SEVELAMER: 5,712 Adverse Event Reports & Safety Profile

11.

Description

The active ingredient in Sevelamer Hydrochloride Tablets is sevelamer hydrochloride, a polymeric amine that binds phosphate and is meant for oral administration. Sevelamer hydrochloride is poly(allylamine hydrochloride) crosslinked with epichlorohydrin in which 40% of the amines are protonated. It is known chemically as poly(allylamine- co -N,N'-diallyl-1,3-diamino-2-hydroxypropane) hydrochloride. Sevelamer hydrochloride is hydrophilic, but insoluble in water. The structure is represented in Figure 1.

Figure

1: Chemical Structure of Sevelamer Hydrochloride a, b = number of primary amine groups a + b = 9 c = number of crosslinking groups c = 1 n = fraction of protonated amines n = 0.4 m = large number to indicate extended polymer network The primary amine groups shown in the structure are derived directly from poly(allylamine hydrochloride). The crosslinking groups consist of two secondary amine groups derived from poly(allylamine hydrochloride) and one molecule of epichlorohydrin.

Sevelamer Hydrochloride

Tablets: Each film-coated tablet of sevelamer hydrochloride contains either 800 mg or 400 mg of sevelamer hydrochloride on an anhydrous basis. The inactive ingredients are colloidal silicon dioxide, diacetylated monoglycerides, hypromellose, lactose monohydrate, maize starch, mannitol, talc and zinc stearate. The imprinting ink for sevelamer hydrochloride tablets has the following components: black iron oxide, butyl alcohol, isopropyl alcohol, propylene glycol, ammonium hydroxide and shellac. chemical-structure

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 )

AND ADMINISTRATION Starting dose of sevelamer carbonate for oral suspension 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 fo r Adult Patients Not Taking a Phosphate Binder. The recommended starting dose of sevelamer carbonate for oral suspension 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 oral suspension 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 for Oral Suspension > 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 for Oral Suspension. Titrate the sevelamer carbonate for oral suspension 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 g 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 for Oral Suspension . Titrate the sevelamer carbonate for oral suspension 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 for oral suspension based on a patient's current calcium acetate dose.

Table

3: Starting Dose for Dialysis Patients Switching from Calcium Acetate to Sevelamer Carbonate for Oral Suspension Table 3: Starting Dose for Dialysis Patients Switching from Calcium Acetate to Sevelamer Carbonate for Oral Suspension Calcium Acetate 667 mg (Tablets per meal)

Sevelamer

Carbonate for Oral Suspension 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 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.

Sevelamer carbonate for oral suspension is contraindicated in patients with bowel obstruction. Sevelamer carbonate for oral suspension is 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 )

REACTIONS Most of the safety experience is with sevelamer tablets and sevelamer hydrochloride. In long-term studies with sevelamer hydrochloride, which contains the same active moiety as sevelamer carbonate, the most common adverse events included: vomiting (22%), nausea (20%), diarrhea (19%), dyspepsia (16%), abdominal pain (9%), flatulence (8%) and constipation (8%). (6.1) To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993; email [email protected]; 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 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. 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 &gt; 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 to 52 weeks, the most common reason for withdrawal from sevelamer hydrochloride was gastrointestinal adverse reactions (3% to 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 post-approval use of sevelamer hydrochloride or sevelamer carbonate: hypersensitivity, pruritus, rash, abdominal pain, 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. To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993; email [email protected]; or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

AND PRECAUTIONS

• Serious cases of dysphagia, bowel obstruction, bleeding gastrointestinal ulcers, colitis, ulceration, necrosis, and perforation have been associated with sevelamer use, some requiring hospitalization and surgery. ( 5.1 )

5.1 Gastrointestinal Adverse Events Patients with dysphagia, swallowing disorders, severe gastrointestinal (GI) motility disorders, including severe constipation, or major GI tract surgery were not included in the sevelamer hydrochloride clinical studies. Dysphagia and esophageal tablet retention have been reported in association with use of sevelamer tablets, some requiring hospitalization and intervention. Consider using sevelamer suspension in patients with a history of swallowing disorders. Cases of bowel obstruction, bleeding gastrointestinal ulcers, colitis, ulceration, necrosis, and perforation have also been reported with sevelamer use <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.2 )]</span> . Inflammatory disorders may resolve upon sevelamer hydrochloride discontinuation. Treatment with sevelamer hydrochloride should be re-evaluated in patients who develop severe gastrointestinal symptoms.

5.2 Monitor Serum Chemistries Bicarbonate and chloride levels should be monitored.

5.3 Monitor for Reduced Vitamins D, E, K (clotting factors) and Folic Acid Levels In preclinical studies in rats and dogs, sevelamer hydrochloride reduced vitamins D, E, and K (coagulation parameters) and folic acid levels at doses of 6 to 10 times the recommended human dose. In short-term clinical trials, there was no evidence of reduction in serum levels of vitamins. However, in a one-year clinical trial, 25-hydroxyvitamin D (normal range 10 to 55 ng/mL) fell from 39 ± 22 ng/mL to 34 ± 22 ng/mL (p less than 0.01) with sevelamer hydrochloride treatment. Most (approximately 75%) patients in sevelamer hydrochloride clinical trials received vitamin supplements, which is typical of patients on dialysis.

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.