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 Pembrolizumab for the Treatment of Relapsed or Refractory Multiple Myeloma After Anti-BCMA CAR-T Therapies (NCT05191472), a na phase 2 study. The primary outcome is Overall Response Rate (ORR).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05191472 |
| Phase | Phase 2 |
| Condition | Multiple Myeloma, Multiple Myeloma in Relapse, Multiple Myeloma, Refractory |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Alfred Chung, MD |
| Results posted | Yes |
2. Clinical Question
Population
People with multiple myeloma whose disease had relapsed after, or was refractory to, anti-BCMA CAR-T therapies. The registry record lists multiple myeloma, relapsed or refractory multiple myeloma, and recurrent or refractory plasma cell myeloma among the conditions. Enrollment was 3. The primary endpoint population is recorded as “Data not collected,” so the analyzed population for the response endpoint is not reported in the registry record.
Intervention
Pembrolizumab, administered intravenously over 30 minutes on day 1 of each cycle. Cycles were scheduled every 21 days for up to 2 years, in the absence of disease progression or unacceptable toxicity.
Comparator
There was no comparator group. The study is described as single-group, with allocation listed as NA and masking listed as none. The registry record therefore does not support a like-for-like comparison between pembrolizumab and another treatment or a control condition.
Primary question
The primary question was whether participants achieved an overall response after 4 cycles of pembrolizumab, assessed using International Myeloma Working Group uniform response criteria. Response was defined as partial response, very good partial response, complete response, or stringent complete response. The registry record describes the endpoint but does not report the response result.
This is a focused question about observed disease response in a narrowly defined clinical setting after prior anti-BCMA CAR-T therapy. It is not a question about comparative benefit, because there is no control group, and the recorded design cannot separate a treatment-associated response from other explanations. The result would also need to be read in light of the small enrollment and the absence of a reported response analysis. The registry record does not report why the study was terminated or whether participants completed the planned endpoint assessment.
3. Trial Design
The registry describes a phase II, single-group study of pembrolizumab for multiple myeloma that relapsed after or was refractory to anti-BCMA CAR-T therapies. The listed allocation is NA and masking is none; the record identifies no control arm. Enrollment was 3. The study status is terminated. Its recorded start date is 2022-05-03, and its primary completion date is 2023-12-31. The reason for termination is not reported in the registry record.
Participants in the treatment group were scheduled to receive pembrolizumab intravenously over 30 minutes on day 1. Cycles were to repeat every 21 days for up to 2 years, unless disease progression or unacceptable toxicity occurred. This describes the planned treatment schedule; the registry record does not report how many participants received treatment, how many cycles they completed, or whether treatment stopped for progression or toxicity.
The primary outcome was overall response rate, assessed up to 4 cycles. The endpoint description defines response by the International Myeloma Working Group uniform response criteria and includes partial response, very good partial response, complete response, and stringent complete response. The description says a 95% confidence interval would also be reported, but no response estimate or confidence interval is reported in the registry record.
Several safety and disease-course outcomes are listed as secondary outcomes, including treatment-related adverse events, cytokine release syndrome, immune-effector cell-associated neurotoxicity syndrome, treatment discontinuation due to toxicity, best achieved response, overall survival at 12 months, and progression-free survival at 12 months and 24 months. The registry record does not report results for these outcomes. It also does not report a statistical analysis plan, an interim-analysis plan, a sample-size justification, or the reason the study ended.
Because the design has no randomized comparator, the study can describe outcomes among treated participants if those outcomes are reported, but it cannot establish a comparative treatment effect. The small enrollment and missing endpoint results further limit what can be concluded from 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 | Treatment (Pembrolizumab) |
|---|---|
| STARTED | 3 |
| COMPLETED | 3 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Data not collected
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 | Treatment (Pembrolizumab) |
|---|---|---|
| Participants analysed | 3 | |
| Age, Customized: 50-59 years | Participants | 1 |
| Age, Customized: 60-69 years | Participants | 1 |
| Age, Customized: 70-79 years | Participants | 1 |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 3 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 |
| Race (NIH/OMB): White | Participants | 2 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Overall Response Rate (ORR), measured over Up to 4 cycles (1 cycle is equal to 21 days).
