Pentostatin

NIPENT is indicated as single-agent treatment for both untreated and alpha-interferon-refractory hairy cell leukemia patients with active disease as defined by clinically significant anemia, neutropenia, thrombocytopenia, or disease-related symptoms.

NIPENT is contraindicated: In patients who have demonstrated hypersensitivity to NIPENT.

See Boxed Warning . Patients with hairy cell leukemia may experience myelosuppression primarily during the first few courses of treatment. Patients with infections prior to NIPENT treatment have in some cases developed worsening of their condition leading to death, whereas others have achieved complete response. Patients with infection should be treated only when the potential benefit of treatment justifies the potential risk to the patient. Efforts should be made to control the infection before treatment is initiated or resumed. In patients with progressive hairy cell leukemia, the initial courses of NIPENT treatment were associated with worsening of neutropenia. Therefore, frequent monitoring of complete blood counts during this time is necessary. If severe neutropenia continues beyond the initial cycles, patients should be evaluated for disease status, including a bone marrow examination. Elevations in liver function tests occurred during treatment with NIPENT and were generally reversible. Renal toxicity was observed at higher doses in early studies; however, in patients treated at the recommended dose, elevations in serum creatinine were usually minor and reversible. There were some patients who began treatment with normal renal function who had evidence of mild to moderate toxicity at a final assessment (See DOSAGE AND ADMINISTRATION ). Rashes, occasionally severe, were commonly reported and may worsen with continued treatment. Withholding of treatment may be required (See DOSAGE AND ADMINISTRATION ). Acute pulmonary edema and hypotension, leading to death, have been reported in the literature in patients treated with pentostatin in combination with carmustine, etoposide and high dose cyclophosphamide as part of the ablative regimen for bone marrow transplant. Pregnancy Pentostatin can cause fetal harm when administered to a pregnant woman. Pentostatin was administered intravenously at doses of 0, 0.01, 0.1, or 0.75 mg/kg/day (0, 0.06, 0.6, and 4.5 mg/m 2 ) to pregnant rats on days 6 through 15 of gestation. Drug-related maternal toxicity occurred at doses of 0.1 and 0.75 mg/kg/day (0.6 and 4.5 mg/m 2 ). Teratogenic effects were observed at 0.75 mg/kg/day (4.5 mg/m 2 ) manifested by increased incidence of various skeletal malformations. In a dose range-finding study, pentostatin was administered intravenously to rats at doses of 0, 0.05, 0.1, 0.5, 0.75, or 1 mg/kg/day (0, 0.3, 0.6, 3, 4.5, 6 mg/m 2 ), on days 6 through 15 of gestation. Fetal malformations that were observed were an omphalocele at 0.05 mg/kg (0.3 mg/m 2 ), gastroschisis at 0.75 mg/kg and 1 mg/kg (4.5 and 6 mg/m 2 ), and a flexure defect of the hindlimbs at 0.75 mg/kg (4.5 mg/m 2 ). Pentostatin was also shown to be teratogenic in mice when administered as a single 2 mg/kg (6 mg/m 2 ) intraperitoneal injection on day 7 of gestation. Pentostatin was not teratogenic in rabbits when administered intravenously on days 6 through 18 of gestation at doses of 0, 0.005, 0.01, or 0.02 mg/kg/day (0, 0.015, 0.03, or 0.06 mg/m 2 ); however maternal toxicity, abortions, early deliveries, and deaths occurred in all drug-treated groups. There are no adequate and well-controlled studies in pregnant women. If NIPENT is used during pregnancy, or if the patient becomes pregnant while taking (receiving) this drug, the patient should be apprised of the potential hazard to the fetus. Women of childbearing potential receiving NIPENT should be advised to avoid becoming pregnant.

