Simulect20 mg/vial

Simulect is a chimeric (murine/human) monoclonal antibody that is FDA-approved for the following use:

• Established/approved use: Prophylaxis (prevention) of acute organ rejection in adult and pediatric patients receiving renal (kidney) transplantation, when used as part of an immunosuppressive regimen that also includes a calcineurin inhibitor (such as cyclosporine) and corticosteroids.
• Adjunct/combination requirement: Simulect is used only as an induction component added to a broader maintenance immunosuppressive regimen; it is not used alone.
• Off-label/guideline-supported use: Some transplant centers use Simulect induction in other types of solid-organ transplantation (e.g., liver, heart, lung, pancreas) as part of institutional protocols; this is not an FDA-approved indication and should only be undertaken by a transplant specialist team.

Each vial of Basiliximab for injection contains basiliximab as a lyophilized (freeze-dried) powder for reconstitution, typically available in 10 mg and 20 mg single-use vial strengths. Reconstituted solution is administered by intravenous (IV) infusion or bolus injection under medical supervision.

Simulect is an interleukin-2 (IL-2) receptor antagonist. It is a chimeric monoclonal antibody produced by recombinant DNA technology that is directed against the alpha subunit (CD25 antigen) of the human IL-2 receptor expressed on the surface of activated T-lymphocytes.

Simulect is supplied as a sterile, lyophilized powder that is reconstituted and given intravenously. It is used exclusively in a hospital/transplant-center setting as part of an induction immunosuppressive regimen to help prevent the body's immune system from rejecting a newly transplanted kidney.

Mechanism of Action

Basiliximab binds with high affinity and specificity to the alpha subunit (CD25) of the IL-2 receptor on the surface of activated T-lymphocytes. This blocks IL-2 from binding to its receptor, which is a critical signal in the proliferation of T-lymphocytes during an immune response. By interrupting this pathway, Basiliximab inhibits the T-cell-mediated immune response responsible for acute rejection of a transplanted organ.

Pharmacokinetics

Following intravenous administration, Basiliximab saturates the IL-2 receptor for approximately 4-6 weeks (dose-dependent), which typically covers the highest-risk early post-transplant period for acute rejection. It is cleared from the body once IL-2 receptor expression declines and via normal antibody catabolism.

Simulect is administered only by intravenous infusion or slow intravenous bolus by a qualified healthcare professional in a hospital/transplant-center setting. Patients should be observed for signs of an acute hypersensitivity reaction during and after administration. It is not a self-administered or outpatient take-home medication.

Simulect has not been shown to have clinically significant pharmacokinetic (e.g., cytochrome P450-mediated) drug interactions, as it is a monoclonal antibody rather than a small molecule.

• Other immunosuppressants (cyclosporine, tacrolimus, mycophenolate mofetil, corticosteroids): Simulect is intentionally combined with these agents as part of the transplant regimen; however, the combined immunosuppressive effect increases the overall risk of infection and lymphoproliferative disorders (see Precautions and Warnings).
• Live vaccines: Concurrent use with live/live-attenuated vaccines should generally be avoided during periods of significant immunosuppression from the overall transplant regimen, due to reduced vaccine efficacy and risk of vaccine-strain infection.

Common Side Effects

• Constipation, nausea, vomiting, diarrhea
• Urinary tract infection
• Hypertension or hypotension
• Headache, tremor
• Peripheral edema
• Fever (pyrexia)
• Surgical wound complications
• Hyperkalemia, hypercholesterolemia
• Anemia
• Upper respiratory tract infection, dyspnea

Serious Side Effects

• Severe acute hypersensitivity reactions, including anaphylaxis (see Precautions and Warnings)
• Serious infections, including opportunistic infections
• Malignancy, including post-transplant lymphoproliferative disorder (PTLD)
• Capillary leak syndrome (rare)

Pregnancy: There are limited human data on the use of Simulect in pregnancy. Simulect should be used during pregnancy only if the potential benefit to the mother justifies the potential risk to the fetus, and only under close specialist supervision, since untreated organ rejection itself carries serious risk to both mother and fetus. Women of reproductive potential should use effective contraception before, during, and for a period after treatment, as advised by their transplant physician.

