Sevelamer Carbonate

RECENT MAJOR CHANGES Indications and Usage (1) 11/2016 Dosage and Administration (2) 11/2016 Contraindications (4) 03/2016

1 INDICATIONS AND USAGE Sevelamer carbonate tablets are indicated for the control of serum phosphorus in adults with chronic kidney disease (CKD) on dialysis. Pediatric use information is approved for Genzyme Corporation’s RENVELA ® (sevelamer carbonate) tablets and RENVELA ® (sevelamer carbonate) for oral suspension. However, due to Genzyme Corporation’s marketing exclusivity rights, these drug products are not labeled with that pediatric information . • Sevelamer carbonate tablets are a phosphate binder indicated for the control of serum phosphorus in adults with chronic kidney disease on dialysis. ( 1 )

2 DOSAGE AND ADMINISTRATION Starting dose of sevelamer carbonate is 0.8 or 1.6 grams administered orally three times per day with meals based on serum phosphorus levels for adult patients and based on body surface area (BSA) category for pediatric patients. ( 2.1 ) Titrate by 0.8 g per meal in two-week intervals for adult patients as needed to obtain serum phosphorus target. ( 2.1 ) Titrate based on BSA category for pediatric patients in two-week intervals for 6 weeks and then every 4 weeks as needed to obtain serum phosphorus target. ( 2.1 ) 2.1 General Dosing Information Starting Dose for Adult Patients Not Taking a Phosphate Binder. The recommended starting dose of sevelamer carbonate is 0.8 to 1.6 g taken orally with meals based on serum phosphorus level. Table 1 provides recommended starting doses of sevelamer carbonate for adult patients not taking a phosphate binder. Table 1: Starting Dose for Adult Dialysis Patients Not Taking a Phosphate Binder Serum Phosphorus Sevelamer Carbonate >5.5 and <7.5 mg/dL 0.8 g three times daily with meals ≥7.5 mg/dL 1.6 g three times daily with meals Dose Titration for Adult Patients Taking Sevelamer Carbonate. Titrate the sevelamer carbonate dose by 0.8 g three times per day with meals at two-week intervals as necessary to achieve target serum phosphorus levels. Based on clinical studies, the average prescribed adult daily dose of sevelamer carbonate is approximately 7.2 g per day. The highest daily adult dose of sevelamer carbonate studied was 14 grams in CKD patients on dialysis. Starting Dose for Pediatric Patients Not Taking a Phosphate Binder. The recommended starting dose for pediatric patients 6 years of age and older is 0.8 to 1.6 g taken three times per day with meals based on the patient's body surface area (BSA) category; see Table 2 . Table 2: Recommended Starting Dosage and Titration Increment Based on Pediatric Patient's Body Surface Area (m 2 ) BSA (m 2 ) Starting Dose Per Meal/Snack Titration Increases/Decreases Per Dose ≥0.75 to <1.2 0.8 g Titrate by 0.4 g ≥1.2 1.6 g Titrate by 0.8 g Dose Titration for Pediatric Patients Taking Sevelamer Carbonate. Titrate the sevelamer carbonate dose as needed to achieve target levels at two-week intervals based on BSA category, as shown in Table 2. Switching from Sevelamer Hydrochloride Tablets. For adult patients switching from sevelamer hydrochloride tablets to sevelamer carbonate tablets or powder, use the same dose in grams. Switching between Sevelamer Carbonate Tablets and Powder. Use the same dose in grams. Switching from Calcium Acetate. Table 3 gives recommended starting doses of sevelamer carbonate based on a patient's current calcium acetate dose. Table 3: Starting Dose for Dialysis Patients Switching from Calcium Acetate to Sevelamer Carbonate Calcium Acetate 667 mg (Tablets per meal) Sevelamer Carbonate 1 tablet 0.8 g 2 tablets 1.6 g 3 tablets 2.4 g 2.2 Sevelamer Carbonate Powder Preparation Instructions Sevelamer carbonate powder is available in 0.8 or 2.4 g packets. For dose increments of 0.4 g, use one half of a 0.8 g packet. Place the sevelamer carbonate powder in a cup and suspend in the amount of water described in Table 4. Table 4: Sevelamer Carbonate Powder Preparation Instructions Amount of Sevelamer Carbonate Powder Minimum Amount of Water for Dose Preparation (either ounces, mL, or tablespoon) Ounces mL Tablespoons 0.4 g 1 30 2 0.8 g 1 30 2 2.4 g 2 60 4 Instruct patients to stir the mixture vigorously (it does not dissolve), resuspend, if necessary, right before administration, and drink the entire preparation within 30 minutes. As an alternative to water, the entire contents of the packet may be pre-mixed with a small amount of food or beverage and consumed immediately (within 30 minutes) as part of the meal. Do not heat sevelamer carbonate powder (e.g., microwave) or add to heated foods or liquids.

