mycophenolic acid
Dosage Form: tablet, delayed release
Myfortic®
(mycophenolic acid*)
delayed-release tablets
*as mycophenolate sodium
Rx only
Prescribing Information
Immunosuppression may lead to increased susceptibility to infection and possible development of lymphoma and other neoplasms. Only physicians experienced in immunosuppressive therapy and management of organ transplant recipients should use Myfortic® (mycophenolic acid). Patients receiving Myfortic should be managed in facilities equipped and staffed with adequate laboratory and supportive medical resources. The physician responsible for maintenance therapy should have complete information requisite for the follow-up of the patient.
Female users of childbearing potential must use contraception. Use of Myfortic® during pregnancy is associated with increased risks of pregnancy loss and congenital malformations.
DESCRIPTION
Myfortic® (mycophenolic acid) delayed-release tablets are an enteric formulation of mycophenolate sodium that delivers the active moiety mycophenolic acid (MPA). Myfortic is an immunosuppressive agent. As the sodium salt, MPA is chemically designated as (E)-6-(4-hydroxy-6-methoxy-7-methyl-3-oxo-1,3-dihydroisobenzofuran-5-yl)-4-methylhex-4-enoic acid sodium salt.
Its empirical formula is C17H19O6Na. The molecular weight is 342.32 and the structural formula is
Myfortic, as the sodium salt, is a white to off-white, crystalline powder and is highly soluble in aqueous media at physiological pH and practically insoluble in 0.1 N hydrochloric acid.
Myfortic is available for oral use as delayed-release tablets containing either 180 mg or 360 mg of mycophenolic acid. Inactive ingredients include colloidal silicon dioxide, crospovidone, lactose anhydrous, magnesium stearate, povidone (K-30), and starch. The enteric coating of the tablet consists of hypromellose phthalate, titanium dioxide, iron oxide yellow, and indigotine (180 mg) or iron oxide red (360 mg).
CLINICAL PHARMACOLOGY
Mechanism of Action
MPA 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. Because 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 potent 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.
Pharmacokinetics
Absorption
In-vitro studies demonstrated that the enteric-coated Myfortic® (mycophenolic acid) 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 Myfortic oral administration without food in several pharmacokinetic studies conducted in renal transplant patients, consistent with its enteric-coated formulation, the median delay (Tlag) in the rise of MPA concentration ranged between 0.25 and 1.25 hours and the median time to maximum concentration (Tmax) of MPA ranged between 1.5 and 2.75 hours. In comparison, following the administration of mycophenolate mofetil, the median Tmax 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 Myfortic delayed-release tablet was 93% and 72%, respectively. Myfortic pharmacokinetics is dose proportional over the dose range of 360 to 2160 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 mycophenolic acid glucuronide (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, mycophenolic acid glucuronide (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 Myfortic 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 Myfortic 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 6–8 hours after Myfortic 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 Myfortic 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 (Cmax), a 3.5-hour delay in the Tlag (range, -6 to 18 hours), and 5.0-hour delay in the Tmax (range, -9 to 20 hours) of MPA. To avoid the variability in MPA absorption between doses, Myfortic should be taken on an empty stomach (see DOSAGE AND ADMINISTRATION and PRECAUTIONS, Information for Patients).
Pharmacokinetics in Renal Transplant Patients
The mean pharmacokinetic parameters for MPA following the administration of Myfortic in renal transplant patients on cyclosporine, USP (MODIFIED) based immunosuppression are shown in Table 1. Single-dose Myfortic pharmacokinetics predicts multiple-dose pharmacokinetics. However, in the early posttransplant period, mean MPA AUC and Cmax were approximately one-half of those measured 6 months posttransplant.
After near equimolar dosing of Myfortic 720 mg BID and mycophenolate mofetil 1000 mg BID (739 mg as MPA) in both the single- and multiple-dose cross-over trials, mean systemic MPA exposure (AUC) was similar.
