Mycophenolic Acid 180 mg Tablet, Delayed Release, 120-count — NDC 59651-621-08 (Billing 59651-0621-08)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Mycophenolic acid (MPA), an immunosuppressant, is an uncompetitive and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), and therefore inhibits the de novo pathway of guanosine nucleotide synthesis without incorporation to DNA. T- and B-lymphocytes are critically dependent for their proliferation on de novo synthesis of purines, whereas other cell types can utilize salvage pathways. MPA has cytostatic effects on lymphocytes.

Mycophenolate sodium has been shown to prevent the occurrence of acute rejection in rat models of kidney and heart allotransplantation. Mycophenolate sodium also decreases antibody production in mice.

12.3Pharmacokinetics Mycophenolic acid delayed-release tablets exhibits linear and dose-proportional pharmacokinetics over the dose-range (360 mg to 2,160 mg) evaluated. The absolute bioavailability of mycophenolic acid delayed-release tablets in stable renal transplant patients on cyclosporine was 72%. MPA is highly protein bound (> 98% bound to albumin).

The predominant metabolite of MPA is the phenolic glucuronide (MPAG) which is pharmacologically inactive. A minor metabolite AcMPAG which is an acyl glucuronide of MPAG is also formed and has pharmacological activity comparable to MPA. MPAG undergoes renal elimination.

A fraction of MPAG also undergoes biliary excretion, followed by deconjugation by gut flora and subsequent reabsorption as MPA. The mean elimination half-lives of MPA and MPAG ranged between 8 and 16 hours, and 13 and 17 hours, respectively. Absorption In vitro studies demonstrated that the enteric-coated mycophenolic acid delayed-release tablet does not release MPA under acidic conditions (pH < 5) as in the stomach but is highly soluble in neutral pH conditions as in the intestine.

Following mycophenolic acid delayed-release tablets oral administration without food in several pharmacokinetic studies conducted in renal transplant patients, consistent with its enteric-coated formulation, the median delay (T lag ) in the rise of MPA concentration ranged between 0.25 and 1.25 hours and the median time to maximum concentration (T max ) of MPA ranged between 1.5 and 2.75 hours. In comparison, following the administration of MMF, the median T max ranged between 0.5 and 1.0 hours. In stable renal transplant patients on cyclosporine, USP MODIFIED based immunosuppression, gastrointestinal absorption and absolute bioavailability of MPA following the administration of mycophenolic acid delayed-release tablet was 93% and 72%, respectively.

Mycophenolic acid delayed-release tablets pharmacokinetics is dose proportional over the dose range of 360 mg to 2,160 mg. Distribution The mean (± SD) volume of distribution at steady state and elimination phase for MPA is 54 (± 25) L and 112 (± 48) L, respectively. MPA is highly protein bound to albumin, > 98%.

The protein binding of MPAG is 82%. The free MPA concentration may increase under conditions of decreased protein binding (uremia, hepatic failure, and hypoalbuminemia). Metabolism MPA is metabolized principally by glucuronyl transferase to glucuronidated metabolites.

The phenolic glucuronide of MPA, MPAG, is the predominant metabolite of MPA and does not manifest pharmacological activity. The acyl glucuronide is a minor metabolite and has comparable pharmacological activity to MPA. In stable renal transplant patients on cyclosporine, USP MODIFIED based immunosuppression, approximately 28% of the oral mycophenolic acid delayed-release tablet dose was converted to MPAG by presystemic metabolism.

The AUC ratio of MPA:MPAG:acyl glucuronide is approximately 1:24:0.28 at steady state. The mean clearance of MPA was 140 (± 30) mL/min. Elimination The majority of MPA dose administered is eliminated in the urine primarily as MPAG (> 60%) and approximately 3% as unchanged MPA following mycophenolic acid delayed-release tablets administration to stable renal transplant patients.

The mean renal clearanc… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Mycophenolic acid (MPA), an immunosuppressant, is an uncompetitive and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), and therefore inhibits the de novo pathway of guanosine nucleotide synthesis without incorporation to DNA. T- and B-lymphocytes are critically dependent for their proliferation on de novo synthesis of purines, whereas other cell types can utilize salvage pathways. MPA has cytostatic effects on lymphocytes.

Mycophenolate sodium has been shown to prevent the occurrence of acute rejection in rat models of kidney and heart allotransplantation. Mycophenolate sodium also decreases antibody production in mice.

12.3Pharmacokinetics Mycophenolic acid delayed-release tablets exhibits linear and dose-proportional pharmacokinetics over the dose-range (360 mg to 2,160 mg) evaluated. The absolute bioavailability of mycophenolic acid delayed-release tablets in stable renal transplant patients on cyclosporine was 72%. MPA is highly protein bound (> 98% bound to albumin).

