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 Pilot Study of Leuprolide to Improve Immune Function After Allogeneic Bone Marrow Transplantation (NCT01338987), a randomized phase 2 study. The primary outcome is Percentage of B Cells at One Year Post-transplant in Participants Who Did/Did Not Receive Leuprolide Following Bone Marrow Transplant (BMT).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01338987 |
| Phase | Phase 2 |
| Condition | Myelodysplastic Syndrome, Acute Lymphocytic Leukemia, Acute Myelogenous Leukemia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 76 |
| Arms in the primary outcome | n/a |
| Lead sponsor | National Cancer Institute (NCI) |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned post-pubertal children and adults undergoing allogeneic bone marrow transplantation for specified blood cancers or high-risk myelodysplastic syndrome. The registry summary describes an age range of 15 to 55 years, with eligibility as young as 9 for those who had gone through puberty. The primary endpoint population was narrower: first-transplant patients with more than 1 year of follow-up without relapse. The record says that this endpoint population included 5 males and 9 females who received leuprolide and 7 males who did not.
Intervention
The intervention of interest was leuprolide given in connection with the first transplant. The registry describes leuprolide as a drug that lowers estrogen or testosterone levels, with the study investigating whether this might influence immune recovery. FLT imaging was also part of the study’s objectives and arm descriptions, but the primary endpoint focused on B-cell percentage rather than an imaging measurement.
Comparator
The clearest stated contrast for the primary question is between first-transplant males who received leuprolide and first-transplant males who did not. Females receiving leuprolide were also included in the primary endpoint population, but the record does not describe a female no-leuprolide group. Other described groups include recipients of a second transplant and healthy volunteers; these are not interchangeable with the first-transplant comparison.
Primary question
The central question was whether the percentage of lymphocytes that were B cells at approximately 12 months after the first transplant differed according to leuprolide receipt. The registry identifies this as a median with the full range as its dispersion measure. It does not report the numerical medians or a numerical between-group estimate, so the size and precision of any difference cannot be assessed from the registry record.
3. Trial Design
This was a phase 2, randomized, open-label, parallel study with an enrollment of 76. The registry lists the study as completed. Its recorded start date is 2011-04-19, and its primary completion date is 2017-12-01. The sponsor was the National Cancer Institute (NCI). Randomization indicates that assignment was intended to involve chance, but the precise allocation procedure, allocation ratio, and sequence-generation method are not reported in the registry record. Masking was listed as none, so the study was not described as blinded.
The intervention and arm descriptions distinguish participants by sex, leuprolide receipt, and transplant status. They include males randomized to receive leuprolide for a first transplant, males not receiving leuprolide for a first transplant, females receiving leuprolide for a first transplant, recipients of a second transplant receiving leuprolide, and a healthy-volunteer group. FLT imaging is also described in several arms. The registry record does not support treating all these groups as a single randomized comparison: they differ in their clinical role and in whether they were described as receiving leuprolide.
The primary endpoint was limited to participants after their first bone marrow transplant who had more than 1 year of follow-up without relapse. The record states that 5 males and 9 females who received leuprolide, and 7 males who did not, were evaluable. It also reports missing data or insufficient follow-up due to death without relapse as reasons for being unevaluable. The specific randomization strata, detailed treatment schedule, protocol deviations, and analysis plan are not reported in the registry record. Although the study is marked completed, completion status alone does not establish that every planned analysis or outcome is reported.
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 | Males That Did Not Receive Leuprolide for 1st Transplant | Males Randomized to Receive Leuprolide for 1st Transplant | Females That Received Leuprolide for 1st Transplant | Matched Related Donors for Transplant | Recipients of 2nd Transplant |
|---|---|---|---|---|---|
| STARTED | 12 | 9 | 22 | 31 | 2 |
| COMPLETED | 10 | 8 | 20 | 31 | 2 |
| NOT COMPLETED | 2 | 1 | 2 | 0 | 0 |
Reasons for not completing this period:
| Reason | Males That Did Not Receive Leuprolide for 1st Transplant | Males Randomized to Receive Leuprolide for 1st Transplant | Females That Received Leuprolide for 1st Transplant | Matched Related Donors for Transplant | Recipients of 2nd Transplant |
|---|---|---|---|---|---|
| enrolled on new protocol | 0 | 0 | 1 | 0 | 0 |
| Disease progression on study | 2 | 1 | 1 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Only first BMT patients (SG1-3) with \>1 year of follow-up without relapse were evaluable. Of evaluable patients, 5 males and 9 females received and 7 males did not receive Lupron. Reasons for patients being inevaluable were missing data (2) or insufficient follow-up due to death without relapse (3), relapse (11), or withdrawal (1) before 1 year.
