A Study Evaluating the Safety and Efficacy of the GMCN-508A Drug Product in Transfusion-dependent α-Thalassemia Participants

Percentage of Participants Who Achieved Transfusion Independence (TI) at Month 24

TI was defined as a weighted average Hb \>= 9 g/dL without any pRBC transfusions for a continuous period of \>= 12 months at any time during the study after GMCN-508A Drug Product infusion.

Time frame: Month 24

Duration of Transfusion Independence (TI)

TI was defined as a weighted average Hb \>= 9 g/dL without any pRBC transfusions for a continuous period of \>= 12 months at any time during the study after GMCN-508A Drug Product infusion. Time period of TI will start when participants achieve a Hb \>= 9 g/dL with no transfusions in the preceding 60 days. Duration of TI was calculated as the time from the start of TI (i.e. first Hb \>= 9 g/dL with no transfusions in the preceding 60 days) up to the last available Hb at which the TI criteria are still met.

Time frame: From time of drug product infusion up to 24 months

Time From GMCN-508A Drug Product Infusion to Achieving Transfusion Independence (TI)

TI was defined as a weighted average Hb \>= 9 g/dL without any pRBC transfusions for a continuous period of \>= 12 months at any time during the study after GMCN-508A Drug Product infusion. Time from drug product infusion to initial achievement of TI was calculated as the time from drug product infusion to the first Hb at which a participant can be declared as TI.

Time frame: From time of drug product infusion up to 24 months

Weighted Average Hemoglobin (Hb) During Period of Transfusion Independence (TI)

The weighted average Hb is an average area under the curve during the period of TI, from the start of TI when the Hb is first \>= 9 g/dL with no transfusions in the preceding 60 days to the last available Hb at which the TI criteria are still met.

Time frame: From time of drug product infusion up to 24 months

Annualized Number of pRBC Transfusions

Annualized number of pRBC transfusions from 12 months post-drug product infusion through Month 24 compared to the annualized number of transfusions during the 24 months prior to enrollment.

Time frame: From 12 to 24 months post drug product infusion

Annualized Volume of pRBC Transfusions

Annualized volume of pRBC transfusions from 12 months post-drug product infusion through Month 24 compared to the annualized volume of transfusions during the 24 months prior to enrollment.

Time frame: From 12 to 24 months post drug product infusion

Proportion of Participants Who Have Not Received Chelation Therapy for At Least 6 Months Following Drug Product Infusion.

Time frame: From 6 to 24 months

Change From Baseline in liver Iron Content by Magnetic Resonance Imaging (MRI)

Time frame: Baseline, Month 12 and 24

Change From Baseline in Cardiac T2* on MRI

Time frame: Baseline, Month 12 and 24

Change From Baseline in Serum Ferritin

Time frame: Baseline, Month 12 and 24

Time to Neutrophil Engraftment

Time to neutrophil engraftment was defined as the time to the first of 3 consecutive absolute neutrophil count (ANC) \>= 0.5 × 10\^9/L obtained on different days after a post-transplant value of \< 0.5 × 10\^9/L. The Day of neutrophil engraftment is the first day of the 3 consecutive measurements, where Day 0 is the day of drug product infusion.

Time frame: From time of drug product infusion up to 24 months

Proportion of Participants With Successful Platelet Engraftment

Platelet engraftment was defined as achieving 3 consecutive platelet values \>= 20 × 10\^9/L on different days after a post-transplant value of \< 20 × 10\^9/L, while no platelet transfusions administered for 7 days immediately preceding and during the evaluation period.

Time frame: From time of drug product infusion up to 24 months

Time to Platelet Engraftment

Platelet engraftment was defined as achieving 3 consecutive platelet values \>= 20 × 10\^9/L on different days after a post-transplant value of \< 20 × 10\^9/L, while no platelet transfusions administered for 7 days immediately preceding and during the evaluation period.

Time frame: From time of drug product infusion up to 24 months

Change From Baseline in Pediatric Quality of Life Inventory (PedsQL) Generic Core Scale (GCS) Score

PedsQL GCS is designed to measure health-related quality of life in pediatric participants and adolescents (2 to 18 years of age). It encompasses 4 dimensions of functioning (physical \[8 items\], emotional \[5 items\], social \[5 items\], school \[3 items\]). Age groups: Toddler (2-4 years), Young pediatric (5-7 years), Pediatric (8-12 years), and Teens (13-18 years). Depending on the participant's age, the questionnaire may be completed by parent/caregiver as appropriate. For the Toddler group, the PedsQL GCS consist of 21 items, using a 5-point Likert scale (0 to 4); for all other groups, the PedsQL GCS consist of 23 items, with a 3-point Likert scale (0, 2, 4) for the young pediatric, and a 5-point Likert scale for the pediatric and teens groups. Scores are transformed on a scale from 0 to 100 where 0=100, 1=75, 2=50, 3=25, and 4=0. Higher scores indicate improved quality of life.

Time frame: Baseline, Month 12 and 24

Change From Baseline in Short Form-36 Health Survey (SF-36)

SF-36 is a generic quality-of-life instrument that had been widely used to assess HRQL of participants. Generic instruments were used in general populations to assess a wide range of domains applicable to a variety of health states, conditions, and diseases. The SF-36 consisted of 36 items that were aggregated into 8 multi-item scales (physical functioning \[1=yes, limited a lot to 3=no, not limited at all\], role-physical \[1=all of the time to 5=none of the time\], bodily pain \[1=very severe to 6=none\], general health \[1=poor to 5=excellent\], vitality \[1=none of the time to 5=all of the time\], social functioning \[1=all of the time: to 5=none of the time\], role emotional \[1=all of the time to 5=none of the time\] and mental health \[1=all of the time to 5=none of the time\]), with scores ranged from 0 to 100. Higher scores indicating better HRQL.

Time frame: Baseline, Month 12 and 24

Proportion of Participants With Successful Neutrophil Engraftment

Neutrophil engraftment was defined as achieving 3 consecutive absolute neutrophil count (ANC) \>= 0.5 × 10\^9/L on different days after a post-transplant value of \< 0.5 × 10\^9/L within 42 days after drug product infusion.

Time frame: From time of drug product infusion up to 24 months

Transplant-related Mortality

Transplant-related mortality was determined by the investigator (any deaths considered related to the transplant.)

Time frame: Through 100 and 365 days post GMCN-508A Drug Product infusion

Proportions of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)

An AE was defined as any unfavorable and unintended sign (including abnormal laboratory findings), symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. A SAE was any AE, occurring at any dose and regardless of causality that: results in death, was life-threatening, required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect.

Time frame: From signing of informed consent to 24 months after the drug product infusion

Overall Survival

Overall survival was defined as time from date of GMCN-508A Drug Product infusion (Day 0) to date of death. Overall survival was censored at the date of last visit if the participant was still alive. Percentage of participants who survived throughout the study were reported.

Time frame: From time of drug product infusion up to 24 months

Incidence of acute and/or chronic graft-versus-host disease (GVHD)

acute and/or chronic graft-versus-host disease (GVHD) was determined by the investigator.

Time frame: From time of drug product infusion up to 24 months

Percentage of Participants Detected With Replication-competent Lentivirus (RCL)

Time frame: From time of drug product infusion up to 24 months

Percentage of Participants with occurrence of malignant disease

Time frame: From time of drug product infusion up to 24 months