| Study Patient | Myfortic® Dosing | n | Dose (mg) | Tmax* (hr) | Cmax (µg/mL) | AUC0-12hr (µg*hr/mL) |
| Adult | Single | 24 | 720 | 2 (0.8 – 8) | 26.1 ± 12.0 | 66.5 ± 22.6** |
| Pediatric*** | Single | 10 | 450 /m2 | 2.5 (1.5 – 24) | 36.3 ± 20.9 | 74.3 ± 22.5** |
| Adult | Multiple x 6 days, BID | 10 | 720 | 2 (1.5 – 3.0) | 37.0 ± 13.3 | 67.9 ± 20.3 |
| Adult | Multiple x 28 days, BID | 36 | 720 | 2.5 (1.5 – 8) | 31.2 ± 18.1 | 71.2 ± 26.3 |
| Adult | Chronic, multiple dose, BID | |||||
| 2 weeks posttransplant | 12 | 720 | 1.8 (1.0 – 5.3) | 15.0 ± 10.7 | 28.6 ± 11.5 | |
| 3 months posttransplant | 12 | 720 | 2 (0.5 – 2.5) | 26.2 ± 12.7 | 52.3 ± 17.4 | |
| 6 months posttransplant | 12 | 720 | 2 (0 – 3) | 24.1 ± 9.6 | 57.2 ± 15.3 | |
| Adult | Chronic, multiple dose, BID | 18 | 720 | 1.5 (0 – 6) | 18.9 ± 7.9 | 57.4 ± 15.0 |
| *median (range), ** AUC0-∞, *** age range of 5-16 years | ||||||
Special Populations
Renal Insufficiency: No specific pharmacokinetic studies in individuals with renal impairment were conducted with Myfortic. However, based on studies of renal impairment with mycophenolate mofetil, MPA exposure is not expected to be appreciably increased over the range of normal to severely impaired renal function following Myfortic administration. In contrast, MPAG exposure would be increased markedly with decreased renal function; MPAG exposure being approximately 8-fold higher in the setting of anuria. Although dialysis may be used to remove the inactive metabolite MPAG, it would not be expected to remove clinically significant amounts of the active moiety MPA. This is in large part due to the high plasma protein binding of MPA.
Hepatic Insufficiency: No specific pharmacokinetic studies in individuals with hepatic impairment were conducted with Myfortic. In a single dose (mycophenolate mofetil 1000 mg) study of 18 volunteers with alcoholic cirrhosis and 6 healthy volunteers, hepatic MPA glucuronidation processes appeared to be relatively unaffected by hepatic parenchymal disease when the pharmacokinetic parameters of healthy volunteers and alcoholic cirrhosis patients within this study were compared. However, it should be noted that for unexplained reasons, the healthy volunteers in this study had about a 50% lower AUC compared to healthy volunteers in other studies, thus making comparison between volunteers with alcoholic cirrhosis and health volunteers difficult. Effects of hepatic disease on this process probably depend on the particular disease. Hepatic disease, such as primary biliary cirrhosis, with other etiologies may show a different effect.
Pediatrics: Limited data are available on the use of Myfortic at a dose of 450 mg/m2 body surface area in children. The mean MPA pharmacokinetic parameters for stable pediatric renal transplant patients, 5–16 years, on cyclosporine, USP (MODIFIED) are shown in Table 1. At the same dose administered based on body surface area, the respective mean Cmax and AUC of MPA determined in children were higher by 33% and 18% than those determined for adults. The clinical impact of the increase in MPA exposure is not known.
Gender: There are no significant gender differences in Myfortic pharmacokinetics.
Elderly: Pharmacokinetics in the elderly have not been formally studied.
CLINICAL STUDIES
The safety and efficacy of Myfortic® (mycophenolic acid) in combination with cyclosporine, USP (MODIFIED) and corticosteroids for the prevention of organ rejection was assessed in two multicenter, randomized, double-blind trials in de novo and maintenance renal transplant patients compared to mycophenolate mofetil.
The de novo study was conducted in 423 renal transplant patients (ages 18-75 years) in Austria, Canada, Germany, Hungary, Italy, Norway, Spain, UK and USA. Cadaveric donor specimens accounted for 84% of randomized patients. Patients were administered either Myfortic 1.44 g/day or mycophenolate mofetil 2 g/day within 48 hours posttransplant 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 Myfortic- and mycophenolate mofetil-treated patients at 6 and 12 months (Table 2). The cumulative incidence of graft loss, death and lost to follow-up at 12 months is also given in Table 2.