3 DOSAGE FORMS AND STRENGTHS Tablets: 800 mg white oval, film-coated, compressed tablets, engraved with RV800 on one side Powder: 0.8 g and 2.4 g pale-yellow powder packaged in an opaque, foil-lined, heat-sealed packets Tablets: 800 mg ( 3 ) Powder: 0.8 g and 2.4 g packets ( 3 )

4 CONTRAINDICATIONS Sevelamer carbonate tablets are contraindicated in patients with bowel obstruction. Sevelamer carbonate tablets are contraindicated in patients with known hypersensitivity to sevelamer carbonate, sevelamer hydrochloride, or to any of the excipients. • Bowel obstruction. ( 4 ) • Known hypersensitivity to sevelamer carbonate, sevelamer hydrochloride, or to any of the excipients. ( 4 )

6 ADVERSE REACTIONS . 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 rates in the clinical trials of another drug and may not reflect the rates observed in practice. There are limited clinical trial data on the safety of sevelamer carbonate tablets. However, because it contains the same active ingredient as the hydrochloride salt, the adverse event profiles of the two salts are expected to be similar. In a cross-over study in hemodialysis patients with treatment durations of eight weeks each and no washout, and another cross-over study in hemodialysis patients with treatment durations of four weeks each and no washout between treatment periods, the adverse reactions on sevelamer carbonate powder were similar to those reported for sevelamer hydrochloride. In a parallel design study of sevelamer hydrochloride with treatment duration of 52 weeks, adverse reactions reported for sevelamer hydrochloride (n=99) were similar to those reported for the active-comparator group (n=101). Overall adverse reactions among those treated with sevelamer hydrochloride occurring in >5% of patients included: vomiting (22%), nausea (20%), diarrhea (19%), dyspepsia (16%), abdominal pain (9%), flatulence (8%), and constipation (8%). A total of 27 patients treated with sevelamer and 10 patients treated with comparator withdrew from the study due to adverse reactions. Based on studies of 8-52 weeks, the most common reason for withdrawal from sevelamer hydrochloride was gastrointestinal adverse reactions (3%-16%). In 143 peritoneal dialysis patients studied for 12 weeks using sevelamer hydrochloride, most common adverse reactions were similar to adverse reactions observed in hemodialysis patients. The most frequently occurring treatment emergent serious adverse reaction was peritonitis (8 reactions in 8 patients [8%] in the sevelamer group and 2 reactions in 2 patients [4%] on active control). Thirteen patients (14%) in the sevelamer group and 9 patients (20%) in the active-control group discontinued, mostly for gastrointestinal adverse reactions. 6.2 Postmarketing Experience Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or to establish a causal relationship to drug exposure. The following adverse reactions have been identified during postapproval use of sevelamer hydrochloride or sevelamer carbonate: hypersensitivity, pruritus, rash, abdominal pain, bleeding gastrointestinal ulcers, colitis, ulceration, necrosis, fecal impaction, and uncommon cases of ileus, intestinal obstruction, and intestinal perforation. Appropriate medical management should be given to patients who develop constipation or have worsening of existing constipation to avoid severe complications.

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 rates in the clinical trials of another drug and may not reflect the rates observed in practice. There are limited clinical trial data on the safety of sevelamer carbonate tablets. However, because it contains the same active ingredient as the hydrochloride salt, the adverse event profiles of the two salts are expected to be similar. In a cross-over study in hemodialysis patients with treatment durations of eight weeks each and no washout, and another cross-over study in hemodialysis patients with treatment durations of four weeks each and no washout between treatment periods, the adverse reactions on sevelamer carbonate powder were similar to those reported for sevelamer hydrochloride. In a parallel design study of sevelamer hydrochloride with treatment duration of 52 weeks, adverse reactions reported for sevelamer hydrochloride (n=99) were similar …

