Fludarabine Phosphate Tablets

Oforta™ (fludarabine phosphate tablets) for oral use is indicated as a single agent for the treatment of adult patients with B-cell chronic lymphocytic leukemia (CLL) whose disease has not responded to or has progressed during or after treatment with at least one standard alkylating-agent containing regimen. Studies demonstrating clinical benefit such as prolongation of survival or relief of symptoms have not been performed. Studies providing a direct comparison of the clinical efficacy and safety of Oforta™ relative to intravenously administered fludarabine phosphate have not been performed.

Dosage Forms And Strengths

10 mg tablets that are capsule shaped and salmon pink in color, marked on one side with 'LN' in a regular hexagon.

Storage And Handling

Oforta™ (fludarabine phosphate tablets) is supplied in 10 milligram tablets that are film-coated, capsule shaped, salmon pink in color, and marked on one side with 'LN' in a regular hexagon. Each film-coated tablet contains 10 mg fludarabine phosphate. The tablets are supplied in blisters, each blister strip containing 5 tablets. Packages of 15 and 20 tablets are available in child-resistant containers.

NDC 0024-5820-15: 15 - 10 milligram film-coated tablets per container. Each film-coated tablet is packaged in an individual blister package; 5 tablets per blister strip; 3 blister strips packaged in a plastic bottle with a child-resistant container closure; each bottle is packaged in an individual chip-board carton.

NDC 0024-5820-20: 20 - 10 milligram film-coated tablets per container. Each film-coated tablet is packaged in an individual blister package; 5 tablets per blister strip; 4 blister strips packaged in a plastic bottle with a child-resistant container closure; each bottle is packaged in an individual chip-board carton.

Store under normal lighting conditions at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP controlled room temperature].

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 of Oforta™ (fludarabine phosphate tablets) . Push tablets through foil to open. Do not remove tablets from individual blisters until immediately prior to taking or administering each scheduled dose. Do not crush tablets. Avoid exposure by direct contact of the skin or mucous membranes or by inhalation. If contact occurs, wash thoroughly with soap and water or wash the eyes immediately with gently flowing water for at least 15 minutes. Consult healthcare provider in case of a skin reaction or if the drug gets in the eyes.

Manufactured for: sanofi-aventis U.S. LLC, Bridgewater, NJ 08807

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The data described below reflect exposure to Oforta™ (fludarabine phosphate tablets) in 159 patients exposed to the drug. Oforta™ (fludarabine phosphate tablets) was studied primarily in Study 1 in 78 patients with CLL who received prior therapy and in Study 2 in 81 patients with CLL who had not received prior therapy.

Based on experience with the intravenous and oral use of fludarabine phosphate, the most common adverse reactions include myelosuppression (neutropenia, thrombocytopenia and anemia), fever and chills, infection, and nausea and vomiting. Other commonly reported events include malaise, fatigue, anorexia, and weakness. Serious opportunistic infections have occurred in patients with CLL treated with fludarabine phosphate. The most frequently reported adverse reactions and those reactions which are more clearly related to the drug, as reported in clinical studies conducted with intravenous and oral fludarabine phosphate, are arranged below according to body system.

Hematologic events (neutropenia, thrombocytopenia, and/or anemia) were reported in the majority of patients with CLL treated with fludarabine phosphate. During intravenous fludarabine phosphate treatment of 133 patients with CLL, the absolute neutrophil count decreased to less than 500/mm 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%. Among 78 patients with B-CLL who were treated with Oforta™ (fludarabine phosphate tablets) , the absolute neutrophil count decreased to less than 500/mm in 37% of patients, hemoglobin decreased from pretreatment values by at least 2 grams percent in 14%, and platelet count decreased from pretreatment values by at least 50% in 17% of patients. Myelosuppression may be severe, cumulative, and may affect multiple cell lines. Bone marrow fibrosis occurred in one CLL patient treated with fludarabine phosphate intravenously. In the pivotal oral fludarabine phosphate study (Study 1), there was one report of a non-fatal case of pancytopenia. Similarly, there was one case of non-fatal pancytopenia reported among the 133 patients with CLL treated with intravenous fludarabine phosphate.

Life-threatening and sometimes fatal autoimmune hemolytic anemias have been reported to occur in patients receiving fludarabine phosphate. [See WARNINGS AND PRECAUTIONS] The majority of patients rechallenged with fludarabine phosphate developed a recurrence in the hemolytic process.

Tumor lysis syndrome has been reported in patients with CLL 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.

