A single-arm, open-label, phase I/II clinical trial of autologous hematopoietic stem and progenitor cells (HSPCs) genetically modified with a lentiviral vector (LVV) encoding for the human programmed death-ligand 1 (hPD-L1) complementary deoxyribonucleic acid (cDNA) for the treatment of patients with type 1 diabetes (T1D) at recent onset and with residual β-cell function (Immunostem)

The primary objective of this clinical trial is to evaluate the safety of autologous hematopoietic stem and progenitor cells genetically modified with a lentiviral vector encoding human programmed death-ligand 1 in patients with recently diagnosed type 1 diabetes who retain residual β-cell function. This assessment is clinically relevant to determine the tolerability and risk profile of this novel gene therapy approach aimed at modulating immune responses in early-stage disease.

The secondary objectives include:

• Evaluation of participant improvements in key clinical parameters of diabetes management.

• Assessment of pharmacodynamic parameters.

• Exploratory assessment of immunologic and other pharmacodynamic parameters.

The sponsor did not provide information regarding the total number of participants enrolled in this clinical trial. The study population includes both **male** and **female** patients diagnosed with **Type 1 diabetes**, with an age range of **18 to 40 years**. Participants are required to have recent disease onset, specifically receiving the investigational product within **180 days** from the first **insulin** administration. The trial population was selected based on specific clinical criteria, including **HbA1c** levels between 53 and 150 mmol/mol, positivity to at least two **autoantibodies** (such as anti-insulin, anti-glutamic acid decarboxylase 65, anti-islet antigen 2, anti-zinc transporter 8, or anti-islet cell antibody), and detectable **basal C-peptide** levels of at least 0.2 nmol/L or stimulated C-peptide peak levels during a 2-hour **mixed meal tolerance test**. Participants must be capable of providing informed consent and complying with all protocol procedures throughout the study duration. The trial involves a vulnerable population and patients with the specified medical condition.

This is a single-arm, open-label, phase I/II clinical trial evaluating the safety and efficacy of autologous **hematopoietic stem and progenitor cells** (HSPCs) genetically modified with a **lentiviral vector** encoding for the human **programmed death-ligand 1** (hPD-L1) complementary deoxyribonucleic acid (cDNA) for the treatment of patients with **type 1 diabetes** at recent onset and with residual β-cell function. The investigational medicinal product consists of an autologous CD34+-enriched population containing HSPCs transduced ex vivo with a third generation VSV-G pseudotyped lentiviral vector encoding the hPD-L1 cDNA, formulated as a suspension for injection and administered via the **intravenous** route. The trial will enroll male and female patients aged 18 to 40 years who have been diagnosed with type 1 diabetes within 180 days from the first insulin administration and demonstrate residual β-cell function with basal **C-peptide** levels of at least 0.2 nmol/L or stimulated C-peptide peak of at least 0.2 nmol/L during a 2-hour **mixed meal tolerance test**. Eligible patients must have **HbA1c** levels between 53 and 150 mmol/mol and test positive for at least two diabetes-related **autoantibodies**, including anti-insulin, anti-glutamic acid decarboxylase 65, anti-islet antigen 2, anti-zinc transporter 8, or anti-islet cell antibody.

The primary objective of the clinical trial is to evaluate the safety of the study treatment. The primary endpoint consists of the evaluation of safety parameters, including the number and description of adverse events based on vital signs, laboratory tests, and the frequency and severity of adverse events and **serious adverse events**. Safety parameters will be assessed over the first 3, 12, and 24 months of follow-up in patients enrolled during the pilot phase. The trial incorporates a **Data Safety Monitoring Board** that will evaluate safety results of the pilot phase at the 3-month assessment, and positive evaluation will allow continuation of enrollment. Secondary endpoints include changes over time in the 3-hour area under curve and normalized area under curve of C-peptide response to a mixed meal tolerance test over 12 and 24 months, changes in glucose metrics from **continuous glucose monitoring** including time in glycaemic target range (>70 to ≤180 mg/dL), time in tight range (70-140 mg/dL), time above range, and time below range during the previous 14 days, exogenous insulin requirement expressed as units per kilogram per day, changes and trend analysis of HbA1c levels over 12 and 24 months, and number of self-reported episodes of severe hypoglycaemia.

