What is congenital athymia?

Congenital athymia is a rare immune condition that requires children and often their families to live in strict isolation1

Congenital athymia is a primary immunodeficiency, which is a type of immune condition that occurs when part of the immune system is missing. Children with congenital athymia are born without a thymus.2,3

The thymus is an organ that sits on top of the heart and plays an important role in how the immune system works. Without one, these children can face life-threatening infections because they are unable to produce enough naive T cells—white blood cells that help fight off the organisms that cause infections.2,4

Approximately 17 to 24 infants are born with congenital athymia in the US each year.1

Role Of Thymus

Complete DiGeorge Syndrome

Complete DiGeorge syndrome often occurs when part of chromosome 22 is missing (22q11.2 deletion syndrome). This may result in a compromised immune system as well as potential heart defects, developmental delay, and hearing loss, among other conditions.2

CHARGE Syndrome

Often associated with a mutation in a gene known as CHD7, this consists of medical and physical conditions that differ from child to child. The CHARGE acronym comes from the first letter of some of the more common features seen in children2:

  • CColoboma, or defects in the way the eye forms
  • HHeart defects
  • AAtresia of the choanae, or blocked nasal passages
  • RRetardation of growth and development
  • GGenital underdevelopment
  • EEar abnormalities

FOXN1 Deficiency

This condition affects the production of critical proteins, which may result in a severely compromised immune system and problems with the growth of hair and nails.2

Diabetic Embryopathy

This condition may be associated with altered fetal thymus size and other congenital abnormalities. Abnormal thymic development has been seen in infants of diabetic mothers.2

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Children with congenital athymia require special care.2

Explore supportive care
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RETHYMIC is the first and only FDA-approved tissue-based treatment for congenital athymia engineered to help children develop an immune system sufficient to fight infections.8,9

Learn about RETHYMIC
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Enzyvant 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 is unlikely to develop prior to 6-12 months after treatment with RETHYMIC. Immune reconstitution is needed for the body to produce cells in the immune system to fight infection. Your child’s doctor should advise you of infection control measures which should be followed immediately after treatment and until the immune system starts working at a sufficient level. Monitor your child closely for signs of infection, including fever. Your child should be maintained on immunoglobulin replacement and prophylactic antimicrobials until certain criteria are met as determined by your 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, enlarged lymph nodes, inflammation of the gastrointestinal system and/or diarrhea.

Autoimmune Disorders: Autoimmune-related adverse events occurred in patients treated with RETHYMIC. These events included: low platelets, low white blood cells, protein in urine, low red blood cells, hair loss, poor thyroid function, inflammation of liver, inflammation of the joints, inflammation of the 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 including performing blood tests.

Kidney Disease: Treatment with RETHYMIC is a risk factor for death in patients with pre-existing kidney disease.

Cytomegalovirus (CMV) Infection: In clinical studies with RETHYMIC, 4 out of 4 patients with pre-existing CMV infection prior to the implantation with RETHYMIC died. Talk to your doctor about the benefits/risks of treatment if your child has pre-existing CMV infection.

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

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

Vaccinations: Your child should not receive any vaccinations until he or she has met certain requirements set by your doctor. Talk to your child’s doctor prior to any vaccinations.

Anti-HLA Antibodies: Prior to 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, he/she will need to receive RETHYMIC from a donor that does not express those HLA proteins.

HLA Typing: If your child has received a hematopoietic cell transplantation (HCT) or a solid organ transplant, they will have a test to look for specific antibodies that could interfere with the effect of RETHYMIC. If they are present, then it will be necessary to receive RETHYMIC from a certain group of donors that do not have these proteins.

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

What are the most common side effects with RETHYMIC?

The most common side effects with RETHYMIC are hypertension (high blood pressure), cytokine release syndrome, rash, hypomagnesemia (low magnesium), renal impairment / failure (decrease of kidney function), thrombocytopenia (low platelets), and graft versus host disease.

These are not all of 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® (allogeneic processed thymus tissue–agdc) 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).

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Sumitomo Pharma is a trademark of Sumitomo Pharma Co., Ltd., used under license. SUMITOMO PHARMA is a trademark of Sumitomo Pharma Co., Ltd., used under license. SUMITOMO is a registered trademark of Sumitomo Chemical Co., Ltd., used under license. Sumitomo Pharma America, Inc. is a U.S. subsidiary of Sumitomo Pharma Co. Ltd. ENZYVANT CONNECT®, RETHYMIC®, and their logos are registered trademarks of Enzyvant Therapeutics GmbH. © 2023 Enzyvant Therapeutics GmbH. All rights reserved. US—2300142 11/2023