Ferric Citrate for Kidney Failure

INDICATIONS AND USAGE Ferric citrate tablets are a phosphate binder indicated for the control of serum phosphorus levels in adult patients with chronic kidney disease on dialysis. ( 1 ) Ferric citrate tablets are an iron replacement product indicated for the treatment of iron deficiency anemia in adult patients with chronic kidney disease not on dialysis. ( 1 ) 1.1 Hyperphosphatemia in Chronic Kidney Disease on Dialysis Ferric citrate tablets are indicated for the control of serum phosphorus levels in adult patients with chronic kidney disease on dialysis. 1.2 Iron Deficiency Anemia in Chronic Kidney Disease Not on Dialysis Ferric citrate tablets are indicated for the treatment of iron deficiency anemia in adult patients with chronic kidney disease not on dialysis.

DOSAGE AND ADMINISTRATION • Hyperphosphatemia in Chronic Kidney Disease on Dialysis: • Starting dose is 2 tablets orally 3 times per day with meals. ( 2.1 ) • Adjust dose by 1 to 2 tablets as needed to maintain serum phosphorus at target levels, up to a maximum of 12 tablets daily. Dose can be titrated at 1-week or longer intervals. ( 2.1 ) • Iron Deficiency Anemia in Chronic Kidney Disease Not on Dialysis: • Starting dose is 1 tablet orally 3 times per day with meals. ( 2.2 ) • Adjust dose as needed to achieve and maintain hemoglobin goal, up to a maximum of 12 tablets daily. ( 2.2 ) 2.1 Dosage for Hyperphosphatemia in Chronic Kidney Disease on Dialysis The recommended starting dose is 2 tablets, swallowed whole, 3 times per day with meals. Ferric citrate tablets must not be chewed or crushed because it may cause discoloration of mouth and teeth. Monitor serum phosphorus levels and titrate the ferric citrate tablets dose in decrements or increments of 1 to 2 tablets per day as needed to maintain serum phosphorus at target levels, up to a maximum dose of 12 tablets daily. Dose can be titrated at 1-week or longer intervals. In a clinical trial, patients required an average of 8 to 9 tablets a day to control serum phosphorus levels. 2.2 Dosage for Iron Deficiency Anemia in Chronic Kidney Disease Not on Dialysis The recommended starting dose is 1 tablet, swallowed whole, 3 times per day with meals. Ferric citrate tablets must not be chewed or crushed because it may cause discoloration of mouth and teeth. Titrate the dose of ferric citrate tablets as needed to achieve and maintain hemoglobin at target levels, up to a maximum dose of 12 tablets daily. In a clinical trial in patients with chronic kidney disease not on dialysis (CKD-NDD), patients required an average of 5 tablets per day to increase hemoglobin levels.

WARNINGS AND PRECAUTIONS • Iron overload: Monitor ferritin and TSAT. Patients may require a reduction in dose or discontinuation of intravenous iron. ( 5.1 ) • Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6 years of age. Keep this product out of reach of children. In case of accidental overdose, call a doctor or poison control center immediately. ( 5.2 ) 5.1 Iron Overload Iron absorption from ferric citrate tablets may lead to excessive elevations in iron stores. Increases in serum ferritin and transferrin saturation (TSAT) levels were observed in clinical trials. In a 56-week safety and efficacy trial evaluating the control of serum phosphate levels in patients with chronic kidney disease on dialysis in which concomitant use of intravenous iron was permitted, 55 (19%) of patients treated with ferric citrate tablets had a ferritin level >1500 ng/mL as compared with 13 (9%) of patients treated with active control. Assess iron parameters (e.g., serum ferritin and TSAT) prior to initiating ferric citrate tablets and monitor iron parameters while on therapy [see Contraindications (4) , Overdosage (10) and Clinical Pharmacology (12.2) ] . Patients receiving intravenous iron may require a reduction in dose or discontinuation of intravenous iron therapy. 5.2 Risk of Overdosage in Children Due to Accidental Ingestion Accidental ingestion and resulting overdose of iron-containing products is a leading cause of fatal poisoning in children under 6 years of age [see Overdosage (10) ] . Advise patients of the risks to children and to keep ferric citrate tablets out of the reach of children.