| Myfortic® 1.44 g/day (n=213) | mycophenolate mofetil 2 g/day (n=210) | |
| 6 Months | n (%) | n (%) |
| Treatment failure# | 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** | 3 (1.4) | 0 |
| 12 Months | n (%) | n (%) |
| Graft loss or death or lost to follow-up*** | 20 (9.4) | 18 (8.6) |
| Treatment failure | 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** | 5 (2.3) | 0 |
| *USP (MODIFIED) **Lost to follow-up indicates patients who were lost to follow-up without prior biopsy-proven acute rejection, graft loss or death ***Lost to follow-up indicates patients who were lost to follow-up without prior graft loss or death (9 Myfortic patients and 4 mycophenolate mofetil patients) #95% confidence interval of the difference in treatment failure at 6 months (Myfortic – mycophenolate mofetil) is (-8.7%, 8.0%). | ||
The maintenance study was conducted in 322 renal transplant patients (ages 18–75 years), who were at least 6 months posttransplant receiving 2 g/day mycophenolate mofetil in combination with cyclosporine USP (MODIFIED), with or without corticosteroids for at least two weeks prior to entry in the study. Patients were randomized to Myfortic 1.44 g/day or mycophenolate mofetil 2 g/day for 12 months. The study was conducted in Austria, Belgium, Canada, Germany, Italy, Spain, and USA. Treatment failure was defined as the first occurrence of biopsy-proven acute rejection, graft loss, death, or lost to follow-up at 6 and 12 months. The incidences of treatment failure at 6 and 12 months were similar between Myfortic- and mycophenolate mofetil-treated patients (Table 3). The cumulative incidence of graft loss, death and lost to follow-up at 12 months is also given in Table 3.
| Myfortic® 1.44 g/day (n = 159) | mycophenolate mofetil 2 g/day (n = 163) | |
| 6 Months | n (%) | n (%) |
| Treatment failure# | 7 (4.4) | 11 (6.7) |
| Biopsy-proven acute rejection | 2 (1.3) | 2 (1.2) |
| Graft loss | 0 | 1 (0.6) |
| Death | 0 | 1 (0.6) |
| Lost to follow-up** | 5 (3.1) | 7 (4.3) |
| 12 Months | n (%) | n (%) |
| Graft loss or death or lost to follow-up*** | 10 (6.3) | 17 (10.4) |
| Treatment failure | 12 (7.5) | 20 (12.3) |
| Biopsy-proven acute rejection | 2 (1.3) | 5 (3.1) |
| Graft loss | 0 | 1 (0.6) |
| Death | 2 (1.3) | 4 (2.5) |
| Lost to follow-up** | 8 (5.0) | 10 (6.1) |
| *USP (MODIFIED) **Lost to follow-up indicates patients who were lost to follow-up without prior biopsy-proven acute rejection, graft loss, or death ***Lost to follow-up indicates patients who were lost to follow-up without prior graft loss or death (8 Myfortic patients and 12 mycophenolate mofetil patients) #95% confidence interval of the difference in treatment failure at 6 months (Myfortic – mycophenolate mofetil) is (-7.4%, 2.7%). | ||
The safety and efficacy of Myfortic has not been studied in hepatic or cardiac transplant trials.
INDICATIONS AND USAGE
Myfortic® (mycophenolic acid) delayed-release tablets are indicated for the prophylaxis of organ rejection in patients receiving allogeneic renal transplants, administered in combination with cyclosporine and corticosteroids.
CONTRAINDICATIONS
Myfortic® (mycophenolic acid) is contraindicated in patients with a hypersensitivity to mycophenolate sodium, mycophenolic acid, mycophenolate mofetil, or to any of its excipients.
WARNINGS (SEE BOXED WARNING)
Lymphoma and Other Malignancies
Patients receiving immunosuppressive regimens involving combinations of drugs, including Myfortic® (mycophenolic acid), as part of an immunosuppressive regimen are at increased risk of developing lymphomas and other malignancies, particularly of the skin (see ADVERSE REACTIONS). The risk appears to be related to the intensity and duration of immunosuppression rather than to the use of any specific agent.
The rates for lymphoproliferative disease or lymphoma in Myfortic-treated patients were comparable to the mycophenolate mofetil group in the de novo and maintenance studies (see ADVERSE REACTIONS). As usual for patients with increased risk for skin cancer, exposure to sunlight and UV light should be limited by wearing protective clothing and using a sunscreen with a high protection factor.
Infections
Oversuppression of the immune system can also increase susceptibility to infection, including opportunistic infections, fatal infections, and sepsis. Fatal infections can occur in patients receiving immunosuppressive therapy (see ADVERSE REACTIONS).
