Sirolimus

12.1 Mechanism of Action Sirolimus inhibits T-lymphocyte activation and proliferation that occurs in response to antigenic and cytokine (Interleukin [IL]-2, IL-4, and IL-15) stimulation by a mechanism that is distinct from that of other immunosuppressants. Sirolimus also inhibits antibody production. In cells, sirolimus binds to the immunophilin, FK Binding Protein-12 (FKBP-12), to generate an immunosuppressive complex. The sirolimus:FKBP-12 complex has no effect on calcineurin activity. This complex binds to and inhibits the activation of the mammalian target of rapamycin (mTOR), a key regulatory kinase. This inhibition suppresses cytokine-driven T-cell proliferation, inhibiting the progression from the G 1 to the S phase of the cell cycle. Mammalian target of rapamycin (mTOR) inhibitors such as sirolimus have been shown in vitro to inhibit production of certain growth factors that may affect angiogenesis, fibroblast proliferation, and vascular permeability. Studies in experimental models show that sirolimus prolongs allograft (kidney, heart, skin, islet, small bowel, pancreatico-duodenal, and bone marrow) survival in mice, rats, pigs, and/or primates. Sirolimus reverses acute rejection of heart and kidney allografts in rats and prolongs the graft survival in presensitized rats. In some studies, the immunosuppressive effect of sirolimus lasts up to 6 months after discontinuation of therapy. This tolerization effect is alloantigen-specific. In rodent models of autoimmune disease, sirolimus suppresses immune-mediated events associated with systemic lupus erythematosus, collagen-induced arthritis, autoimmune type I diabetes, autoimmune myocarditis, experimental allergic encephalomyelitis, graft-versus-host disease, and autoimmune uveoretinitis. Lymphangioleiomyomatosis involves lung tissue infiltration with smooth muscle-like cells that harbor inactivating mutations of the tuberous sclerosis complex (TSC) gene (LAM cells). Loss of TSC gene function activates the mTOR

1 INDICATIONS AND USAGE Sirolimus is an mTOR inhibitor immunosuppressant indicated for the prophylaxis of organ rejection in patients aged ≥13 years receiving renal transplants: Patients at low- to moderate-immunologic risk: Use initially with cyclosporine (CsA) and corticosteroids. CsA withdrawal is recommended 2 months to 4 months after transplantation ( 1.1 ). Patients at high-immunologic risk: Use in combination with CsA and corticosteroids for the first 12 months following transplantation (1.1). Safety and efficacy of CsA withdrawal has not been established in high risk patients ( 1.1 , 1.2 , 14.3 ). Sirolimus is an mTOR inhibitor indicated for the treatment of patients with lymphangioleiomyomatosis ( 1.3 ). 1.1 Prophylaxis of Organ Rejection in Renal Transplantation Sirolimus tablets are indicated for the prophylaxis of organ rejection in patients aged 13 years or older receiving renal transplants. In patients at low- to moderate-immunologic risk, it is recommended that sirolimus tablets be used initially in a regimen with cyclosporine and corticosteroids; cyclosporine should be withdrawn 2 to 4 months after transplantation [ see Dosage and Administration ( 2.2 ) ]. In patients at high-immunologic risk (defined as Black recipients and/or repeat renal transplant recipients who lost a previous allograft for immunologic reason and/or patients with high panel-reactive antibodies [PRA; peak PRA level > 80%]), it is recommended that sirolimus tablets be used in combination with cyclosporine and corticosteroids for the first year following transplantation [ see Dosage and Administration ( 2.3 ), Clinical Studies ( 14.3 ) ]. 1.2 Limitations of Use in Renal Transplantation Cyclosporine withdrawal has not been studied in patients with Banff Grade 3 acute rejection or vascular rejection prior to cyclosporine withdrawal, those who are dialysis-dependent, those with serum creatinine > 4.5 mg/dL, Black patients, patients of multi-organ transplants, secondary transplants, or

