Evaluation of Safety and Exploratory Efficacy of CARTISTEM®, a Cell Therapy Product for Articular Cartilage Defects: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Safety and Exploratory Efficacy of CARTISTEM®, a Cell Therapy Product for Articular Cartilage Defects (NCT01733186), a na phase 1, phase 2 study. The primary outcome is IKDC Score.

2. Clinical Question

3. Trial Design

This was a Phase I/IIa clinical trial listed as completed. The registry classifies its model as single-group, its allocation as NA, and its masking as none. Enrollment was 12. The study began on 2013-01-07, and primary completion was recorded as 2017-06-02. These dates describe the registry timeline; they do not provide information about follow-up completeness or when individual participants completed assessments.

CARTISTEM® was the listed biological intervention. The product description specifies allogeneic-unrelated, umbilical cord blood-derived mesenchymal stem cells, ex vivo cultured and combined with sodium hyaluronate. The administration description states 0.5 mL per cm² of cartilage defect. The registry includes a Dose A Cohort and a Dose B Cohort in its safety information, with 6 participants at risk in each cohort for the listed serious and other adverse-event summaries. Details of the dose distinction and the basis for assigning participants to cohorts are not reported in the registry record.

The record does not describe a randomized control group or a masking procedure. Consequently, changes from baseline are not comparisons against an untreated or alternative-treatment group. The safety cohorts should not be read as randomized arms: allocation is listed as NA, and the record identifies the design as single-group. Further details about recruitment, sites, eligibility criteria, treatment delivery, and the analysis population are not reported in the registry record.

The primary outcome was the IKDC score at Month 12 expressed as post-operative change from baseline. VAS, Lysholm Score, KOOS Score, and IKDC Score are listed among the secondary outcomes. The registry lists 5 outcome measures, but does not report numerical results for the primary outcome in the record. It records 0 analyses. The statistical analysis plan, including any prespecified model or approach to missing observations, is 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

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.

6. Primary Endpoint

The registry lists the primary outcome as IKDC Score, measured over 12 months.

The primary endpoint was change from baseline in the IKDC score at the Month 12 visit. IKDC is the International Knee Documentation Committee subjective knee evaluation. The registry describes it as a self-assessment intended to detect improvement or deterioration in symptoms, function, and sports activities related to knee impairment. Its possible score ranges from 0 to 100; 100 represents no limitation with daily or sporting activities and absence of symptoms.

Using a patient-reported measure can capture how a person experiences knee function, rather than relying only on a clinician’s examination. As a general statistical point, a change score compares a follow-up measurement with the same measure at baseline, giving the result a within-person reference. It does not, by itself, distinguish change associated with treatment from change associated with time, recovery, expectations, or other influences. A control group and suitable analysis can help address such questions, but no control group is listed for this trial.

The registry says the Month 12 score was used as the primary indicator of post-operative change and that the outcome was presented as change from baseline. The numerical estimate, its dispersion, and any confidence interval are not reported in the registry record. Therefore, the magnitude and precision of the IKDC change cannot be described from the record. VAS, Lysholm Score, KOOS Score, and IKDC Score are listed as secondary outcomes, but their numerical results are also not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with the question a design can answer. This study is classified as single-group, with allocation recorded as NA and masking as none. The listed primary outcome is a change in IKDC score from baseline to Month 12. That setup describes change over time among treated participants; it does not directly estimate the difference between CARTISTEM® and a concurrent control. General statistical explanation: a randomized control group can help distinguish treatment-associated change from changes that might have occurred over time for other reasons. Such a comparison is not listed in this record.

What does a change score represent?

A change score is formed by comparing a participant’s follow-up measurement with that participant’s baseline measurement. The registry describes the Month 12 IKDC score as the primary indicator of post-operative change. If the mean change were reported, it would describe the average change in the analyzed group under the chosen calculation. It would not mean that every participant changed by that amount. The mean can also be affected by unusually large or small individual changes, so a measure of dispersion is useful for understanding variation.

The record identifies the primary outcome as a mean with standard deviation, but does not give the numerical mean change or standard deviation. General statistical explanation: a standard deviation describes spread among observations around their mean. It is not the same as the standard error, which describes uncertainty in an estimated mean, and neither one alone gives a full account of the data distribution. Without the posted estimate and dispersion, the amount of change and the variability across participants cannot be assessed.

How should uncertainty be read?

In general, a confidence interval communicates the uncertainty around an estimate under a specified statistical method. A narrow interval indicates greater precision than a wide interval, while both the estimate and its interval are needed to understand the range of values compatible with the data. The registry record does not report a confidence interval for the primary IKDC change. It also lists 0 analyses, and does not report a p-value or a statistical analysis plan. No inference about statistical significance or precision should be made in the absence of those results.

General statistical explanation: a p-value, when used, measures how unusual the observed data would be under a specified null model and its assumptions. It does not measure the probability that a treatment works, nor does it describe the size or clinical importance of an effect. An estimate and uncertainty interval are generally more informative for understanding magnitude and precision. No p-value is reported in this registry record.

