How is RETHYMIC made?

Donation

When an infant 9 months of age or younger has cardiac surgery, some thymus tissue may need to be removed to access the heart. With consent of the infant donor’s parents or guardian, the thymus tissue is donated to make RETHYMIC.

Unlike many other medications, RETHYMIC is not an off-the-shelf product. The tissue from a single pediatric donor allows for the manufacturing of RETHYMIC for one child.

Illustration of a microscope

Manufacturing

The amount of time the engineering process takes depends on multiple factors and can be completed between 12 and 21 days.

During this 12- to 21-day engineering process, most of the donor’s pre-T cells are removed and the tissue is tested repeatedly to ensure the product meets FDA safety standards.

Through this process, the donor thymus tissue becomes the FDA-approved treatment, RETHYMIC.

Illustration of implanted RETHYMIC

Implantation

The available dosage is based on the donor thymus tissue, and the amount implanted is based on the recipient’s body surface area.

Once released from the manufacturing facility, RETHYMIC must be implanted within a limited time frame at the treatment center.

Explore the efficacy and safety of RETHYMIC, studied across 10 clinical trials.

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Find out how your child’s healthcare provider can begin the referral process.

Getting started

RETHYMIC Connect™ provides support and resources to children with congenital athymia and their caregivers.

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Indication and Important Safety Information

Important Safety Information

Infection Control: Immune reconstitution sufficient to protect from infection usually develops between 6-12 months after treatment with RETHYMIC. For some children, it may take up to 2 years. Taking medications that prevent infection and other infection control measures, such as hand washing and isolation, should be continued until your child’s doctor confirms that immune function has been reconstituted through immune tests and the criteria for discontinuing certain medications have been met. Immediately report signs and symptoms of infection, such as fever, to your child’s doctor.

Graft versus Host Disease (GVHD): RETHYMIC may cause or make pre-existing GVHD worse. Your child will be monitored for GVHD and treated if needed. Symptoms of GVHD may include fever, rash, swollen lymph nodes, inflammation of the digestive system, and/or diarrhea.

Autoimmune Disorders: Autoimmune-related side effects (when your immune system attacks healthy cells by mistake) occurred in patients treated with RETHYMIC. These included low platelets, white blood cells, or red blood cells; protein in the urine; hair loss; poor thyroid function; inflammation of the liver, joints, or spinal cord; loss of pigment in the skin, eyes and hair; overactive thyroid function; and loss of function of the ovaries. Your doctor will monitor your child regularly.

Kidney Disease: Children with kidney disease have a higher risk of death when treated with RETHYMIC.

Cytomegalovirus (CMV) Infection: In clinical studies, 4 out of 4 patients with CMV infection prior to treatment with RETHYMIC died.

Cancer: Due to your child’s weakened immune system, there is an increased risk of developing blood cancer. Your child’s doctor will monitor your child through testing for Epstein-Barr virus and CMV, which are two viruses that can cause cancer.

Transmission of Serious Infections and Transmissible Infectious Diseases: Because RETHYMIC is made from human tissue, and animal products are used in the manufacturing process, transmission of infectious diseases may occur.

Vaccine Administration: Notify your child’s doctor to evaluate your child’s immune status before receiving vaccinations. Live virus vaccines should not be given until the doctor determines that your child has met criteria for and received inactivated vaccines.

Anti-HLA Antibodies: Before receiving RETHYMIC, your child will be tested for HLA antibodies, which are proteins that may be present in your child’s blood. If your child has these antibodies, your child should receive RETHYMIC from a specific donor, which will be determined by your child’s doctor.

HLA Typing: If your child received a hematopoietic cell transplantation (HCT) or a solid organ transplant, testing to match your child with RETHYMIC from a compatible donor is required. Children who have received an HCT are at an increased risk of developing GVHD after RETHYMIC if the HCT donor does not fully match with RETHYMIC.

Deaths: Of the 105 children who participated in the clinical studies, 29 patients died, including 23 in the first year after implantation of RETHYMIC.

