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 Blinatumomab & Pembrolizumab for Adults With Relapsed/Refractory B-cell ALL With High Marrow Lymphoblasts (NCT03160079), a na phase 1, phase 2 study. The primary outcome is Best Overall Response Rate (ORR).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03160079 |
| Phase | Phase 1, Phase 2 |
| Condition | B-Cell Acute Lymphoblastic Leukemia, Adult |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 16 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Diego |
| Results posted | Yes |
2. Clinical Question
Population
Adults with relapsed or refractory B-lineage acute lymphoblastic leukemia and a high percentage of bone marrow lymphoblasts. The brief summary specifies >50% lymphoblasts. This is a restricted clinical population, not a general adult leukemia population.
Intervention
Blinatumomab in combination with pembrolizumab. The registry identifies both drugs and describes the study as evaluating the combination. The combination regimen is not described in full in the registry record.
Comparator
The stated objective refers to blinatumomab alone as the comparator. However, the study is listed as single-group, allocation is recorded as NA, and the record flags that the arms are not a like-for-like control comparison. The method by which the safety groups were formed is not reported in the registry record.
Primary question
The stated clinical question is whether adding pembrolizumab to blinatumomab improves complete response and complete response with partial hematologic recovery relative to blinatumomab alone. The registered primary outcome is best overall response rate, defined as CR plus CRh, with a timeframe of 28 weeks. The registry record does not report response results or an analysis comparing the treatments.
3. Trial Design
The registry identifies NCT03160079 as a Phase I/II study of blinatumomab in combination with pembrolizumab for adults with relapsed or refractory B-lineage acute lymphoblastic leukemia with high bone marrow lymphoblast percentage. The record lists 16 participants enrolled and gives the study status as completed. The recorded start date is 2017-08-04 and the primary completion date is 2021-12-21.
The study is classified as single-group, with allocation recorded as NA and masking recorded as none. These design details do not support treating the listed groups as randomized, exchangeable treatment arms. Although the objective describes comparison with blinatumomab alone, the registry explicitly flags that the comparison is not randomized and that the arms are not a like-for-like control comparison. How participants came to be represented in the two safety group listings is not reported in the registry record.
The intervention listing names blinatumomab and pembrolizumab. The arm description gives some blinatumomab dosing and cycle information for the combination group, but the description ends before providing a complete account of the regimen. A full treatment schedule and the basis for any blinatumomab-only group are not reported in the registry record.
The primary outcome is best overall response rate, defined from CR and CRh, at 28 weeks. Secondary outcomes listed include complete response rate, MRD negativity among subjects achieving CR or CRh, 2 Year Relapse-free Survival Rate, and 2-year Overall Survival Rate. Outcome results, participant flow, eligibility details beyond the stated population, 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 | Blinatumomab + Pembrolizumab | Blinatumomab Only |
|---|---|---|
| STARTED | 12 | 4 |
| Completed Course 1 | 8 | 4 |
| Completed Course 2 | 5 | 0 |
| Completed Course 3 | 3 | 0 |
| Completed Course 4 | 1 | 0 |
| Completed Course 5 | 1 | 0 |
| COMPLETED | 8 | 4 |
| NOT COMPLETED | 4 | 0 |
Reasons for not completing this period:
| Reason | Blinatumomab + Pembrolizumab | Blinatumomab Only |
|---|---|---|
| Adverse Event | 2 | 0 |
| Disease Progression | 1 | 0 |
| Physician Decision | 1 | 0 |
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: Demographics were recorded for all patients who enrolled
| Characteristic | Unit | Blinatumomab + Pembrolizumab | Blinatumomab Only | Total |
|---|---|---|---|---|
| Participants analysed | 12 | 4 | 16 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 11 | 3 | 14 |
| Age, Categorical: >=65 years | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Female | Participants | 8 | 2 | 10 |
| Sex: Female, Male: Male | Participants | 4 | 2 | 6 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 9 | 2 | 11 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 | 2 | 5 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 1 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 | 1 | 2 |
| Race (NIH/OMB): White | Participants | 10 | 1 | 11 |
| Race (NIH/OMB): More than one race | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 1 | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Best Overall Response Rate (ORR), measured over 28 weeks.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is best overall response rate (ORR), measured as a count of participants. The registry defines ORR as the complete response (CR) rate plus the complete response with hematologic recovery (CRh) rate after combination treatment, with a timeframe of 28 weeks. CR is defined as <5% lymphoblast in bone marrow without evidence of circulating lymphoblasts or extramedullary disease. CRh uses the same response criteria, with platelet count >50,000/microliter, hemoglobin >7 g/dL, and neutrophil (ANC) >500/microliter.
