Thymus Transplantation in DiGeorge Syndrome #668

Study Overview
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Brief Summary
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The study purpose is to determine whether cultured thymus tissue implantation (CTTI) is effective in treating typical complete DiGeorge syndrome.

Detailed Description
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There is no safe and effective treatment for DiGeorge syndrome and most patients die by the age of two. Complete DiGeorge syndrome is characterized by very low T cell or very low naïve T cell numbers. In this study, typical complete DiGeorge syndrome subjects underwent human postnatal cultured thymus tissue implantation (CTTI). Thymus tissue that would otherwise be discarded was processed and then implanted into complete DiGeorge subjects in the operating room. At the time of CTTI, a skin biopsy may have been obtained to look for any preexisting T cells. After CTTI, subjects were followed by routine research immune evaluations, using blood samples obtained approximately every 2-4 weeks. At approximately 2-3 months post-CTTI subjects underwent an open biopsy of the allograft. The biopsy was done under general anesthesia in the operating room. At the time of the graft biopsy, another skin biopsy was obtained to look for clonal populations of T cells. The protocol aims include: assessing thymopoiesis in the allograft biopsy; assessing immunoreconstitution of complete DiGeorge syndrome subjects after postnatal allogeneic cultured thymus tissue implantation; assessing minimally invasive methods of assessing thymopoiesis (flow cytometry and polymerase chain reaction (PCR); assessing pre-implant T cells which do not proliferate in response to mitogens (focusing on NK-T cells); and, assessing cultured thymus tissue implantation safety and toxicity.

Official Title
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Phase II Study of Thymus Transplantation in Complete DiGeorge Syndrome #668

Conditions
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DiGeorge Syndrome, Complete Typical DiGeorge Anomaly

Intervention / Treatment
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* Biological: Cultured Thymus Tissue for Implantation (CTTI)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: The subject's parent(s) signed the ICF. For a diagnosis of DiGeorge Syndrome (DGS), the subject had one of the following: Heart defect Hypoparathyroidism 22q11 hemizygosity 10p13 hemizygosity Coloboma, heart defect, choanal atresia, growth and development retardation, genital hypoplasia, ear anomalies/ deafness CHARGE association mutation (CHD7 deletion); PHA proliferative responses less than 20-fold above background. Subjects with typical Complete DiGeorge Anomaly (cDGA) had to have one of the following on 2 separate occasions: Circulating CD3+ T cells by flow cytometry < 50/mm3 or PHA < 20-fold over background If CD3+ were > 50/mm3, then CD45RA+ (cluster of differentiation 45RA) CD62L+ had to be < 50/mm3 Or T cell receptor rearrangement excision circles (TRECs) by PCR had to be < 100 per 100,000 CD3+ cells. Subjects with atypical cDGA had to have both of the following with 2 studies each: Circulating CD3+ T cells by flow cytometry > 500/mm3 and CD45RA+ CD62L+ CD3+ T cells < 50/mm3 and TRECs less than 100 per 100,000 CD3+ cells. T cell proliferative response to PHA more than 20-fold over background. Circulating CD3+ T cells by flow cytometry > 500/mm3 and CD45RA+ CD62L+ CD3+ T cells < 50/mm3 and TRECs less than 100 per 100,000 CD3+ cells. T cell proliferative response to PHA more than 20-fold over background. While T cell response to PHA might have been seen, eligible subjects were to have no T cell proliferative response to antigens (less than 20-fold response) and were to have serious clinical problems related to immunodeficiency, such as opportunistic infection or failure to thrive. Exclusion Criteria: Subjects on ventilators, with tracheostomies, with cytomegalovirus (CMV) infections, or requiring ongoing steroids could still be enrolled, but their data were to be analyzed separately Subjects who had heart surgery < 4 weeks prior to transplant Heart surgery anticipated within 3 months of the proposed time of transplantation Ongoing parenteral steroid therapy between enrollment and transplantation Present or past lymphadenopathy Rash associated with T cell infiltration of the dermis and epidermis Rejection by the surgeon or anesthesiologist as surgical candidates Lack of sufficient muscle tissue to accept a transplant of 4 g/m2 body surface area (BSA) of the recipient Prior attempts at immune reconstitution, such as bone marrow transplantation or previous thymus transplantation Human immunodeficiency virus (HIV) infection
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Cultured Thymus Tissue Implantation in Complete DiGeorge<br>Participants with Complete DiGeorge Syndrome, who were eligible, received cultured thymus tissue implantation (CTTI). No specific dose was assigned. There was a one time administration of the cultured thymus tissue. | Biological: Cultured Thymus Tissue for Implantation (CTTI)<br>* Cultured thymus tissue for implantation (CTTI) (previously described as transplantation) is done using allogeneic cultured postnatal tissue from unrelated thymus donors. Thymus tissue, the thymus donor, & thymus donor's birth mother were screened for safety. Approximately 2-3 weeks post-harvest thymus slices were implanted into the recipient's quadriceps. Dose was number of grams of cultured thymus tissue divided by the recipient's weight in kilograms. Minimum dose was 4 g/m2. Maximum dose 18g/m2. At time of CTTI, a skin biopsy was obtained to look for preexisting T cells. 2-3 months post-CTTI allograft biopsy to evaluate for thymopoiesis & graft rejection. At time of biopsy, skin biopsy done to look for T cell clonal populations. Post-CTTI, subjects followed by routine research immune evaluations, using blood samples for approximately 2 years.<br>* Other names: CTTI;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Survival at 1 Year Post-Cultured Thymus Tissue Implantation (CTTI) | Survival at 1 year post CTTI was assessed using the Kaplan Meier Estimated Survival. This mathematical function estimates the survival for a certain length of time. | 1 year post-CTTI | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Survival at 2 Years Post-CTTI | Survival at 2 years post CTTI was assessed using the Kaplan Meier Estimated Survival. This mathematical function estimates the survival for a certain length of time. | 2 years post-CTTI | 
| Immune Reconstitution Efficacy - Total CD3 T Cells | The development of total CD3 T cells at one year as measured using flow cytometry | 1 year post-CTTI | 
| Immune Reconstitution Efficacy - Total CD4 T Cells | The development of total CD4 T cells at one year as measured using flow cytometry | 1 year post-CTTI | 
| Immune Reconstitution Efficacy - Total CD8 T Cells | The development of total CD8 T cells at one year as measured using flow cytometry | 1 year post-CTTI | 
| Immune Reconstitution Efficacy - Naive CD4 T Cells | The development of naive CD4 T cells at one year as measured using flow cytometry | 1 year post-CTTI | 
| Immune Reconstitution Efficacy - Naive CD8 T Cells | The development of naive CD8 T cells at one year as measured using flow cytometry | 1 year post-CTTI | 
| Immune Reconstitution Efficacy - Response to Mitogens | The development of a T cell proliferative response to the mitogen phytohemagglutinin. | 1 year post-CTTI | 
| Thymus Allograft Biopsy | Evidence, on biopsy of the thymus tissue implanted in muscle, that shows the development of new T cells. | 2 to 3 months post-CTTI | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Primary immunodeficiency, Thymus Transplantation, DiGeorge Syndrome, Athymia, Low T cell numbers, Immunoreconstitution, DiGeorge Anomaly, Complete DiGeorge, Typical DiGeorge, Cultured Thymus Tissue Implantation (CTTI)