High-Dose Gemcitabine, Busulfan and Melphalan With Hematopoietic-Cell Support for Patients With Poor-Risk Myeloma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for High-Dose Gemcitabine, Busulfan and Melphalan With Hematopoietic-Cell Support for Patients With Poor-Risk Myeloma (NCT01237951), a na phase 2 study. The primary outcome is Participants Who Had Measurable Disease at Time of Transplant and Achieved a Stringent Complete Remission.

2. Clinical Question

3. Trial Design

This is a phase 2, completed, single-group clinical trial sponsored by M.D. Anderson Cancer Center. The registry record lists enrollment of 75 and identifies myeloma as the condition. It describes an open-label design: masking is listed as none. Allocation is listed as NA, consistent with the record's single-group model. No randomized control group or concurrent comparator is described.

The intervention is the GemBuMel regimen: gemcitabine, busulfan and melphalan, with autologous hematopoietic-cell support. The record also lists palifermin, dexamethasone, G-CSF and stem cell transplant among the interventions. Some regimen details appear in the arm description, including doses and treatment days, but the description ends before the full regimen is specified. It is therefore not possible to reconstruct every treatment detail from the registry record.

The primary endpoint is a participant count for stringent complete remission at 100 days post-transplant, assessed among those with measurable disease at transplant. The registry record says that this endpoint population included 65 participants. That endpoint population is not interchangeable with the overall enrollment: eligibility for the response assessment is defined by measurable disease at transplant.

Other listed outcomes are progression-free survival, overall survival and the percent of participants dying from treatment-related complications. The record lists four outcome measures, but no analyses are listed. The registry entries do not include the primary response count, a time-to-event result, or an estimate for treatment-related mortality. The trial's completion status indicates the registry record marks it completed; it does not supply those missing outcome estimates.

Because there is no randomized comparison, any outcomes describe this study group under its treatment and follow-up conditions. Differences from outcomes in other populations cannot be interpreted as treatment effects using this design alone. The registry record does not report a statistical analysis plan, the planned sample-size justification, or whether interim analyses were conducted.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Only 65 participants had measurable disease at the time of ASCT.

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 Participants Who Had Measurable Disease at Time of Transplant and Achieved a Stringent Complete Remission, measured over 100 days post-transplant.

The primary endpoint counts participants with measurable disease at transplant who achieved stringent complete remission by 100 days post-transplant. The registry defines this response using findings from serum, urine and bone marrow, along with assessment of soft tissue plasmacytomas and the free light chain ratio. Requiring these findings together makes the endpoint more restrictive than a response definition based on a single measure. In general, a stringent response endpoint aims to capture a deep response across multiple disease assessments.

The timeframe is important: the endpoint concerns response at 100 days post-transplant, not response at any point during follow-up. It is also a participant count, rather than a continuous measurement or a time-to-event endpoint. The eligible population is stated as participants with measurable disease at transplant; the registry record reports that this included 65 participants. The primary outcome result itself is not reported in the registry record.

This endpoint can describe whether participants met the stated criteria at the specified assessment. It does not, by itself, establish how long a remission lasted, whether progression was delayed, or whether survival changed. Progression-free survival and overall survival are listed separately as secondary outcomes. Since the primary count and its uncertainty are absent, the posted record does not allow assessment of the observed response frequency or how precisely it was estimated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods are useful only when their inputs, assumptions and target question are clear. In this study, the primary question is expressed as a participant count for stringent complete remission by 100 days post-transplant among those with measurable disease at transplant. The registry record gives the endpoint definition and says that this population included 65 participants. It does not report the observed remission count or any analyses. Without the outcome count, the response estimate and its uncertainty cannot be assessed from the registry record.

What does a participant count represent?

A participant count records how many people meet a specified outcome definition during the stated assessment period. For a binary outcome such as meeting or not meeting the remission criteria, an analysis may also express the count relative to the eligible population. In general, that proportion describes the observed frequency in the analyzed group; it does not, on its own, establish that treatment caused the outcome. The registry record's primary result is a count endpoint, but the count is not reported.

Counts and denominators must be interpreted together. The primary endpoint applies to participants with measurable disease at transplant, not automatically to everyone enrolled. The safety record separately reports a denominator of 74 for adverse-event categories. These populations and denominators should not be treated as identical without a registry statement establishing that they are. The registry entries do not explain why those denominators differ, and no reason should be inferred.

What would a confidence interval add?

General explanation: a confidence interval describes statistical uncertainty around an estimate under the method's assumptions. For a response proportion, the interval would reflect the amount of information in the observed outcome data and the analysis method. A narrow interval indicates greater precision than a wide interval, while neither interval alone resolves the possibility of bias or establishes a causal treatment effect. The registry record does not include a confidence interval for the primary endpoint.

A p-value, if used, would address how compatible the observed data are with a specified statistical null model. It would not measure the probability that the treatment works, and it would not convey the size or clinical importance of an effect. No p-value or primary endpoint analysis is reported in the registry record. It is therefore not possible to characterize the result as statistically significant or not statistically significant.

How does the design affect inference?