General Therapy with NIPENT requires regular patient observation and monitoring of hematologic parameters and blood chemistry values. If severe adverse reactions occur, the drug should be withheld (see DOSAGE AND ADMINISTRATION ), and appropriate corrective measures should be taken according to the clinical judgment of the physician. NIPENT treatment should be withheld or discontinued in patients showing evidence of nervous system toxicity. Information for Patients Patients should be advised of the signs and symptoms of adverse events associated with NIPENT therapy (See ADVERSE REACTIONS ). Laboratory Tests Prior to initiating therapy with NIPENT, renal function should be assessed with a serum creatinine and/or a CL cr assay (See CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION ). Complete blood counts and serum creatinine should be performed before each dose of NIPENT and at other appropriate periods during therapy (see DOSAGE AND ADMINISTRATION ). Severe neutropenia has been observed following the early courses of treatment with NIPENT and therefore frequent monitoring of complete blood counts is recommended during this time. If hematologic parameters do not improve with subsequent courses, patients should be evaluated for disease status, including a bone marrow examination. Periodic monitoring of the peripheral blood for hairy cells should be performed to assess the response to treatment. In addition, bone marrow aspirates and biopsies may be required at 2 to 3 month intervals to assess the response to treatment. Drug Interactions Allopurinol and NIPENT are both associated with skin rashes. Based on clinical studies in 25 refractory patients who received both NIPENT and allopurinol, the combined use of NIPENT and allopurinol did not appear to produce a higher incidence of skin rashes than observed with NIPENT alone. There has been a report of one patient who received both drugs and experienced a hypersensitivity vasculitis that resulted in death. It was unclear whether this adverse event and subsequent death resulted from the drug combination. Biochemical studies have demonstrated that pentostatin enhances the effects of vidarabine, a purine nucleoside with antiviral activity. The combined use of vidarabine and NIPENT may result in an increase in adverse reactions associated with each drug. The therapeutic benefit of the drug combination has not been established. The combined use of NIPENT and fludarabine phosphate is not recommended because it may be associated with an increased risk of fatal pulmonary toxicity (see WARNINGS ). Acute pulmonary edema and hypotension, leading to death, have been reported in the literature in patients treated with pentostatin in combination with carmustine, etoposide and high dose cyclophosphamide as part of the ablative regimen for bone marrow transplant. Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis: No animal carcinogenicity studies have been conducted with pentostatin. Mutagenesis: Pentostatin was nonmutagenic when tested in Salmonella typhimurium strains TA-98, TA-1535, TA-1537, and TA-1538. When tested with strain TA-100, a repeatable statistically significant response trend was observed with and without metabolic activation. The response was 2.1 to 2.2 fold higher than the background at 10 mg/plate, the maximum possible drug concentration. Formulated pentostatin was clastogenic in the in vivo mouse bone marrow micronucleus assay at 20, 120, and 240 mg/kg. Pentostatin was not mutagenic to V79 Chinese hamster lung cells at the HGPRT locus exposed 3 hours to concentrations of 1 to 3 mg/mL, with or without metabolic activation. Pentostatin did not significantly increase chromosomal aberrations in V79 Chinese hamster lung cells exposed 3 hours to 1 to 3 mg/mL in the presence or absence of metabolic activation. Impairment of Fertility: No fertility studies have been conducted in animals; however, in a 5-day intravenous toxicity study in dogs, mild seminiferous tubular degeneration was observed with doses of 1 and 4 mg/kg. The possible adverse effects on fertility in humans have not been determined. Advise patients on the potential risks for infertility. Contraception in Males and Females Due to the genotoxicity and embryo-fetal toxicity findings in nonclinical studies, advise females of reproductive potential to use effective contraception during treatment and for 6 months following the last dose of NIPENT. Due to the genotoxicity findings in nonclinical studies, advise male patients with female partners of reproductive potential to use effective contraception during treatment and for 3 months following the last dose of NIPENT. Pregnancy (See WARNINGS ) Nursing Mothers It is not known whether NIPENT is excreted in human milk. Because many drugs are excreted in human milk, and because of the potential for serious adverse reactions in the breast-fed child due to pentostatin, advise patients not to breast-feed while on NIPENT therapy and for 1 week following the last dose of treatment. Pediatric Use Safety and effectiveness in children or adolescents have not been established.

