) patients was a loading bolus of 10.5 mg/m 2/day followed by a continuous infusion of 30.5 mg/m 2/day for 5 days. In 12 pediatric patients with solid tumors, dose-limiting myelosuppression was observed with a loading dose of 8 mg/m 2/day followed by a continuous infusion of 23.5 mg/m 2/day for 5 days. The maximum tolerated dose was a loading dose of 7 mg/m 2/day followed by a continuous infusion of 20 mg/m 2/day for 5 days. Treatment toxicity included bone marrow suppression. Platelet counts appeared to be more sensitive to the effects of fludarabine phosphate for injection than hemoglobin and white blood cell counts. Other adverse events included fever, chills, asthenia, rash, nausea, vomiting, diarrhea, and infection.  There were no reported occurrences of peripheral neuropathy or pulmonary hypersensitivity reaction.

Vaccination

During and after treatment with fludarabine phosphate for injection, vaccination with live vaccines should be avoided.

Disease Progression

Richter's syndrome has been reported in CLL patients.

Hematopoietic Systems

Hematologic events (neutropenia, thrombocytopenia, and/or anemia) were reported in the majority of CLL patients treated with fludarabine phosphate for injection. During fludarabine phosphate for injection treatment of 133 patients with CLL, the absolute neutrophil count decreased to less than 500/mm 3 in 59% of patients, hemoglobin decreased from pretreatment values by at least 2 grams percent in 60%, and platelet count decreased from pretreatment values by at least 50% in 55%. Myelosuppression may be severe, cumulative, and may affect multiple cell lines. Bone marrow fibrosis occurred in one CLL patient treated with fludarabine phosphate for injection.

Several instances of trilineage bone marrow hypoplasia or aplasia resulting in pancytopenia, sometimes resulting in death, have been reported in postmarketing surveillance. The duration of clinically significant cytopenia in the reported cases has ranged from approximately 2 months to approximately 1 year. These episodes have occurred both in previously treated or untreated patients.

Life-threatening and sometimes fatal autoimmune phenomena such as hemolytic anemia, autoimmune thrombocytopenia/thrombocytopenic purpura (ITP), Evans syndrome, and acquired hemophilia have been reported to occur in patients receiving fludarabine phosphate for injection (see WARNINGS section). The majority of patients rechallenged with fludarabine phosphate for injection developed a recurrence in the hemolytic process.

In postmarketing experience, cases of myelodysplastic syndrome and acute myeloid leukemia, mainly associated with prior, concomitant or subsequent treatment with alkylating agents, topoisomerase inhibitors, or irradiation have been reported.

Infections

Serious, and sometimes fatal infections, including opportunistic infections and reactivations of latent viral infections such as VZV (herpes zoster), Epstein-Barr virus and JC virus (progressive multifocal leukoencephalopathy) have been reported in patients treated with fludarabine phosphate for injection.

Rare cases of Epstein-Barr Virus (EBV) associated lymphoproliferative disorders have been reported in patients treated with fludarabine phosphate for injection.

In postmarketing experience, cases of progressive multifocal leukoencephalopathy have been reported. Most cases had a fatal outcome. Many of these cases were confounded by prior and/or concurrent chemotherapy. The time to onset has ranged from a few weeks to approximately one year after initiating treatment.

Of the 133 adult CLL patients in the two trials, there were 29 fatalities during study, approximately 50% of which were due to infection.

Metabolic

Tumor lysis syndrome has been reported in CLL patients treated with fludarabine phosphate for injection. This complication may include hyperuricemia, hyperphosphatemia, hypocalcemia, metabolic acidosis, hyperkalemia, hematuria, urate crystalluria, and renal failure. The onset of this syndrome may be heralded by flank pain and hematuria.

Nervous System

(See WARNINGS section.)

Objective weakness, agitation, confusion, seizures, visual disturbances, optic neuritis, optic neuropathy, blindness and coma have occurred in CLL patients treated with fludarabine phosphate for injection at the recommended dose. Peripheral neuropathy has been observed in patients treated with fludarabine phosphate for injection and one case of wrist-drop was reported. There have been additional reports of cerebral hemorrhage though the frequency is not known.

Pulmonary System

Pneumonia, a frequent manifestation of infection in CLL patients, occurred in 16% and 22% of those treated with fludarabine phosphate for injection in the MDAH and SWOG studies, respectively. Pulmonary hypersensitivity reactions to fludarabine phosphate for injection characterized by dyspnea, cough and interstitial pulmonary infiltrate have been observed.

