Warnings for Iwilfin
Included as part of the "PRECAUTIONS" Section
Precautions for Iwilfin
Myelosuppression
IWILFIN can cause myelosuppression. In the pooled safety population [see ADVERSE REACTIONS], Grade 3 or 4 neutropenia occurred in 4.2% of patients. Febrile neutropenia occurred in 0.6% of patients. Bone marrow failure occurred in 1 patient. Grade 3 or 4 thrombocytopenia occurred in 1.4% of patients. Grade 3 anemia occurred in 3.3% of patients.
Monitor blood counts including neutrophil count, platelet count, and hemoglobin level prior to administration of IWILFIN and periodically during treatment. Withhold, reduce the dose, or permanently discontinue IWILFIN based on severity [see DOSAGE AND ADMINISTRATION].
Hepatotoxicity
IWILFIN can cause hepatotoxicity. In the pooled safety population [see ADVERSE REACTIONS], Grade 3 or 4 events of increased alanine aminotransferase (ALT) occurred in 11% of patients. Grade 3 or 4 events of increased aspartate aminotransferase (AST) occurred in 6% of patients. Grade 3 or 4 events of increased bilirubin occurred in 0.3% of patients. Increased ALT/AST leading to dose interruption or reduction occurred in 2.5% of patients. IWILFIN was discontinued due to increased ALT/AST in 0.6% of patients.
Perform liver function tests (ALT, AST, and total bilirubin) prior to the start of IWILFIN, every month for the first six months of treatment, then once every 3 months or as clinically indicated, with more frequent testing in patients who develop transaminase or bilirubin elevations. Withhold and reduce the dose or permanently discontinue IWILFIN based on severity [see DOSAGE AND ADMINISTRATION and ADVERSE REACTIONS].
Hearing Loss
IWILFIN can cause hearing loss. In the pooled safety population [see ADVERSE REACTIONS], 81% of patients had an abnormal audiogram at baseline. New or worsening hearing loss occurred in 13% of patients who received IWILFIN; hearing loss worsened from baseline to Grade 3 or 4 in 12% of patients. Tinnitus occurred in 1 patient. Hearing loss leading to dose interruption or reduction occurred in 4% of patients. New or worsening hearing loss requiring new use of hearing aids occurred in 7% of patients. IWILFIN was discontinued due to hearing loss in 1.4% of patients. Among all patients with new or worsening hearing loss during IWILFIN treatment, the hearing loss resolved to baseline in 9% of patients. Among 18 patients who experienced new or worsening hearing loss and had dose modifications, 67% (N=12) improved or resolved to baseline.
Perform audiogram prior to initiation of therapy and at 6 month intervals, or as clinically indicated, to monitor for potential hearing loss. Withhold and reduce the dose or permanently discontinue IWILFIN based on severity [see DOSAGE AND ADMINISTRATION].
Embryo-Fetal Toxicity
Based on findings from animal studies and its mechanism of action, IWILFIN can cause fetal harm when administered to a pregnant woman. In animal reproduction studies, oral administration of eflornithine to pregnant rats and rabbits during the period of organogenesis resulted in embryolethality at doses equivalent to the recommended human dose.
Advise pregnant women and females of reproductive potential of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with IWILFIN and for 1 week after the last dose. Advise males with female partners of reproductive potential to use effective contraception during treatment with IWILFIN and for 1 week after the last dose [see Use In Specific Populations].
Patient Counseling Information
Advise the patient to read the FDA-approved patient labeling (PATIENT INFORMATION).
Myelosuppression
Inform patients and caregivers of the risk of bone marrow suppression and to promptly report any signs or symptoms of thrombocytopenia, anemia, or infection [see WARNINGS AND PRECAUTIONS].
Hepatotoxicity
Inform patients and caregivers of the risk of hepatotoxicity and to promptly report any signs or symptoms of hepatotoxicity [see WARNINGS AND PRECAUTIONS].
Hearing Loss
Inform patients and caregivers of the risk of hearing loss, and to promptly report any signs or symptoms of new or worsening hearing loss [see WARNINGS AND PRECAUTIONS].
Embryofetal Toxicity
Inform patients and caregivers that IWILFIN can be harmful to a developing fetus and cause loss of pregnancy [see WARNINGS AND PRECAUTIONS]. Advise females of reproductive potential to use effective contraception during treatment with IWILFIN and for 1 week after the last dose. Advise males with female partners of reproductive potential to use effective contraception during treatment with IWILFIN and for 1 week after the last dose [see Use In Specific Populations].
Lactation
Advise women not to breastfeed during treatment with IWILFIN and for 1 week after the last dose [see Use In Specific Populations].
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
In a 2-year carcinogenicity study, once daily oral administration of eflornithine to female rats did not result in drug-related neoplasms at doses up to 600 mg/kg/day (10.5 times the human Cmax at the recommended clinical dose of 1152 ± 384 mg/m2).
