Post-treatment
expectations

Post-treatment care is critically important after your patient receives RETHYMIC1

Immune reconstitution sufficient to protect against infection is unlikely to develop prior to 6 to 12 months after treatment with RETHYMIC. For some patients, it may take up to 2 years.1

After treatment with RETHYMIC, patients will return to the care of the referring healthcare provider and should be monitored regularly for autologous graft versus host disease and autoimmune disorders. Tests for monitoring autoimmune disorders will include/measure1-3:

  • Complete blood count with differential
  • Liver enzymes
  • Serum creatinine levels
  • Urinalysis
  • Thyroid function

Once T cells reach certain levels, additional testing can be done to determine if patients can discontinue the following3:

  • Immunosuppressants
  • Immunoglobulin (IgG) replacement therapy
  • Antibiotics
  • Antifungals

Inactivated and live vaccines should not be administered until requirements outlined in the RETHYMIC Prescribing Information have been met.1

Careful monitoring and isolation are required to ensure your patients avoid infections after treatment with RETHYMIC. Your patients should also be monitored for other complications, like GVHD and autoimmune disorders. Consider how best to work with the care teams and caregivers of your patients to determine what measures can be lifted and when.1

For additional guidance, please see below.

Young girl with congenital athymia with shapes of light coming out of her thigh

Immunosuppressants and IgG replacement therapy

Discontinuing immunosuppressants and IgG replacement therapy

Patients can be weaned off immunosuppressants when at least 10% of CD3+ T cells are naive in phenotype.1

  • Patients should be maintained on IgG replacement therapy until all of the following criteria are met1:
    • No longer taking immunosuppressants
    • At least 9 months post-treatment
    • Phytohemagglutinin response within normal limits
    • Normal serum immunoglobulin A is desired but not required

Two months after stopping IgG replacement therapy, the IgG trough level should be checked. If the trough level is in the normal range for age, the patients can remain off therapy. If it is lower than the normal range for age, therapy should be restarted and continued for a year before being retested.1

Prophylaxis for Pneumocystis jirovecii

Discontinuing prophylaxis for Pneumocystis jirovecii

Patients should be maintained on Pneumocystis jirovecii pneumonia prophylaxis until all of the following criteria are met1:

  • No longer taking immunosuppressants
  • At least 9 months post-treatment
  • Phytohemagglutinin response within normal limits
  • CD4+ T-cell count is >200 cells/mm3

Live and inactivated vaccines

Administering vaccines

Inactivated vaccines may be administered to patients who have received RETHYMIC when all of the following criteria have been met1:

  • No longer taking immunosuppressants
  • IgG replacement therapy has been discontinued
  • Total CD4+ T-cell count is >200 cells/mm3 and there are more CD4+ T cells than CD8+ T cells

Live virus vaccines should not be administered until the criteria for inactivated vaccines have been met and the patient has received vaccinations with inactivated agents (eg, tetanus toxoid).1

It is recommended that no more than 2 inactivated vaccines be given per month. With the exception of the inactivated influenza vaccine, no vaccines should be given within 6 months after the patient receives a measles-containing vaccine or within 2 months of receiving the varicella vaccine. Consider verifying response to vaccination with appropriate testing, in particular varicella and measles.1

Isolation

Relaxing strict isolation

As patients' immunities build and reach thresholds for fighting off infections, consider how best to work with the care teams and caregivers of your patients to determine what measures can be lifted and when.1

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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