Lactation: It is not known whether Simulect is excreted in human breast milk. Because many antibodies and immunosuppressants can pass into breast milk and effects on a nursing infant are unknown, a decision should be made in consultation with a physician whether to discontinue breastfeeding or discontinue Simulect, taking into account the benefits of breastfeeding and the mother's clinical need for the drug.

Severe Hypersensitivity Reactions

Severe, sometimes fatal, acute hypersensitivity reactions, including anaphylaxis, have been reported with Simulect, occasionally on first exposure and also with re-exposure after an initial course. Simulect should be administered only in a facility equipped and staffed to recognize and manage such reactions (e.g., resuscitation equipment, epinephrine, oxygen). If a severe hypersensitivity reaction occurs, Simulect should be permanently discontinued.

Infections and Malignancy

As part of an overall immunosuppressive regimen, Simulect increases the risk of infections, including serious and opportunistic infections, as well as the risk of malignancy, particularly lymphoproliferative disease/post-transplant lymphoproliferative disorder (PTLD). Patients should be closely monitored for signs and symptoms of infection throughout treatment.

Specialist Use Only

Simulect must be prescribed and administered only by a physician/transplant team experienced in immunosuppressive therapy and management of organ transplant patients. It does not replace the need for other maintenance immunosuppressive medications in the transplant regimen.

Vaccination

Live vaccines should generally be avoided during periods of significant immunosuppression resulting from the overall transplant regimen.

Doses of Simulect higher than the recommended regimen have been studied without evidence of acute toxic effects; there is no specific antidote. In the event of a suspected overdose, seek immediate medical attention or contact emergency services/a poison control center. Management is supportive, with close monitoring for hypersensitivity reactions and infection, under the care of a transplant specialist team.

Store Simulect vials in a refrigerator at 2°C to 8°C (36°F to 46°F). Do not freeze. Keep the vial in the outer carton to protect from light. After reconstitution, use the solution promptly; if not used immediately, the reconstituted solution may be stored under refrigeration and used within the timeframe specified by the manufacturer (generally within 24 hours). Keep out of reach of children.

Pediatric Use

Simulect is approved for use in pediatric renal transplant patients, with weight-based dosing (10 mg if under 35 kg; 20 mg if 35 kg or more). Safety and efficacy in neonates and infants under 1 year of age have not been established.

Elderly (Geriatric) Use

Clinical experience in patients over 65 years of age is limited. No overall differences in safety or effectiveness have been reported, but caution and individualized dosing decisions are advised.

Renal/Hepatic Impairment

No specific dose adjustment has been established as necessary; use should be individualized under transplant specialist supervision.

Simulect is given as a short, fixed two-dose induction course (Day 0 and Day 4 relative to transplantation) rather than as ongoing chronic therapy. It is not repeated beyond this induction course except under specific specialist direction (e.g., for a subsequent transplant), and re-exposure carries an increased risk of hypersensitivity reactions.

Simulect is supplied as a lyophilized powder that must be reconstituted before use. Reconstitute the 10 mg vial with 2.5 mL and the 20 mg vial with 5 mL of Sterile Water for Injection to yield a solution of approximately 4 mg/mL. Gently swirl to dissolve; do not shake. The reconstituted solution may be given as a slow IV bolus or further diluted in at least 25 mL of normal saline or 5% dextrose for infusion over 20-30 minutes. Use immediately after reconstitution when possible, or per manufacturer storage guidance if delayed. Discard any unused portion; do not mix with other medications in the same infusion line.

Immunosuppressant; Interleukin-2 (IL-2) receptor antagonist; Anti-CD25 monoclonal antibody

Basiliximab selectively binds to the CD25 (alpha) subunit of the IL-2 receptor on the surface of activated T-lymphocytes, competitively blocking IL-2-mediated activation and proliferation of T-cells, thereby suppressing the cell-mediated immune response that drives acute rejection of a transplanted organ.

Category B (legacy FDA pregnancy category, per original product labeling)

Simulect is FDA-approved for use in pediatric kidney transplant recipients as part of an immunosuppressive regimen, with dosing based on body weight (10 mg per dose if under 35 kg; 20 mg per dose if 35 kg or more), given on Day 0 and Day 4 relative to transplantation. Safety and efficacy have not been established in neonates and infants under 1 year of age. Pediatric patients require the same close monitoring for hypersensitivity, infection, and malignancy as adults, under transplant specialist supervision.