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 | Males That Did Not Receive Leuprolide for 1st Transplant | Males Randomized to Receive Leuprolide for 1st Transplant | Females That Received Leuprolide for 1st Transplant | Matched Related Donors for Transplant | Recipients of 2nd Transplant | Total |
|---|---|---|---|---|---|---|---|
| Participants analysed | 12 | 9 | 22 | 31 | 2 | 76 | |
| Age, Categorical: <=18 years | Participants | 1 | 0 | 0 | 3 | 0 | 4 |
| Age, Categorical: Between 18 and 65 years | Participants | 11 | 9 | 22 | 28 | 2 | 72 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Age, Continuous | years | 33 (SD 9.30) | 26.77 (SD 5.71) | 36.05 (SD 6.10) | 33.86 (SD 11.49) | 23.05 (SD 3.61) | 33.61 (SD 10.03) |
| Sex: Female, Male: Female | Participants | 0 | 0 | 22 | 17 | 0 | 39 |
| Sex: Female, Male: Male | Participants | 12 | 9 | 0 | 14 | 2 | 37 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 8 | 6 | 15 | 26 | 1 | 56 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 4 | 3 | 7 | 5 | 1 | 20 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 1 | 1 | 0 | 2 |
| Race (NIH/OMB): Asian | Participants | 1 | 0 | 0 | 0 | 0 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 | 1 | 3 | 2 | 0 | 8 |
| Race (NIH/OMB): White | Participants | 9 | 5 | 15 | 28 | 2 | 59 |
| Race (NIH/OMB): More than one race | Participants | 0 | 1 | 0 | 0 | 0 | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 2 | 3 | 0 | 0 | 5 |
| Region of Enrollment: United States | Participants | 12 | 9 | 22 | 31 | 2 | 76 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of B Cells at One Year Post-transplant in Participants Who Did/Did Not Receive Leuprolide Following Bone Marrow Transplant (BMT), measured over after first Bone Marrow Transplant, approximately 12 months post-transplant.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | percentage of cells |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the percentage of lymphocytes that were B cells at approximately 12 months after the first bone marrow transplant. The registry defines B-cell percentage as the percentage of lymphocytes that are B cells and specifies a median with the full range as the summary. This measurement describes the composition of the lymphocyte population at a particular post-transplant time point. It is an immune-reconstitution measure, not a direct measure of survival, infection, or overall clinical benefit.
In general, a proportion such as B-cell percentage can describe a particular component of a broader cell population. A median summarizes the middle of the observed values and is less influenced by extreme observations than an arithmetic mean. The full range gives the lowest and highest observed values, but it does not show how densely observations are distributed between those extremes. These are general explanations of the statistics named in the record.
The endpoint was selected in keeping with the study’s stated interest in immune recovery after transplantation. However, the numerical endpoint values, group medians, and full ranges are not reported in the registry record. The precise measurement schedule, laboratory method, and handling of measurements taken outside the stated approximate time point are also not reported. Without the observed endpoint values, the direction, magnitude, and precision of the B-cell percentage comparison cannot be described.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies B-cell percentage at approximately 12 months after the first transplant as the primary endpoint, but it does not report the endpoint’s numerical results. In particular, the registry record does not give group medians, full ranges, a between-group estimate, a confidence interval, or a p-value for this outcome. Consequently, no effect size or statistical uncertainty for the primary comparison can be assessed from the posted results. The description of the endpoint and the number of evaluable participants do not by themselves establish whether the groups differed.
The primary endpoint population was defined by first transplant and more than 1 year of follow-up without relapse. The registry reports 5 males and 9 females who received leuprolide and 7 males who did not as evaluable. This makes clear that the reported evaluable groups were not balanced in their described sex composition. It does not, however, establish how the study handled sex in the analysis or whether any adjusted comparison was planned. Such details are not reported in the registry record.
