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 Limbal Stem Cell Deficiency (LSCD) Treatment With Cultivated Stem Cell (CALEC) Graft (NCT02592330), a na phase 1, phase 2 study. The primary outcome is Primary Safety Events of Interest.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02592330 |
| Phase | Phase 1, Phase 2 |
| Condition | Limbal Stem Cell Deficiency |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 23 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Massachusetts Eye and Ear Infirmary |
| Results posted | Yes |
2. Clinical Question
Population
People with limbal stem cell deficiency who received a CALEC transplant or a CLAU transplant. The registry lists enrollment as 23, but does not report how many participants contributed data to each outcome or analysis.
Intervention
The intervention centers on a cultivated autologous limbal epithelial cell graft. The registry describes collecting limbal epithelial stem cells by biopsy from a non-diseased eye, cultivating the cells into a graft, and transplanting the CALEC graft. It does not report the full procedural protocol in the registry record.
Comparator
No randomized comparator is identified. The record names both CALEC and CLAU groups in the adverse-event information, but explicitly indicates that the arms are not a like-for-like control comparison. Details of the CLAU group are not reported in the registry record.
Primary question
The primary question is whether specified safety events occurred in the recipient eye during 18 Months of follow-up. Events of interest were ocular infection, corneal perforation, and graft detachment of at least 50%. The primary outcome is a count of participants, but endpoint-specific results are not reported in the registry record.
The stated main aim is to determine the safety and feasibility of cultivated autologous limbal epithelial cell transplantation for limbal stem cell deficiency. A secondary outcome is described as a measure of transplant efficacy. The registry record does not provide enough detail to determine how efficacy was defined or what its results were. The clinical question is therefore principally a safety-and-feasibility question, not a test of comparative effectiveness against a randomized control group.
3. Trial Design
The registry identifies NCT02592330 as a Phase 1/Phase 2 study with a single-group model, no masking, and allocation listed as not applicable. The record lists enrollment as 23 and status as completed. It gives a start date of 2016-08-01 and a primary completion date of 2023-03-31. These registry entries describe the study record; they do not establish how many participants were included in each outcome analysis.
The intervention sequence includes a biopsy to collect limbal epithelial stem cells, cultivation of the cells into a graft, and CALEC transplantation. The arm description says that the biopsy is performed in the participant’s non-diseased eye and that the resulting graft is made at the Good Manufacturing Practice Laboratory at Dana Farber Cancer Institute before being transported to Mass. Eye and Ear Infirmary for application. Further procedural details are not reported in the registry record.
The record includes CALEC and CLAU labels in its adverse-event information, but its design fields identify a single-group study and flag that the arms are not a randomized, like-for-like control comparison. The meaning and full description of CLAU are not reported in the registry record. Accordingly, differences between those adverse-event groups should not be interpreted as treatment effects.
The primary safety outcome covers events during 18 Months of follow-up in the recipient eye among participants receiving a CALEC or CLAU transplant. The registry lists three outcome measures and one secondary efficacy outcome, but reports no analyses. Details of allocation procedures beyond the not-applicable designation, masking beyond none, and the statistical analysis plan 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 | Cultivated Autologous Limbal Epithelial Cell (CALEC) Graft | Control Conjunctival Limbal Autograft (CLAU) |
|---|---|---|
| STARTED | 16 | 1 |
| COMPLETED | 14 | 1 |
| NOT COMPLETED | 2 | 0 |
Reasons for not completing this period:
| Reason | Cultivated Autologous Limbal Epithelial Cell (CALEC) Graft | Control Conjunctival Limbal Autograft (CLAU) |
|---|---|---|
| Withdrawal by Subject | 1 | 0 |
| Failed Biopsy | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: All participants receiving a CALEC transplant or CLAU transplant.
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.