General explanation: random allocation to a comparator can help balance prognostic factors between groups, on average, and supports a direct treatment contrast. This record describes a single-group study, with allocation listed as NA and no masking. There is no concurrent comparator in the posted design. As a result, an observed outcome in the study group would be descriptive; it would not provide a randomized estimate of the difference between the regimen and another treatment. Open-label status also means the record does not describe masking of participants or study personnel.

The registry identifies the study as phase 2. That label describes the trial's phase, but it does not disclose the statistical methods used to analyze the outcomes. The statistical plan, sample-size justification and interim-analysis procedures are not reported in the registry record. They should not be reconstructed from the phase designation or enrollment figure.

What do the planning assumptions mean?

General explanation: sample-size calculations can illustrate how many participants per arm might be needed under specified assumptions to detect a chosen effect with a chosen significance level and power. Such calculations are planning tools, not observed results and not evidence that a trial had a particular probability of detecting an effect after the fact. The registry information describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and the effect expressed as a fraction of the observed effect. Those assumptions do not turn this single-group study into a two-arm trial, and they are not the trial's own design justification. The registry record does not report that justification.

For time-to-event outcomes, general sample-size methods may focus on the total number of events; for other outcomes, planning may be expressed as participants per arm. These are distinct planning quantities and should not be confused with the trial's enrollment or its observed event counts. Any sample-size illustration is conditional on its stated assumptions. It is not observed power, a measure of the study's achieved precision, or a substitute for an outcome estimate and confidence interval.

Why can event categories overlap?

General explanation: adverse-event summaries may count participants affected by each event category, and one participant can experience more than one type of event. Thus category counts or percentages need not add to an overall count. The registry record reports serious and other adverse-event categories for the Gemcitabine/Busulfan/Melphalan group, as well as percentages for selected serious terms. The registry entries do not specify whether the selected terms are mutually exclusive, so adding their percentages would not be justified.

These statistical concepts help distinguish description, uncertainty and comparison. In this record, the design and outcome definitions are available, as are some safety counts. However, the primary response result and analyses are not reported in the registry record. Without those results, statistical methods cannot recover an effect estimate, its precision, or a comparison that the design did not include.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Gemcitabine/Busulfan/Melphalan")
n      <- c(65)
events <- c(16)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Gemcitabine/Busulfan/Melphalan  65  16  24.6  14.8  36.9  15.8  36.3  15.8  36.4

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists four outcome measures, including the primary remission endpoint and secondary outcomes of progression-free survival, overall survival and percent of participants dying from treatment-related complications. It lists no analyses. The statistical plan is not reported in the registry record, so it is not possible to determine which outcomes were tested, what models were planned, or whether any multiplicity adjustment was used.

General explanation: when several outcomes or statistical tests are examined, the chance of at least one apparently notable result can increase if each is judged separately without accounting for the family of tests. Prespecified primary and secondary outcomes, along with a stated testing strategy, help readers understand how to interpret multiple results. The posted information does not establish that such a strategy was or was not used; it is not reported in the registry record.

Missing-data methods and outcome-specific analysis populations are also not reported. The registry record does state that only 65 participants had measurable disease at the time of ASCT for the primary endpoint. That eligibility description clarifies the intended endpoint population, but does not explain how missing assessments, withdrawals, or other unavailable outcomes were handled. The enrollment figure is 75, while safety denominators are reported as 74; the reason for the denominator used in safety summaries is not reported in the registry record. No additional population definition or missing-data assumption should be inferred.

These omissions matter because endpoint estimates depend on who is included and how absent observations are treated. Without the analysis plan and results, readers cannot evaluate whether analyses followed prespecified rules, whether outcomes were complete, or how sensitive findings might be to alternative assumptions.

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 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: mucositis (17.6%), hyperbilirubinemia (12.2%), dermatitis (6.8%), infection (6.8%), diarrhea (2.7%).

The adverse-event summary is for the Gemcitabine/Busulfan/Melphalan group. It reports 31 of 74 participants affected by serious adverse events and 71 of 74 affected by other adverse events. These are participant counts within the categories recorded in the registry; they are not measures of event severity beyond the stated serious classification, and they should not be combined into a new total.

The listed serious-event terms and percentages are mucositis at 17.6%, hyperbilirubinemia at 12.2%, dermatitis at 6.8%, infection at 6.8%, diarrhea at 2.7%, and cardiac at 2.7%. These figures describe the listed terms, not necessarily distinct groups of participants. A participant may appear under more than one term, and the record does not establish that categories are mutually exclusive.

The registry record reports five deaths for this group. The registry entries do not specify that these deaths were treatment-related, nor do they provide timing, cause or an analysis linking deaths to the regimen. The listed secondary outcome of percent dying from treatment-related complications is not accompanied by a result. The safety counts therefore describe recorded events but cannot answer that separate outcome question.

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

The record establishes that a phase 2, completed, single-group study evaluated high-dose gemcitabine, busulfan and melphalan with autologous hematopoietic-cell support in poor-risk myeloma. It defines a stringent complete remission endpoint at 100 days post-transplant for participants with measurable disease at transplant. It also lists survival and treatment-related mortality outcomes and provides certain adverse-event summaries.