Combining CR and CRh into an overall response outcome is a way to capture participants meeting either of the two stated response categories. In general, a binary response endpoint summarizes whether participants meet a prespecified response definition during a stated assessment period. It does not, by itself, describe how long a response lasts or provide information about survival.
The registry record does not report the number of participants meeting CR or CRh, an ORR estimate, or uncertainty around the estimate. It therefore does not permit an assessment of the observed response frequency or the precision of that estimate.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record defines a clinically specific response question, but it does not report the primary endpoint results. There is no reported count of participants with CR or CRh, no posted ORR estimate, and no reported confidence interval or hypothesis test for the primary outcome. Consequently, the registry record does not establish the magnitude or precision of response in this study.
The study is listed as single-group, and the registry flags the treatment comparison as nonrandomized and not like-for-like. The stated objective refers to comparing the combination with blinatumomab alone, but the available design information does not support interpreting the group listings as a randomized comparison. The safety record lists 12 participants at risk in the combination group and 4 in the blinatumomab-only group. Those counts describe the safety listings; the registry record does not report how group membership was determined or provide an efficacy comparison between them.
The listed serious adverse event counts are 4 affected participants among 12 at risk in the blinatumomab-plus-pembrolizumab group and 1 among 4 at risk in the blinatumomab-only group. These counts do not establish that treatment caused or prevented events. A comparison between groups would require careful interpretation of how participants were assigned or selected, along with outcome definitions, follow-up, and relevant analyses. Those details are not reported in the registry record.
The record lists one death in the combination group and none in the blinatumomab-only group. It does not identify the cause of death or provide information needed to interpret the difference in context. The registry also lists serious event terms and percentages, but without further information about definitions, timing, attribution, or analysis, these entries should be read as descriptive safety reporting.
Overall, the posted record supports describing the planned response endpoint, the study classification, and the recorded safety counts. It does not support a conclusion about whether adding pembrolizumab changes response, survival, or safety relative to blinatumomab alone. The primary results and the analysis needed to answer that comparative question are not reported in the registry record.
9. Statistical Methods Explained
What does a single-group classification mean?
The registry classifies the study as single-group, with allocation recorded as NA and masking as none. In general, a single-group study describes outcomes among participants receiving a study treatment without a randomized concurrent control group. Such a design can describe observed outcomes in the enrolled population, but treatment effects relative to an alternative are harder to isolate because differences can reflect participant selection, the course of disease, follow-up, or other factors.
Here, the objective mentions blinatumomab alone, and the safety listing contains a blinatumomab-only group. The registry nonetheless flags that this is not a randomized comparison and that the groups are not like-for-like controls. The method of assigning or selecting participants into the safety group listings is not reported in the registry record. Therefore, any apparent difference between group counts should not be interpreted as an unbiased treatment effect.
How should a binary response endpoint be understood?
The registered primary outcome counts participants with an overall response, defined as CR or CRh, at 28 weeks. A binary endpoint classifies each participant according to whether the prespecified response definition is met. The count can be translated into a response proportion when the relevant denominator is known, but the registry record does not report primary outcome counts or an estimate. No response proportion should therefore be inferred from the enrollment or safety counts.
In general, a confidence interval describes the range of effect estimates compatible with the observed data under a statistical model. It communicates uncertainty and precision; it is not a guarantee that the true value lies within a particular interval. No confidence interval for ORR is reported in the registry record, so precision cannot be evaluated.
What can the safety counts tell readers?
The safety record reports participants at risk and participants affected for serious and other adverse events in two group listings, as well as deaths. These are descriptive counts. In general, counts need to be interpreted alongside a clearly defined population, observation period, event definitions, and consistent ascertainment. A count alone does not establish whether an event was caused by treatment. Comparisons also require caution when groups are not randomized or otherwise shown to be comparable.
The registry lists serious event terms with percentages, including intracranial hemorrhage/hematoma at 25.0% and cytokine release syndrome, fever, seizure, hypoxia, and acute disseminating intravascular coagulation at 8.3% each. These entries describe the posted safety reporting; the registry record does not provide further details about attribution, timing, severity grading, or whether participants could contribute more than one event term.
What inferential analysis is available?
The registry record reports no analyses. It does not provide a statistical analysis plan, a test for the primary endpoint, an adjusted or unadjusted treatment effect, or a confidence interval. The information needed to assess model choice, covariate adjustment, handling of repeated assessments, or analysis populations is not reported in the registry record.
In general, statistical tests evaluate how compatible observed data are with a specified null hypothesis under assumptions. A p-value does not measure the size or clinical importance of an effect, and it cannot replace an effect estimate with an interval. Because no primary outcome analysis is reported, there is no p-value or effect estimate to interpret for the registered response question.