Population: Participants receiving a CALEC transplant, or the standard of care treatment (CLAU)
| Characteristic | Unit | CALEC | CLAU (Control) | Total |
|---|---|---|---|---|
| Participants analysed | 14 | 1 | 15 | |
| Age, Continuous | Years | 42.0 (24.0 to 78.0) | 53.0 (53.0 to 53.0) | 46.0 (24.0 to 78.0) |
| Sex: Female, Male: Female | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Male | Participants | 13 | 0 | 13 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 12 | 1 | 13 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 | 0 | 1 |
| Region of Enrollment: United States | Participants | 14 | 1 | 15 |
| Epithelial Integrity | Participants | 4 | 0 | 4 |
| Epithelial Integrity | units on a scale | 15.0 (10.0 to 15.0) | 10.0 (10.0 to 10.0) | 15.0 (10.0 to 15.0) |
| Neovascularization | Neovascular Area (% of total area) | 7.5 (0.5 to 24.2) | 3.6 (3.6 to 3.6) | 7.2 (0.5 to 24.2) |
| Ocular Surface Disease Index Score | units on a scale | 40.6 (6.8 to 100.0) | 95.5 (95.5 to 95.5) | 41.7 (6.8 to 100.0) |
| Symptom Assessment in Dry Eye Score | units on a scale | 35.4 (6.5 to 82.0) | 72.7 (72.7 to 72.7) | 39.1 (6.5 to 82.0) |
6. Primary Endpoint
The registry lists the primary outcome as Primary Safety Events of Interest, measured over 18 Months.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants who experienced any of a specified set of safety events in the recipient eye during 18 Months of follow-up. The events are ocular infection, defined to include endophthalmitis or microbial keratitis of bacterial, fungal, or parasitic origin; corneal perforation; and graft detachment involving at least 50%. The registry describes the outcome as a count of participants, rather than a continuous measurement.
A composite endpoint can collect several clinically important event types under one outcome. In general, this can provide a compact way to monitor a range of potential safety concerns. However, a combined count does not by itself show which event type occurred, how often each type occurred, or whether the events differed in seriousness or timing. Those details require event-specific results.
The endpoint is suited to the study’s stated safety and feasibility aim because it tracks specified complications following transplantation. The population includes recipients of either a CALEC or CLAU transplant. The registry record does not report the endpoint-specific participant counts, event breakdowns, or analysis results. The posted adverse-event figures should therefore not be assumed to be the primary endpoint results: they are not identified as counts of the three endpoint events.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a completed Phase 1/Phase 2, single-group study of cultivated autologous limbal epithelial cell transplantation for limbal stem cell deficiency. Its stated primary focus is safety and feasibility. The specified safety endpoint concerns ocular infection, corneal perforation, and graft detachment of at least 50% during 18 Months of follow-up. Although the endpoint is clearly described, its results are not reported in the registry record.
The adverse-event information lists 16 CALEC participants at risk for serious adverse events, with 1 affected, and 16 at risk for other adverse events, with 16 affected. For CLAU, it lists 1 participant at risk for serious adverse events, with 0 affected, and 1 at risk for other adverse events, with 1 affected. Deaths are listed as 0 for both groups. These entries are adverse-event summaries, not a clearly identified report of the primary composite endpoint. The record does not explain the relationship between these counts and the primary endpoint, or give event-level timing and detail.
The groups do not form a randomized comparison. The registry identifies a single-group design and explicitly warns that the arms are not a like-for-like control comparison. The differing numbers at risk also mean the group counts cannot be read as direct evidence that one treatment has a higher or lower risk. The record does not report a comparative estimate, confidence interval, or hypothesis test for these groups.
The registry lists Vomiting at 6.2% among the top serious terms. The denominator and the precise counting basis for this percentage are not reported in the registry record, so it should not be converted into a participant count or interpreted as a rate for the study population.
There are no reported analyses, and no endpoint-specific effect estimate or precision measure. A confidence interval, in general, describes the range of values compatible with an estimate under the method’s assumptions. Without a reported estimate and interval, the precision of the primary safety result cannot be assessed. The registry also does not provide efficacy results for its secondary measure. As a result, the posted information supports a description of the study design and adverse-event entries, but not a quantitative conclusion about the primary endpoint or transplant efficacy.