The most common side effects are high blood pressure, cytokine release syndrome, rash, low magnesium, decrease in kidney function, low platelets, and GVHD.

These are not all the possible side effects of RETHYMIC. Talk to your child’s doctor about any side effect that bothers your child or does not go away.

You are encouraged to report side effects to the FDA at 1-800-FDA-1088 or www.fda.gov/safety/medwatch.

Indication

RETHYMIC® is indicated for immune reconstitution in pediatric patients with congenital athymia.

RETHYMIC is not for use in patients who have been diagnosed with severe combined immunodeficiency (SCID).

References: 1. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 2. Sumitomo Pharma America, Inc. Enzyvant receives FDA approval for RETHYMIC® (allogeneic processed thymus tissue-agdc), a one-time regenerative tissue-based therapy for pediatric congenital athymia. Accessed June 27, 2024. https://www.us.sumitomo-pharma.com/newsroom/press-releases/Enzyvant-Receives-FDA-Approval-for-RETHYMIC-allogeneic-processed-thymus-tissue-agdc-a-One-Time-Regenerative-Tissue-Based-Therapy-for-Pediatric/ 3. Markert ML, McCarthy EA, Gupton SE, Lim AP. Cultured thymus tissue transplantation. In: Sullivan KE, Stiehm ER, eds. Stiehm’s Immune Deficiencies: Inborn Errors of Immunity. 2nd ed. Elsevier; 2020:1229-1239.

References: 1. Collins C, Sharpe E, Silber A, Kulke S, Hsieh EWY. Congenital athymia: genetic etiologies, clinical manifestations, diagnosis, and treatment. J Clin Immunol. 2021;41(5):881-895. doi:10.1007/s10875-021-01059-7 2. Markert ML, Gupton SE, McCarthy EA. Experience with cultured thymus tissue in 105 children. J Allergy Clin Immunol. 2022;149(2):747-757. doi:10.1016/j.jaci.2021.06.028 3. Immune Deficiency Foundation. Patient & Family Handbook for Primary Immunodeficiency Diseases. 6th ed. 2019. 4. Hsieh EWY, Kim-Chang JJ, Kulke S, Silber A, O’Hara M, Collins C. Defining the clinical, emotional, social, and financial burden of congenital athymia. Adv Ther. 2021;38(8):4271-4288. doi:10.1007/s12325-021-01820-9 5. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 6. Sumitomo Pharma America, Inc. Enzyvant receives FDA approval for RETHYMIC® (allogeneic processed thymus tissue-agdc), a one-time regenerative tissue-based therapy for pediatric congenital athymia. Accessed June 27, 2024. https://www.us.sumitomo-pharma.com/newsroom/press-releases/Enzyvant-Receives-FDA-Approval-for-RETHYMIC-allogeneic-processed-thymus-tissue-agdc-a-One-Time-Regenerative-Tissue-Based-Therapy-for-Pediatric/

References: 1. Collins C, Sharpe E, Silber A, Kulke S, Hsieh EWY. Congenital athymia: genetic etiologies, clinical manifestations, diagnosis, and treatment. J Clin Immunol. 2021;41(5):881-895. doi:10.1007/s10875-021-01059-7 2. Markert ML, Gupton SE, McCarthy EA. Experience with cultured thymus tissue in 105 children. J Allergy Clin Immunol. 2022;149(2):747-757. doi:10.1016/j.jaci.2021.06.028 3. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 4. Sumitomo Pharma America, Inc. Enzyvant receives FDA approval for RETHYMIC® (allogeneic processed thymus tissue-agdc), a one-time regenerative tissue-based therapy for pediatric congenital athymia. Accessed June 27, 2024. https://www.us.sumitomo-pharma.com/newsroom/press-releases/Enzyvant-Receives-FDA-Approval-for-RETHYMIC-allogeneic-processed-thymus-tissue-agdc-a-One-Time-Regenerative-Tissue-Based-Therapy-for-Pediatric/