The trial was randomized and parallel, but randomization does not resolve every interpretive issue. The record describes multiple distinct groups, including recipients of a second transplant and healthy volunteers, as well as first-transplant groups separated by sex and leuprolide receipt. The primary endpoint population excludes some of those groups. The specific primary analysis and the intended role of each arm in that analysis are not reported in the registry record. The overall enrollment of 76 should therefore not be treated as the sample size for the primary endpoint comparison.
The outcome’s evaluability rules also matter. Requiring more than 1 year of follow-up without relapse means the endpoint describes a selected subset rather than everyone enrolled. The registry gives missing data (2) and insufficient follow-up due to death without relapse (3) as reasons for inevaluability. It does not report how these participants were handled in any statistical analysis or whether other participants were excluded for other reasons. These omissions make it difficult to judge how missing observations or selection into the evaluable subset may have influenced the observed endpoint.
The safety record lists counts of participants affected by serious and non-serious adverse events in several groups, along with deaths. These are descriptive counts, not a reported randomized safety comparison. The groups include matched related donors and recipients of a second transplant as well as first-transplant recipient groups, so the counts should not be read as a single like-for-like comparison. The registry does not provide enough information to establish whether an event was caused by leuprolide or to attribute differences between groups to treatment.
9. Statistical Methods Explained
The study is described as randomized, open-label, and parallel. In general, random allocation is used to reduce systematic differences between treatment groups at the time of assignment. It does not guarantee that groups will be identical, particularly in a pilot study, and it cannot correct for missing outcome data or selective availability of measurements. The registry does not report the randomization procedure, allocation ratio, stratification factors, or concealment method. Those methodological details therefore cannot be assessed from the record.
Open-label means masking was listed as none. In general, lack of masking can matter when care decisions, reporting, or measurement could be influenced by knowledge of treatment assignment. The primary endpoint is a cell percentage, but the record does not describe laboratory assessment procedures or whether laboratory personnel knew treatment assignment. It is therefore not possible to determine from the registry record how measurement was standardized or whether endpoint assessment was masked.
The endpoint is a continuous percentage summarized using a median and full range. In general, the median is the middle value after observations are ordered; the full range reports the observed extremes. This presentation can be useful when data are skewed or include extreme values, but the range is sensitive to those extremes and does not convey the precision of a group comparison. A confidence interval would give information about uncertainty in an estimated quantity, but one is not reported for the primary endpoint. The numerical medians and ranges themselves are also not reported in the registry record.
The endpoint timing was approximately 12 months after the first transplant. A time-specific endpoint can make groups comparable at a stated point after treatment, but follow-up and eligibility rules affect who contributes a measurement. Here, the primary endpoint population required more than 1 year of follow-up without relapse. The registry reports 5 males and 9 females who received leuprolide and 7 males who did not as evaluable. It does not report whether the time point was defined by a visit window, how measurements outside that window were handled, or whether the endpoint was analyzed as a proportion, percentage-point difference, or another contrast.
In general, over-dispersion means that observed variation is greater than a statistical model expects. It can make standard errors too small if a model does not account for the extra variation. The registry record does not describe a model for this endpoint or indicate whether over-dispersion was assessed. No assumption about a model or its diagnostics can therefore be made. Similarly, the record does not state whether the comparison was adjusted for baseline characteristics, sex, or other variables.
The registry lists an illustrative sample-size approach based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation; the effect to detect is described as a fraction of the observed effect. This is a planning illustration, not an account of the trial’s original design justification and not observed power. The resulting sample-size values are not reported in the registry record. The actual trial enrollment was 76, but enrollment is not the same as the number contributing to the primary endpoint and should not be treated as the sample size in each comparison group.
A p-value, when reported, addresses how compatible data are with a specified null model under its assumptions; it is not a measure of clinical importance or the probability that the null hypothesis is true. A confidence interval describes uncertainty around an estimate and the range of values reasonably compatible with the data and method. Neither a p-value nor a confidence interval for the primary endpoint is reported in the registry record. Without the numerical estimate and its uncertainty, statistical significance, precision, and magnitude cannot be evaluated.
The record identifies one primary endpoint and lists a secondary outcome concerning serious and non-serious adverse events assessed by CTCAE v4.0. It does not report the testing strategy, any adjustment for multiple outcomes, interim analyses, or stopping rules. These are not inferable merely from the phase, design label, or completion status. No statistical analysis plan is described in sufficient detail to identify the precise estimand, analysis population, covariate adjustment, or missing-data method.