9. Statistical Methods Explained
The registry identifies the primary outcome as a count of participants experiencing specified safety events. It does not report an analysis method or endpoint results. The explanations below describe general statistical concepts relevant to interpreting this kind of outcome; they are not claims about analyses performed in this study.
What does a participant count represent?
A participant count records how many people meet an outcome definition. For a safety endpoint that combines event types, the count generally concerns participants with at least one qualifying event, but the registry record does not report an endpoint result or clarify whether individual event types were also counted separately. Counts should be read alongside the number of participants assessed and the period of observation. The primary endpoint specifies 18 Months of follow-up, while the adverse-event entries separately list the numbers at risk for each group.
Counts alone do not express uncertainty or make a comparison. A statistical estimate often combines an observed count with a denominator and an analysis method to quantify uncertainty. Neither a primary endpoint estimate nor a confidence interval is reported in the registry record. It is therefore not possible to assess the precision of the primary safety outcome from the posted information.
Why does the study design matter?
In general, random allocation helps make groups comparable on average, so that a difference in outcomes can be interpreted within a defined comparative design. This registry record lists allocation as not applicable and identifies a single-group model. It also flags that the CALEC and CLAU arms are not a like-for-like control comparison. The group labels in the adverse-event data do not change those design details. A difference between their counts cannot be treated as a randomized treatment-effect estimate.
Masking is listed as none. In general, masking can reduce the influence of knowledge about treatment assignment on some aspects of care, outcome assessment, or reporting. The registry does not explain how outcomes were assessed, whether assessors were independent, or what safeguards were used. Those details are not reported in the registry record.
What can an interval or test add?
In general, a confidence interval communicates the uncertainty around an estimated quantity. A narrow interval indicates greater precision under the analysis assumptions, while a wide interval indicates less precision. A hypothesis test addresses compatibility between observed data and a specified null hypothesis; a p-value is not the probability that a treatment works or that the null hypothesis is true. The registry lists no analyses, effect estimates, confidence intervals, or p-values. None should be inferred from the adverse-event counts.
For uncommon safety events, estimates can be imprecise when few participants experience events. This is a general statistical consideration, not a calculation about this trial. It reinforces why a point count without an endpoint-specific denominator, uncertainty interval, and detailed follow-up information is not enough to establish how precisely the event risk is known.
How should the planning assumptions be understood?
The registry includes general assumptions for sample-size planning illustrations: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of an observed effect. These assumptions describe planning illustrations, not the trial’s own design or a reported analysis. The record does not report the trial’s sample-size justification, and the actual illustration values are not reported in the registry record.
In general, a sample-size calculation asks how many observations a hypothetical design might need under specified assumptions. It is not a measure of the probability that the completed study found an effect, and it is not observed power. The planning assumptions should not be mistaken for evidence that this study had equal allocation, used a two-arm randomized design, or performed a particular test. The registry’s single-group designation and non-comparable arm warning remain central to interpreting its data.
For a time-to-event endpoint, methods may use event totals rather than participants per arm; for other outcomes, planning illustrations may use participants per arm. The registry’s stated conventions do not establish that a time-to-event analysis was conducted. The primary outcome is described as a participant count, and the registry reports no analysis method. No model, adjustment, or method for handling follow-up time is reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists three outcome measures, identifies primary safety events of interest, and names a secondary outcome, Measure of Transplant Efficacy. It reports no analyses. The statistical plan for selecting, ordering, or testing outcomes is not reported in the registry record, nor is any adjustment for testing multiple outcomes or event types.
In general, multiplicity arises when several hypotheses or outcome measures are examined. Without an appropriate analysis plan, repeated testing can increase the chance of at least one apparently unusual result. That general concern does not establish that such testing occurred in this study. Because no analyses are reported, the registry does not indicate whether any formal tests were conducted or how their interpretation would account for multiple outcomes.
Missing-data procedures are not reported in the registry record. The information does not describe whether any participants had incomplete follow-up, how missing outcome information was handled, or whether an analysis included all enrolled participants or a defined subset. Enrollment is listed as 23, while the adverse-event data show group-specific numbers at risk; the record does not explain how those numbers relate to enrollment or to the primary endpoint analysis.