In postmarketing experience, cases of severe pulmonary toxicity have been observed with fludarabine phosphate for injection use which resulted in ARDS, respiratory distress, pulmonary hemorrhage, pulmonary fibrosis, pneumonitis and respiratory failure. After an infectious origin has been excluded, some patients experienced symptom improvement with corticosteroids.

Gastrointestinal System

Gastrointestinal disturbances such as nausea and vomiting, anorexia, diarrhea, stomatitis and gastrointestinal bleeding and hemorrhage have been reported in patients treated with fludarabine phosphate for injection. Elevations of pancreatic enzyme levels have also been reported.

Cardiovascular

Edema has been frequently reported. One patient developed a pericardial effusion possibly related to treatment with fludarabine phosphate for injection. There have been additional reports of heart failure and arrhythmia though the frequency is rare.  No other severe cardiovascular events were considered to be drug related.

Genitourinary System

Rare cases of hemorrhagic cystitis have been reported in patients treated with fludarabine phosphate for injection.

Skin

Skin toxicity, consisting primarily of skin rashes, has been reported in patients treated with fludarabine phosphate for injection.  Erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, and pemphigus have been reported, with fatal outcomes in some cases.

Neoplasms

Worsening or flare up of preexisting skin cancer lesions, as well as new onset of skin cancer, has been reported in patients during or after treatment with fludarabine phosphate for injection.

Hepatobiliary Disorders

Elevations of hepatic enzyme levels have been reported.

Data in the following table are derived from the 133 patients with CLL who received fludarabine phosphate for injection in the MDAH and SWOG studies.

More than 3000 adult patients received fludarabine phosphate for injection in studies of other leukemias, lymphomas, and other solid tumors. The spectrum of adverse effects reported in these studies was consistent with the data presented above.

Usual Dose

The recommended adult dose of fludarabine phosphate for injection is 25 mg/m 2 administered intravenously over a period of approximately 30 minutes daily for five consecutive days. Each 5 day course of treatment should commence every 28 days. Dosage may be decreased or delayed based on evidence of hematologic or nonhematologic toxicity. Physicians should consider delaying or discontinuing the drug if neurotoxicity occurs.

A number of clinical settings may predispose to increased toxicity from fludarabine phosphate for injection. These include advanced age, renal impairment, and bone marrow impairment. Such patients should be monitored closely for excessive toxicity and the dose modified accordingly.

The optimal duration of treatment has not been clearly established. It is recommended that three additional cycles of fludarabine phosphate for injection be administered following the achievement of a maximal response and then the drug should be discontinued.

Renal Impairment

Adjustments to the starting dose are recommended to provide appropriate drug exposure in patients with creatinine clearance 30 to 79 mL/min, as estimated by the Cockroft-Gault equations. These adjustments are based on a pharmacokinetic study in patients with renal impairment. Fludarabine phosphate for injection should not be administered to patients with creatinine clearance less than 30 mL/min.

Renally impaired patients should be monitored closely for excessive toxicity and the dose modified accordingly.

Preparation of Solutions

Fludarabine phosphate for injection should be prepared for parenteral use by aseptically adding Sterile Water for Injection, USP. When reconstituted with 2 mL of Sterile Water for Injection, USP, the solid cake should fully dissolve in 15 seconds or less; each mL of the resulting solution will contain 25 mg of fludarabine phosphate, 25 mg of mannitol, and sodium hydroxide to adjust the pH to 7.7. The pH range for the final product is 7.2 to 8.2. In clinical studies, the product has been diluted in 100 cc or 125 cc of 5% Dextrose Injection, USP or 0.9% Sodium Chloride, USP.

Reconstituted fludarabine phosphate for injection contains no antimicrobial preservative and thus should be used within 8 hours of reconstitution. Care must be taken to assure the sterility of prepared solutions. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration.

Fludarabine phosphate for injection should not be mixed with other drugs.

Handling and Disposal

Procedures for proper handling and disposal should be considered. Consideration should be given to handling and disposal according to guidelines issued for cytotoxic drugs. Several guidelines on this subject have been published. 1-4  

Caution should be exercised in the handling and preparation of fludarabine phosphate for injection solution. The use of latex gloves and safety glasses is recommended to avoid exposure in case of breakage of the vial or other accidental spillage. If the solution contacts the skin or mucous membranes, wash thoroughly with soap and water; rinse eyes thoroughly with plain water. Avoid exposure by inhalation or by direct contact of the skin or mucous membranes.

Storage Conditions

Store refrigerated between 2° and 8°C (36° and 46°F).

Sterile, Nonpyrogenic, Preservative-free.