The predominant metabolite of MPA is the phenolic glucuronide (MPAG) which is pharmacologically inactive. A minor metabolite AcMPAG which is an acyl glucuronide of MPAG is also formed and has pharmacological activity comparable to MPA. MPAG undergoes renal elimination.

A fraction of MPAG also undergoes biliary excretion, followed by deconjugation by gut flora and subsequent reabsorption as MPA. The mean elimination half-lives of MPA and MPAG ranged between 8 and 16 hours, and 13 and 17 hours, respectively. Absorption In vitro studies demonstrated that the enteric-coated mycophenolic acid delayed-release tablet does not release MPA under acidic conditions (pH < 5) as in the stomach but is highly soluble in neutral pH conditions as in the intestine.

Following mycophenolic acid delayed-release tablets oral administration without food in several pharmacokinetic studies conducted in renal transplant patients, consistent with its enteric-coated formulation, the median delay (T lag ) in the rise of MPA concentration ranged between 0.25 and 1.25 hours and the median time to maximum concentration (T max ) of MPA ranged between 1.5 and 2.75 hours. In comparison, following the administration of MMF, the median T max ranged between 0.5 and 1.0 hours. In stable renal transplant patients on cyclosporine, USP MODIFIED based immunosuppression, gastrointestinal absorption and absolute bioavailability of MPA following the administration of mycophenolic acid delayed-release tablet was 93% and 72%, respectively.

Mycophenolic acid delayed-release tablets pharmacokinetics is dose proportional over the dose range of 360 mg to 2,160 mg. Distribution The mean (± SD) volume of distribution at steady state and elimination phase for MPA is 54 (± 25) L and 112 (± 48) L, respectively. MPA is highly protein bound to albumin, > 98%.

The protein binding of MPAG is 82%. The free MPA concentration may increase under conditions of decreased protein binding (uremia, hepatic failure, and hypoalbuminemia). Metabolism MPA is metabolized principally by glucuronyl transferase to glucuronidated metabolites.

The phenolic glucuronide of MPA, MPAG, is the predominant metabolite of MPA and does not manifest pharmacological activity. The acyl glucuronide is a minor metabolite and has comparable pharmacological activity to MPA. In stable renal transplant patients on cyclosporine, USP MODIFIED based immunosuppression, approximately 28% of the oral mycophenolic acid delayed-release tablet dose was converted to MPAG by presystemic metabolism.

The AUC ratio of MPA:MPAG:acyl glucuronide is approximately 1:24:0.28 at steady state. The mean clearance of MPA was 140 (± 30) mL/min. Elimination The majority of MPA dose administered is eliminated in the urine primarily as MPAG (> 60%) and approximately 3% as unchanged MPA following mycophenolic acid delayed-release tablets administration to stable renal transplant patients.

The mean renal clearance of MPAG was 15.5 (± 5.9) mL/min. MPAG is also secreted in the bile and available for deconjugation by gut flora. MPA resulting from the deconjugation may then be reabsorbed and produce a second peak of MPA approximately 6 to 8 hours after mycophenolic acid delayed-release tablets dosing.

The mean elimination half-life of MPA and MPAG ranged between 8 and 16 hours, and 13 and 17 hours, respectively. Food Effect Compared to the fasting state, administration of mycophenolic acid delayed-release tablets 720 mg with a high-fat meal (55 g fat, 1000 calories) had no effect on the systemic exposure (AUC) of MPA. However, there was a 33% decrease in the maximal concentration (C max ), a 3.5-hour d… [Excerpted — this section continues on DailyMed.]

14 CLINICAL STUDIES

14.1Prophylaxis of Organ Rejection in Patients Receiving Allogeneic Renal Transplants The safety and efficacy of mycophenolic acid delayed-release tablets in combination with cyclosporine, USP MODIFIED and corticosteroids for the prevention of organ rejection was assessed in two multicenter, randomized, double-blind, active-controlled trials in de novo and conversion renal transplant patients compared to MMF. The de novo trial was conducted in 423 renal transplant patients (ages 18 to 75 years) in Austria, Canada, Germany, Hungary, Italy, Norway, Spain, UK, and USA.

Eighty-four percent of randomized patients received kidneys from deceased donors. Patients were excluded if they had second or multiorgan (e.g., kidney and pancreas) transplants, or previous transplant with any other organs; kidneys from non-heart beating donors; panel reactive antibodies (PRA) of > 50% at last assessment prior to transplantation, and presence of severe diarrhea, active peptic ulcer disease, or uncontrolled diabetes mellitus. Patients were administered either mycophenolic acid delayed-release tablets 1.44 grams per day or MMF 2 grams per day within 48 hours post-transplant for 12 months in combination with cyclosporine, USP MODIFIED and corticosteroids.

