Allogeneic Processed Thymus Tissue-agdc (Rethymic)

• Allogeneic processed thymus tissue-agdc (Rethymic® ) surgical implantation for administration by a healthcare professional

• For immune reconstitution in pediatric patients with congenital athymia 
• Limitations of use: Not indicated for treatment of patients with severe combined immunodeficiency (SCID)

The restricted product(s) may be considered medically necessary when the following criteria are met: 

1. The patient is 3 years of age or younger; AND
2. The patient has a diagnosis of congenital athymia confirmed by flow cytometry demonstrating fewer than 50 naïve T-cells/mm3 (CD45RA+ , CD62L+ ) in the peripheral blood or less than 5% of total T-cells being naïve in phenotype [medical record documentation required]; AND
3. The patient has complete DiGeorge syndrome (cDGS) and at least one of the following (medical record documentation required): 
   1. Congenital heart defect (medical record documentation required); OR
   2. Hypoparathyroidism or hypocalcemia requiring calcium replacement (medical record documentation required); OR
   3. 22q11.2 deletion syndrome (medical record documentation required); OR 
   4. 10p13 hemizygosity (medical record documentation required); OR
   5. CHARGE (coloboma, heart defects, choanal atresia, growth and development retardation, genital hypoplasia, and ear anomalies including deafness) syndrome (medical record documentation required); OR
   6. CHD7 mutation (medical record documentation required); OR
4. The patient has confirmed FOXN1 deficiency (medical record documentation required); AND
5. The patient is NOT being treated for severe combined immunodeficiency (SCID) (medical record documentation required); AND
6. The patient has been screened for anti-HLA antibodies prior to receiving treatment with the requested agent (medical record documentation required); AND
7. For patients who received prior solid organ (e.g., thymus) or hematopoietic cell transplantation, the patient has undergone HLA matching of the requested agent to recipient alleles (medical record documentation required); AND
8. The requested quantity does NOT exceed the maximum units allowed for the duration of approval (see table below). 

Duration of Approval: 180 days (one treatment course per lifetime)

All information referenced is from FDA package insert unless otherwise noted below.

1. Collins C, Sharpe E, Silber A, et al. Congenital athymia: genetic etiologies, clinical manifestations, diagnosis, and treatment. J Clin Immunol. 2021;41(5): 881-895.
2. Markert ML, Gupton SE, McCarthy EA. Experience with cultured thymus tissue in 105 children. J Allergy Clin Immunol. 2021;S0091- 6749(21):01056-3.

January 2022: Original medical policy criteria issued.