Polyomavirus Infections
Patients receiving immunosuppressants, including Myfortic are at increased risk for opportunistic infections, including Polyomavirus infections. Polyomavirus infections in transplant patients may have serious, and sometimes, fatal outcomes. These include cases of JC virus associated progressive multifocal leukoencephalopathy (PML) and Polyomavirus associated nephropathy (PVAN) especially due to BK virus infection which have been observed in patients receiving Myfortic.
PVAN, especially due to BK virus infection, is associated with serious outcomes, including deteriorating renal function and renal graft loss (see ADVERSE REACTIONS). Patient monitoring may help detect patients at risk for PVAN.
Cases of PML, have been reported in patients treated with MPA derivatives which include mycophenolate mofetil (MMF) and mycophenolate sodium (see ADVERSE REACTIONS). PML, which is sometimes fatal, commonly presents with hemiparesis, apathy, confusion, cognitive deficiencies and ataxia. Risk factors for PML include treatment with immunosuppressant therapies and impairment of immune function. In immunosuppressed patients, physicians should consider PML in the differential diagnosis in patients reporting neurological symptoms and consultation with a neurologist should be considered as clinically indicated.
Reduction in immunosuppression should be considered for patients who develop evidence of PML or PVAN. Physicians should also consider the risk that reduced immunosuppression represents to the functioning allograft.
Blood Dyscrasias Including Pure Red Cell Aplasia
Cases of pure red cell aplasia (PRCA) have been reported in patients treated with mycophenolic acid (MPA) derivatives in combination with other immunosuppressive agents. The mechanism for MPA derivatives induced PRCA is unknown; the relative contribution of other immunosuppressants and their combinations in an immunosuppressive regimen is also unknown. In some cases PRCA was found to be reversible with dose reduction or cessation of therapy with MPA derivatives. In transplant patients, however, reduced immunosuppression may place the graft at risk. Changes to Myfortic therapy should only be undertaken under appropriate supervision in transplant recipients in order to minimize the risk of graft rejection (see ADVERSE REACTIONS, Postmarketing Experience).
Patients receiving Myfortic should be monitored for blood dyscrasias (e.g. neutropenia or anemia (see PRECAUTIONS, Laboratory Tests). The development of neutropenia may be related to Myfortic itself, concomitant medications, viral infections, or some combination of these events. If blood dyscrasias occur (e.g. neutropenia (ANC <1.3x103/ µL or anemia)), dosing with Myfortic should be interrupted or the dose reduced, appropriate diagnostic tests performed, and the patient managed appropriately (see DOSAGE AND ADMINISTRATION).
Patients receiving Myfortic should be instructed to immediately report any evidence of infection, unexpected bruising, bleeding, or any other manifestation of bone marrow suppression.
Concomitant Use
Myfortic has been administered in combination with the following agents in clinical trials: antithymocyte/lymphocyte immunoglobulin, muromonab-CD3, basiliximab, daclizumab, cyclosporine, and corticosteroids. The efficacy and safety of Myfortic in combination with other immunosuppression agents have not been determined.
Pregnancy: Teratogenic Effects: Pregnancy Category D
Mycophenolate mofetil (MMF) can cause fetal harm when administered to a pregnant woman. Following oral or IV administration, MMF is metabolized to mycophenolic acid (MPA), the active ingredient in Myfortic and the active form of the drug. Use of Myfortic during pregnancy is associated with an increased risk of first trimester pregnancy loss and an increased risk of congenital malformations, especially external ear and other facial abnormalities including cleft lip and palate, and anomalies of the distal limbs, heart, esophagus, and kidney. In the National Transplantation Pregnancy Registry (NTPR), there were data on 33 MMF-exposed pregnancies in 24 transplant patients; there were 15 spontaneous abortions (45%) and 18 live-born infants. Four of these 18 infants had structural malformations (22%). In postmarketing data (collected from 1995 to 2007) on 77 women exposed to systemic MMF during pregnancy, 25 had spontaneous abortions and 14 had a malformed infant or fetus. Six of 14 malformed offspring had ear abnormalities. Because these postmarketing data are reported voluntarily, it is not always possible to reliably estimate the frequency of particular adverse outcomes. These malformations are similar to findings in animal reproductive toxicology studies. For comparison, the background rate for congenital anomalies in the United States is about 3%, and NTPR data show a rate of 4-5% among babies born to organ transplant patients using other immunosuppressive drugs.