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is overall response rate (ORR), defined as the proportion of participants who achieve partial response, very good partial response, complete response, or stringent complete response after 4 cycles of pembrolizumab. Response is to be assessed using International Myeloma Working Group uniform response criteria. The stated timeframe is up to 4 cycles, with each cycle equal to 21 days.
In general, a response-rate endpoint condenses a clinical assessment into a proportion: participants meeting the defined response threshold contribute to the response count, relative to the relevant analysis population. The endpoint is used to describe whether tumor response was observed during the specified assessment period. Its interpretation depends on consistent response criteria, the timing and completeness of assessments, and a clearly defined denominator. These details matter because missing assessments or an unclear analysis population can affect how the proportion should be understood.
The registry record states that a 95% confidence interval would also be reported. In general, a confidence interval communicates the precision of an estimate by indicating a range of values compatible with the data under the statistical method used; it does not remove uncertainty or establish causation. Here, no ORR estimate, response count, confidence interval, or analysis population is reported in the registry record. The primary endpoint is therefore described, but its observed value and precision cannot be evaluated from the posted results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies overall response rate after 4 cycles as the primary outcome, but does not report the observed response result. It also records the primary endpoint population as “Data not collected.” Consequently, the central descriptive question—how many participants met the response definition in the analyzed population—cannot be answered from the registry record. The endpoint description and its planned use of a 95% confidence interval are not substitutes for a reported estimate.
Enrollment was 3, and the study was single-group with no comparator. Even if an outcome estimate were available, a single-group result would describe what was observed in this cohort rather than estimate a contrast against another treatment or control condition. In general, comparative interpretation requires a suitable comparison and attention to how groups were formed. That comparison is absent. The record also lists no masking, so assessments were not described as blinded; how response evaluations were conducted is not reported in the registry record.
The posted safety data report 0 serious adverse events among 3 participants at risk, and 2 participants with other adverse events among 3 at risk. Deaths are recorded as 0. These are counts from a very small enrolled group and should be read as limited descriptive observations, not as precise estimates of event frequency. The registry record does not provide serious-event terms, and no event details or participant-level timelines are available in the posted data. It also does not report results for the listed treatment-related adverse-event outcome, cytokine release syndrome, immune-effector cell-associated neurotoxicity syndrome, or treatment discontinuation due to toxicity.
The status is terminated, but the reason for termination is not reported in the registry record. The record does not say whether termination was related to safety, feasibility, recruitment, efficacy, or another consideration; none of those explanations should be inferred. It also does not report whether participants completed the planned response assessment or the intended treatment schedule.
In general, small samples produce imprecise estimates because each participant can have substantial influence on a count or proportion. That issue is especially important when the endpoint result and confidence interval are absent. The available information supports a description of the design, enrollment, status, and recorded safety counts. It does not support a conclusion about the response rate, the precision of a response estimate, comparative effects, or the reason the study ended.
The registry record lists outcomes for overall survival and progression-free survival at specified time points, as well as best achieved response. No results for these outcomes are reported. They cannot be interpreted as either favorable or unfavorable based on their presence in the outcome list alone. Likewise, the study’s phase designation does not itself provide evidence about the outcome. The relevant statistical distinction is between an outcome that was planned or listed and a numerical result that was actually posted.
9. Statistical Methods Explained
The registry record describes the endpoint and design but does not report an analysis plan or numerical result for the primary response outcome. The statistical concepts below are general explanations of how such outcomes are commonly read; they do not establish which methods were used in this study beyond the endpoint details stated in the record.
What does a response rate describe?
