The goal of this clinical trial is to test the safety and efficacy of hUC-MSCs in children with severe BPD. There are three specific objectives as follow:
- To evaluate the long-term safety and efficacy of intravenous hUC-MSCs to children with severe BPD.
- To test the hypothesis that administration of hUC-MSCs can reduce the duration of mechanical ventilation and oxygen, and improve the impairment of pulmonary structure in children with severe BPD.
- To explore the potential therapeutic mechanism regarding hUC-MSCs for severe BPD.
Study design and setting
The MSC-BPD trial had been registered at www.clinicaltrials.gov (NCT03601416), which is a randomized, single-center and dose-escalation phase II trial to evaluate safety and efficacy of hUC-MSCs in a total 48 children with severe BPD. A study flow chart of the trial is shown in Fig. 1. The study protocol will be reported based on SPIRIT guidelines (Additional file 1).
This trial will be conducted at Children’s hospital of Chongqing Medical University (CHCMU) in Chongqing of China.
Sample size and calculation
The phase II trial is a randomized, controlled trial, and its size is calculated by power analysis using online calculator, Power and Sample Size (http://powerandsamplesize.com/ ). The trial is designed to investigate the hypotheses of two interventions compared to control, but not powered to test differences between the two interventions groups. The primary outcome measure is the change in the cumulative duration of oxygen therapy. The cumulative duration of oxygen therapy of severe BPD is patients reported as 90±15d [4, 13]. This trial is powered to find a difference of 15% (from 90d in the control group to 77d in the intervention groups) in participants who accept the interventions. Meanwhile, the power is set at 0.8, type I error ɑ is 0.05 and type II error β is 0.20. The calculated sample size is 14 for each group. To account for the possibility rate of patients being lost to follow-up is about 10%, the final sample size will be 16 and the total size is 48 in phase II trial.
Patient and public involvement
All the participants will not be involved in the development of the trial including the design, recruitment and conduct of the study, the selection of research question and outcome measures. The participation will be voluntary and the participants will have freedom to participate or withdraw this trial at any time throughout the study. The privacy of participants will be protected.
Participants will be enrolled into this study according to the inclusion and exclusion criteria (Table 1). The parents or guardians of all participants should provide written informed consent form approved by the Ethics Committee of Stem Cell Clinical Research of CHCMU.
Inclusion and exclusion criteria
The inclusion and exclusion criteria are listed in Tables 1. Participants' age is between 0 and 1 year old. The diagnostic criteria and severity gradation for BPD refers to the criteria established by NICHD workshop . The Silverman and Andersen Score is used to access the severity of abnormal respiratory manifestations .
Patients can only be enrolled in this study after passing the citywide consultation resolution and signing the informed consent form.
There are three sources to recruit the participants. Firstly, potentially eligible hospitalized patients diagnosed as severe BPD will be informed, and asked the permission to join in this study. Secondly, patients with severe BPD who had been discharged, physicians will generate lists of patients with a diagnosis of BPD within one year in the electronic medical records from CHCMU. Investigators or physicians will contact with parents by phone or send them a research leaflet and recruitment letter. Thirdly, physicians will post study flyers at the outpatient department, the official website and WeChat public platform of CHCMU for those diagnosed as severe BPD in other hospitals. If these patients with severe BPD are interesting about this research, we will initiate the screening flow.
There will hold a multidisciplinary consultation to confirm whether these potential participants meet the general diagnostic criteria of BPD, and the inclusion and exclusion criteria. The consultation will consist of at least a neonatologist, a respiratory physician, a radiologist, a laboratory physician, an expert of Department of Critical Care Medicine (ICU), researchers of the stem cell treatment center, a staff of medical department. If more than 80% experts agree on the hUC-MSCs treatment, these patients will be viewed as the potential participants. The researcher then will arrange a meeting to communicate with the legal representative or parents about the clinical trial research detail and sign the written informed consent form.
All the matters of the clinical trial is fully explained to the guardians of patients: (1) the purpose of the study; (2) the background of the research; (3) the number of participants and duration of patient participation; (4) the procedures of the research; (5) the potential discomforts and risks of their treatment; (6) the expected benefits; (7) the protection of confidentiality and privacy; (8) the participation is voluntary. The legal representative or parents sign the informed consent after all the items above are fully understood. After that, the baseline of patients will be recorded by clinicians as listed (Table 2).
Randomization and blinding
Participants will be randomized into three groups in a 1:1:1 ratio after collecting of baseline data. The allocation sequence will be generated and sent to the investigators by a statistician. Participants will not be blinded during the phase II trial and the patients in control group will not accept the hUC-MSCs treatment.
The hUC-MSCs produced by Ever Union Biotechnology Co. Ltd. (hereinafter referred to as "EUBIO") are transported to the ward on the day of infusion. hUC-MSCs are suspended into 0.9% normal saline. In addition to inspection the quality of hUC-MSCs product by EUBIO, the staff of the stem cell center in CHCMU confirm the cell viability and the quality of hUC-MSCs product before infusion.
There is no effective therapy for BPD patients nowadays, and these patients are often given traditional supportive treatments such as nutritional support, fluid restriction, and respiratory support (including ventilator support and oxygen supply) so that all the participants will be given with traditional supportive treatments to ensure safety. That means, the intervention groups will be given the traditional supportive treatments and extra low or high dose of hUC-MSCs infusion, meanwhile, the control group will be only given the traditional supportive treatments. Participants will be unable to use glucocorticoids 3 days before or after the hUC-MSCs treatment.
A total of 48 Patients in the intervention groups will be randomized in a 1:1:1 pattern to receive a low dose of hUC-MSCs (n=16, 2.5 million cells/kg) or a high dose of hUC-MSCs (n=16, 5 million cells/kg) in combination with traditional supportive treatments or traditional supportive treatments alone (n=16).
