This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Study of Modified Stem Cells (SB623) in Patients With Chronic Motor Deficit From Ischemic Stroke (NCT02448641), a randomized phase 2 study. The primary outcome is Proportion of Subjects Whose Fugl-Meyer Motor Total Score (FMMS) Improved by ≥ 10 Points at Month 6 From Baseline.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02448641 |
| Phase | Phase 2 |
| Condition | Chronic Ischemic Stroke |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 163 |
| Arms in the primary outcome | n/a |
| Lead sponsor | SanBio, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
People with chronic motor deficits from ischemic stroke. The primary endpoint population is described as the modified Intent-to-Treat population: randomized participants who completed the surgery treatment procedure. The registry record does not report further eligibility details in the information available for this analysis.
Intervention
Stereotactic intracranial implantation of SB623 cells, in two dose groups: 2.5 million cells and 5 million cells. The registry record describes the study as controlled and double-blind.
Comparator
Sham surgery. This provides a procedural comparison for a trial in which the active interventions involve surgery. Further details of the sham procedure are not reported in the registry record.
Primary question
At Month 6, what proportion of participants had an improvement of at least 10 points from baseline on the Fugl-Meyer Motor Total Score? The registry record does not report the primary endpoint result or a statistical comparison between groups.
3. Trial Design
This was a randomized, double-blind, parallel-group Phase 2b study of SB623 in people with chronic motor deficits from ischemic stroke. The registry lists an enrollment of 163 and a completed study. The recorded study dates are 2016-03-08 for the start and 2018-12-05 for primary completion.
Participants were assigned to an SB623 implant containing 2.5 million cells, an SB623 implant containing 5 million cells, or sham surgery. The record describes the SB623 intervention as stereotactic, intracranial injection. A parallel design compares groups assigned to different interventions over the study period, rather than switching participants between interventions. Random allocation is intended to reduce systematic differences between groups at the point of assignment. Double masking is intended to limit the influence of knowledge of assignment on participant experience or outcome assessment, although details of who was masked and how masking was maintained are not reported in the registry record.
The sham procedure is the control condition. In a surgical trial, a sham comparator can help distinguish changes associated with the intervention from changes related to the procedure, study participation, or assessment. The precise sham procedures and the methods used to assess whether masking was maintained are not reported in the registry record.
The primary endpoint concerns the proportion of participants reaching a specified improvement threshold on the Fugl-Meyer Motor Total Score at Month 6. Secondary outcomes include response definitions based on the Modified Rankin Scale, the Action Research Arm Test, gait velocity, Neurological Quality of Life subdomains, and the Global Rating of Perceived Change. These outcomes capture different aspects of function and perceived change. Their definitions do not establish that results were statistically significant or clinically important. Results for the primary and secondary outcomes are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | SB623 Implant (2.5M) | SB623 Implant (5.0M) | Sham Control |
|---|---|---|---|
| STARTED | 55 | 56 | 52 |
| COMPLETED | 54 | 51 | 48 |
| NOT COMPLETED | 1 | 5 | 4 |
Analysis population for the primary outcome, as defined in the registry: Modified Intent-to-Treat (mITT) Population: Included all randomized subjects who completed the surgery treatment procedure. A total of 111 subjects received treatment with SB623; 55 subjects were randomized to receive 2.5 million SB623 cells and 56 subjects to receive 5 million SB623 cells.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | SB623 Implant (2.5M) | SB623 Implant (5.0M) | Sham Control | Total |
|---|---|---|---|---|---|
| Participants analysed | 55 | 56 | 52 | 163 | |
| Age, Continuous | years | 57.5 (SD 11.08) | 58.9 (SD 9.99) | 55.2 (SD 11.57) | 57.2 (SD 10.92) |
| Sex: Female, Male: Female | Participants | 21 | 20 | 19 | 60 |
| Sex: Female, Male: Male | Participants | 34 | 36 | 33 | 103 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 3 | 3 | 0 | 6 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 52 | 53 | 52 | 157 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Asian | participants | 1 | 2 | 6 | 9 |
| Race/Ethnicity, Customized: Native Hawaiian or Other Pacific Islander | participants | 0 | 0 | 1 | 1 |
| Race/Ethnicity, Customized: Black or African American | participants | 6 | 1 | 2 | 9 |
| Race/Ethnicity, Customized: White | participants | 45 | 51 | 42 | 138 |
| Race/Ethnicity, Customized: Other | participants | 3 | 2 | 1 | 6 |
| Region of Enrollment: United States | participants | 55 | 56 | 52 | 163 |
6. Primary Endpoint
The registry lists the primary outcome as Proportion of Subjects Whose Fugl-Meyer Motor Total Score (FMMS) Improved by ≥ 10 Points at Month 6 From Baseline, measured over 6 months.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the proportion of participants whose Fugl-Meyer Motor Total Score improved by at least 10 points from baseline at Month 6. It is a binary response outcome: each participant either meets the stated improvement threshold or does not. The endpoint therefore describes the share of the analyzed group reaching that threshold, rather than the average score change across all participants.