In general, a response rate is a proportion. Its numerator consists of participants who meet a prespecified response definition, and its denominator is the analysis population used for that endpoint. The registry definition includes partial response, very good partial response, complete response, and stringent complete response after 4 cycles. The response criteria are identified as the International Myeloma Working Group uniform response criteria. The registry record does not report the response count, the denominator used for analysis, or an ORR estimate. The primary endpoint population is recorded as “Data not collected.” Therefore, there is no posted response proportion to interpret.
The endpoint timeframe is described as up to 4 cycles, with each cycle equal to 21 days. In general, a defined assessment window helps specify when an outcome is measured. For a response endpoint, it is also important to know whether all participants had an assessment in that window and how assessments outside it were handled. Those details are not reported in the registry record. The planned schedule should not be mistaken for confirmation that every participant received treatment through the assessment or had a response evaluation.
What would a confidence interval add?
The endpoint description says a 95% confidence interval would be reported. In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the statistical method. For a response proportion, it would help convey how much precision the data support. It would not make a small cohort equivalent to a larger one, and it would not address bias caused by the absence of a comparator or incomplete assessments. No confidence interval is reported in the registry record, so the precision of the planned response estimate cannot be assessed.
In general, confidence intervals are interpreted together with the estimate, the analysis population, and the method used to calculate them. Without the estimate and denominator, there is no basis to reconstruct or check an interval. The registry record does not state which interval method would be used, so no particular method should be attributed to this study.
What does the design permit?
The study is listed as single-group, with no masking and no randomized comparison. In general, a single-group study can report outcomes observed among participants receiving the intervention, but it cannot directly estimate how those outcomes differ from outcomes under a comparator. Differences in participant characteristics, disease course, assessment, or other factors cannot be separated from treatment effects without an appropriate design and analysis. The registry record does not report an adjustment strategy or an alternative comparison group.
In general, masking can reduce the influence of knowledge about treatment assignment on some assessments, but the record lists masking as none. The record does not describe who assessed response or whether any independent review was used. It would therefore be inappropriate to assume a blinded response assessment.
How should safety counts be read?
The posted safety data give counts of participants at risk and affected. The record reports 0 serious adverse events among 3 at risk, 2 participants with other adverse events among 3 at risk, and 0 deaths. These are descriptive counts. In general, event counts in a small cohort are sensitive to the experience of each participant and have limited precision. The registry does not list serious-event terms, and the reported “other” adverse-event count should not be treated as a count of treatment-related events unless the record specifically identifies it that way. The listed secondary outcome of treatment-related adverse events has no reported result.
The registry also lists cytokine release syndrome, immune-effector cell-associated neurotoxicity syndrome, and treatment discontinuation due to toxicity as secondary outcomes. Their results are not reported. The absence of posted values cannot be read as evidence that no such events occurred. The record does not describe the event-collection window, grading approach, or relationship assessment for individual events.
What can be said about planning and analysis?
The record gives no sample-size justification, statistical analysis plan, or interim-analysis information. It also records no analysis entries. In general, a sample-size calculation depends on design assumptions and a target effect, while an analysis plan specifies how outcomes, missing data, and analysis populations will be handled. Without those details, it is not possible to assess whether the planned enrollment was tied to a particular precision or decision threshold. A planning illustration, if presented elsewhere, should not be confused with observed power or with the trial’s own design justification.
In general, power is a design concept concerning the chance of detecting a specified effect under stated assumptions. It is not a property that can establish whether a result is true, and it cannot be inferred from an outcome that is not reported. No observed response result is available from which to assess an effect or its precision. The registry record also does not provide enough information to reproduce an analysis independently.
Overall, the methods information supports a clear description of the intended response definition, assessment timing, and treatment schedule. It does not specify the response analysis population, missing-data handling, interval method, analysis plan, or interim monitoring. Those omissions limit statistical interpretation independently of the small enrollment and the absence of reported endpoint results.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists a primary response outcome and several secondary outcomes. The secondary outcomes cover treatment-related adverse events, cytokine release syndrome, immune-effector cell-associated neurotoxicity syndrome, treatment discontinuation due to toxicity, best achieved response, overall survival at 12 months, and progression-free survival at 12 months and 24 months. Results for these outcomes are not reported in the registry record.