Most patients treated for hairy cell leukemia in the five NCI-sponsored Phase 2 studies and the Phase 3 SWOG study experienced an adverse event. The following table lists the most frequently occurring adverse events in patients treated with NIPENT (both frontline and IFN-refractory patients) compared with IFN (frontline only), regardless of drug association. The drug association of some adverse events is uncertain as they may be associated with the disease itself (e.g., infection, hematologic suppression), but other events, such as the gastrointestinal symptoms, rashes, and abnormal liver function tests, can in many cases be attributed to the drug. Most adverse events that were assessed for severity were either mild or moderate, and diminished in frequency with continued therapy. NR = Not Reported Percent of Patients All Adverse Events Occurring in more than 10% of patients, in any group, regardless of drug association Frontline, Treated With NIPENT N=180 Frontline, Treated With IFN N=176 IFN-Refractory, Treated With NIPENT N=197 Nausea and/or Vomiting 63 22 53 Includes only nausea with vomiting Fever 46 59 42 Rash 43 30 26 Fatigue 42 55 29 Leukopenia 22 15 60 Pruritus 21 6 10 Coughing/Increased Cough 20 15 17 Myalgia 19 36 11 Chills 19 34 11 Headache 17 29 13 Diarrhea 17 17 15 Abdominal Pain 16 15 4 Anorexia 13 10 16 Upper Respiratory Infection 13 8 16 Asthenia 12 13 10 Stomatitis 12 7 5 Rhinitis 11 15 10 Dyspnea 11 13 8 Anemia 8 5 35 Pain 8 19 20 Pharyngitis 8 11 10 Sweating/Increased Sweating 8 21 10 Viral Infection 8 17 NR Infection 7 These figures represent only unspecified infections. Refer to infection table. 2 36 Arthralgia 6 14 3 Thrombocytopenia 6 6 32 Skin Disorder 4 5 17 Allergic Reaction 2 1 11 Hepatic Disorder/Elevated Liver Function Tests Elevated liver enzymes and liver disorder for SWOG 2 2 19 Neurologic Disorder, CNS/CNS Toxicity 1 NR 11 Lung Disorder/Disease NR 1 12 Nausea NR NR 22 Genitourinary Disorder NR NR 15 The total incidence for all types of infections is considerably higher for both treatment groups in the SWOG 8691 study than is listed in the table above. An intent-to-treat analysis of infections found that 38% of patients treated with NIPENT and 34% of patients treated with IFN averaged 2.4 and 1.9 documented infections during treatment, respectively. The following table lists the different types of infections that were reported as adverse events during the initial phase of the SWOG study. There were no apparent differences in the types of infection between the 2 treatment groups, with the possible exception of herpes zoster which was reported more frequently for NIPENT (8%) than for IFN (1%). Percent of Patients Type of Infection Frontline, Treated With NIPENT N=180 Frontline, Treated With IFN N=176 Upper Respiratory Infection 13 8 Rhinitis 11 15 Herpes Zoster 8 1 Pharyngitis 8 11 Viral Infection 8 17 Infection (Unspecified) 7 2 Sinusitis 6 4 Cellulitis 6 3 Bacterial Infection 5 4 Pneumonia 5 7 Conjunctivitis 4 2 Furunculosis 4 <1 Herpes Simplex 4 1 Bronchitis 3 2 Sepsis 3 2 Urinary Tract Infection 3 3 Abscess, Skin 2 4 Moniliasis, Oral 2 <1 Mycotic Infection, Skin <1 3 Osteomyelitis 1 0 The drug relatedness of the adverse events listed below cannot be excluded. The following adverse events occurred in 3% to 10% of NIPENT-treated patients in the initial phase of the SWOG study: Body as a Whole —Chest Pain, Death, Face Edema, Peripheral Edema Cardiovascular System —Hemorrhage, Hypotension Digestive System —Dental Abnormalities, Dyspepsia, Flatulence, Gingivitis Hematologic System —Agranulocytosis Laboratory Deviations —Elevated Creatinine Musculoskeletal System —Arthralgia Nervous System —Confusion, Dizziness, Insomnia, Paresthesia, Somnolence Psychobiologic Function —Anxiety, Depression, Nervousness Respiratory System —Asthma Skin & Appendages —Skin Dry, Urticaria The remaining adverse events which occurred in less than 3% of NIPENT-treated patients during the initial phase of the SWOG study: Body as a Whole —Flu-like Symptoms, Hangover Effect, Neoplasm Cardiovascular System —Angina Pectoris, Arrhythmia, A-V Block, Bradycardia, Extrasystoles Ventricular, Heart Arrest, Heart Failure, Hypertension, Pericardial Effusion, Phlebitis, Pulmonary Embolus, Sinus Arrest, Tachycardia, Thrombophlebitis Deep, Vasculitis Digestive System —Constipation, Dysphagia, Glossitis, Ileus Hematologic System —Acute Leukemia, Anemia-Hemolytic, Aplastic Anemia Laboratory Deviations —Hypercalcemia, Hyponatremia Musculoskeletal System —Arthritis, Gout Nervous System —Amnesia, Ataxia, Convulsions, Dreaming Abnormal, Dysarthria, Encephalitis, Hyperkinesia, Meningism, Neuralgia, Neuritis, Neuropathy, Paralysis, Syncope, Twitching, Vertigo Psychobiologic Function —Decrease/Loss Libido, Emotional Lability, Hallucination, Hostility, Neurosis, Thinking Abnormal Respiratory System —Bronchospasm, Larynx Edema Skin and Appendages —Acne, Alopecia, Eczema, Petechial Rash, Photosensitivity Reaction Special Senses —Amblyopia, Deafness, Earache, Eyes Dry, Labyrinthitis, Lacrimation Disorder, Nonreactive Eye, Photophobia, Retinopathy, Tinnitus, Unusual Taste, Vision Abnormal, Watery Eyes Urogenital System —Amenorrhea, Breast Lump, Impotence, Kidney Function Abnormal, Nephropathy, Renal Failure, Renal Insufficiency, Renal Stone One patient with hairy cell leukemia treated with NIPENT during another clinical study developed unilateral uveitis with vision loss. Nineteen (5%) patients withdrew from the Phase 3 SWOG 8691 study because of adverse events; 9 during initial NIPENT treatment, 4 during NIPENT crossover, 5 during initial IFN treatment, and 1 during both initial IFN treatment and NIPENT crossover. In the Phase 2 studies in IFN-refractory hairy cell leukemia, 11% of patients withdrew from treatment with NIPENT due to an adverse event. Postmarketing Experience The following adverse reactions have been identified during post-approval use of NIPENT. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Hematologic System —Febrile Neutropenia, Hemolytic Uremic Syndrome, Thrombotic Thrombocytopenic Purpura, Autoimmune Thrombocytopenia Respiratory System —Acute Respiratory Failure Skin and Appendages —Exfoliative Dermatitis