The record also does not report a sample-size justification or an interim analysis plan. Planning calculations based on an observed effect, when available, are illustrations of assumptions rather than evidence about the study's design or observed power. No efficacy result is available in the registry record on which to base such a planning illustration.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary response outcome and several secondary outcomes, including complete response rate, MRD negativity among subjects achieving CR or CRh, 2 Year Relapse-free Survival Rate, and 2-year Overall Survival Rate. It also records five outcome measures in total. The remaining outcome measure and the analysis plan for the listed outcomes are not reported in the registry record.
When a study evaluates multiple outcomes or performs multiple statistical tests, the chance of at least one apparently notable result can increase. In general, a multiplicity strategy may specify which outcome is primary, how tests are ordered, or whether significance thresholds are adjusted. The registry record does not report a multiplicity procedure, a testing hierarchy, or whether any adjustments were planned or used. Since no analyses are reported, the effect of multiplicity on inferential conclusions cannot be assessed.
The registry record also does not report how missing outcome data were handled, how response assessments were scheduled beyond the primary timeframe, or which participants were included in each analysis population. It does not state whether participants who discontinued treatment, missed assessments, or had incomplete follow-up were included in the primary endpoint analysis. These details matter because the analyzed population and assumptions about missing observations can affect both the estimated response frequency and its uncertainty.
In general, missing-data methods make assumptions about why observations are unavailable and how missing outcomes relate to observed information. Different assumptions can lead to different estimates. Without a reported method or analysis population, readers cannot determine how incomplete response data were treated. The registry record does not report an analysis plan sufficient to resolve these questions.
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 |
|---|---|---|---|
| Blinatumomab + Pembrolizumab | 4 | 12 | 33.3% |
| Blinatumomab Only | 1 | 4 | 25.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Blinatumomab + Pembrolizumab | 1 of 12 |
| Blinatumomab Only | 0 of 4 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Blinatumomab + Pembrolizumab | 12 of 12 |
| Blinatumomab Only | 4 of 4 |
Most frequent serious adverse event terms
| Event term | Organ system | Blinatumomab + Pembrolizumab | Blinatumomab Only |
|---|---|---|---|
| Intracranial Hemorrhage/Hematoma | Nervous system disorders | 1 of 12 | 1 of 4 |
| Cytokine Release Syndrome | Immune system disorders | 1 of 12 | 0 of 4 |
| Fever | General disorders | 1 of 12 | 0 of 4 |
| Seizure | Nervous system disorders | 1 of 12 | 0 of 4 |
| Hypoxia | Respiratory, thoracic and mediastinal disorders | 1 of 12 | 0 of 4 |
| Acute Disseminating Intravascular Coagulation | Blood and lymphatic system disorders | 1 of 12 | 0 of 4 |
| Macrophage Activation Syndrome | Blood and lymphatic system disorders | 1 of 12 | 0 of 4 |
| Neck Edema | General disorders | 1 of 12 | 0 of 4 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Blinatumomab + Pembrolizumab | Blinatumomab Only |
|---|---|---|---|
| Cytokine Release Syndrome | Immune system disorders | 7 of 12 | 3 of 4 |
| Headache | Nervous system disorders | 9 of 12 | 1 of 4 |
| NEUTROPHIL COUNT DECREASED | Investigations | 10 of 12 | 0 of 4 |
| Fever | General disorders | 6 of 12 | 2 of 4 |
| Ventricular tachycardia | Cardiac disorders | 6 of 12 | 2 of 4 |
| Aspartate Aminotransaminase Increased | Investigations | 4 of 12 | 3 of 4 |
| Fatigue | General disorders | 5 of 12 | 2 of 4 |
| Chills | General disorders | 5 of 12 | 1 of 4 |
| Alanine aminotransaminase increased | Investigations | 4 of 12 | 1 of 4 |
| Anorexia | Metabolism and nutrition disorders | 3 of 12 | 2 of 4 |
Serious events with the highest arm-level rate: intracranial hemorrhage/hematoma (25.0%), cytokine release syndrome (8.3%), fever (8.3%), seizure (8.3%), hypoxia (8.3%).
The safety listing reports serious adverse events for 4 of 12 participants at risk in the blinatumomab-plus-pembrolizumab group and 1 of 4 at risk in the blinatumomab-only group. For other adverse events, the counts are 12 of 12 and 4 of 4, respectively. The record lists 1 death in the combination group and 0 in the blinatumomab-only group.
Serious adverse event terms include intracranial hemorrhage/hematoma, reported as 25.0%, and cytokine release syndrome, fever, seizure, hypoxia, and acute disseminating intravascular coagulation, each reported as 8.3%. The registry does not report further details about event timing, attribution, severity grading, or whether terms refer to unique participants or event episodes.