2 DOSAGE AND ADMINISTRATION Sirolimus tablets are to be administered orally once daily, consistently with or without food [ see Dosage and Administration ( 2.5 ), Clinical Pharmacology ( 12.3 ) ]. Tablets should not be crushed, chewed or split. Patients unable to take the tablets should be prescribed the solution and instructed in its use. Renal Transplant Patients : Administer once daily by mouth, consistently with or without food ( 2 ). Administer the initial dose as soon as possible after transplantation and 4 hours after CsA ( 2.1 , 7.1 ). Adjust the sirolimus maintenance dose to achieve sirolimus trough concentrations within the target-range ( 2.5 ). Hepatic impairment: Reduce maintenance dose in patients with hepatic impairment ( 2.7 , 8.6 , 12.3 ). In renal transplant patients at low-to moderate-immunologic risk : Sirolimus and CsA Combination Therapy: One loading dose of 6 mg on day 1, followed by daily maintenance doses of 2 mg ( 2.2 ). Sirolimus Following CsA Withdrawal: 2 months to 4 months post-transplantation, withdraw CsA over 4 weeks to 8 weeks ( 2.2 ). In renal transplant patients at high-immunologic risk: Sirolimus and CsA Combination Therapy (for the first 12 months posttransplantation): One loading dose of up to 15 mg on day 1, followed by daily maintenance doses of 5 mg ( 2.3 ). Lymphangioleiomyomatosis Patients: Administer once daily by mouth, consistently with or without food ( 2 ). Recommended initial sirolimus dose is 2 mg/day ( 2.4 ). Adjust the sirolimus dose to achieve sirolimus trough concentrations between 5 to 15 ng/mL ( 2.4 ). Hepatic impairment: Reduce maintenance dose in patients with hepatic impairment ( 2.7 , 8.6 , 12.3 ). Therapeutic drug monitoring is recommended for all patients ( 2.5 , 5.17 ). 2.1 General Dosing Guidance for Renal Transplant Patients The initial dose of sirolimus tablets should be administered as soon as possible after transplantation. It is recommended that sirolimus tablets be taken 4 hours after administration of cyclosporine oral solution (MODIFIED) and or/cyclosporine capsules (MODIFIED) [ see Drug Interactions ( 7.2 ) ]. Frequent sirolimus tablets dose adjustments based on non-steady-state sirolimus concentrations can lead to overdosing or underdosing because sirolimus has a long half-life. Once sirolimus tablets maintenance dose is adjusted, patients should continue on the new maintenance dose for at least 7 to 14 days before further dosage adjustment with concentration monitoring. In most patients, dose adjustments can be based on simple proportion: new sirolimus tablets dose = current dose x (target concentration/current concentration). A loading dose should be considered in addition to a new maintenance dose when it is necessary to increase sirolimus trough concentrations: sirolimus loading dose = 3 x (new maintenance dose - current maintenance dose). The maximum sirolimus tablets dose administered on any day should not exceed 40 mg. If an estimated daily dose exceeds 40 mg due to the addition of a loading dose, the loading dose should be administered over 2 days. Sirolimus trough concentrations should be monitored at least 3 to 4 days after a loading dose(s). Two milligrams (2 mg) of Sirolimus Oral Solution have been demonstrated to be clinically equivalent to 2 mg Sirolimus Tablets; hence, at this dose these two formulations are interchangeable. However, it is not known if higher doses of Sirolimus Oral Solution are clinically equivalent to higher doses of Sirolimus Tablets on a mg-to-mg basis [ see Clinical Pharmacology ( 12.3 ) ]. 2.2 Renal Transplant Patients at Low- to Moderate-Immunologic Risk Sirolimus and Cyclosporine Combination Therapy For de novo renal transplant patients, it is recommended that sirolimus tablets be used initially in a regimen with cyclosporine and corticosteroids. A loading dose of sirolimus equivalent to 3 times the maintenance dose should be given, i.e. a daily maintenance dose of 2 mg should be preceded with a loading dose of 6 mg. Therapeutic drug monitoring should be used to maintain sirolimus drug concentrations within the target-range [ see Dosage and Administration ( 2.5 ) ]. Sirolimus Following Cyclosporine Withdrawal At 2 to 4 months following transplantation, cyclosporine should be progressively discontinued over 4 to 8 weeks, and the sirolimus dose should be adjusted to obtain sirolimus whole blood trough concentrations within the target-range [ see Dosage and Administration ( 2.5 ) ]. Because cyclosporine inhibits the metabolism and transport of sirolimus, sirolimus concentrations may decrease when cyclosporine is discontinued, unless the sirolimus dose is increased [ see Clinical Pharmacology ( 12.3 ) ]. 2.3 Renal Transplant Patients at High-Immunologic Risk In patients with high-immunologic risk, it is recommended that sirolimus be used in combination with cyclosporine and corticosteroids for the first 12 months following transplantation [ see Clinical Studies ( 14.3 ) ]. The safety and efficacy of