DRUG INTERACTIONS Table 2: Oral drugs that can be administered concomitantly with Ferric Citrate Tablets Amlodipine Aspirin Atorvastatin Calcitriol Clopidogrel Digoxin Diltiazem Doxercalciferol Enalapril Fluvastatin Glimepiride Levofloxacin Losartan Metoprolol Pravastatin Propranolol Sitagliptin Warfarin Oral drugs that have to be separated from Ferric Citrate Tablets and meals Dosing Recommendations Doxycycline Take at least 1 hour before ferric citrate tablets Ciprofloxacin Take at least 2 hours before or after ferric citrate tablets Oral medications not listed in Table 2 There are no empirical data on avoiding drug interactions between ferric citrate tablets and most concomitant oral drugs. For oral medications where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy, consider separation of the timing of the administration of the two drugs. The duration of separation depends upon the absorption characteristics of the medication concomitantly administered, such as the time to reach peak systemic levels and whether the drug is an immediate release or an extended release product. Consider monitoring clinical responses or blood levels of concomitant medications that have a narrow therapeutic range. When clinically significant drug interactions are expected, consider separation of the timing of administration. Consider monitoring clinical responses or blood levels of the concomitant medication. ( 7 )

ADVERSE REACTIONS Most common adverse reactions (incidence ≥5%) are discolored feces, diarrhea, constipation, nausea, vomiting, cough, abdominal pain, and hyperkalemia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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 adverse reaction rates in the clinical trials of another drug and may not reflect the rates observed in practice. Hyperphosphatemia in Chronic Kidney Disease on Dialysis A total of 289 patients were treated with ferric citrate tablets and 149 patients were treated with active control (sevelamer carbonate and/or calcium acetate) during the 52-week, randomized, open-label, active control phase of a trial in patients on dialysis. A total of 322 patients were treated with ferric citrate tablets for up to 28 days in three short-term trials. Across these trials, 557 unique patients were treated with ferric citrate tablets; dosage regimens in these trials ranged from 210 mg to 2,520 mg of ferric iron per day, equivalent to 1 to 12 tablets of ferric citrate. Adverse reactions reported in more than 5% of patients treated with ferric citrate tablets in these trials included diarrhea (21%), discolored feces (19%), nausea (11%), constipation (8%), vomiting (7%), and cough (6%). During the 52-week, active-control period, 61 patients (21%) on ferric citrate tablets discontinued study drug because of an adverse reaction, as compared to 21 patients (14%) in the active control arm. Patients who were previously intolerant to any of the active control treatments (calcium acetate and sevelamer carbonate) were not eligible to enroll in the study. Gastrointestinal adverse reactions were the most common reason for discontinuing ferric citrate tablets (14%). Iron Deficiency Anemia in Chronic Kidney Disease Not on Dialysis Across two trials, 190 patients with CKD-NDD were treated with ferric citrate tablets. This included a study of 117 patients treated with ferric citrate tablets and 116 patients treated with placebo in a 16-week, randomized, double-blind period and a study of 75 patients treated with ferric citrate tablets and 73 treated with placebo in a 12-week randomized double-blind period. Dosage regimens in these trials ranged from 210 mg to 2,520 mg of ferric iron per day, equivalent to 1 to 12 tablets of ferric citrate. Adverse reactions reported in at least 5% of patients treated with ferric citrate tablets in these trials are listed in Table 1. Table 1: Adverse Reactions Reported in Two Clinical Trials in at least 5% of patients receiving Ferric Citrate Tablets Body System Adverse Reaction Ferric Citrate Tablets % (N=190) Placebo % (N=188) Any Adverse Reaction 75 62 Metabolism and Nutrition Disorders Hyperkalemia 5 3 Gastrointestinal Disorders Discolored Feces 22 0 Diarrhea 21 12 Constipation 18 10 Nausea 10 4 Abdominal Pain 5 2 During the 16-week, placebo-control trial, 12 patients (10%) on ferric citrate tablets discontinued study drug because of an adverse reaction, as compared to 10 patients (9%) in the placebo control arm. Diarrhea was the most common adverse reaction leading to discontinuation of ferric citrate tablets (2.6%).