References: 1. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 2. Sumitomo Pharma America, Inc. Enzyvant receives FDA approval for RETHYMIC® (allogeneic processed thymus tissue-agdc), a one-time regenerative tissue-based therapy for pediatric congenital athymia. Accessed June 27, 2024. https://www.us.sumitomo-pharma.com/newsroom/press-releases/Enzyvant-Receives-FDA-Approval-for-RETHYMIC-allogeneic-processed-thymus-tissue-agdc-a-One-Time-Regenerative-Tissue-Based-Therapy-for-Pediatric/ 3. Markert ML, McCarthy EA, Gupton SE, Lim AP. Cultured thymus tissue transplantation. In: Sullivan KE, Stiehm ER, eds. Stiehm’s Immune Deficiencies: Inborn Errors of Immunity. 2nd ed. Elsevier; 2020:1229-1239.

References: 1. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 2. Markert ML, Gupton SE, McCarthy EA. Experience with cultured thymus tissue in 105 children. J Allergy Clin Immunol. 2022;149(2):747-757. doi:10.1016/j.jaci.2021.06.028 3. Markert ML, McCarthy EA, Gupton SE, Lim AP. Cultured thymus tissue transplantation. In: Sullivan KE, Stiehm ER, eds. Stiehm’s Immune Deficiencies: Inborn Errors of Immunity. 2nd ed. Elsevier; 2020:1229-1239.

References: 1. Markert ML, McCarthy EA, Gupton SE, Lim AP. Cultured thymus tissue transplantation. In: Sullivan KE, Stiehm ER, eds. Stiehm’s Immune Deficiencies: Inborn Errors of Immunity. 2nd ed. Elsevier; 2020:1229-1239. 2. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 3. Food and Drug Administration. Summary Basis for Regulatory Action. October 8, 2021. BLA STN: 125685/0 4. Sumitomo Pharma America, Inc. Enzyvant receives FDA approval for RETHYMIC® (allogeneic processed thymus tissue-agdc), a one-time regenerative tissue-based therapy for pediatric congenital athymia. Accessed June 27, 2024. https://www.us.sumitomo-pharma.com/newsroom/press-releases/Enzyvant-Receives-FDA-Approval-for-RETHYMIC-allogeneic-processed-thymus-tissue-agdc-a-One-Time-Regenerative-Tissue-Based-Therapy-for-Pediatric/

References: 1. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 2. Sumitomo Pharma America, Inc. Enzyvant receives FDA approval for RETHYMIC® (allogeneic processed thymus tissue-agdc), a one-time regenerative tissue-based therapy for pediatric congenital athymia. Accessed June 27, 2024. https://www.us.sumitomo-pharma.com/newsroom/press-releases/Enzyvant-Receives-FDA-Approval-for-RETHYMIC-allogeneic-processed-thymus-tissue-agdc-a-One-Time-Regenerative-Tissue-Based-Therapy-for-Pediatric/

References: 1. Hsieh EWY, Kim-Chang JJ, Kulke S, Silber A, O’Hara M, Collins C. Defining the clinical, emotional, social, and financial burden of congenital athymia. Adv Ther. 2021;38(8):4271-4288. doi:10.1007/s12325-021-01820-9 2. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023.

References: 1. RETHYMIC [package insert]. Marlborough, MA: Sumitomo Pharma America, Inc; 2023. 2. Markert ML, McCarthy EA, Gupton SE, Lim AP. Cultured thymus tissue transplantation. In: Sullivan KE, Stiehm ER, eds. Stiehm’s Immune Deficiencies: Inborn Errors of Immunity. 2nd ed. Elsevier; 2020:1229-1239 3. Gupton SE, McCarthy EA, Markert ML. Care of children with DiGeorge before and after cultured thymus tissue implantation. J Clin Immunol. 2021;41(5):896-905. doi:10.1007/s10875-021-01044-0