The Fugl-Meyer Motor Score is used to assess motor impairment after stroke. The motor component covers upper- and lower-extremity function and includes assessment of range of motion, reflex activity, volitional movement, and coordination. Its upper-extremity subscale has 33 items and ranges from 0 to 66; its lower-extremity subscale has 17 items and ranges from 0 to 34. Items use an ordinal scoring scale: 0 means cannot perform, 1 means partial motion, and 2 means full motion. The subscale scores are summed to form the motor total score, which ranges from 0 to 100, with higher scores representing better motor performance.
A threshold response can be easy to interpret as a participant-level milestone, but it does not describe how far scores changed for people who did not reach the threshold. It also depends on the chosen cutoff and assessment time. The registry record defines the response threshold and time point but does not report the primary endpoint results, the distribution of score changes, or a rationale for selecting the threshold.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary question clearly: whether participants achieved an improvement of at least 10 points on the Fugl-Meyer Motor Total Score at Month 6. However, it does not report the number or proportion of responders in any group, an estimated difference between groups, a confidence interval, or a statistical test for this endpoint. The treatment effect and its precision therefore cannot be interpreted from the endpoint description alone. The record does not report the primary endpoint results.
The design includes two SB623 dose groups and a sham-surgery group. A complete interpretation would require the outcome counts for each group, the intended group comparisons, and the analysis method. Those results and details are not reported in the registry record. Without them, there is no basis for judging whether the groups differed, how large any difference was, or how compatible the data were with no difference. The absence of a reported result in this record is not evidence that the groups were the same.
The primary outcome is a threshold-based response. Such outcomes summarize whether a prespecified level of change was reached, but can conceal variation within each response category. A participant just below the threshold and a participant with little change are both classified as nonresponders, while different amounts of improvement above the threshold are treated alike. The record does not report the underlying score distributions or other information that would show how the threshold relates to the full pattern of change.
The registry lists eight outcome measures and six analyses. Those counts indicate that multiple outcomes or analyses are recorded, but do not establish how many comparisons were planned, which were primary for inference, or how multiplicity was handled. The statistical analysis plan is not reported in the registry record. This limits assessment of whether reported analyses, if any, were prespecified and how uncertainty from multiple comparisons should be understood.
The safety information lists serious adverse events, other adverse events, and deaths by group. These counts provide a descriptive safety record, but do not by themselves establish whether an event was caused by an intervention. Differences in counts can reflect chance, exposure, follow-up, or other factors; a causal interpretation requires appropriate analyses and context. The registry record does not report comparative safety estimates or statistical tests.
In short, the record describes the trial design, endpoint, and some adverse-event counts, but the primary efficacy results and relevant inferential details are not reported in the registry record. No conclusion about comparative efficacy or the magnitude of any treatment effect can be drawn from the endpoint definition alone.
9. Statistical Methods Explained
What does a responder endpoint measure?
In general, a responder endpoint converts a continuous or scored outcome into a yes-or-no classification using a chosen cutoff. In this trial, a participant is defined as a responder if the Fugl-Meyer Motor Total Score improves by at least 10 points from baseline at Month 6. The group-level quantity of interest is the proportion meeting that definition. This is different from comparing average score change: the responder analysis focuses on reaching the threshold, while an average-change analysis uses the score information across participants.
Thresholds make results more directly interpretable as the frequency of a specified improvement, but they discard detail. Participants just on opposite sides of a cutoff are classified differently even if their scores are close. Participants with very different changes can fall into the same response category. General interpretation should therefore consider the threshold result alongside continuous score summaries where those are available. Such summaries are not reported in the registry record.
How does randomization help?
In general, random allocation aims to make treatment groups comparable with respect to both measured and unmeasured characteristics at the time of assignment. It does not guarantee identical groups, especially in a trial of finite size, and it does not remove the need for careful outcome assessment and analysis. In this study, the registry describes randomized assignment to two SB623 dose groups or sham surgery. Details of the allocation sequence, concealment, and any stratification are not reported in the registry record.