In a teratology study performed with mycophenolate sodium in rats, at a dose as low as 1 mg/kg, malformations in the offspring were observed, including anophthalmia, exencephaly and umbilical hernia. The systemic exposure at this dose represents 0.05 times the clinical exposure at the dose of 1.44 g/day Myfortic. In teratology studies in rabbits, fetal resorptions and malformations occurred from 80 mg/kg/day, in the absence of maternal toxicity (dose levels are equivalent to about 0.8 times the recommended clinical dose, corrected for BSA). There are no relevant qualitative or quantitative differences in the teratogenic potential of mycophenolate sodium and mycophenolate mofetil.
If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus. In certain situations, the patient and her healthcare practitioner may decide that the maternal benefits outweigh the risks to the fetus. Women using Myfortic at any time during pregnancy should be encouraged to enroll in the National Transplantation Pregnancy Registry.
Pregnancy Exposure Prevention
Women of childbearing potential should have a negative serum or urine pregnancy test with a sensitivity of at least 25 mIU/mL within 1 week prior to beginning therapy. Myfortic therapy should not be initiated until a negative pregnancy test report is obtained.
Women of childbearing potential (including pubertal girls and perimenopausal women) taking Myfortic must receive contraceptive counseling and use effective contraception. The patient should begin using her two chosen methods of contraception 4 weeks prior to starting Myfortic therapy, unless abstinence is the chosen method. She should continue contraceptive use during therapy and for 6 weeks after stopping Myfortic. Patients should be aware that Myfortic reduces blood levels of the hormones in the oral contraceptive pill and could theoretically reduce its effectiveness (see PRECAUTIONS, Information for Patients and PRECAUTIONS, Drug Interactions, Oral Contraceptives).
PRECAUTIONS
General
Gastrointestinal bleeding (requiring hospitalization) has been reported in de novo renal transplant patients (1.0%) and maintenance patients (1.3%) treated with Myfortic® (mycophenolic acid) (up to 12 months). Intestinal perforations, gastrointestinal hemorrhage, gastric ulcers and duodenal ulcers have rarely been observed. Most patients receiving Myfortic were also receiving other drugs known to be associated with these complications. Patients with active peptic ulcer disease were excluded from enrollment in studies with Myfortic. Because MPA derivatives have been associated with an increased incidence of digestive system adverse events, including infrequent cases of gastrointestinal tract ulceration, hemorrhage, and perforation, Myfortic should be administered with caution in patients with active serious digestive system disease (see ADVERSE REACTIONS).
Subjects with severe chronic renal impairment (GFR <25 mL/min/1.73 m2) may present higher plasma MPA and MPAG AUCs relative to subjects with lesser degrees of renal impairment or normal healthy volunteers. No data are available on the safety of long-term exposure to these levels of MPAG.
In the de novo study, 18.3% of Myfortic patients versus 16.7% in the mycophenolate mofetil group experienced delayed graft function (DGF). Although patients with DGF experienced a higher incidence of certain adverse events (anemia, leukopenia, and hyperkalemia) than patients without DGF, these events in DGF patients were not more frequent in patients receiving Myfortic compared to mycophenolate mofetil. No dose adjustment is recommended for these patients; however, such patients should be carefully observed (see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION).
In view of the significant reduction in the AUC of MPA by cholestyramine when administered with mycophenolate mofetil, caution should be used in the concomitant administration of Myfortic with drugs that interfere with enterohepatic recirculation because of the potential to reduce the efficacy (see PRECAUTIONS, Drug Interactions).
On theoretical grounds, because Myfortic is an IMPDH Inhibitor, it should be avoided in patients with rare hereditary deficiency of hypoxanthine-guanine phosphoribosyl-transferase (HGPRT) such as Lesch-Nyhan and Kelley-Seegmiller syndrome.
During treatment with Myfortic, the use of live attenuated vaccines should be avoided and patients should be advised that vaccinations may be less effective (see PRECAUTIONS, Drug Interactions, Live Vaccines).
Information for Patients
- It is recommended that Myfortic be administered on an empty stomach, one hour before or two hours after food intake (see DOSAGE AND ADMINISTRATION).
- In order to maintain the integrity of the enteric coating of the tablet, patients should be instructed not to crush, chew, or cut Myfortic tablets and to swallow the tablets whole.
- Give patients complete dosage instructions and inform them about the increased risk of lymphoproliferative disease and certain other malignancies.