7 DRUG INTERACTIONS There are no empirical data on avoiding drug interactions between sevelamer carbonate tablets and most concomitant oral drugs. For oral medication where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy (e.g., cyclosporine, tacrolimus, levothyroxine), consider separation of the timing of the administration of the two drugs [see Clinical Pharmacology (12.3) ] . 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. Where possible consider monitoring clinical responses and/or blood levels of concomitant drugs that have a narrow therapeutic range. Table 3. Sevelamer Drug Interactions Oral drugs for which sevelamer did not alter the pharmacokinetics when administered concomitantly Digoxin Enalapril Iron Metoprolol Warfarin Oral drugs that have demonstrated interaction with sevelamer and are to be dosed separately from sevelamer carbonate tablets Ciprofloxacin Mycophenolate mofetil Dosing Recommendations Take at least 2 hours before or 6 hours after sevelamer Take at least 2 hours before sevelamer • For oral medication 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 administration and/or monitor clinical responses or blood levels of the concomitant medication. ( 7 ) • Sevelamer did not alter the pharmacokinetics of digoxin, enalapril, iron, metoprolol and warfarin. ( 7 ) • Sevelamer has demonstrated interaction with ciprofloxacin, mycophenolate mofetil, and therefore these drugs should be dosed separately from sevelamer carbonate tablets. ( 7 )

Drug Interactions In vivo Sevelamer carbonate has been studied in human drug-drug interaction studies (9.6 grams once daily with a meal) with warfarin and digoxin. Sevelamer hydrochloride, which contains the same active moiety as sevelamer carbonate, has been studied in human drug-drug interaction studies (2.4 to 2.8 grams single dose or three times daily with meals or two times daily without meals) with ciprofloxacin, digoxin, enalapril, iron, metoprolol, mycophenolate mofetil and warfarin. Co-administered single dose of 2.8 grams of sevelamer hydrochloride in fasted state decreased the bioavailability of ciprofloxacin by approximately 50% in healthy subjects. Concomitant administration of sevelamer and mycophenolate mofetil in adult and pediatric patients decreased the mean MPA C max and AUC 0–12h by 36% and 26% respectively. Sevelamer carbonate or sevelamer hydrochloride did not alter the pharmacokinetics of enalapril, digoxin, iron, metoprolol and warfarin when co-administered. During postmarketing experience, cases of increased thyroid stimulating hormone (TSH) levels have been reported in patients co-administered sevelamer hydrochloride and levothyroxine. Reduction in concentrations of cyclosporine and tacrolimus leading to dose increases has also been reported in transplant patients when co-administered with sevelamer hydrochloride without any clinical consequences (for example, graft rejection). The possibility of an interaction cannot be excluded with these drugs.

8 USE IN SPECIFIC POPULATIONS . 8.1 Pregnancy Risk Summary Sevelamer carbonate is not absorbed systemically following oral administration and maternal use is not expected to result in fetal exposure to the drug. Clinical Considerations Sevelamer carbonate may decrease serum levels of fat soluble vitamins and folic acid in pregnant women [see Clinical Pharmacology (12.2) ]. Consider supplementation. Data Animal data In pregnant rats given dietary doses of 0.5, 1.5, or 4.5 g/kg/day of sevelamer hydrochloride during organogenesis, reduced or irregular ossification of fetal bones, probably due to a reduced absorption of fat-soluble vitamin D, occurred in mid and high-dose groups (human equivalent doses approximately equal to 3-4 times the maximum clinical trial dose of 13 g). In pregnant rabbits given oral doses of 100, 500, or 1000 mg/kg/day of sevelamer hydrochloride by gavage during organogenesis, an increase of early resorptions occurred in the high-dose group (human equivalent dose twice the maximum clinical trial dose). 8.2 Lactation Risk Summary Sevelamer carbonate tablets are not absorbed systemically by the mother following oral administration, and breastfeeding is not expected to result in exposure of the child to sevelamer carbonate tablets. Clinical Considerations Sevelamer carbonate may decrease serum levels of fat soluble vitamins and folic acid in pregnant women [see Clinical Pharmacology (12.2) ]. Consider supplementation. 8.4 Pediatric Use The safety and efficacy of sevelamer carbonate in lowering serum phosphorus levels was studied in patients 6 years of age and older with CKD. In this study, sevelamer carbonate was apparently less effective in children with a low baseline serum phosphorus, which described children <13 years of age and children not on dialysis. Given its mechanism of action, sevelamer carbonate is expected to be effective in lowering serum phosphorus levels in pediatric patients with CKD. Most adverse events that were reported as related, or possibly related, to sevelamer carbonate were gastrointestinal in nature. No new risks or safety signals were identified with the use of sevelamer carbonate in the trial. Sevelamer carbonate has not been studied in pediatric patients below 6 years of age. 8.5 Geriatric Use Clinical studies of sevelamer carbonate tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range.