Discontinuation may be due to participants’ death, SAEs, other serious disease limiting participation or study withdrawal requested by the guardian. If the participant withdraws from the trial, the reason for the withdrawal and all the results of observations should be recorded in detail. Meanwhile, a new participant will be enrolled in the trial to replace the withdrawing subject.
Adverse Events (AEs) are defined as adverse medical event that occur after the subjects provide written informed consent until the end of the study visit. AEs include abnormal laboratory results, symptoms or diseases. All the AEs will be recorded in Case Report Form (CRF) and researcher should provide comprehensive clinical reports. Once AEs occur, we will follow the principle of “the first priority of the participants”, take the necessary treatment according to the specific situation of the patients, and decide whether to suspend the clinical research. The main investigator should immediately inform Scientific Research Office, Medical Service, and Ethics Committee of CHCMU. The report of severe adverse events (SAEs) should be submitted in writing within 24 hours, and a follow-up report of SAEs should be submitted to Human Research Ethics Committee.
An insurance policy will be prepared for all participants in the study. They will be provided with ancillary and post-trial care for injury or death as a result of their participation in the trial.
The outcome measures and their time frames of this trial are listed in Table 3. The primary endpoint is the cumulative duration of oxygen therapy, which means the total time of oxygen therapy from the time of starting oxygen treatment until the time of stopping oxygen treatment.
The secondary endpoints include the safety outcomes and the efficacy outcomes. The safety of the study is accessed by the number of the adverse events including SAEs, acute infusion associated adverse events (AIA-AEs) and the late infusion associated adverse events (LIA-AEs). SAEs include death, malignant cardiac event (new ventricular tachycardia, ventricular fibrillation, or asystole, cardiac arrest), acute pulmonary embolism, stroke, anaphylactic shock, acute transplant rejection and any other diseases which extend the hospital stay. AIA-AEs include: fever, general allergic reaction (rash, edema, erythema, pale), infection of injection site, vital signs changes, laboratory test changes (the indicators of liver and kidney functions, cardiac markers, the indicators of hematology and immunity, markers of Hepatitis/Syphilis/HIV/Tuberculosis, and urinalysis, et al.). The LIA-AEs include tumorigenic events (tumor formation) and teratogenic events.
The efficacy endpoints are listed as follow: duration of oxygen therapy, duration of invasive mechanical ventilation, duration of noninvasive mechanical ventilation, the first time of stopping oxygen supplement, the rate of re-oxygen supplement, blood oxygen saturation, chest radiography changes, pulmonary function changes, mortality, times of hospital readmissions, complications of preterm birth.
Follow-up assessments will be performed at 1, 3, 6, 12 and 24 months (m) after hUC-MSCs injection (Table 2). There are five times of follow-up, which will be conducted through two methods, including telephone follow-up and outpatient follow-up. The first two follow-up will be carried at 1, 3m after hUC-MSCs treatment through making a phone call to parents to ask the condition of their kid(s). The details of inquiry on the phone are shown in table 4. The next three follow-ups will be arranged at 6, 12 and 24m at the outpatient, the follow-up items are listed in table 5. The key outcome during follow-up will be the chest radiography changes.
The independent Data and Safety Monitoring Board (DSMB) will supervise the safety oversight during the trial. The members of DSMB are independent of the sponsor and trial investigators, and they have no competing interests. The DSMB will review and evaluate clinical safety and efficacy data collected according to the specified time interval in the protocol. If the the threshold of safety data exceeds a predefined threshold, the DSMB will be notified. Furthermore, the DSMB will conduct the interim analysis of all AEs occurrences during the study every 6 months. Only the data management and study designers have access to all the data in the trial. Data will be locked by the data management team when the trial completed. All the data will be provided to DSMB. If the trial terminated earlier than the expected end date, the DSMB would take part in that decision.
The data generated during the trial will be recorded in the original medical record and CRF. The quality control personnel check the consistency of the CRF data with the original record to ensure that the data is accurately entered into the CRF. There are nine data collection points: baseline, 1d, 3d, 7d, 1m, 3m, 6m, 12m and 24m (Table 2). Within 3 days after the completion of the collection, the research records will be submitted to the research leader for review, and all these data will be submitted to the project leader within 10 days. Next, the auditor reviews each original research record to confirm that the clinical trial data records are timely, precise, and standardized. Then, data check and entry are disposed by the statistical data manager, and data is analyzed by the statisticians.
The data of this trial will be disseminated through both national and international conferences and peer-reviewed publications. Our data set will be available after the completion of this trial.
SPSS version 17 (SPSS Inc, Chicago, Illinois) statistical analysis software will be used to analyze the data in the study. Significant difference was determined at the α level of 0.05.
The continuous variables will be reported as means and standard deviations (SD) if the variables meet normal distribution, and t-test will be used to test the significance of difference between the two groups. Continuous variables that do not satisfied the normal distribution were expressed as X50% (X25%, X75%), and the Wilcoxon rank sum test will be used for comparison between the two groups. The categorical variables were reported as numbers (n) and percentages of the total (%), and χ2 test will be used to test the difference between two groups.
Baseline among groups will be compared using the ANOVA. The primary outcome, the duration of oxygen therapy, will be analyzed by one-way analysis of variance (ANOVA), followed by the Bonferroni test. Outcomes including the duration of mechanical ventilation, pulmonary function tests and the quantitative scores of chest radiography changes will be compared using the ANOVA. The rate including mortality, the rate of re-oxygen supplement, hospital readmission rate will be tested by χ2 test. 24-month mortality should be analyzed by Kaplan-Meier curves.