Double masking can reduce the risk that knowledge of assignment affects participant reporting, care, or outcome measurement. Its value depends on who was masked and whether masking was maintained. Those implementation details are not reported in the registry record. Masking also does not prevent every possible source of bias, including missing outcome data or deviations from assigned treatment.
What would a group comparison need to show?
For a binary response, a statistical comparison would generally use each group’s responder and nonresponder counts to estimate the response proportion and a contrast between groups. A confidence interval expresses the uncertainty around an estimate: it gives a range of values compatible with the data and the method used, under its assumptions. A narrower interval indicates greater precision, while a wider interval indicates greater uncertainty. A p-value, if reported, measures how surprising the observed data would be under a specified null hypothesis and model; it is not the probability that the null hypothesis is true and does not measure clinical importance.
The registry record does not report the primary endpoint counts, group estimates, confidence intervals, p-values, or the method used for the primary analysis. It is therefore not possible to describe the precision or statistical evidence for a group difference. A result should not be inferred from the endpoint definition or from the trial’s completed status.
How should planning illustrations be read?
In general, a sample-size calculation is conditional on assumptions about the target effect, variability or event frequency, significance level, power, allocation, and statistical method. The planning illustration associated with this analysis is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Its target effect is a stated fraction of the observed effect. For outcomes other than time-to-event outcomes, the resulting quantities are participants per arm; time-to-event illustrations use a total number of events.
These are planning illustrations based on the observed effect, not the trial’s original design justification. Their values are not reported in the registry record. They should not be described as observed power: observed power is not a substitute for examining an estimate and its confidence interval. The trial’s own sample-size justification and any original design assumptions are not reported in the registry record.
Why can event counts need a different model?
General statistical principle: count outcomes may vary more than a simple model assumes. Over-dispersion means that the observed variability is greater than the model’s expected variability. If it is ignored, standard errors can be too small and confidence intervals can be too narrow. A suitable model may account for this extra variability. The primary endpoint in this trial is described as a participant response count, not a rate of recurrent events, and the registry record does not report a count-model analysis or a dispersion estimate. No over-dispersion conclusion can be drawn from the endpoint description.
Different outcome types also call for different analytic approaches. Binary responses, continuous scores, ordinal scales, and time-to-event outcomes do not all have the same assumptions or estimands. The listed secondary outcomes span several types of measurement. The methods used for their analyses, including any model adjustments, are not reported in the registry record. Without that information, it is not possible to evaluate model fit, adjustment choices, or whether the analysis matched the outcome scale.
What can adverse-event counts establish?
Descriptive adverse-event counts report how many participants in a group had an event under the registry’s reporting definitions. A count is not by itself a comparative effect estimate. Meaningful comparisons also depend on exposure duration, event definitions, severity criteria, follow-up completeness, and whether events were counted once per participant or repeatedly. The record provides affected-participant counts and participants at risk for serious and other adverse events, but does not report comparative estimates or the detailed analysis methods. The event counts should therefore be read descriptively rather than as causal evidence.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists eight outcome measures and six analyses, including a primary endpoint and several secondary outcomes. Considering several outcomes or group comparisons raises the general issue of multiplicity: when many hypotheses are tested, the chance of at least one apparently unusual result can increase. Statistical plans may address this through a defined testing sequence, adjustment procedures, or a clear distinction between confirmatory and exploratory analyses. The approach used in this trial is not reported in the registry record, so the implications of multiple analyses cannot be assessed.
For the primary endpoint, the stated analysis population is the modified Intent-to-Treat population, defined as randomized participants who completed the surgery treatment procedure. The record also reports that 111 participants received SB623: 55 were randomized to the 2.5 million-cell group and 56 to the 5 million-cell group. The corresponding sham group size for the primary analysis is not reported in the registry record. The record does not explain how participants who did not complete the procedure, lacked a Month 6 assessment, or otherwise had missing endpoint data were handled.