Eflornithine was not mutagenic in the in vitro bacterial reverse mutation (Ames) assay.
Dedicated fertility studies were not conducted with eflornithine.
Use In Specific Populations
Pregnancy
Risk Summary
Based on findings from animal studies and its mechanism of action [see CLINICAL PHARMACOLOGY], IWILFIN can cause fetal harm when administered to a pregnant woman. In animal reproduction studies, oral administration of eflornithine to pregnant rats and rabbits during the period of organogenesis resulted in embryolethality at doses equivalent to the recommended human dose [see Data]. There are no available data on the use of IWILFIN in pregnant women. Advise pregnant women and females of reproductive potential of the potential risk to a fetus.
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data
Animal Data
In an embryo-fetal development study, once daily oral administration of 30, 80 or 200 mg/kg/day eflornithine to pregnant rats during the period of organogenesis (gestation day 6 to 7) resulted in reduced fetal body weights and an increase in the incidence of skeletal variations (presence of a 14th rudimentary rib, 14th full rib, 27th presacral vertebrae) at 200 mg/kg/day [approximately 0.8 to 2 times the recommended human dose of 1152 ± 384 mg/m2/day based on body surface area (BSA)]. In a dose range-finding embryo-fetal development study, pregnant rats receiving oral administration of up to 2000 mg/kg/day eflornithine during the period of organogenesis exhibited increased early resorptions and post-implantation loss beginning at 300 mg/kg/day (approximately 1 to 2 times the recommended human dose of 1152 ± 384 mg/m2/day based on BSA), with 100% post-implantation loss and no viable fetuses at ≥800 mg/kg/day (approximately ≥3 to 6 times the recommended human dose of 1152 ± 384 mg/m2/day based on BSA).
In an embryo-fetal development study in rabbits, once daily oral administration of 15, 45 or 135 mg/kg/day eflornithine to pregnant animals during the period of organogenesis (gestation day 7 to 20) resulted in reduced gravid uterine weight accompanied by increased pre-implantation and post-implantation loss, increased early resorptions, and reduced fetal body weights at 135 mg/kg/day (approximately 1 to 2 times the recommended human dose of 1152 ± 384 mg/m2/day based on BSA). Eflornithine resulted in abortions in one animal at 15 mg/kg/day (approximately 0.1 to 0.2 times the recommended human dose of 1152 ± 384 mg/m2/day based on BSA) and one animal at 135 mg/kg/day. In a dose range-finding embryo-fetal development study, pregnant rabbits receiving oral administration of up to 500 mg/kg/day eflornithine during the period of organogenesis exhibited 100% post-implantation loss and no viable fetuses at 500 mg/kg/day (approximately 4 to 8 times the recommended human dose of 1152 ± 384 mg/m2/day based on BSA). There was no clear evidence of eflornithine-related fetal malformations in rats or rabbits.
Lactation
Risk Summary
There are no data on the presence of eflornithine in human milk, the effects on the breastfed child, or on milk production. Because of the potential for serious adverse reactions in breastfed children, advise women not to breastfeed during treatment with IWILFIN and for 1 week after the last dose.
Females And Males Of Reproductive Potential
Based on animal data and its mechanism of action, IWILFIN can cause fetal harm when administered to a pregnant woman [see Pregnancy].
Pregnancy Testing
Verify pregnancy status in females of reproductive potential prior to initiating IWILFIN [see Pregnancy].
Contraception
Females
Advise females of reproductive potential to use effective contraception during treatment with IWILFIN and for 1 week after the last dose.
Males
Advise males with female partners of reproductive potential to use effective contraception during treatment with IWILFIN and for 1 week after the last dose.
Pediatric Use
The safety and effectiveness of IWILFIN have been established to reduce the risk of relapse in pediatric patients with high-risk neuroblastoma (HRNB) who have demonstrated at least a partial response to prior multiagent, multimodality therapy including anti-GD2 immunotherapy. Use of IWILFIN for this indication is supported by evidence from adequate and well-controlled studies in pediatric patients with a median age of 4 years (range: 1 to 17) [see ADVERSE REACTIONS, CLINICAL PHARMACOLOGY, Clinical Studies].
The safety and effectiveness of IWILFIN have not been established in pediatric patients for other indications [see INDICATIONS].
Renal Impairment
Patients with moderate (eGFR <60 mL/min) and severe (eGFR <30 mL/min) renal impairment have a higher exposure to eflornithine than patients with normal renal function which can increase the risk for toxicity [see CLINICAL PHARMACOLOGY]. Reduce the dose in patients with severe renal impairment [see DOSAGE AND ADMINISTRATION]. Monitor patients with moderate renal impairment closely for increased adverse reactions including hepatotoxicity, myelosuppression, and hearing loss [see DOSAGE AND ADMINISTRATION].