10. Multiplicity, Missing Data and Analysis Populations
The registry names a primary endpoint and a secondary safety outcome, but a strategy for handling multiple statistical tests is not reported in the registry record. In general, testing several outcomes or comparisons can increase the chance of at least one apparently unusual result when all tests are interpreted without accounting for multiplicity. The record does not state whether the primary endpoint was the only confirmatory test, whether secondary outcomes were considered exploratory, or whether any adjustment was planned. It also does not report interim analyses or stopping rules.
The primary endpoint population excluded first-transplant patients who did not have more than 1 year of follow-up without relapse. For the endpoint, the record lists 5 males and 9 females receiving leuprolide and 7 males not receiving it as evaluable. Reasons for inevaluability included missing data (2) and insufficient follow-up due to death without relapse (3). These exclusions mean that the endpoint population is not simply everyone enrolled. The record does not explain how the listed reasons map to treatment groups or whether other exclusions occurred.
In general, missing outcome data can affect interpretation if the likelihood of having a measurement is related to treatment assignment or the outcome itself. Requiring follow-up without relapse also defines a selected population, so the endpoint describes those meeting that criterion rather than all randomized participants. The registry does not report an intention-to-treat analysis, imputation, sensitivity analysis, or other missing-data approach. It is therefore not possible to determine how missingness or the follow-up requirement was incorporated into the statistical analysis.
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 |
|---|---|---|---|
| Males That Did Not Receive Leuprolide for 1st Transplant | 5 | 10 | 50.0% |
| Males Randomized to Receive Leuprolide for 1st Transplant | 6 | 8 | 75.0% |
| Females That Received Leuprolide for 1st Transplant | 15 | 20 | 75.0% |
| Matched Related Donors for Transplant | 2 | 31 | 6.5% |
| Recipients of 2nd Transplant | 2 | 2 | 100.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Males That Did Not Receive Leuprolide for 1st Transplant | 4 of 10 |
| Males Randomized to Receive Leuprolide for 1st Transplant | 3 of 8 |
| Females That Received Leuprolide for 1st Transplant | 8 of 20 |
| Matched Related Donors for Transplant | 0 of 31 |
| Recipients of 2nd Transplant | 2 of 2 |
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 |
|---|---|
| Males That Did Not Receive Leuprolide for 1st Transplant | 10 of 10 |
| Males Randomized to Receive Leuprolide for 1st Transplant | 8 of 8 |
| Females That Received Leuprolide for 1st Transplant | 20 of 20 |
| Matched Related Donors for Transplant | 4 of 31 |
| Recipients of 2nd Transplant | 2 of 2 |
Most frequent serious adverse event terms
| Event term | Organ system | Males That Did Not Receive Leuprolide for 1st Transplant | Males Randomized to Receive Leuprolide for 1st Transplant | Females That Received Leuprolide for 1st Transplant | Matched Related Donors for Transplant | Recipients of 2nd Transplant |
|---|---|---|---|---|---|---|
| Respiratory failure | Respiratory, thoracic and mediastinal disorders | 1 of 10 | 1 of 8 | 4 of 20 | 0 of 31 | 2 of 2 |
| Hypotension | Vascular disorders | 0 of 10 | 0 of 8 | 5 of 20 | 2 of 31 | 0 of 2 |
| Infections and infestations - Other, Fever, neutropenia | Infections and infestations | 1 of 10 | 0 of 8 | 5 of 20 | 0 of 31 | 0 of 2 |
| Sepsis | Infections and infestations | 0 of 10 | 2 of 8 | 4 of 20 | 0 of 31 | 0 of 2 |
| Death NOS | General disorders | 1 of 10 | 1 of 8 | 3 of 20 | 0 of 31 | 0 of 2 |
| Hypoxia | Respiratory, thoracic and mediastinal disorders | 0 of 10 | 1 of 8 | 3 of 20 | 0 of 31 | 0 of 2 |
| Acidosis | Metabolism and nutrition disorders | 1 of 10 | 0 of 8 | 1 of 20 | 0 of 31 | 1 of 2 |
| Febrile neutropenia | Blood and lymphatic system disorders | 2 of 10 | 1 of 8 | 0 of 20 | 0 of 31 | 0 of 2 |