Missing-data methods matter because participants with unavailable outcomes may differ from those with observed outcomes. General approaches include assumptions about the missingness process and methods that reflect those assumptions, but the appropriate method depends on the trial and the missing-data pattern. The statistical analysis plan, missing-data assumptions, and sensitivity analyses are not reported in the registry record. It is also not reported whether the endpoint analysis followed an intention-to-treat strategy or used another analysis population beyond the stated modified Intent-to-Treat definition.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| SB623 Implant (2.5M) | 15 | 55 | 27.3% |
| SB623 Implant (5.0M) | 15 | 56 | 26.8% |
| Sham Control | 10 | 52 | 19.2% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| SB623 Implant (2.5M) | 0 of 55 |
| SB623 Implant (5.0M) | 1 of 56 |
| Sham Control | 0 of 52 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| SB623 Implant (2.5M) | 52 of 55 |
| SB623 Implant (5.0M) | 53 of 56 |
| Sham Control | 51 of 52 |
Most frequent serious adverse event terms
| Event term | Organ system | SB623 Implant (2.5M) | SB623 Implant (5.0M) | Sham Control |
|---|---|---|---|---|
| Seizure | Nervous system disorders | 4 of 55 | 4 of 56 | 3 of 52 |
| Subdural haematoma | Injury, poisoning and procedural complications | 3 of 55 | 1 of 56 | 0 of 52 |
| Nausea | Gastrointestinal disorders | 2 of 55 | 0 of 56 | 0 of 52 |
| Pyrexia | General disorders | 0 of 55 | 2 of 56 | 0 of 52 |
| Pneumonia | Infections and infestations | 2 of 55 | 0 of 56 | 0 of 52 |
| Sepsis | Infections and infestations | 1 of 55 | 0 of 56 | 1 of 52 |
| Subdural haemorrhage | Injury, poisoning and procedural complications | 0 of 55 | 2 of 56 | 0 of 52 |
| Haemorrhagic anaemia | Blood and lymphatic system disorders | 1 of 55 | 0 of 56 | 0 of 52 |
| Leukocytosis | Blood and lymphatic system disorders | 0 of 55 | 1 of 56 | 0 of 52 |
| Atrial fibrillation | Cardiac disorders | 0 of 55 | 1 of 56 | 0 of 52 |
Most frequent non-serious adverse event terms
| Event term | Organ system | SB623 Implant (2.5M) | SB623 Implant (5.0M) | Sham Control |
|---|---|---|---|---|
| Headache | Nervous system disorders | 35 of 55 | 41 of 56 | 32 of 52 |
| Procedural headache | Injury, poisoning and procedural complications | 8 of 55 | 9 of 56 | 13 of 52 |
| Nausea | Gastrointestinal disorders | 13 of 55 | 12 of 56 | 3 of 52 |
| Procedural pain | Injury, poisoning and procedural complications | 11 of 55 | 5 of 56 | 6 of 52 |
| Incision site pain | Injury, poisoning and procedural complications | 5 of 55 | 5 of 56 | 10 of 52 |
| Vomiting | Gastrointestinal disorders | 10 of 55 | 6 of 56 | 1 of 52 |
| Fall | Injury, poisoning and procedural complications | 5 of 55 | 5 of 56 | 4 of 52 |
| Constipation | Gastrointestinal disorders | 5 of 55 | 2 of 56 | 4 of 52 |
| Fatigue | General disorders | 3 of 55 | 3 of 56 | 4 of 52 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 0 of 55 | 4 of 56 | 5 of 52 |
Serious events with the highest arm-level rate: seizure (7.3%), subdural haematoma (5.5%), nausea (3.6%), pneumonia (3.6%), pyrexia (3.6%).
The registry reports serious adverse events and other adverse events as participant counts by group, alongside the number of participants at risk. For serious adverse events, the listed affected-participant counts are 15 among 55 at risk in the 2.5 million-cell group, 15 among 56 at risk in the 5 million-cell group, and 10 among 52 at risk in the sham-control group. For other adverse events, the listed counts are 52 among 55, 53 among 56, and 51 among 52, respectively. These are descriptive counts; no rates or comparative estimates are calculated.
Deaths are listed as 0 in the 2.5 million-cell group, 1 in the 5 million-cell group, and 0 in the sham-control group. The record also lists seizure at 7.3%, subdural haematoma at 5.5%, and nausea, pneumonia, pyrexia, and subdural haemorrhage each at 3.6% among the leading serious adverse-event terms. Group-specific attribution for those terms is not reported in the registry record.
These counts do not establish that an event was caused by an intervention, and they do not establish comparative safety. Interpretation depends on event definitions, follow-up, exposure, and the statistical analysis, which are not fully reported in the registry record.
12. What the Result Does, and Does Not, Mean
The trial addresses a focused question about motor response after SB623 implantation compared with sham surgery in people with chronic motor deficits following ischemic stroke. Its randomized, double-blind, parallel design is intended to support a controlled comparison, and the primary endpoint defines a clear response threshold at Month 6. Those design features describe how the question was framed; they do not answer it.