Objective weakness, agitation, confusion, visual disturbances, and coma< have occurred in patients with CLL treated with fludarabine phosphate at the recommended dose. Peripheral neuropathy and one case of wrist-drop have been observed with intravenous administration of fludarabine phosphate. In Study 1 for Oforta™ (fludarabine phosphate tablets) , there was one report of severe impairment of consciousness that presented concurrent with hemolytic anemia. This patient had enrolled in the study with pre-existing peripheral neurotoxicity. [See WARNINGS AND PRECAUTIONS]

Pneumonia, a frequent manifestation of infection in patients with CLL, was observed in two clinical trials conducted with intravenous fludarabine phosphate (16% and 22%) and in two clinical trials with Oforta (fludarabine phosphate tablets) ™ (8% and 3%). Pulmonary hypersensitivity reactions to fludarabine phosphate characterized by dyspnea, cough and interstitial pulmonary infiltrate have been observed. In Study 1 conducted with Oforta™ (fludarabine phosphate tablets) , severe pulmonary toxicity was reported in 5 of 78 patients, often in conjunction with respiratory or pulmonary infections and hence not regarded as isolated drug related pulmonary toxicity.

Gastrointestinal disturbances such as nausea and vomiting, anorexia, diarrhea, stomatitis and gastrointestinal bleeding have been reported in patients treated with fludarabine phosphate. Nausea and vomiting occurred in up to 38% of patients following treatment with Oforta™ (fludarabine phosphate tablets) in the clinical trials.

Edema has been frequently reported. One patient developed a pericardial effusion possibly related to treatment with Oforta™ (fludarabine phosphate tablets) . No other severe cardiovascular events were considered to be drug related.

Hemorrhagic cystitis has been reported in patients treated intravenously with fludarabine phosphate.

Skin toxicity, consisting primarily of skin rashes, has been reported in patients treated with oral and intravenous fludarabine phosphate.

Data in Table 2 are derived from the 159 patients with CLL who received Oforta™ (fludarabine phosphate tablets) in Study 1 and Study 2.

TABLE 2: Incidence (≥ 5%) of Non-Hematologic Adverse Reactions in Patients with CLL Treated with Oforta™ (fludarabine phosphate tablets)

Post Marketing Experience

The following adverse reactions have been identified during post approval use of Oforta™ (fludarabine phosphate tablets) . Because these reactions are reported voluntarily from a population of uncertain size, it is not always possibly to reliably estimate their frequency or establish a causal relationship to drug exposure.

Several instances of trilineage bone marrow hypoplasia or aplasia resulting in pancytopenia, sometimes resulting in death, have been reported in post-marketing 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.

In post-marketing 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 median time to onset was approximately one year.

In post-marketing experience, cases of severe pulmonary toxicity have been observed with fludarabine phosphate use which resulted in acute respiratory distress syndrome, respiratory distress, pulmonary hemorrhage, pulmonary fibrosis, and respiratory failure. After exclusion of an infectious origin, some patients experienced symptom improvement with corticosteroids.

Mechanism of Action

Fludarabine phosphate (2F-ara-AMP) is a synthetic purine nucleotide antimetabolite agent. Upon administration, 2F-ara-AMP is rapidly dephosphorylated in the plasma to 2F-ara-A, which then enters into the cell. Intracellularly, 2F-ara-A is converted to the 5'-triphosphate, 2-fluoro-ara-ATP (2F-ara-ATP). 2F-ara-ATP competes with deoxyadenosine triphosphate for incorporation into DNA. Once incorporated into DNA, 2F-ara-ATP functions as a DNA chain terminator, inhibits DNA polymerase alpha, gamma, and delta, and inhibits ribonucleoside diphosphate reductase. 2F-ara-A also inhibits DNA primase and DNA ligase I. The mechanism of action of this antimetabolite is not completely characterized and may be multi-faceted.

Pharmacodynamics

In a randomized, uncontrolled, open-label, parallel study, patients with B-cell CLL were administered a single dose of Oforta™ 40 mg/m2 (n = 42) or intravenous fludarabine phosphate 25 mg/m (n=14). The maximum increase in the baseline-corrected mean change in QTcI (individual-corrected QT interval) following treatment with Oforta™ (fludarabine phosphate tablets) was less than 10 milliseconds.

Pharmacokinetics

Studies with the intravenous product have demonstrated that fludarabine phosphate is converted to the active metabolite, 2F-ara-A. Clinical pharmacology studies have focused on 2F-ara-A pharmacokinetics.

Following administration of the intravenous product, systemic plasma clearance of 2F-ara-A is approximately 117 mL/min to 145 mL/min. After five daily 30 minute intravenous infusions of 25 mg 2F-ara- AMP/m2 to cancer patients, trough concentrations of 2F-ara-A increased by a factor of about 2. The terminal half-life of 2F-ara-A was approximately 20 hours. Plasma protein binding of 2F-ara-A was approximately 19% to 29%. A correlation was noted between the degree of absolute granulocyte count nadir and increased area under the concentration x time curve (AUC).