- Inform patients that they need repeated appropriate laboratory tests while they are taking Myfortic.
- Inform women of childbearing potential that use of Myfortic in pregnancy is associated with an increased risk of first trimester pregnancy loss and an increased risk of birth defects, and that they must use effective contraception.
- Discuss pregnancy plans with female patients of childbearing potential.
- Any female of childbearing potential must use highly effective (two methods) contraception 4 weeks prior to starting Myfortic therapy and continue contraception until 6 weeks after stopping Myfortic treatment, unless abstinence is the chosen method (see WARNINGS, Pregnancy).
- A patient who is planning a pregnancy should not use Myfortic unless she can not be successfully treated with other immunosuppressant drugs. Risks and benefits of Myfortic and alternative immunosuppressants should be discussed with the patient.
Laboratory Tests
Complete blood count should be performed weekly during the first month, twice monthly for the second and the third month of treatment, then monthly through the first year. If neutropenia develops (ANC <1.3×103/µL), dosing with Myfortic should be interrupted or the dose reduced, appropriate tests performed, and the patient managed accordingly (see WARNINGS).
Drug Interactions
The following drug interaction studies have been conducted with Myfortic:
Gastroprotective agents
Antacids with magnesium and aluminum hydroxides:
Absorption of a single dose of Myfortic was decreased when administered to 12 stable renal transplant patients also taking magnesium-aluminum-containing antacids (30 mL): the mean Cmax and AUC(0-t) values for MPA were 25% and 37% lower, respectively, than when Myfortic was administered alone under fasting conditions. It is recommended that Myfortic and antacids not be administered simultaneously.
Proton Pump inhibitors:
In a study conducted in 12 healthy volunteers, the pharmacokinetics of MPA were observed to be similar when a single dose of 720 mg Myfortic was administered alone and following concomitant administration of Myfortic and pantoprazole, which was administered at a dose of 40 mg BID for 4 days.
Cyclosporine: When studied in stable renal transplant patients, cyclosporine, USP (MODIFIED) pharmacokinetics were unaffected by steady-state dosing of Myfortic.
The following recommendations are derived from drug interaction studies conducted following the administration of mycophenolate mofetil:
Acyclovir/Ganciclovir: May be taken with Myfortic; however, during the period of treatment, physicians should monitor blood cell counts. Both acyclovir/ganciclovir and MPAG concentrations are increased in the presence of renal impairment, their coexistence may compete for tubular secretion and further increase in the concentrations of the two.
Azathioprine/Mycophenolate Mofetil: Given that azathioprine and mycophenolate mofetil inhibit purine metabolism, it is recommended that Myfortic not be administered concomitantly with azathioprine or mycophenolate mofetil.
Cholestyramine and Drugs that Bind Bile Acids: These drugs interrupt enterohepatic recirculation and reduce MPA exposure when coadministered with mycophenolate mofetil. Therefore, do not administer Myfortic with cholestyramine or other agents that may interfere with enterohepatic recirculation or drugs that may bind bile acids, for example bile acid sequestrates or oral activated charcoal, because of the potential to reduce the efficacy of Myfortic.
Oral Contraceptives: Given the different metabolism of Myfortic and oral contraceptives, no drug interaction between these two classes of drug is expected. However, in a drug-drug interaction study, mean levonorgesterol AUC was decreased by 15% when coadministered with mycophenolate mofetil. Therefore, it is recommended that oral contraceptives are coadministered with Myfortic with caution and additional birth control methods be considered (see PRECAUTIONS, Pregnancy).
Live Vaccines: During treatment with Myfortic, the use of live attenuated vaccines should be avoided and patients should be advised that vaccinations may be less effective. Influenza vaccination may be of value. Prescribers should refer to national guidelines for influenza vaccination (see PRECAUTIONS, General).
Drugs that alter the gastrointestinal flora may interact with Myfortic by disrupting enterohepatic recirculation. Interference of MPAG hydrolysis may lead to less MPA available for absorption.
