Registry Study of Revcovi Treatment in Patients With ADA-SCID

Study Overview
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Brief Summary
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This registry is conducted in patients with adenosine deaminase severe combined immune deficiency (ADA-SCID) treated with Revcovi™ to collect periodic clinical and biochemical data on safety and dose adjustment.

Detailed Description
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Patients with ADA-SCID who require treatment with Revcovi as Enzyme Replacement Therapy (ERT) will be followed until the last enrolled patient has reached a minimum of 24 months of Revcovi treatment or until undergoing HSCT or HSCGT, whichever occurs first. Patients undergoing HSCT or HSC-GT will be followed one month after last Revcovi dose and again at six months to assess adverse events (AEs) and survival. Throughout the duration of the study, patients will be assessed continually for AEs. Patients/Parents/Caregivers will self-administer weekly intramuscular (IM) dose(s) of Revcovi and will be followed according to the Suggested Schedule of Assessments for trough dAXP and ADA activity. Treatment dosing and monitoring will be individualized per provider and patient characteristics in adherence with each study sites' standards of care. Patients in the Phase 3 Revcovi™ study (STP-2279-002) will be given the opportunity to enroll in this registry study and proceed to the Treatment Month 6 Visit per the Suggested Schedule of Assessments for Adagen-Transitioning Patients.

Official Title
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Single Arm, Open-Label, Multicenter, Registry Study of Revcovi (Elapegademase-lvlr) Treatment in ADA-SCID Patients Requiring Enzyme Replacement Therapy

Conditions
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Adenosine Deaminase Deficiency, Severe Combined Immunodeficiency

Intervention / Treatment
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* Biological: elapegademase-lvlr


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients currently receiving chronic ERT with Adagen® and transitioned/transitioning to Revcovi; Infants diagnosed via newborn screening and definitive testing for ADA deficiency prescribed Revcovi; Patients receiving Revcovi while preparing for Hematopoietic Stem Cell Transplant (HSCT) or Hematopoietic Stem Cell Gene Therapy (HSCGT) Patients who decline, are ineligible or do not respond to HSCT or HSC-GT and resume/start Revcovi. Exclusion Criteria: Any condition that, in the opinion of the Investigator, makes the patient unsuitable for the study.

Ages Eligible for Study
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Minimum Age: 0 Months
Maximum Age: 65 Years

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ERT with ADA<br>Patients with diagnosis of ADA-SCID treated with ERT with Revcovi or transitioning to Revcovi from Adagen | Biological: elapegademase-lvlr<br>* Patients transitioning from Adagen: For patients currently receiving Adagen at ≤ 30 U/kg/wk or an unknown Adagen dose, the suggested dosage of Revcovi is 0.2 mg/kg/wk IM. For patients currently receiving Adagen at > 30 U/kg/wk the suggested equivalent Revcovi dosage (mg/kg/wk) is the Adagen dosage in U/kg/wk divided by 150. At the investigator's discretion, the total weekly dose may be divided and administered in multiple IM injections, increased by 0.033 mg/kg/wk if trough ADA activity is < 30 mmol/hr/L, dAXP is > 0.02 mmol/L, and/or the immune reconstitution is inadequate. Adagen-naïve patients: The suggested starting Revcovi dosage is 0.2 mg/kg twice weekly IM based on ideal body weight, for a minimum of 12 to 24 weeks until immune reconstitution is achieved. At the investigator's discretion, the dosage may be gradually increased to maintain trough ADA activity > 30 mmol/hr/L, dAXP < 0.02 mmol/L, and/or to maintain adequate immune reconstitution.<br>* Other names: Revcovi;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Deoxyadenosine nucleotides (dAXP) activity | Total trough erythrocyte dAXP activity | Month 24 | 
| ADA activity | Trough plasma ADA activity | Month 24 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immune status (SSA/PI) | Absolute lymphocyte count and subset B, T, and NK analysis. Immunoglobulin (Ig) concentrations (IgG, IgA, and IgM). Measurement of immune response at Investigator discretion. | Month 24 | 
| Clinical status | Infections (clinically or microbiologically documented) Incidence and duration of hospitalizations Growth for patients < 18 years old Overall survival through the end of study | Month 24 | 
| Safety assessed by determining adverse events (AEs), serious adverse events (SAEs) | Assessed by determining adverse events (AEs), serious adverse events (SAEs), clinical signs and symptoms from physical examinations, and laboratory examinations | Month 24 |