6 ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the label. Increased susceptibility to infection, lymphoma, and malignancy [ see Boxed Warning, Warnings and Precautions ( 5.1 ) ] Excess mortality, graft loss, and hepatic artery thrombosis in liver transplant patients [ see Boxed Warning, Warnings and Precautions ( 5.2 ) ] Bronchial anastomotic dehiscence in lung transplant patients [ see Boxed Warning, Warnings and Precautions ( 5.3 ) ] Hypersensitivity reactions [ see Warnings and Precautions ( 5.4 ) ] Exfoliative dermatitis [ see Warnings and Precautions ( 5.4 ) ] Angioedema [ see Warnings and Precautions ( 5.5 ) ] Fluid accumulation and impairment of wound healing [ see Warnings and Precautions ( 5.6 ) ] Hypertriglyceridemia, hypercholesterolemia [ see Warnings and Precautions ( 5.7 ) ] Decline in renal function in long-term combination of cyclosporine with sirolimus [ see Warnings and Precautions ( 5.8 ) ] Proteinuria [ see Warnings and Precautions ( 5.9 ) ] Interstitial lung disease [ see Warnings and Precautions ( 5.11 ) ] Increased risk of calcineurin inhibitor-induced HUS/TTP/TMA [ see Warnings and Precautions ( 5.13 ) ] Embryo-fetal toxicity [see Warnings and Precautions ( 5.15 )] Male infertility [see Warnings and Precautions ( 5.16 )] The most common (≥ 30%) adverse reactions observed with sirolimus in clinical studies for organ rejection prophylaxis in recipients of renal transplantation are: peripheral edema, hypertriglyceridemia, hypertension, hypercholesterolemia, creatinine increased, constipation, abdominal pain, diarrhea, headache, fever, urinary tract infection, anemia, nausea, arthralgia, pain, and thrombocytopenia. The most common (≥20%) adverse reactions observed with sirolimus in the clinical study for the treatment of LAM are: stomatitis, diarrhea, abdominal pain, nausea, nasopharyngitis, acne, chest pain, peripheral edema, upper respiratory tract infection, headache, dizziness, myalgia, and hypercholesterolemia. The following adverse reactions resulted in a rate of discontinuation of > 5% in clinical trials for renal transplant rejection prophylaxis: creatinine increased, hypertriglyceridemia, and TTP. In patients with LAM, 11% of subjects discontinued due to adverse reactions, with no single adverse reaction leading to discontinuation in more than one patient being treated with sirolimus. Prophylaxis of organ rejection in patients receiving renal transplants: Most common adverse reactions (incidence ≥ 30%) are peripheral edema, hypertriglyceridemia, hypertension, hypercholesterolemia, creatinine increased, abdominal pain, diarrhea, headache, fever, urinary tract infection, anemia, nausea, arthralgia, pain, and thrombocytopenia ( 6 ). Lymphangioleiomyomatosis: Most common adverse reactions (incidence ≥20%) are stomatitis, diarrhea, abdominal pain, nausea, nasopharyngitis, acne, chest pain, peripheral edema, upper respiratory tract infection, headache, dizziness, myalgia, and hypercholesterolemia ( 6.6 ). To report SUSPECTED ADVERSE REACTIONS, contact Zydus Pharmaceuticals (USA) Inc. at 1-877-993-8779, or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Studies Experience in Prophylaxis of Organ Rejection Following Renal Transplantation The safety and efficacy of sirolimus oral solution for the prevention of organ rejection following renal transplantation were assessed in two randomized, double blind, multicenter, controlled trials [ see Clinical Studies ( 14.1 ) ]. The safety profiles in the two studies were similar. The incidence of adverse reactions in the randomized, double blind, multicenter, placebo-controlled trial (Study 2) in which 219 renal transplant patients received sirolimus oral solution 2 mg/day, 208 received sirolimus oral solution 5 mg/day, and 124 received placebo is presented in Table 1 below. The study population had a mean age of 46 years (range 15 to 71 years), the distribution was 67% male, and the composition by