Carcinogenesis, 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/kg, the highest dose tested. This dose resulted in approximately 0.6-1.2 times the systemic exposure (based upon plasma AUC) observed in renal transplant patients at the recommended dose of 1.44 g/day. Similar results were observed in a parallel study in rats performed with mycophenolate mofetil. In a 104-week oral carcinogenicity study in mice, mycophenolate mofetil was not tumorigenic at a daily dose level as high as 180 mg/kg (which corresponds to 0.6 times the proposed mycophenolate sodium therapeutic dose based upon 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, & 102) or the chromosomal aberration assay in human lymphocytes. Mycophenolate mofetil generated similar genotoxic activity. The genotoxic activity of 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/kg and exhibited no testicular or spermatogenic effects at daily oral doses of 20 mg/kg for 13 weeks (approximately two-fold the therapeutic systemic exposure of MPA). No effects on female fertility were seen up to a daily dose of 20 mg/kg, which was approximately three-fold higher than the recommended therapeutic dose based upon systemic exposure.
Pregnancy
Teratogenic Effects: Pregnancy Category D. (See WARNINGS.)
Nursing Mothers
It is not known whether MPA is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from MPA, a decision should be made whether to discontinue the drug or to discontinue nursing while on treatment or within 6 weeks after stopping therapy, taking into account the importance of the drug to the mother.
Pediatric Use
De novo Renal Transplant
The safety and effectiveness of Myfortic in de novo pediatric renal transplant patients have not been established.
Stable Renal Transplant
There are no pharmacokinetic data available for pediatric patients <5 years. The safety and effectiveness of Myfortic have been established in the age group 5-16 years in stable pediatric renal transplant patients. Use of Myfortic in this age group is supported by evidence from adequate and well-controlled studies of Myfortic in stable adult renal transplant patients. Limited pharmacokinetic data are available for stable pediatric renal transplant patients in the age group 5-16 years. Pediatric doses for patients with BSA <1.19 m2 cannot be accurately administered using currently available formulations of Myfortic tablets (see CLINICAL PHARMACOLOGY, Special Populations and DOSAGE AND ADMINISTRATION).
Geriatric Use
Patients ≥65 years may generally be at increased risk of adverse drug reactions due to immunosuppression. Clinical studies of Myfortic 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, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
ADVERSE REACTIONS
The incidence of adverse events for Myfortic® (mycophenolic acid) was determined in randomized, comparative, active-controlled, double-blind, double-dummy trials in prevention of acute rejection in de novo and maintenance kidney transplant patients.
The principal adverse reactions associated with the administration of Myfortic include constipation, nausea, and urinary tract infection in de novo patients and nausea, diarrhea and nasopharyngitis in maintenance patients.
Adverse events reported in ≥20% of patients receiving Myfortic or mycophenolate mofetil in the 12-month de novo renal study and maintenance renal study, when used in combination with cyclosporine, USP (MODIFIED) and corticosteroids, are listed in Table 4. Adverse event rates were similar between Myfortic and mycophenolate mofetil in both de novo and maintenance patients.
| de novo Renal Study | Maintenance Renal Study | |||
| Myfortic® 1.44 g/day (n=213) | mycophenolate mofetil 2 g/day (n=210) | Myfortic® 1.44 g/day (n=159) | mycophenolate mofetil 2 g/day (n=163) | |
| Blood and Lymphatic System Disorders | ||||
| Anemia | 21.6 | 21.9 | – | – |
| Leukopenia | 19.2 | 20.5 | – | – |
| Gastrointestinal System Disorders | ||||
| Constipation | 38.0 | 39.5 | – | – |
| Nausea | 29.1 | 27.1 | 24.5 | 19.0 |
| Diarrhea | 23.5 | 24.8 | 21.4 | 24.5 |
| Vomiting | 23.0 | 20.0 | – | – |
| Dyspepsia | 22.5 | 19.0 | – | – |
| Infections and Infestations | ||||
| Urinary Tract Infection | 29.1 | 33.3 | – | – |
| CMV Infection | 20.2 | 18.1 | – | – |
| Nervous System Disorder | ||||
| Insomnia | 23.5 | 23.8 | – | – |
| Surgical and Medical Procedure | ||||
| Postoperative Pain | 23.9 | 18.6 | – | – |
Table 5 summarizes the incidence of opportunistic infections in de novo and maintenance transplant patients, which were similar in both treatment groups.
| de novo Renal Study | Maintenance Renal Study | |||
| Myfortic® 1.44 g/day (n = 213) | mycophenolate mofetil 2 g/day (n = 210) | Myfortic® 1.44 g/day (n = 159) | mycophenolate mofetil 2 g/day (n = 163) | |
| (%) | (%) | (%) | (%) | |
| Any Cytomegalovirus | ||||
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