What do the planning illustrations mean?

The sample-size planning assumptions describe an illustration based on the observed effect, rather than the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is described as a stated fraction of the observed effect. The assumptions also distinguish participant counts per arm from total event counts for time-to-event outcomes. These are planning concepts, not evidence that the trial was designed with those assumptions or had a particular probability of detecting an effect.

General statistical explanation: a planning calculation depends on the assumed effect size, variability, significance level, allocation, and analysis method. Changing those assumptions can change the resulting sample-size estimate. Such an estimate is not observed power and does not describe the probability that a completed study’s result is correct. The trial is recorded as single-group, whereas the planning assumptions describe equal allocation between two arms; the illustration therefore should not be mistaken for the study’s recorded design. The numerical planning outputs are not described in the registry record.

Why can two cohorts not establish a treatment contrast?

The safety entries use the labels Dose A Cohort and Dose B Cohort. The record does not describe random assignment between these cohorts, and allocation is listed as NA. Without a documented assignment process and a prespecified comparative analysis, apparent differences between cohorts could reflect characteristics other than dose. No comparative IKDC estimates are reported. General statistical explanation: a valid between-group contrast depends not only on calculating a difference but also on whether the design supports interpreting that difference as attributable to the treatment contrast.

Over-dispersion is a general concern when count data vary more than a simple model assumes; accounting for it can prevent uncertainty from being understated. The record does not report a count model or an analysis of adverse-event rates, so it is not possible to determine whether over-dispersion was relevant or addressed. Likewise, the record does not provide enough detail to assess distributional assumptions for the continuous IKDC measure or the method used to handle missing measurements.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Dose A Cohort", "Dose B Cohort")
n   <- c(6, 6)
m   <- c(32, 25.5)
sp  <- c(27.7, 18.9)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Dose A Cohort  6  32.000  27.700  2.931  61.069
CARM  Dose B Cohort  6  25.500  18.900  5.666  45.334

11. Multiplicity, Missing Data and Analysis Populations

The registry lists VAS, Lysholm Score, KOOS Score, and IKDC Score among the secondary outcomes, and reports 5 outcome measures. It identifies the Month 12 IKDC change as the primary outcome. The statistical analysis plan is not reported in the registry record, so the prespecified hierarchy of outcomes, if any, is unknown. Adjustments for multiple comparisons, selective reporting procedures, and any distinction between confirmatory and exploratory tests are not reported in the registry record.

General statistical explanation: when researchers test or estimate many outcomes, the chance of finding an apparently notable result by chance can increase. Multiplicity procedures can address that issue, but the appropriate approach depends on the study aims and analysis plan. The record does not give enough information to determine whether such procedures were planned or used. Since numerical results for the outcomes are not reported in the registry record, their consistency and relative emphasis cannot be evaluated.

Missing-data methods and the number of participants contributing to each outcome are not reported in the registry record. The record does not state how missing Month 12 IKDC assessments were handled, whether any imputation was used, or whether analyses were based on all enrolled participants or a defined subset. These omissions matter because a mean change calculated among participants with observed follow-up may differ from the change that would have been estimated if follow-up were complete, particularly if missingness is related to outcomes or participant characteristics.

The registry lists 0 analyses. It does not report sensitivity analyses, interim analyses, or the analysis populations. These items should be treated as unreported rather than assumed absent from all study conduct. The posted record therefore does not allow assessment of how missing observations, multiple endpoints, or alternative analytic choices affected the reported findings.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The safety record lists 6 participants at risk for serious events in the Dose A Cohort and 0 affected. For the Dose B Cohort, it likewise lists 6 at risk and 0 affected. The record lists 6 participants at risk for other adverse events and 6 affected in each cohort. Deaths are recorded as 0 in each cohort. No serious-event terms are listed.

These are registry counts, not a complete description of event burden. The record does not report the event names for the other adverse events, their severity, timing, duration, recurrence, or relationship to CARTISTEM®. It also does not explain the adverse-event definitions or provide an exposure-adjusted rate. The figures therefore should not be interpreted as showing that no adverse events occurred: the record lists other adverse events in both cohorts, while listing none as serious.

General statistical explanation: an observed count of zero serious events does not prove that the underlying risk is zero. Rare outcomes can be difficult to characterize in small cohorts, and estimates of risk are uncertain when few participants are observed. The registry entries describe what was recorded, but do not by themselves establish the frequency of events in a wider population or across longer follow-up.

13. What the Result Does, and Does Not, Mean

The study addresses a defined clinical question: whether CARTISTEM® was safe and had exploratory efficacy for knee articular cartilage defects, with the primary outcome focused on change in self-assessed IKDC score at Month 12. The registry provides the intervention description, broad design classification, outcome definition, and safety counts. It records a completed Phase I/IIa study with enrollment of 12.