Multiplicity arises in general when several outcomes or statistical tests are considered, because repeated testing can increase the chance of a misleading positive finding if no strategy is specified. The record does not report a multiplicity adjustment, a hierarchy for secondary outcomes, or a strategy for interpreting multiple endpoints. It is therefore not possible to determine how the listed outcomes were intended to contribute to formal statistical conclusions.
The registry record does not report how missing outcome data were handled, whether participants who stopped treatment remained in an analysis, or how the analysis population was defined. The primary endpoint population is recorded as “Data not collected.” In general, missing assessments can affect a response proportion if the denominator or the treatment of participants without an assessment is unclear. No assumption about missing participants, imputation, or endpoint completion should be made in the absence of a stated approach.
The record does not report interim analyses, stopping boundaries, or a statistical analysis plan. It also does not report results for the time-to-event outcomes, including how censoring or incomplete follow-up was handled. These are relevant methodological details, but their absence does not establish that a particular method was or was not used outside what is recorded. The registry record leaves the multiplicity strategy, missing-data approach, and analysis populations unreported.
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 |
|---|---|---|---|
| Treatment (Pembrolizumab) | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment (Pembrolizumab) | 0 of 3 |
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 |
|---|---|
| Treatment (Pembrolizumab) | 2 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment (Pembrolizumab) |
|---|---|---|
| Diarrhea | Gastrointestinal disorders | 1 of 3 |
| Nausea | Gastrointestinal disorders | 1 of 3 |
| Oral pain | Gastrointestinal disorders | 1 of 3 |
| Anemia | Blood and lymphatic system disorders | 1 of 3 |
| Weight Loss | Investigations | 1 of 3 |
The posted safety data list 3 participants at risk for serious adverse events, with 0 affected, and 3 at risk for other adverse events, with 2 affected. The deaths count is 0. These figures are descriptive counts in the treatment group; they are not comparative estimates because the study has no comparator group.
In general, a count of zero observed events does not establish that an event cannot occur or that risk is absent. With enrollment of 3, the safety observations are limited, and the record does not provide a basis for a precise estimate of event frequency. The record lists no serious adverse-event terms. It also does not report the detailed timing, severity, duration, or participant-level course of the events counted as other adverse events.
The registry lists treatment-related adverse events, cytokine release syndrome, immune-effector cell-associated neurotoxicity syndrome, and discontinuation due to toxicity as secondary outcomes, but their results are not reported. The count of 2 with other adverse events should not be taken as a treatment-related count: the posted safety summary does not identify those events as treatment-related. The available counts do not establish whether participants completed treatment or whether any event led to discontinuation.
12. What the Result Does, and Does Not, Mean
The registry record shows that a phase II, single-group study of pembrolizumab was conducted for multiple myeloma relapsing after or refractory to anti-BCMA CAR-T therapies. Enrollment was 3, and the study status is terminated. The primary endpoint was defined as overall response after 4 cycles using International Myeloma Working Group uniform response criteria. The record does not report an ORR result, response count, analysis population, or confidence interval.
That distinction is central: a planned endpoint is not an observed finding. Without a posted response estimate, the record cannot show how many participants met the response definition or how precise an estimate would be. The stated intention to report a 95% confidence interval does not supply that missing result.
The safety summary reports 0 serious adverse events among 3 at risk, 2 with other adverse events among 3 at risk, and 0 deaths. These counts describe the recorded experience in a very small group. They do not establish a general safety profile, and the registry does not give event terms or a treatment-related classification for the “other” adverse events. Results for several listed safety outcomes are not reported.