Forty-one percent of patients received antibody therapy as induction treatment. Treatment failure was defined as the first occurrence of biopsy-proven acute rejection, graft loss, death or lost to follow-up at 6 months. The incidence of treatment failure was similar in mycophenolic acid delayed-release tablets and MMF-treated patients at 6 and 12 months (Table 7).

The cumulative incidence of graft loss, death and lost to follow-up at 12 months is also shown in Table 7. Table 7: Treatment Failure in De novo Renal Transplant Patients (Percentage of Patients) at 6 and 12 Months of Treatment When Administered in Combination With Cyclosporine a and Corticosteroids Mycophenolic acid delayed-release tablets 1.44 grams per day (n = 213) Mycophenolate mofetil (MMF) 2 grams per day (n = 210) 6 Months n (%) n (%) Treatment failure b 55 (25.8) 55 (26.2) Biopsy-proven acute rejection 46 (21.6) 48 (22.9) Graft loss 7 (3.3) 9 (4.3) Death 1 (0.5) 2 (1.0) Lost to follow-up c 3 (1.4) 0 12 Months n (%) n (%) Graft loss or death or lost to follow-up d 20 (9.4) 18 (8.6) Treatment failure e 61 (28.6) 59 (28.1) Biopsy-proven acute rejection 48 (22.5) 51 (24.3) Graft loss 9 (4.2) 9 (4.3) Death 2 (0.9) 5 (2.4) Lost to follow-up c 5 (2.3) 0 a USP MODIFIED. b 95% confidence interval of the difference in treatment failure at 6 months (mycophenolic acid delayed-release tablets–MMF) is (-8.7%, 8.0%). c Lost to follow-up indicates patients who were lost to follow-up without prior biopsy-proven acute rejection, graft loss or death. d Lost to follow-up indicates patients who were lost to follow-up without prior graft loss or death (9 mycophenolic acid delayed-release tablets patients and 4 MMF patients). e 95% confidence interval of the difference in treatment failure at 12 months (mycophenolic acid delayed-release tablets–MMF) is (-8.0%, 9.1%).

The conversion trial was conducted in 322 renal transplant patients (ages 18 to 75 years), who were at least 6 months post-transplant and had undergone primary or secondary, deceased donor, living related, or unrelated donor kidney transplant, stable graft function (serum creatinine < 2.3 mg/mL), no change in immunosuppressive regimen due to graft malfunction, and no known clinically significant physical and/or laboratory changes for at least 2 months prior to enrollment. Patients were excluded if they had 3 or more kidney transplants, multiorgan transplants (e.g., kidney and pancreas), previous organ transplants, evidence of graft rejection or who had been treated for acute rejection within 2 months prior to screening, clinically significant infections requiring continued therapy, presence of severe diarrhea, active peptic ulcer disease, or uncontrolled diabetes mellit… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility In a 104-week oral carcinogenicity study in rats, mycophenolate sodium was not tumorigenic at daily doses up to 9 mg per kg, the highest dose tested. This dose resulted in approximately 0.6 to 1.2 times the systemic exposure (based on plasma AUC) observed in renal transplant patients at the recommended dose of 1,440 mg per day. Similar results were observed in a parallel study in rats performed with MMF.

In a 104-week oral carcinogenicity study in mice, MMF was not tumorigenic at a daily dose level as high as 180 mg per kg (which corresponds to 0.6 times the recommended mycophenolate sodium therapeutic dose, based on body surface area). The genotoxic potential of mycophenolate sodium was determined in five assays. Mycophenolate sodium was genotoxic in the mouse lymphoma/thymidine kinase assay, the micronucleus test in V79 Chinese hamster cells, and the in vivo mouse micronucleus assay.

Mycophenolate sodium was not genotoxic in the bacterial mutation assay ( Salmonella typhimurium TA 1535, 97a, 98, 100, and 102) or the chromosomal aberration assay in human lymphocytes. Mycophenolate mofetil generated similar genotoxic activity. The genotoxic activity of mycophenolic acid (MPA) is probably due to the depletion of the nucleotide pool required for DNA synthesis as a result of the pharmacodynamic mode of action of MPA (inhibition of nucleotide synthesis).

Mycophenolate sodium had no effect on male rat fertility at daily oral doses as high as 18 mg per kg and exhibited no testicular or spermatogenic effects at daily oral doses of 20 mg per kg for 13 weeks (approximately 2 times the systemic exposure of MPA at the recommended therapeutic dose). No effects on female fertility were seen up to a daily dose of 20 mg per kg (approximately 3 times the systemic exposure of MPA at the recommended therapeutic dose).