Allopurinol and NIPENT are both associated with skin rashes. Based on clinical studies in 25 refractory patients who received both NIPENT and allopurinol, the combined use of NIPENT and allopurinol did not appear to produce a higher incidence of skin rashes than observed with NIPENT alone. There has been a report of one patient who received both drugs and experienced a hypersensitivity vasculitis that resulted in death. It was unclear whether this adverse event and subsequent death resulted from the drug combination. Biochemical studies have demonstrated that pentostatin enhances the effects of vidarabine, a purine nucleoside with antiviral activity. The combined use of vidarabine and NIPENT may result in an increase in adverse reactions associated with each drug. The therapeutic benefit of the drug combination has not been established. The combined use of NIPENT and fludarabine phosphate is not recommended because it may be associated with an increased risk of fatal pulmonary toxicity (see WARNINGS ). Acute pulmonary edema and hypotension, leading to death, have been reported in the literature in patients treated with pentostatin in combination with carmustine, etoposide and high dose cyclophosphamide as part of the ablative regimen for bone marrow transplant.

(See WARNINGS )

It is not known whether NIPENT is excreted in human milk. Because many drugs are excreted in human milk, and because of the potential for serious adverse reactions in the breast-fed child due to pentostatin, advise patients not to breast-feed while on NIPENT therapy and for 1 week following the last dose of treatment.

Safety and effectiveness in children or adolescents have not been established.