| Pneumothorax | Respiratory, thoracic and mediastinal disorders | 0 of 10 | 1 of 8 | 1 of 20 | 0 of 31 | 1 of 2 |
| Abdominal pain | Gastrointestinal disorders | 1 of 10 | 0 of 8 | 1 of 20 | 0 of 31 | 0 of 2 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Males That Did Not Receive Leuprolide for 1st Transplant | Males Randomized to Receive Leuprolide for 1st Transplant | Females That Received Leuprolide for 1st Transplant | Matched Related Donors for Transplant | Recipients of 2nd Transplant |
|---|---|---|---|---|---|---|
| Neutrophil count decreased | Investigations | 10 of 10 | 7 of 8 | 15 of 20 | 0 of 31 | 2 of 2 |
| Platelet count decreased | Investigations | 10 of 10 | 7 of 8 | 14 of 20 | 0 of 31 | 2 of 2 |
| White blood cell decreased | Investigations | 10 of 10 | 4 of 8 | 16 of 20 | 0 of 31 | 2 of 2 |
| Anemia | Blood and lymphatic system disorders | 9 of 10 | 5 of 8 | 12 of 20 | 3 of 31 | 2 of 2 |
| Hypophosphatemia | Metabolism and nutrition disorders | 8 of 10 | 4 of 8 | 12 of 20 | 0 of 31 | 2 of 2 |
| Alanine aminotransferase increased | Investigations | 6 of 10 | 4 of 8 | 14 of 20 | 0 of 31 | 1 of 2 |
| Aspartate aminotransferase increased | Investigations | 5 of 10 | 3 of 8 | 13 of 20 | 0 of 31 | 0 of 2 |
| Diarrhea | Gastrointestinal disorders | 4 of 10 | 5 of 8 | 10 of 20 | 0 of 31 | 2 of 2 |
| Hypokalemia | Metabolism and nutrition disorders | 6 of 10 | 3 of 8 | 10 of 20 | 0 of 31 | 1 of 2 |
| Nausea | Gastrointestinal disorders | 4 of 10 | 1 of 8 | 9 of 20 | 0 of 31 | 1 of 2 |
Serious events with the highest arm-level rate: respiratory failure (100.0%), acidosis (50.0%), dyspnea (50.0%), infections and infestations - other, candida glabrata in blood (50.0%), pneumothorax (50.0%).
The safety record lists, for each named group, the number at risk and the number affected by serious or other adverse events, as well as deaths. For males who did not receive leuprolide for the first transplant, the record lists 10 at risk for serious events and 5 affected; for males randomized to receive leuprolide, it lists 8 at risk and 6 affected. For females receiving leuprolide, the corresponding figures are 20 at risk and 15 affected. The record also lists matched related donors for transplant and recipients of a second transplant, which are distinct groups and should not be combined with recipient treatment arms.
The listed death counts are 4, 3, and 8 for the three first-transplant recipient groups, respectively; the record also lists 0 for matched related donors and 2 for recipients of a second transplant. These counts do not establish that deaths or adverse events were caused by a study intervention. The registry does not report a comparative safety analysis or the follow-up period for these counts.
Serious-event terms include respiratory failure (100.0%), acidosis (50.0%), dyspnea (50.0%), Candida glabrata in blood (50.0%), pneumothorax (50.0%), and hypotension (25.0%). The denominator underlying each percentage is not reported in the registry record, so the percentages should not be interpreted as rates among all enrolled participants.
12. What the Result Does, and Does Not, Mean
The study record establishes that a randomized, open-label, parallel phase 2 pilot study of leuprolide after allogeneic bone marrow transplantation was conducted and completed, with an enrollment of 76. It also establishes that B-cell percentage at approximately 12 months after the first transplant was the named primary endpoint, defined as the percentage of lymphocytes that were B cells. The endpoint population was restricted to first-transplant patients with more than 1 year of follow-up without relapse.
What the record does not establish is the observed primary outcome. The numerical medians, full ranges, and a statistical comparison are not reported in the registry record. As a result, the posted information does not show the size or direction of a difference in B-cell percentage, how precisely that difference was estimated, or whether a statistical test supported a difference. The absence of numerical results in the record should not be interpreted as evidence that groups were the same, or that one group had a better outcome.