The registry record does not report the number of primary endpoint responders, the response proportions, or a comparison between groups. It also does not report an effect estimate or confidence interval. Consequently, the record does not show whether one group had a higher response proportion, how large a difference might have been, or how precisely any difference was estimated. A missing result in the registry record should not be interpreted as evidence of no effect or as evidence of benefit.
The endpoint is a threshold-based measure of change in motor impairment. It does not, by itself, establish changes in every aspect of daily function, quality of life, gait, or perceived improvement. The registry lists secondary outcomes addressing some of these domains, but their results are not reported in the registry record. Nor does the endpoint description establish whether the chosen threshold corresponds to a change that participants would regard as important.
The adverse-event counts describe reported safety events, but they do not establish causation or comparative safety. The registry record does not report the analysis needed to account for uncertainty or provide context such as comparative estimates. Overall, the available record describes the study question, design, outcome definitions, and selected safety counts. It does not provide enough primary efficacy information to draw a conclusion about the comparative effect of SB623 and sham surgery.
13. Why This Trial Matters Statistically
This trial is statistically notable for using a randomized, double-blind comparison with a sham procedure in a setting where the active intervention involves intracranial surgery. A sham comparator can help separate the experience and assessment effects of a procedure from those associated with the active intervention. The strength of that comparison depends on the details of randomization, masking, follow-up, and analysis, several of which are not reported in the registry record.
The primary outcome illustrates an important distinction between a response threshold and a continuous measure. Counting participants who improve by at least 10 points offers an interpretable threshold-based summary, while the full motor-score distribution could reveal the amount and variability of change. A threshold can make results sensitive to where the cutoff is set, so estimates and uncertainty are important for understanding the evidence. Those primary outcome results are not reported in the registry record.
The study also includes several secondary outcomes covering impairment, function, quality of life, and perceived change. A broad set of outcomes can capture different dimensions of a condition, but it also makes prespecification and multiplicity handling important. The registry lists eight outcome measures and six analyses; the statistical plan for interpreting them is not reported.
Finally, the registry’s safety counts illustrate why descriptive numbers and comparative inference are different. Counts can help readers understand what was recorded in each group, but they do not, without further analysis and context, quantify a causal effect. Taken together, the design and endpoint make the scientific question explicit, while the absence of primary results and analysis details limits what can be concluded from the registry record.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The central limitation for interpreting efficacy is that the primary endpoint result is not reported in the registry record. There are no responder counts or proportions, between-group estimates, confidence intervals, or statistical tests in the information available. The primary efficacy comparison therefore cannot be evaluated for direction, magnitude, or precision.
The registry describes the primary analysis population as randomized participants who completed the surgery treatment procedure. This is a modified Intent-to-Treat definition rather than an all-randomized population. The record does not report the reasons participants may have been excluded from that population, the number with missing Month 6 outcomes, or how missing data were handled. This makes it difficult to assess the potential impact of incomplete follow-up or exclusions after randomization.
Important design and analysis details are also not reported in the registry record. These include the allocation-concealment procedure, who was masked, whether masking was maintained, the primary statistical model, covariate adjustments, multiplicity handling, and sensitivity analyses. The record does not report the original sample-size justification or the reasoning for the primary response threshold.
The endpoint uses a cutoff to classify response, which loses information about the degree of score change within each category. Results for the continuous score and the listed secondary outcomes are not reported in the registry record. Safety data are presented as counts, but comparative estimates, follow-up context, and group-specific results for the listed leading serious-event terms are not reported. These limitations constrain both the efficacy and safety interpretation; they do not, by themselves, indicate a particular treatment effect.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of Modified Stem Cells (SB623) in Patients With Chronic Motor Deficit From Ischemic Stroke — NCT02448641.
- Registry record last updated 2020-10-08; status last verified 2020-04.
- Results first posted 2020-04-17.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT02448641 is a completed randomized, double-blind, parallel Phase 2b study sponsored by SanBio, Inc. It enrolled 163 people with chronic motor deficits from ischemic stroke and compared stereotactic intracranial SB623 implantation at 2.5 million cells or 5 million cells with sham surgery.
The primary endpoint was the proportion of participants whose Fugl-Meyer Motor Total Score improved by at least 10 points from baseline at Month 6. Its stated analysis population was the modified Intent-to-Treat population, defined as randomized participants who completed the surgery treatment procedure. The registry record does not report the primary endpoint results, the statistical analysis plan, or the handling of missing endpoint data.
The record lists secondary outcomes in motor function, gait, quality of life, and perceived change, as well as serious adverse events, other adverse events, and deaths by group. These safety counts are descriptive and do not establish causation or comparative safety.