8.1 Pregnancy Risk Summary Sevelamer carbonate is not absorbed systemically following oral administration and maternal use is not expected to result in fetal exposure to the drug. Clinical Considerations Sevelamer carbonate may decrease serum levels of fat soluble vitamins and folic acid in pregnant women [see Clinical Pharmacology (12.2) ]. Consider supplementation. Data Animal data In pregnant rats given dietary doses of 0.5, 1.5, or 4.5 g/kg/day of sevelamer hydrochloride during organogenesis, reduced or irregular ossification of fetal bones, probably due to a reduced absorption of fat-soluble vitamin D, occurred in mid and high-dose groups (human equivalent doses approximately equal to 3-4 times the maximum clinical trial dose of 13 g). In pregnant rabbits given oral doses of 100, 500, or 1000 mg/kg/day of sevelamer hydrochloride by gavage during organogenesis, an increase of early resorptions occurred in the high-dose group (human equivalent dose twice the maximum clinical trial dose).

8.2 Lactation Risk Summary Sevelamer carbonate tablets are not absorbed systemically by the mother following oral administration, and breastfeeding is not expected to result in exposure of the child to sevelamer carbonate tablets. Clinical Considerations Sevelamer carbonate may decreas …

12.1 Mechanism of Action Sevelamer carbonate tablets contains sevelamer carbonate, a non-absorbed phosphate-binding cross-linked polymer, free of metal and calcium. It contains multiple amines separated by one carbon from the polymer backbone. These amines exist in a protonated form in the intestine and interact with phosphate molecules through ionic and hydrogen bonding. By binding phosphate in the gastrointestinal tract and decreasing absorption, sevelamer carbonate lowers the phosphate concentration in the serum (serum phosphorus).

11 DESCRIPTION The active ingredient is sevelamer carbonate, a polymeric amine that binds phosphate and is meant for oral administration. It was developed as a pharmaceutical alternative to sevelamer hydrochloride. Sevelamer carbonate is an anion exchange resin, with the same polymeric structure as sevelamer hydrochloride, in which carbonate replaces chloride as the counterion. While the counterions differ for the two salts, the polymer itself, the active moiety involved in phosphate binding, is the same. Sevelamer carbonate is known chemically as poly(allylamine- co -N,N′-diallyl-1,3-diamino-2-hydroxypropane) carbonate salt. Sevelamer carbonate is hygroscopic, but insoluble in water. The structure is represented in Figure 1. Figure 1: Chemical Structure of Sevelamer Carbonate a, b = number of primary amine groups a + b = 9 c = number of cross-linking groups c = 1 m = large number to indicate extended polymer network Chemical Structure Sevelamer carbonate tablets: Each film-coated tablet contains 800 mg of sevelamer carbonate on an anhydrous basis. The inactive ingredients are hypromellose, diacetylated monoglycerides, microcrystalline cellulose, sodium chloride, and zinc stearate. Sevelamer carbonate powder: Each packet contains 0.8 or 2.4 g of sevelamer carbonate on an anhydrous basis. The inactive ingredients are natural and artificial citrus flavor, propylene glycol alginate, sodium chloride, sucralose, and ferric oxide (yellow).

10 OVERDOSAGE In CKD patients on dialysis, the maximum dose studied was 14 grams of sevelamer carbonate and 13 grams of sevelamer hydrochloride. There are no reports of overdosage with sevelamer carbonate or sevelamer hydrochloride in patients. Since sevelamer is not absorbed, the risk of systemic toxicity is low.

16 HOW SUPPLIED/STORAGE AND HANDLING Tablets: Sevelamer carbonate Tablets 800 mg are supplied as white to off-white, oval, film-coated tablets plain on one side and imprinted ‘R789’ on other side, containing 800 mg of sevelamer carbonate on an anhydrous basis, ammonium hydroxide, colloidal silicon dioxide, crospovidone, hydroxypropyl cellulose, lecithin, mannitol, polyvinyl alcohol, propylene glycol, shellac, talc, xanthan gum and zinc stearate. The tablet imprint contains iron oxide black ink. Cartons of 50 film-coated tablets (10 film-coated tablets each blister pack x 5), NDC 0904-6707-06 Cartons of 100 film-coated tablets (4 film-coated tablets each blister pack x 25), NDC 0904-6707-82 WARNING: This Unit Dose package is not child resistant and is Intended for Institutional Use Only. Keep this and all drugs out of the reach of children. Storage: Store at 20°-25°C (68°-77°F); [See USP Controlled Room Temperature] Protect from moisture.