The registry record does not report the numerical primary outcome, its standard deviation, a confidence interval, or a p-value. It therefore does not support a quantitative statement about the amount or precision of IKDC change. The record also does not report numerical results for the listed secondary outcomes. Describing the endpoint and study purpose is not equivalent to evidence that the intervention improved knee function.

The design is single-group, with no separate control treatment listed, allocation recorded as NA, and masking recorded as none. General statistical interpretation: observed change from baseline in a single-group study cannot isolate a treatment effect from other influences over time. The Dose A and Dose B safety cohorts do not supply a randomized control comparison according to the registry record. The available information therefore does not establish a causal effect relative to another treatment or to no treatment.

The safety summary records no serious events or deaths in either cohort, and records other adverse events in each. These entries should be read with their limited detail: event terms and timing are not reported for the other events, and the record provides no rate analysis or longer-term safety estimate. They do not establish the absence of risk.

In short, the record documents an exploratory single-group trial and a set of outcome and safety definitions, but leaves key result statistics and analysis details unreported. It cannot establish how large or precise the measured IKDC change was, whether that change was caused by CARTISTEM®, or how the recorded safety experience generalizes beyond the trial.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of the difference between defining an outcome and reporting evidence about that outcome. The registry clearly identifies IKDC change at Month 12 as the primary endpoint and explains what the scale is intended to measure. But the numerical change and its uncertainty are not reported in the registry record. Readers can understand the intended measurement without being able to assess the magnitude or precision of the observed result.

The design classification is also important to interpretation. A single-group study can describe outcomes over time after treatment, but it does not provide a concurrent control estimate. The record lists allocation as NA and masking as none. These design features make it especially important not to read baseline-to-follow-up change as a treatment effect without qualification. The Dose A and Dose B safety cohorts do not change that conclusion because the registry does not describe a randomized comparison between them.

The safety record illustrates why event categories and denominators need to be read together. It separately reports participants at risk and affected for serious and other adverse events, and records deaths. Yet the absence of serious events in the listed cohorts does not describe the types or timing of other events, and does not quantify uncommon risks precisely. More complete event definitions and follow-up details would be needed for a fuller statistical assessment.

Finally, the record lists multiple outcome measures but does not report the analysis plan, missing-data methods, or multiplicity approach. These are not minor technical details: they shape how estimates should be interpreted and how selectively reported findings can be assessed. The study matters statistically because its registry description supports careful questions about design, endpoint meaning, uncertainty, and reporting completeness, while the record does not contain the numerical results needed to answer those questions fully.

15. 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 registry record does not include the numerical Month 12 IKDC change or its standard deviation, despite identifying the primary outcome as a mean with standard deviation. No confidence interval or hypothesis-test result is reported. This prevents evaluation of the observed magnitude, variability, and precision. Numerical results for VAS, Lysholm Score, and KOOS Score are also not reported in the registry record.

The study is classified as single-group, with allocation recorded as NA and masking as none. No separate control treatment is listed. The record therefore does not support a randomized comparative interpretation, and change from baseline alone cannot separate treatment-associated change from other changes over time. The Dose A Cohort and Dose B Cohort are present in the safety summary, but the dose distinction and assignment process are not reported in the registry record.

Other design and analysis details are also missing from the registry record, including eligibility criteria beyond the broad population description, analysis populations, participant flow, follow-up completeness, missing-data handling, and the statistical analysis plan. The record lists 0 analyses. It does not report whether multiplicity adjustments, sensitivity analyses, or interim analyses were planned or conducted.

The safety information is limited to counts of participants at risk and affected, plus deaths. Event terms for the other adverse events, timing, severity, duration, and treatment relationship are not reported in the registry record. The listed serious-event counts cannot establish that the underlying risk is zero, particularly without further detail on observation and follow-up. These limitations restrict both causal interpretation of the efficacy outcome and the scope of conclusions about safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of Safety and Exploratory Efficacy of CARTISTEM®, a Cell Therapy Product for Articular Cartilage Defects — NCT01733186.
• Registry record last updated 2026-01-29; status last verified 2026-01.
• Results first posted 2021-07-30.
• 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.

19. Record Summary

NCT01733186 is a completed Phase I/IIa study evaluating CARTISTEM® for articular cartilage defects of the knee. The registry classifies it as single-group, with allocation recorded as NA and masking as none; enrollment was 12. The intervention is described as allogeneic-unrelated, umbilical cord blood-derived mesenchymal stem cells, ex vivo cultured and combined with sodium hyaluronate.

The primary outcome was change from baseline in IKDC score at Month 12. The registry describes IKDC as a self-assessment of knee symptoms, function, and sports activities, with a possible score from 0 to 100. VAS, Lysholm Score, KOOS Score, and IKDC Score are listed as secondary outcomes. The numerical outcome results and statistical analysis plan are not reported in the registry record.

Safety entries list 0 serious events and 0 deaths in each dose cohort, and 6 participants affected by other adverse events in each cohort. These counts do not include event details for the other adverse events. The record supports description of the trial design and registry entries, but does not provide the numerical efficacy results or analysis details needed to assess treatment effects and their precision.