The registry does not report analysis populations, such as an intention-to-treat population or a per-protocol population, and it does not describe exclusions from analysis. These omissions limit assessment of attrition, completeness, and the population to which any result might apply. They should not be filled in by assuming a conventional approach. The safest interpretation is that the record describes the planned safety question and some adverse-event entries, while leaving the handling of multiplicity, missing observations, and analysis populations unspecified.
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 |
|---|---|---|---|
| CALEC | 1 | 16 | 6.2% |
| CLAU | 0 | 1 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| CALEC | 0 of 16 |
| CLAU | 0 of 1 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| CALEC | 16 of 16 |
| CLAU | 1 of 1 |
Most frequent serious adverse event terms
| Event term | Organ system | CALEC | CLAU |
|---|---|---|---|
| Vomiting | Gastrointestinal disorders | 1 of 16 | n/a of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | CALEC | CLAU |
|---|---|---|---|
| Corneal Epithelium Defect | Eye disorders | 15 of 16 | 1 of 1 |
| Corneal Epithelium Defect | Eye disorders | 14 of 16 | 0 of 1 |
| Eye Pain | Eye disorders | 12 of 16 | 1 of 1 |
| Subconjunctival Hemorrhage | Eye disorders | 12 of 16 | 1 of 1 |
| Conjunctival Hyperemia | Eye disorders | 12 of 16 | 0 of 1 |
| Subconjunctival Hemorrhage | Eye disorders | 11 of 16 | 0 of 1 |
| Conjunctival Hyperemia | Eye disorders | 10 of 16 | 0 of 1 |
| Eye Pain | Eye disorders | 10 of 16 | 0 of 1 |
| Headache | Nervous system disorders | 9 of 16 | 1 of 1 |
| Corneal Bleeding | Eye disorders | 9 of 16 | 0 of 1 |
Serious events with the highest arm-level rate: vomiting (6.2%).
The adverse-event entries list separate numbers at risk, affected participants, and deaths for CALEC and CLAU. For CALEC, 16 are listed at risk for serious adverse events and 1 as affected; 16 are listed at risk for other adverse events and 16 as affected; deaths are 0. For CLAU, the corresponding figures are 1 at risk and 0 affected for serious events, 1 at risk and 1 affected for other events, and 0 deaths. These are registry entries, not a randomized comparison.
The record lists Vomiting at 6.2% among the top serious terms. It does not report the denominator or clarify how this percentage was calculated. The term should not be treated as a primary endpoint event: the primary endpoint is defined around ocular infection, corneal perforation, and graft detachment of at least 50%, and the registry does not identify Vomiting as one of those events.
In general, an adverse-event count can refer to participants, event episodes, or a defined reporting category; interpretation depends on the registry’s counting rules. The record does not provide all such definitions or link the adverse-event entries to the primary endpoint. It also does not provide event timing, severity details beyond the serious/other labels, or a comparative estimate. Since the arms are explicitly not like-for-like controls, the counts should be read descriptively, not as evidence of a treatment difference.
12. What the Result Does, and Does Not, Mean
The registry record establishes the study’s stated purpose and design: a completed Phase 1/Phase 2 study of cultivated autologous limbal epithelial cell transplantation for limbal stem cell deficiency, with safety and feasibility as the main aim. It describes a primary safety endpoint based on specified events in the recipient eye during 18 Months of follow-up. It also provides adverse-event summaries for CALEC and CLAU groups.
Those summaries do not answer whether the primary endpoint events occurred. Endpoint-specific counts and analyses are not reported in the registry record. The adverse-event figures cannot substitute for those results because the registry does not identify them as counts of ocular infection, corneal perforation, or graft detachment of at least 50%. The listed serious term Vomiting likewise does not establish an endpoint event or its frequency among participants, since its denominator and counting basis are not reported.