What the posted information does not establish is the observed primary remission result. The response count is not reported in the registry record, so neither the observed response frequency nor its statistical precision can be described. The listed secondary outcomes likewise have no outcome estimates in the registry record. This means the record cannot support a numerical statement about progression-free survival, overall survival or treatment-related deaths.

The single-group design is another boundary on interpretation. Even if an outcome estimate were available, this design would describe the study group rather than provide a randomized comparison with another treatment. It cannot, by itself, separate the effect of the regimen from other influences on outcomes. No treatment conclusion follows from an endpoint definition or from a study's completion status.

The adverse-event figures do provide descriptive information: the registry reports serious and other adverse events, selected serious-event terms and five deaths. Those data should be read with their denominators and with the possibility that event categories overlap. The registry entries do not establish that the reported deaths were caused by treatment. Nor do these summaries replace the separate endpoint concerning deaths from treatment-related complications.

In general, clinical interpretation depends on the outcome estimate, its uncertainty, the population analyzed, follow-up and a suitable comparator for causal claims. Several of these elements are not reported in the registry record. The appropriate reading is therefore limited: the study's question and design are described, some safety counts are posted, but the primary efficacy result and key analysis details are absent.

14. Why This Trial Matters Statistically

This trial is statistically notable for the gap between a clearly defined primary endpoint and the absence of its result in the registry record. The endpoint specifies a response definition, a post-transplant assessment time and a population with measurable disease at transplant. Those details make the intended question understandable, but they cannot substitute for the observed count, denominator-specific estimate or uncertainty interval.

The design also illustrates why a study result and a comparative treatment effect are different quantities. A single-group trial can document outcomes and safety experience among participants treated under the study regimen. Without a control group, it does not estimate how outcomes would differ under an alternative treatment. That distinction remains important even if the observed response were known.

Outcome populations also require attention. Enrollment is reported as 75, while the primary endpoint applies to the subgroup with measurable disease at transplant, reported as 65 participants. The safety summaries use a denominator of 74. These figures correspond to different record descriptions; the registry entries do not explain the difference or establish that the groups are identical. Preserving each stated population prevents unsupported denominator changes.

Finally, a list of secondary outcomes and adverse events is not the same as a complete analysis. The registry record lists progression-free survival, overall survival and treatment-related complications, but supplies no analyses. It does report selected adverse-event terms and counts, which can be read descriptively. For clinical and statistical interpretation, transparent reporting of estimates, uncertainty, analysis populations, missing-data handling and multiplicity procedures would be needed. Their absence leaves important questions unresolved rather than answering them.

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 principal trial-specific limitation in the posted record is the absence of the primary endpoint result. Although stringent complete remission is defined and the relevant population is identified, no remission count or uncertainty estimate is reported. The listed secondary outcomes also have no results in the registry record. This prevents assessment of the observed efficacy outcomes and their precision.

The single-group, open-label design has no concurrent comparator. It therefore does not support a randomized comparison, and outcomes cannot be attributed to the regimen alone from this design. The registry record does not report the statistical analysis plan, sample-size justification, interim analyses, missing-data methods, or multiplicity procedures. It is not possible to assess adherence to an analysis plan or the influence of missing observations.

The population descriptions are not fully reconciled in the posted information. Enrollment is 75, the primary endpoint applies to 65 participants with measurable disease at transplant, and the safety summaries use 74 as the denominator. The registry record does not explain why these figures differ, so no explanation should be assumed. The arm description is also incomplete in the registry record, limiting reconstruction of the full regimen from the posted details.

Safety summaries list selected serious-event terms and deaths, but do not specify in the registry record whether event categories overlap, the causes of the deaths, or whether those deaths were treatment-related. The separate treatment-related mortality outcome has no reported result. These limitations restrict both efficacy interpretation and a fuller accounting of treatment-related harms.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: High-Dose Gemcitabine, Busulfan and Melphalan With Hematopoietic-Cell Support for Patients With Poor-Risk Myeloma — NCT01237951.
• Registry record last updated 2020-05-05; status last verified 2020-04.
• Results first posted 2020-05-05.
• 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

The registry record describes NCT01237951, a completed phase 2, single-group, open-label study sponsored by M.D. Anderson Cancer Center. It lists enrollment of 75 and evaluates high-dose gemcitabine, busulfan and melphalan with autologous hematopoietic-cell support for poor-risk myeloma.

The primary outcome is the count of participants with measurable disease at transplant who achieved stringent complete remission at 100 days post-transplant. The record says that this endpoint population included 65 participants, but the outcome result is not reported in the registry record. Secondary outcomes include progression-free survival, overall survival and percent dying from treatment-related complications; no analyses are listed.

Safety information reports serious and other adverse-event counts for the Gemcitabine/Busulfan/Melphalan group, selected serious-event terms and five deaths. The record does not establish that these deaths were treatment-related. The design has no comparator, and the statistical plan, missing-data methods and multiplicity approach are not reported in the registry record.