race was: White (78%), Black (11%), Asian (3%), Hispanic (2%), and Other (5%). All patients were treated with cyclosporine and corticosteroids. Data (≥ 12 months post-transplant) presented in the following table show the adverse reactions that occurred in at least one of the sirolimus treatment groups with an incidence of ≥ 20%. The safety profile of the tablet did not differ from that of the oral solution formulation [ see Clinical Studies ( 14.1 ) ]. In general, adverse reactions related to the administration of sirolimus were dependent on dose/concentration. Although a daily maintenance dose of 5 mg, with a loading dose of 15 mg, was shown to be safe and effective, no efficacy advantage over the 2 mg dose could be established for renal transplant patients. Patients receiving 2 mg of sirolimus oral solution per day demonstrated an overall better safety profile than did patients receiving 5 mg of sirolimus oral solution per day. Because clinical trials are conducted under widely vary

7 DRUG INTERACTIONS Sirolimus is known to be a substrate for both cytochrome P-450 3A4 (CYP3A4) and p-glycoprotein (P-gp). Inducers of CYP3A4 and P-gp may decrease sirolimus concentrations whereas inhibitors of CYP3A4 and P-gp may increase sirolimus concentrations. Avoid concomitant use with strong CYP3A4/P-gp inducers or strong CYP3A4/P-gp inhibitors that decrease or increase sirolimus concentrations ( 7.4 , 12.3 ). Therapeutic drug monitoring and dose reduction for sirolimus should be considered when sirolimus is co-administered with cannabidiol ( 5.21 , 7.5 ). See full prescribing information for complete list of clinically significant drug interactions ( 12.3 ). 7.1 Use with Cyclosporine Cyclosporine, a substrate and inhibitor of CYP3A4 and P-gp, was demonstrated to increase sirolimus concentrations when coadministered with sirolimus. In order to diminish the effect of this interaction with cyclosporine, it is recommended that sirolimus be taken 4 hours after administration of cyclosporine oral solution (MODIFIED) and/or cyclosporine capsules (MODIFIED). If cyclosporine is withdrawn from combination therapy with sirolimus, higher doses of sirolimus are needed to maintain the recommended sirolimus trough concentration ranges [ see Dosage and Administration ( 2.2 ), Clinical Pharmacology ( 12.3 ) ]. 7.2 Strong Inducers and Strong Inhibitors of CYP3A4 and P-gp Avoid concomitant use of sirolimus with strong inducers (e.g., rifampin, rifabutin) and strong inhibitors (e.g., ketoconazole, voriconazole, itraconazole, erythromycin, telithromycin, clarithromycin) of CYP3A4 and P-gp. Alternative agents with lesser interaction potential with sirolimus should be considered [ see Warnings and Precautions ( 5.20 ), Clinical Pharmacology ( 12.3 ) ]. 7.3 Grapefruit Juice Because grapefruit juice inhibits the CYP3A4-mediated metabolism of sirolimus, it must not be taken with or be used for dilution of sirolimus [ see Drug Interactions ( 7.3 ), Clinical Pharmacology ( 12.3 ) ]. 7.4 Weak and Moderate Inducers or Inhibitors of CYP3A4 and P-gp Exercise caution when using sirolimus with drugs or agents that are modulators of CYP3A4 and P-gp. The dosage of sirolimus and/or the coadministered drug may need to be adjusted [ see Clinical Pharmacology ( 12.3 ) ]. Drugs that could increase sirolimus blood concentrations: Bromocriptine, cimetidine, cisapride, clotrimazole, danazol, diltiazem, fluconazole, letermovir, protease inhibitors (e.g., HIV and hepatitis C that include drugs such as ritonavir, indinavir, boceprevir, and telaprevir), metoclopramide, nicardipine, troleandomycin, verapamil Drugs and other agents that could decrease sirolimus concentrations: Carbamazepine, phenobarbital, phenytoin, rifapentine, St. John's Wort (Hypericum perforatum) Drugs with concentrations that could increase when given with sirolimus: Verapamil 7.5 Cannabidiol The blood levels of sirolimus may increase upon concomitant use with cannabidiol. When cannabidiol and sirolimus are co-administered, closely monitor for an increase in sirolimus blood levels and for adverse reactions suggestive of sirolimus toxicity. A dose reduction of sirolimus should be considered as needed when sirolimus is co-administered with cannabidiol [see Dosage and Administration ( 2.5 ) and Warnings and Precautions ( 5.21 )].