In general, an uncontrolled study can describe what happened among its participants, but it cannot by itself determine what would have happened under a different treatment or no treatment. Because this study has no comparator, it does not provide a direct comparative effect estimate. The record also does not describe why the study was terminated, so no reason for termination can be inferred from its status alone.
The appropriate reading is therefore narrow. The registry record documents the study question, intended treatment schedule, response definition, enrollment, status, and limited adverse-event counts. It does not establish an efficacy result, comparative benefit, a precise risk estimate, or the reason the study ended. The absence of posted outcomes should be kept distinct from a finding of no response or no events.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates the difference between a clearly defined endpoint and an available result. The registry specifies overall response rate, the response categories, the assessment window, and the use of a 95% confidence interval. Yet no response estimate or interval is reported. Readers therefore cannot evaluate either the observed response or its precision, despite the endpoint being described in detail.
The single-group design also shapes the scope of inference. In general, outcome data from one group can describe the group’s experience, but a comparator is needed for a direct treatment contrast. Since the record identifies no comparator and no randomized comparison, any result would have to be interpreted as descriptive rather than as a controlled estimate of treatment effect.
Enrollment of 3 makes precision an especially important concern. In general, small cohorts provide limited information about how representative an observed count may be, and individual observations can have substantial influence on a summary. Here, the primary result and its confidence interval are not reported, so the uncertainty cannot be quantified from the posted record. The limited safety counts likewise should not be treated as stable estimates of event frequency.
The record also highlights the importance of transparent reporting of analysis populations, missing-data handling, multiplicity, and reasons for study status. Those details are not reported in the registry record. Their absence limits assessment of how the planned outcomes would have been analyzed and how incomplete assessments might have been addressed. The study’s terminated status is documented, but its reason is not.
These are statistical limits, not evidence for or against pembrolizumab. The registry record is informative about the intended question and the information that was recorded, while leaving the central response result unresolved.
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 trial-specific limitation is that the registry record does not report the primary endpoint result. Although ORR is defined and a 95% confidence interval is described as planned, there is no posted response estimate, response count, interval, or analysis population. The endpoint population is recorded as “Data not collected.” This prevents assessment of both the observed response and its precision.
Enrollment was 3, limiting the amount of information available even for outcomes that are reported. The safety summary gives counts, but no serious-event terms and no detailed event descriptions. The listed secondary safety and disease-course outcomes have no reported results. The record therefore does not support a detailed assessment of adverse-event types, response patterns, survival, progression-free survival, or treatment discontinuation due to toxicity.
The design is single-group and unmasked, with no comparator. As a result, the record cannot provide a like-for-like treatment comparison. The registry does not describe who assessed response, whether assessments were independently reviewed, or how outcome data were handled if an assessment was missing. It also does not report the analysis plan, multiplicity strategy, interim analyses, or sample-size justification.
The status is terminated, but the reason is not reported in the registry record. Treatment exposure, cycle completion, follow-up completeness, and whether participants reached the primary assessment are also not reported. These limitations leave uncertainty about both the conduct of the planned assessments and the context for the study’s status. They should not be resolved by assuming a particular cause, analysis choice, or unposted result.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pembrolizumab for the Treatment of Relapsed or Refractory Multiple Myeloma After Anti-BCMA CAR-T Therapies — NCT05191472.
- 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
The registry record describes a phase II, single-group study of pembrolizumab in multiple myeloma relapsing after or refractory to anti-BCMA CAR-T therapies. Enrollment was 3; the study is listed as terminated. Pembrolizumab was scheduled intravenously on day 1 of cycles repeating every 21 days for up to 2 years, absent progression or unacceptable toxicity.
The primary endpoint was overall response rate after 4 cycles, using International Myeloma Working Group uniform response criteria. The record does not report an ORR result, confidence interval, or analysis population. Safety data list 0 serious adverse events among 3 at risk, 2 participants with other adverse events among 3 at risk, and 0 deaths. The reason for termination, analysis plan, missing-data handling, and results for listed secondary outcomes are not reported in the registry record.