These entries are descriptive. The group sizes differ, and the registry flags that the groups are not a like-for-like control comparison. The counts therefore cannot establish a relative risk or a causal treatment effect. The registry record does not report a comparative safety analysis or the method used to form the group listings.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed Phase I/II study enrolled 16 participants and evaluated a blinatumomab-plus-pembrolizumab regimen in adults with relapsed or refractory B-cell acute lymphoblastic leukemia and high marrow lymphoblast percentage. It defines best overall response rate as CR plus CRh at 28 weeks and gives definitions for these response categories.
It does not report the primary response results, the number of participants achieving CR or CRh, or an estimate of ORR. It also does not report inferential analyses or confidence intervals for efficacy. The record therefore cannot establish how frequently responses occurred or how precisely that frequency was estimated.
The objective describes the addition of pembrolizumab relative to blinatumomab alone, but the study is recorded as single-group and the registry explicitly warns that the arms are not a like-for-like control comparison. The two safety group listings do not by themselves support a causal comparison. No conclusion about the effect of adding pembrolizumab on response, survival, or adverse events can be drawn from the reported information.
The available safety entries document serious adverse events, other adverse events, and deaths in the listed groups. They do not establish that an event was caused by a treatment, and the registry does not provide the additional analysis and context needed to compare safety between groups.
These limits concern what can be concluded from the registry record, not what may have been observed or analyzed outside it. Efficacy results, detailed analysis methods, missing-data handling, and the basis for the group listings are not reported in the registry record.
13. Why This Trial Matters Statistically
This study addresses an explicitly defined response question in adults with relapsed or refractory B-lineage acute lymphoblastic leukemia and a high percentage of bone marrow lymphoblasts. The endpoint combines CR and CRh, with the registry specifying response criteria and a 28-week timeframe. Those definitions make the intended outcome interpretable in principle, but interpretation still depends on posted results and analysis details.
Statistically, the key issue is the distance between the stated comparative objective and the recorded design. The study is classified as single-group, allocation is NA, and the registry warns that the groups are not like-for-like controls. The blinatumomab-only safety listing does not make the study a randomized comparison. Without a valid basis for comparability, differences between groups could reflect how the groups were formed rather than a treatment effect.
A second issue is the absence of efficacy results and analyses in the registry record. Enrollment and a defined endpoint do not reveal the observed response frequency. Without an effect estimate and a measure of uncertainty, readers cannot assess either the size or precision of the response outcome. The absence of analysis details also prevents evaluation of missing data, analysis populations, and multiplicity.
The record remains useful for identifying the registered question, design classification, outcome definitions, and reported safety counts. Its statistical importance lies partly in recognizing the boundary between those descriptive details and claims that require comparative evidence. The posted record does not resolve whether adding pembrolizumab changes outcomes relative to blinatumomab 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 trial-specific limitation for interpreting efficacy is that the registry record does not report primary outcome results. Although best overall response rate is defined as CR plus CRh at 28 weeks, the number of participants meeting either response definition and the estimated ORR are not reported. No confidence interval, test, or comparative effect estimate is available.
The design is classified as single-group, and the registry states that the arms are not a like-for-like control comparison. The stated objective refers to blinatumomab alone as a comparator, but the method for forming or assigning the two safety groups is not reported in the registry record. This prevents treating the listed groups as equivalent treatment arms for a causal comparison.
The registry record does not report the full treatment regimen, complete eligibility criteria, participant flow, detailed follow-up, or the handling of missing outcome data. It does not identify the analysis populations or explain how participants with incomplete assessments were handled. These omissions limit assessment of how the primary outcome would be estimated and how representative the analyzed participants might be.
The safety reporting provides counts and selected event terms but does not report event attribution, timing, severity grading details, or a comparative safety analysis. The statistical analysis plan, sample-size justification, and multiplicity approach are also not reported in the registry record. As a result, the posted information supports a descriptive account but not a firm efficacy or comparative safety interpretation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Blinatumomab & Pembrolizumab for Adults With Relapsed/Refractory B-cell ALL With High Marrow Lymphoblasts — NCT03160079.
- Registry record last updated 2025-11-10; status last verified 2025-10.
- Results first posted 2025-11-10.
- 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
NCT03160079 is recorded as a completed Phase I/II study of blinatumomab with pembrolizumab in adults with relapsed or refractory B-lineage acute lymphoblastic leukemia with high bone marrow lymphoblast percentage. Enrollment is listed as 16. The study is classified as single-group, with allocation recorded as NA and masking as none.
The primary outcome is best overall response rate, defined as CR plus CRh, with a timeframe of 28 weeks. The registry record does not report the response results or any analyses. Safety listings include a combination group and a blinatumomab-only group; the registry flags that these are not a like-for-like control comparison. Efficacy results, analysis methods, missing-data handling, and the basis for the safety group listings are not reported in the registry record.