Registry Study of Revcovi Treatment in Patients With ADA-SCID

Completed

Brief Summary: This registry study is being conducted in patients with adenosine deaminase severe combined immune deficiency (ADA-SCID) who require enzyme replacement therapy (ERT) treatment with Revcovi. Data on safety and on measures of efficacy are collected.

Detailed Description: Patients with ADA-SCID who require ERT will receive Revcovi on a dosage and schedule determined by the treating physician. They will be followed for safety throughout the study, and will be monitored for the efficacy markers of adenosine deaminase (ADA) activity and deoxyadenosine nucleotide (dAXP) concentration according to a suggested schedule. Some subjects will be new to ERT; some will have transitioned from Adagen, which was the ERT available before Revcovi; and some will have previously participated in an earlier Phase 3 trial of Revcovi (study STP-2279-002). Patients will be followed either until they are able to successfully undergo a stem cell transplant or stem cell gene therapy and thus no longer require ERT treatment, or until all ongoing participants have received a minimum of 24 months of Revcovi treatment.

Note: Due to the nature of this study, all analyses are descriptive and no statistical hypotheses will be tested.

Recruitment & Eligibility

Inclusion Criteria

Male or female, aged newborn to adult
In need of ERT treatment due to one of the following circumstances:
- Waiting to receive a stem cell transplant
- Previously declined, had been found to be ineligible for, or did not respond to a stem cell transplant
- Waiting to enrol in a clinical trial on gene therapy, or had been found to be ineligible for or had failed such a trial
One of the following histories of ERT treatment:
- Revcovi only
- Previously on Adagen but had transitioned to Revcovi
- Not yet on any ERT but about to start on Revcovi

Exclusion Criteria

Any condition that, in the opinion of the Investigator, makes the patient unsuitable for the study.

Arm && Interventions

Group	Intervention	Description
Patients with ADA-SCID in need of ERT treatment	elapegademase-lvlr	All participants will receive Revcovi. For analysis purposes, there will be three groups, who differ with respect to ERT history: * Adagen-naïve: Subjects starting on ERT for the first time * Adagen-transitioning: Subjects switching from Adagen to Revcovi * STP-2279-002 participants: Subjects who had taken part in an earlier Phase III trial of Revcovi (study STP-2279-002) in which they had been switched from Adagen to Revcovi. This last group differs from the Adagen-transitioning group in that they will have been on Revcovi the longest.

Primary Outcome Measures

Name	Time	Method
Number of Subjects Meeting the Toxicity Threshold for Deoxyadenosine Nucleotide (dAXP) Concentration at the Last Measurement	From enrollment to end of treatment up to Month 24	A deficiency in the ADA enzyme results in a build-up of dAXP nucleotides, which are toxic to lymphocytes and lead to impairment of immune function. A detoxified level of dAXP concentration is defined as a trough value of 0.02 millimoles per liter (mmol/L) or lower. Data are presented as the number of subjects who met the targeted threshold at the final measurement, whether that took place at Month 24 or earlier.
Number of Subjects Meeting the Optimal Threshold for ADA Activity at the Last Measurement	From enrollment to end of treatment up to Month 24	An optimal level of ADA plasma activity is defined as a trough value of 30 millimoles per hour per liter (mmol/h/L) or greater. Data are presented as the number of subjects who met the targeted threshold at the final measurement, whether that took place at Month 24 or earlier.
Safety of Revcovi	From enrollment to end of treatment up to Month 24	The number of subjects reporting adverse events (AEs). Due to the nature of ADA-SCID, only AEs deemed to be at least possibly related to Revcovi treatment were documented.

Secondary Outcome Measures

Name	Time	Method

Locations (14): Seattle Children's
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Seattle, Washington, United States
University of California Los Angeles
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Los Angeles, California, United States
UPMC Children's Hospital of Pittsburgh
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Pittsburgh, Pennsylvania, United States
Childrens Hospital of New Orleans
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New Orleans, Louisiana, United States
Allergy & Asthma Medical Group and Research Center, A P.C.
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San Diego, California, United States
UCSF - University of California
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San Francisco, California, United States
Children's National
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Washington, District of Columbia, United States
University of South Florida Allergy Immunology Clinic
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Saint Petersburg, Florida, United States
Children's Minnesota
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Minneapolis, Minnesota, United States
Duke University Hospital
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Durham, North Carolina, United States
St. Louis Children's Hospital - Washington University School of Medicine
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Saint Louis, Missouri, United States
UBMD Pediatrics Outpatient Center
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Buffalo, New York, United States
Le Bonheur Children's Hospital
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Memphis, Tennessee, United States
Penn State Children's Hospital
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Hershey, Pennsylvania, United States