Additional secondary endpoints include longitudinal analysis of **vector copy number** in peripheral blood samples to assess frequency and persistence of infused cells and their progenies, and in cases where vector copy number exceeds the limit of quantification, execution of **vector insertion site analysis**. Exploratory endpoints encompass estimated glucose disposal rate, changes in autoantibody titres (including anti-insulin, anti-glutamic acid decarboxylase 65, anti-islet antigen 2, anti-zinc transporter 8, and anti-islet cell antibody), correlation between vector copy number and continuous glucose monitoring-derived glucose, and changes in extended immunophenotype analyses including **NK cells**, **B cells** and **T cells**, T cell subpopulations, and **T regulatory cells** (including FOXP3+ cells). The trial is designed as a single-arm, open-label study without randomization or blinding, representing a first-in-human clinical trial using gene therapy with autologous stem cells. The estimated recruitment start date is August 2025, with an estimated end date of August 2029, indicating an overall trial duration of approximately four years. Participant involvement will extend for a minimum of 24 months following treatment administration to allow for comprehensive safety and efficacy assessments. Conditions that may lead to early termination from the study would be determined based on safety considerations as evaluated by the Data Safety Monitoring Board, occurrence of unacceptable adverse events, participant withdrawal of consent, or inability to comply with protocol procedures.

The experimental treatment under investigation is IMMUNOSTEM, an autologous CD34+ hematopoietic stem and progenitor cell (HSPC) product that has been genetically modified ex vivo. The product consists of a CD34+-enriched cell population transduced with a third-generation VSV-G pseudotyped lentiviral vector (LVV) encoding the human programmed death-ligand 1 (hPD-L1) complementary deoxyribonucleic acid (cDNA). This represents an advanced therapy medicinal product classified as a gene therapy involving autologous cells of human origin. The pharmaceutical form is a suspension for injection intended for intravenous administration. The product is a genetically modified organism (GMO) as it involves gene transfer through a lentiviral vector, although the genetic modification is performed ex vivo rather than in vivo. The gene of interest incorporated into the autologous HSPCs is the human programmed death-ligand 1 (hPD-L1) gene.

The clinical trial is designed as a single-arm, open-label, phase I/II study evaluating this investigational cell therapy product in patients with type 1 diabetes at recent onset who retain residual β-cell function. The primary objective focuses on evaluating the safety of the study treatment. As this is a single-arm trial design, no comparator treatment or placebo control group is specified in the available trial documentation.

The primary endpoint will be the evaluation of safety of the study treatment, including the number and description of adverse events based on vital signs, laboratory tests, frequency and severity of **adverse events** and **serious adverse events**. Safety parameters will be assessed over the first 3, 12, and 24 months of follow-up in the patients enrolled during the pilot phase. Secondary endpoints include changes over time of the 3-hour area under curve (AUC) and ΔAUC normalized by baseline glucose blood levels of **C-peptide** response to a **mixed meal tolerance test** (MMTT) over 12 and 24 months. Changes in glucose metrics from **continuous glucose monitoring** over 12 and 24 months will be evaluated, including time in glycemic target range expressed as a daily average of the percentage of time in a 24-hour day a participant's blood glucose is greater than 70 but less than or equal to 180 mg/dL (greater than 3.9 to less than or equal to 10.0 mmol/L) during the previous 14 days, time in tight range (70-140 mg/dL) during the previous 14 days, time above range (180-250 and greater than 250 mg/dL) during the previous 14 days, and time below range (level 1: 54-70 and level 2: less than 54 mg/dL). Additional secondary endpoints include exogenous insulin requirement defined as a daily average in units per kilogram per day (U/kg/day) during the previous 14 days, changes and trend analysis of **HbA1c** levels over 12 and 24 months, and the number of self-reported episodes of severe hypoglycemia (CTCAE version 5.0 grade 3). Longitudinal analysis of **vector copy number** (VCN) in peripheral blood samples will be performed to assess frequency and persistence of infused cells and their progenies. In case of VCN greater than the limit of quantification, **vector insertion site analysis** (VISA) will be executed. Exploratory endpoints include estimated glucose disposal rate (eGDR), changes in **autoantibody** titres (including but not limited to anti-insulin, anti-glutamic acid decarboxylase 65, anti-islet antigen 2, anti-zinc transporter 8, anti-islet cell antibody), correlation between VCN and CGM-derived glucose, and changes in extended immunophenotype analyses including NK, B and T cells, T cell subpopulations, and **T regulatory cells** (including FOXP3+ cells).