The listed adverse-event and death counts are descriptive information across several different groups. They do not, by themselves, estimate a causal effect of leuprolide. The record does not provide a comparative safety analysis that would account for the differences among first-transplant recipients, donors, and second-transplant recipients. Nor does it report enough detail to determine the extent to which missing data or the endpoint eligibility requirement affected results.
In general, a pilot study can help describe feasibility and generate information for later research, but its purpose and conclusions depend on its protocol and analyses. The registry does not report the sample-size justification or a full statistical plan, so the intended evidential role of this study cannot be established from the record alone. The findings that can be stated are limited to the design, endpoint definition, evaluable-population description, and safety counts actually recorded.
13. Why This Trial Matters Statistically
This study raises an important statistical distinction between a trial’s overall enrollment and the population contributing to a specific endpoint. Although enrollment was 76, the primary endpoint applied only to first-transplant participants with more than 1 year of follow-up without relapse. The registry reports 5 males and 9 females who received leuprolide and 7 males who did not as evaluable. Those numbers describe the endpoint population, not necessarily every randomized participant or every study group.
The record also illustrates why a clearly defined estimand matters. An endpoint among participants who remain under follow-up without relapse answers a different descriptive question from an endpoint among all randomized participants. In general, exclusions based on post-randomization events or follow-up can change the population to which an estimate applies. The record does not report a broader analysis of all randomized participants or a strategy for addressing the excluded observations.
A second statistical issue is the separation of treatment comparisons from descriptive groups. The study includes first-transplant groups differentiated by sex and leuprolide receipt, as well as a second-transplant group, matched related donors, and healthy volunteers. Their purposes are not interchangeable, and the registry does not provide enough detail to treat every group as part of one comparison. This makes careful definition of the target comparison essential.
Finally, a stated endpoint is not the same as a reported result. Without the numerical medians, ranges, and uncertainty estimates, readers cannot judge effect magnitude or precision. The record’s safety counts are also not a substitute for a comparative analysis. Together, these features show why interpretation depends on complete outcome reporting, transparent analysis populations, and clear specification of the statistical plan—not design labels alone.
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 main limitation for statistical interpretation is that numerical results for the primary endpoint are not reported in the registry record. The endpoint is identified and its summary measure is specified, but the group medians, full ranges, and between-group estimate are unavailable. There is consequently no reported confidence interval or p-value with which to assess precision or statistical evidence.
The endpoint population is restricted to first-transplant patients with more than 1 year of follow-up without relapse. The record lists missing data (2) and insufficient follow-up due to death without relapse (3) as reasons for inevaluability, but does not detail the analysis treatment of these cases. The effect of this selection on the endpoint cannot be assessed from the registry record.
The described evaluable group includes males and females receiving leuprolide, but only males are described as not receiving it. The registry does not report a female untreated group for this endpoint or explain whether the analysis accounted for sex. It also does not specify the randomization procedure, allocation ratio, analysis model, covariate adjustment, multiplicity plan, interim analyses, or missing-data method. These details cannot be inferred from the study’s randomized label.
Several other groups appear in the record, including second-transplant recipients, matched related donors, and healthy volunteers. Their roles in relation to the primary endpoint are not fully described. Safety counts also lack a reported comparative analysis and follow-up detail, and the denominators for the listed serious-event percentages are not reported. These limitations constrain conclusions about both primary outcomes and safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pilot Study of Leuprolide to Improve Immune Function After Allogeneic Bone Marrow Transplantation — NCT01338987.
- Registry record last updated 2021-03-18; status last verified 2021-03.
- Results first posted 2019-04-23.
- 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
NCT01338987 is a completed phase 2, randomized, open-label, parallel pilot study sponsored by the National Cancer Institute (NCI). The study enrolled 76 participants and investigated leuprolide in relation to immune recovery after allogeneic bone marrow transplantation. Its recorded start date was 2011-04-19, and its primary completion date was 2017-12-01.
The primary endpoint was the percentage of lymphocytes that were B cells at approximately 12 months after the first transplant, summarized as a median with full range. The evaluable population required more than 1 year of follow-up without relapse. The registry reports 5 males and 9 females who received leuprolide and 7 males who did not as evaluable, but numerical endpoint results are not reported in the registry record.
The registry also lists adverse-event and death counts across distinct groups. It does not report the primary outcome comparison, a detailed statistical analysis plan, or a comparative safety analysis.