2F-ara-A exhibits dose proportional increases in AUC and Cmax after single oral doses of 50 mg, 70 mg or 90 mg of 2F-ara-AMP. Cmax of 2F-ara-A occurs 1 hour to 2 hours after single or multiple oral doses and is approximately 20 % to 30 % of the maximum plasma concentrations produced at the end of a 30 minute intravenous infusion of the same dose. The absolute oral bioavailability of 2F-ara-A is 50 - 65% following single and repeated doses of Oforta™ (fludarabine phosphate tablets) . Similar systemic exposure (AUC) was observed after a single 40 mg/m Oforta™ and a single 25 mg/m2 fludarabine phosphate intravenous dose. The terminal half-life of 2F-ara-A was similar to that following intravenous administration; approximately 20 hours. The Cmax, AUC and terminal half-life of 2F-ara-A are unaffected when administered with a high fat meal, although Tmax is slightly delayed from 1.3 hours to 2.2 hours.

Following intravenous administration, renal clearance of 2F-ara-A represents approximately 40% of the total body clearance of fludarabine phosphate, and total body clearance is inversely correlated with serum creatinine and creatinine clearance. In two patients with median creatinine clearance of 22 mL/min/1.73 m2, 2F-ara-A clearance was reduced by 56%. Dosage adjustment based on creatinine clearance is recommended as follows:

Reduce dose by 20% in patients with mild to moderate renal impairment (creatinine clearance 30 to 70 mL/min/1.73 m2). [See WARNINGS AND PRECAUTIONS]

Reduce dose by 50% in patients with severe renal impairment (creatinine clearance < 30 mL/min/1.73 m2). [See WARNINGS AND PRECAUTIONS]

Clinical Studies

Study 1, a single-arm, open-label study of Oforta™ (fludarabine phosphate tablets) was conducted in 78 adult patients with CLL refractory to at least one prior standard alkylating-agent containing regimen. In this multicenter study patients were treated with Oforta™ (fludarabine phosphate tablets) at a dose of 40 mg/m daily for 5 days every 28 days. The patient population median age was 64.5 years and consisted of 72% males and 28% females. Ninety-nine percent of the patients were Caucasian. The Rai stage for patients entering the study was: Stage 0 (3.9%), Stage I (20.5%), Stage II (32.1%), Stage III (11.5%), and Stage IV (32.1%). The mean number of treatment cycles was 5.1 with a mean daily dose of Oforta™ (fludarabine phosphate tablets) of 38 mg/m2. The overall objective response, according to standardized response criteria developed by the National Cancer Institute CLL Working Group (NCI criteria), was 51%, including 18% complete responses and 33% partial responses. The overall response rate, according to standardized criteria developed by the International Workshop on CLL (IWCLL criteria), was 46%, including 21% complete responses and 26% partial responses. Data on duration of response was not collected.

In Study 2, a supportive single-arm, open-label study, Oforta™ (fludarabine phosphate tablets) was administered to 81 previously untreated patients with B-CLL. In this multicenter study each patient was treated with Oforta™ (fludarabine phosphate tablets) at a dose of 40 mg/m2 daily for 5 days every 28 days. The patient population median age was 64.0 years and consisted of 63% males and 37% females. Ninety-nine percent of the patients were Caucasian. The Rai stage for patients entering the study was: Stage 0 (3.7%), Stage I (37.0%), Stage II (37.0%), Stage III (9.9%), and Stage IV (12.3%). The mean number of treatment cycles was 5.9 with a mean daily dose per patient of 71 mg to 74 mg. The overall responses rate, according to NCI criteria, was 80%, including 12% complete responses and 68% partial responses. The overall response rate, according to IWCLL criteria, was 72%, including 37% complete responses and 35% partial responses. The median duration of response was 22.9 months.

Study 3 was a supportive randomized controlled open label study in patients with previously untreated B-CLL that included fludarabine phosphate monotherapy and fludarabine phosphate combination therapy arms. In this study 107 evaluable patients received Oforta™ (fludarabine phosphate tablets) 40mg/m orally daily for 5 days every 28 days. The overall response rate according to modified NCI criteria was 74% and the CR plus nodular PR rate was 41%.

REFERENCES

1. Preventing Occupational Exposures to Antineoplastic and Other Hazardous Drugs in Health Care Settings. NIOSH Alert 2004-165.

2. OSHA Technical Manual, TED 1-0.15A, Section VI: Chapter 2. Controlling Occupational Exposure to Hazardous Drugs. OSHA, 1999. http://www.osha.gov/dts/osta/otm/otm_vi/otm_vi_2 .html

3. American Society of Health-System Pharmacists. ASHP guidelines on handling hazardous drugs. Am J Health-Syst Pharm. 2006;63:1172-1193.

4. Polovich, M., White, J. M., & Kelleher, L.O. (eds.) 2005. Chemotherapy and biotherapy guidelines and recommendations for practice (2nd. ed.) Pittsburgh, PA: Oncology Nursing Society.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Avoid activities that increase your risk of bleeding or injury. Brush your teeth gently and use extra care while shaving.

If you have a fever, avoid taking any fever medication without first asking your doctor.