The record does not show a randomized comparison, and it expressly cautions that its arms are not a like-for-like control comparison. Therefore, the group entries cannot establish comparative safety or efficacy. The registry’s secondary efficacy outcome has no reported result, and the absence of analyses means there is no posted effect estimate, confidence interval, or p-value to interpret.
In general, a study’s design and the precision of its estimates affect what can be inferred. Here, the registry supports a description of the study question, interventions, follow-up window, and adverse-event entries. It does not provide enough outcome detail to quantify the primary safety result or evaluate efficacy. These limits are about what the registry record reports; they are not evidence that an unreported event did or did not occur.
13. Why This Trial Matters Statistically
This study is statistically notable because its safety question is stated as a participant-count outcome with an explicit event definition and follow-up period. Clear outcome definitions help readers understand what the study intended to measure. The specified events—ocular infection, corneal perforation, and substantial graft detachment—provide a defined safety focus for recipients of CALEC or CLAU transplantation.
The design description is equally important. The registry identifies the study as single-group, with allocation not applicable and no masking. Although CALEC and CLAU appear as separate labels in adverse-event entries, the record warns that they are not a like-for-like control comparison. That distinction prevents descriptive group counts from being mistaken for a randomized treatment effect.
The record also illustrates why reporting the analysis matters. Counts without primary-endpoint results, analysis methods, uncertainty measures, and clear analysis populations leave important questions unresolved. Readers cannot judge the precision of the safety estimate or determine how missing information and multiple outcomes were handled when those details are not reported. This is especially relevant when interpreting adverse-event summaries alongside a separately defined primary endpoint.
In general, transparent reporting makes it easier to distinguish the study’s intended question from what its observed data can establish. The registry supplies a clear safety aim and endpoint definition, but its posted results do not include the endpoint analysis or the secondary efficacy result. Recognizing both the useful design information and the limits of the results is central to a statistically careful reading.
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 primary limitation is that endpoint-specific results are not reported in the registry record. The endpoint definition and its 18 Months timeframe are available, but no count of participants meeting that definition, event breakdown, estimate, or uncertainty interval is posted. The adverse-event summaries are not identified as the primary endpoint results.
The registry lists enrollment as 23, but does not report the number included in the primary endpoint analysis or explain how enrollment relates to the numbers at risk in the adverse-event entries. The handling of incomplete follow-up, missing observations, and analysis populations is not reported in the registry record. This makes it difficult to assess completeness or determine precisely which participants contribute to each result.
The study is described as single-group, and the registry explicitly warns that CALEC and CLAU are not a like-for-like control comparison. The full CLAU description and the rationale for its appearance as a separate adverse-event group are not reported in the registry record. The groups should not be used to infer comparative effects.
Although three outcome measures and a secondary efficacy measure are listed, the registry reports no analyses. The statistical plan, sample-size justification, multiplicity approach, and methods for assessing outcomes are not reported. The sample-size planning assumptions do not fill those gaps or establish that the trial was designed around the posted endpoint. Finally, the listed serious term Vomiting is accompanied by a percentage but no reported denominator or counting basis. These limitations constrain interpretation of the posted safety information and prevent assessment of efficacy.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Limbal Stem Cell Deficiency (LSCD) Treatment With Cultivated Stem Cell (CALEC) Graft — NCT02592330.
- Registry record last updated 2025-01-15; status last verified 2025-01.
- Results first posted 2025-01-15.
- 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.
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18. Record Summary
NCT02592330 is a completed Phase 1/Phase 2, single-group study of cultivated autologous limbal epithelial cell transplantation for limbal stem cell deficiency. The registry lists enrollment as 23, no masking, and allocation as not applicable. The intervention includes biopsy, cell cultivation, and CALEC transplantation.
The primary outcome counts participants with specified recipient-eye safety events during 18 Months of follow-up. The registry also lists a secondary measure of transplant efficacy. It reports no analyses, primary endpoint results, or efficacy results. Adverse-event entries are listed for CALEC and CLAU, but the registry warns that these groups are not a like-for-like control comparison. Details on missing data, analysis populations, and the statistical plan are not reported in the registry record.