Strimvelis Registry Study to Follow-up Patients With Adenosine Deaminase Severe Combined Immunodeficiency (ADA-SCID)

Adenosine Deaminase Severe Combined Immunodeficiency (ADA-SCID) Registry for Patients Treated With Strimvelis (Previously GSK2696273) Gene Therapy: Long-Term Prospective, Non-Interventional Follow-up of Safety and Effectiveness

Adenosine deaminase (ADA) enzyme deficiency results in severe combined immunodeficiency (SCID), a fatal autosomal recessive inherited immune disorder. Strimvelis (or GSK2696273) is a gene therapy intended for patients with ADA-SCID and for whom no suitable human leukocyte antigen (HLA) matched related stem cell donor is available. This therapy aims to restore ADA function in hematopoietic cell lineages, and in doing so prevents the pathology caused by purine metabolites (i.e., impaired immune function). This registry evaluates the long term safety and effectiveness outcomes of subjects who have received Strimvelis and is conducted as a post approval safety study associated with EMA marketing authorisation of Strimvelis™. In this study will be also included patients for whom the gene therapy medicinal product has been prepared starting from mobilized peripheral blood (mPB)-derived CD34+ cells (mPB-GT).

Study Overview

• Status: Enrolling by invitation
• Conditions: Immunologic Deficiency Syndromes
• Intervention / Treatment: Genetic: Strimvelis

Detailed Description

This is a prospective and retrospective, non-interventional follow-up registry of patients with ADA-SCID treated with Strimvelis™. The registry does not have a comparator group and the product will have been given on a single occasion prior to entering this registry. Safety and effectiveness will be assessed for a target number of 50 patients who will have received Strimvelis™ or GSK2696273 or mPB-GT. The end of enrollment will be after the recruitment of the 50th patient and the registry will close when the 50th patient finishes the 15- year follow-up.

• Study Type: Observational
• Enrollment (Estimated): 50

Contacts and Locations

Study Locations

• Italy
  • Lombardy
    • Milan, Lombardy, Italy, 20132
      • Ospedale San Raffaele

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This registry will include all subjects who have received Strimvelis (or GSK2696273) or mPB-GT and consented to participate in the registry. A target number of 50 subjects will be enrolled in the registry.

Description

Inclusion Criteria

1. Patients with ADA-SCID, treated with Strimvelis™ or GSK2696273, as part of its clinical development program or mPB-GT.
2. Adult patients, or patients for whom their parents or legal guardians have signed the informed consent form for participation in the registry.

There are no formal exclusion criteria for participation as this registry will follow all patients who have received Strimvelis™ or GSK2696273, or mPB-GT prior to enrollment, subject to informed consent.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

ADA-SCID subjects treated with Strimvelis; Subjects with ADA-SCID who have received Strimvelis (previously GSK2696273) gene therapy, comprising patients treated prior to marketing authorisation (i.e. clinical studies and compassionate use programs) and those treated after marketing authorisation. In this study will be also included patients for whom the gene therapy medicinal product has been prepared starting from mobilized peripheral blood (mPB)-derived CD34+ cells, treated under hospital exemption (HE) frame, according to the Italian Decree of the Ministry of Health, January 16th 2015, "Provisions on advanced therapy drugs prepared on a non-repetitive basis".

Genetic: Strimvelis; Strimvelis is a CD34+ cell enriched dispersion of human autologous bone marrow derived hematopoietic stem/progenitor cells transduced with a retroviral vector containing the human ADA gene. It will be administered as an intravenous infusion once only. In this study will be also included patients for whom the gene therapy medicinal product has been prepared starting from mobilized peripheral blood (mPB)-derived CD34+ cells, treated under hospital exemption (HE) frame, according to the Italian Decree of the Ministry of Health, January 16th 2015, "Provisions on advanced therapy drugs prepared on a non-repetitive basis".

