Diagnosing
congenital athymia

Early diagnosis is key to making the right supportive care decisions1

Newborn screening plays a crucial role in the early detection of congenital athymia. T cell receptor excision circle (TREC) screening, a test mandated in all 50 states in the US, provides the first indication of naive T-cell deficiency, signaling a need for further testing. TREC screening may identify severe combined immunodeficiency (SCID) as well as congenital athymia.1

Congenital athymia and SCID are distinct conditions

Although they’re both primary immunodeficiency disorders and detected through the same screening test, congenital athymia and SCID have different underlying causes. Distinguishing between the two is critical as they have different treatment requirements.1

Diagram showing the steps for diagnosing congenital athymia vs SCID

Differentiating typical vs atypical phenotypes

There are two phenotypes of congenital athymia, typical and atypical, with different characteristics. These include2:

Typical congenital athymia2

  • T-cell lymphopenia
  • Absence of rash or lymphadenopathy
  • Lack of mitogen-stimulated T-cell proliferation

Atypical congenital athymia2

Signs and symptoms of autologous graft versus host disease (GVHD):

  • Rash
  • Lymphadenopathy
  • High numbers of circulating T cells (from oligoclonal T-cell expansion)
  • T-cell proliferation in response to mitogens (eg, phytohemagglutinin)

For currently unknown reasons, some patients with typical congenital athymia can, over time, develop the atypical phenotype.2

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RETHYMIC is a first-of-its-kind, FDA-approved tissue-based treatment for congenital athymia engineered to help patients develop an immune system sufficient to fight infections.3,4

Learn about RETHYMIC
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Learn how to access RETHYMIC and begin the referral process.

Initiating treatment
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RETHYMIC Connect™ provides support and resources for patients with congenital athymia and their caregivers.

Enroll your patients
Indication and Important Safety Information
Important Safety Information

Infection Control and Immunoprophylaxis: Immune reconstitution sufficient to protect from infection is unlikely to develop prior to 6-12 months after treatment with RETHYMIC. Follow infection control measures until the development of thymic function is established as measured by flow cytometry. Closely monitor patients for signs of infection. If fever develops, assess the patient via lab results and treat as clinically indicated. Patients should be maintained on immunoglobulin replacement therapy (IgG) and Pneumocystis jirovecii pneumonia prophylaxis until specified criteria are met. IgG trough level should be checked 2 months after stopping IgG to determine whether the patient may remain off IgG.

Graft versus Host Disease (GVHD): RETHYMIC may cause or exacerbate pre-existing GVHD, for which patients should be closely monitored and treated. Risk factors include atypical complete DiGeorge anomaly phenotype, prior hematopoietic cell transplantation (HCT), and maternal engraftment. Patients with specified elevated baseline T cell proliferative response to PHA should receive immunosuppressants to decrease this risk. GVHD may manifest as fever, rash, lymphadenopathy, elevated bilirubin and liver enzymes, enteritis, and/or diarrhea.

Autoimmune Disorders: Autoimmune-related adverse events occurred in patients treated with RETHYMIC. These events included thrombocytopenia, neutropenia, proteinuria, hemolytic anemia, alopecia, hypothyroidism, autoimmune hepatitis, autoimmune arthritis, transverse myelitis, albinism, hyperthyroidism, and ovarian failure. Monitor complete blood counts with differential, liver enzymes, serum creatinine, urinalysis, and thyroid function.

Renal Impairment: Pre-existing renal impairment is a risk factor for death.

Cytomegalovirus Infection (CMV): In the clinical studies, 4 out of 4 patients with pre-existing CMV infection died.

Malignancy: Due to underlying immune deficiency, patients who receive RETHYMIC may be at risk of developing post-treatment lymphoproliferative disorder. Patients should be tested for Epstein-Barr virus and CMV prior to and 3 months after treatment or after any suspected exposure.

Transmission of Serious Infections and Transmissible Infectious Diseases: Transmission of infectious disease may occur because RETHYMIC is derived from human tissue, and product manufacturing includes porcine- and bovine-derived reagents.

Vaccine Administration: Immunizations should not be given in patients treated with RETHYMIC until immune-function criteria have been met. Live virus vaccines should not be given until patients have met the criteria for and received inactivated vaccines.

Anti-HLA Antibodies: All patients should be screened for anti-HLA antibodies prior to receiving RETHYMIC. Patients testing positive should receive RETHYMIC from a donor who does not express those HLA alleles.

HLA Typing: HLA matching is required in patients who have received a prior HCT or a solid organ transplant. Patients who have received a HCT are at increased risk of developing GVHD after RETHYMIC if the HCT donor does not fully match with RETHYMIC.

Deaths: Of the 105 patients in clinical studies, 29 patients died, including 23 deaths in the first year (<365 days) after implantation.

Adverse Reactions: The most common (>10%) adverse events included hypertension, cytokine release syndrome, rash, hypomagnesemia, renal impairment/failure, thrombocytopenia, and GVHD.

Indication

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

Limitations of Use: RETHYMIC is not indicated for the treatment of patients 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. RETHYMIC ®, RETHYMIC Connect™, and its logos are trademarks of Sumitomo Pharma Switzerland GmbH. © 2024 Sumitomo Pharma Switzerland GmbH. All rights reserved. RET-US-0381-24    11/2024