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number (%) of subjects with fertility and positive pregnancy outcomes	Fertility and pregnancy related outcomes will be listed and/or summarised as appropriate. Number (%) of subjects with fertility and pregnancy outcome will be reported. If the registry remains open after an individual patient has been followed for 15 years post treatment, fertility and pregnancy related events and outcomes will continue to be solicited or spontaneously reported, every 2 years until the registry closes.	Up to 15 years
The number (%) of subjects with an abnormal retroviral insertion site (RIS) analysis.	Data from RIS will be collected only if an HCP has performed these tests (e.g. following suspected malignancy or after a diagnosis of malignancy). The number (%) of subjects with an abnormal result will be summarized.	Up to 15 years.
Frequency of adverse events of special interest	The following adverse events of interest will be evaluated: AEs and SAEs related to medical or surgical procedures associated with Strimvelis™ administration (e.g. central venous catheter, busulfan conditioning).; Oncogenesis.; Autoimmunity/autoinflammatory events.; Unsuccessful response to gene therapy.; Risks related to short shelf-life of product.; Non-immunologic manifestations of ADA-SCID (e.g. hepatic steatosis, cognitive defects, behavioral abnormalities, hearing impairment).; Risks related to residuals present in the drug product administered to the patient.; Hypersensitivity to the product.; Replication competent retrovirus. The number (%) of patients experiencing AESIs in each of these categories along with the number of events will be summarized by System Organ Class (SOC) and Preferred Term (PT).	Up to 15 years
Frequency of reported AEs and SAEs/ADRs	The number (%) of patients experiencing AEs along with the number of events will be summarized by System Organ Class (SOC) and Preferred Term (PT).; overall;; by severity grade;; AEs grade 3 or higher;; AEs related to treatment;; SAEs;; SAEs grade 3 or higher;; SAEs related to treatment;; AEs leading to study discontinuation. These summaries will be repeated for the rate of events per person year.	Up to 15 years
Actual values of laboratory blood test results (i.e. biochemistry, haematology) at each annual visits.	The baseline evaluation for each parameter will be the final evaluation prior to treatment with Strimvelis™. For each parameter, the actual value will be summarized at each annual visit using descriptive statistics. Laboratory evaluations will be flagged against the normal range as low/normal/high. For each parameter, the number (%) of subjects with evaluations that were low/normal/high relative to the normal range will be summarized by annual visit. Out of range values will be assessed for their clinical significance. For each parameter, the number (%) of subjects with clinically significant evaluations will be summarized by annual visit and at any time post-treatment.	At each annual visit up to 15 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall Survival	Number and cause of deaths and time to onset of fatal events will be summarised. Starting time will be the date of therapy administration.	Up to 15 years
Event (Intervention) free survival	Event (Intervention) free survival will be evaluated using the time in years from treatment with Strimvelis to either the first intervention (Hematopoietic Stem Cell Transplant or >3 months of Enzyme Replacement Therapy). Summary statistics, proportions and rates will be provided.	Up to 15 years.
Growth	Growth (i.e. height and weight) percentiles will be calculated and compared to World Health Organisation (WHO) standard growth charts.	Up to 15 years.
Number and proportion of patients with severe infections, and associated length of stay	Severe infections, defined as infections requiring hospitalization or prolonging hospitalization, will be identified from the adverse event data. The rate of infection will be calculated as number of severe infections divided by the person-years of observation after treatment with Strimvelis™. The cumulative number (%) of patients with severe infections and the cumulative rate of severe infections will be presented at each year post treatment along their 95% CI.	Up to 15 years.
The number (%) of subjects falling into each category for pediatric development and quality of life assessments	Pediatric development assessments will include: whether the child is attending a school appropriate for age; whether the child is in an age-appropriate grade/class at school; whether the child requires special educational support (e.g. dedicated tutor); participation in sports as desired by child; requirement for hearing aid(s); impact of the child's health on the guardian's employment. For each of these assessments, the number (%) of subjects falling into each category for these assessments will be summarized over time. For Karnofsky and Lansky scores, the actual value and change from baseline will be summarized at each annual visit using descriptive statistics.	Up to 15 years.
Patient (or proxy) reported Peds-QL	Data from patient (or proxy) reported outcome measures and development questionnaires [e.g. Peds-QL] where they are used routinely as part of a physician's standard of care or where permitted by local authorities as non-interventional assessments, will also be summarised. Absolute scores will be calculated.	Up to 15 years.
The number (%) of subjects requiring use of treatments of interest	The medications/treatments of interest in this study are ERT, HSCT, Immunoglobulins, radiotherapy and cytotoxic agents. Categorical responses for whether subjects have received these treatments are captured per annual visit. The number (%) of subjects requiring each of these treatments and any of these treatments will be summarized at each annual visit throughout the follow-up period and overall. For ERT, the duration of treatment and number of patients requiring more than three months of continuous treatment will be summarized.	Up to 15 years.
Immune reconstitution	Peripheral lymphocytes and T cell function from response to mitogens will be evaluated. Actual counts and the change from baseline will be summarized at each annual visit using summary statistics (n, mean, 95% CI, SD, geometric mean, (gCV), minimum, median, maximum).	Baseline and annually up to 15 years.
Systemic metabolite detoxification	Systemic metabolite detoxification will be assessed using dAXP levels in RBCs and ADA activity in plasma, RBCs and lymphocytes. Actual values and the change from baseline will be summarized at each annual visit using summary statistics (n, mean, 95% CI, SD, geometric mean, gCV, minimum, median, maximum). The geometric mean and 95% CI will be plotted over time. In addition, individual plots over time will be produced. Adequate ADA activity is defined as a level of >= 210 nmol/h/mg, adequate dAXP in RBC is defined as < 100 nmol/mL. The number (%) of patients with adequate levels of ADA activity and dAXP will be summarized.	Baseline and annually up to 15 years.
Vector copy number, measured in PBMCs (peripheral blood mononuclear cells) and subpopulations.	Vector copy number (VCN) will be measured in PBMCs and and subpopulations CD3+, CD4+, CD8+, CD19+, CD15+ and CD56+ cells and summarized. VCN will be summarized by visit using summary statistics (n, mean, 95% CI, SD, geometric mean, gCV, minimum, median, maximum).	Up to 15 years.
Response to childhood vaccinations	Response to vaccinations against tetanus toxoid, diphtheria, pertussis, hepatitis B, hemophilius influenzae B (HIB), pneumococcus and measles, mumps and rubella (MMR) will be assessed. The number of subjects receiving each vaccination and any vaccination will be summarized along with the number (%) of those subjects with a positive response. The exact binomial 95% confidence interval will be provided for each response category of each vaccination type.	Up to 15 years.

Collaborators and Investigators

• Sponsor: Fondazione Telethon
• Investigators: Study Director: Fondazione Telethon, Fondazione Telethon

Publications and helpful links

General Publications

• Migliavacca M, Barzaghi F, Fossati C, Rancoita PMV, Gabaldo M, Dionisio F, Giannelli S, Salerio FA, Ferrua F, Tucci F, Calbi V, Gallo V, Recupero S, Consiglieri G, Pajno R, Sambuco M, Priolo A, Ferri C, Garella V, Monti I, Silvani P, Darin S, Casiraghi M, Corti A, Zancan S, Levi M, Cesana D, Carlucci F, Pituch-Noworolska A, AbdElaziz D, Baumann U, Finocchi A, Cancrini C, Ladogana S, Meinhardt A, Meyts I, Montin D, Notarangelo LD, Porta F, Pasquet M, Speckmann C, Stepensky P, Tommasini A, Rabusin M, Karakas Z, Galicchio M, Leonardi L, Duse M, Guner SN, Di Serio C, Ciceri F, Bernardo ME, Aiuti A, Cicalese MP. Long-term and real-world safety and efficacy of retroviral gene therapy for adenosine deaminase deficiency. Nat Med. 2024 Feb;30(2):488-497. doi: 10.1038/s41591-023-02789-4. Epub 2024 Feb 14.

Study record dates

Study Major Dates

• Study Start (Actual): May 5, 2017
• Primary Completion (Estimated): December 31, 2045
• Study Completion (Estimated): December 31, 2045

Study Registration Dates

• First Submitted: March 23, 2018
• First Submitted That Met QC Criteria: March 23, 2018
• First Posted (Actual): March 27, 2018

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: gene therapy; ADA-SCID; retroviral vector; Strimvelis; inherited immune disorder; previously GSK2696273
• Additional Relevant MeSH Terms: Immune System Diseases; Immunologic Deficiency Syndromes; Severe combined immunodeficiency due to adenosine deaminase deficiency
• Other Study ID Numbers: STRIM-003

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No