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 EL625 in Persistent Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma (NCT00636155), a na phase 2 study. The primary outcome is Number of Patients With an Overall Response (Complete Response + Partial Response).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00636155 |
| Phase | Phase 2 |
| Condition | Lymphoma, Small Lymphocytic, Leukemia, Lymphocytic, Chronic |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 20 |
| Arms in the primary outcome | n/a |
| Lead sponsor | David Rizzieri |
| Results posted | Yes |
2. Clinical Question
Population
Patients with persistent chronic lymphocytic leukemia or small lymphocytic lymphoma. The primary outcome description specifies patients completing at least 2 cycles of treatment as the population for the response measure.
Intervention
EL625, also listed as cenersen sodium, combined with rituximab, fludarabine, and cyclophosphamide.
Comparator
There was no separate comparator arm. The registry describes a single-group study, with all patients receiving the combination.
Primary question
The study sought to assess the number of patients with an overall response, defined as a complete response or partial response, with response assessed every 3 cycles.
The registry frames the research question as whether EL625 added to traditional chemotherapy would be effective in persistent chronic lymphocytic leukemia or small lymphocytic lymphoma. Because every patient was assigned to the same treatment group and there was no control arm, the study cannot directly compare the combination with chemotherapy alone or another treatment. Its primary endpoint is a count of patients meeting response criteria, rather than a comparative treatment effect.
The registry also lists progression-free survival and overall survival as secondary outcomes. It does not report their results or the time-to-event analyses used to evaluate them. The primary response count and its statistical analysis are likewise not reported in the registry record. Consequently, the research question can be described from the planned endpoint and treatment assignment, but the registry record does not provide the result needed to quantify the observed response experience.
3. Trial Design
This was a phase II, single-group study with an enrollment of 20. The record lists no allocation scheme and no masking. All patients were assigned to EL625 combined with rituximab, fludarabine, and cyclophosphamide. Since there was no separate comparison group, any observed clinical changes would be described within the treated group; the design does not provide a concurrent estimate of what would have happened under another treatment.
The study concerned persistent chronic lymphocytic leukemia or small lymphocytic lymphoma. The primary outcome description identifies patients completing at least 2 cycles of treatment as the response population. The endpoint was assessed every 3 cycles. The record does not state how many patients completed the specified treatment exposure, how many contributed to the response assessment, or whether the analysis population differed from everyone enrolled.
The study start is recorded as 2008-02, and primary completion as 2011-08. Its status is TERMINATED. The reason for termination, whether the study stopped according to an original plan, and whether the planned enrollment was reached are not reported in the registry record. Termination status alone does not establish why the study ended or what happened to individual participants.
Progression-free survival and overall survival are listed as secondary outcomes, but the registry record does not provide their outcome values, analysis methods, or follow-up details. It also does not report a statistical analysis plan, a control-group strategy, or a sample-size justification for the trial itself. Planning illustrations based on an observed effect should therefore be distinguished from the study’s original design; the registry record does not establish that such illustrations were used to plan this trial.
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 | All Patients |
|---|---|
| STARTED | 20 |
| COMPLETED | 2 |
| NOT COMPLETED | 18 |
Reasons for not completing this period:
| Reason | All Patients |
|---|---|
| Adverse Event | 8 |
| Lack of Efficacy | 1 |
| Withdrawal by Subject | 3 |
| Stem cell transplant | 1 |
| Physician Decision | 5 |
Analysis population for the primary outcome, as defined in the registry: Patients completing at least 2 cycles of treatment
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 | All Patients |
|---|---|---|
| Participants analysed | 20 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 12 |
| Age, Categorical: >=65 years | Participants | 8 |
| Age Continuous | years | 62 (45 to 77) |
| Sex: Female, Male: Female | Participants | 3 |
| Sex: Female, Male: Male | Participants | 17 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 |
| 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 | 18 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Patients With an Overall Response (Complete Response + Partial Response), measured over every 3 cycles.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of patients with an overall response, defined as complete response plus partial response. The record says response was assessed every 3 cycles and specifies patients completing at least 2 cycles of treatment as the population for this measure. It does not report the resulting response count.
In the registry definition, complete response requires absence of lymphadenopathy, hepatomegaly or splenomegaly, and constitutional symptoms, together with a normal CBC. Bone marrow must be at least normocellular for age, with less than 30% of nucleated cells being lymphocytes and no lymphoid nodules. Partial response requires at least 50% decrease in one of the listed measures—peripheral blood lymphocyte count, lymphadenopathy, liver and/or spleen enlargement, or bone marrow involvement by CLL—and at least one hematologic parameter met for 2 months.
In general, a response endpoint converts specified clinical and laboratory criteria into a count of participants meeting them. Combining complete and partial response gives a summary of patients meeting either response category, but it does not by itself describe response duration, progression-free survival, overall survival, or the comparative effect of treatment. Those questions require their own reported outcomes and analyses. The registry record does not report the response count, uncertainty around it, or the detailed assessment results needed to independently evaluate the endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record identifies a clinically specific question and a defined response endpoint, but it does not report the primary response result. It therefore supports a description of what the study set out to measure, not a numerical conclusion about the response experience. The enrollment is 20, yet the endpoint population is patients completing at least 2 cycles; the number who met that criterion is not reported in the registry record. Enrollment should not be treated as the endpoint denominator without that information.
The single-group design is central to interpretation. A response count among treated patients can describe outcomes observed under the combination, but without a concurrent comparator it cannot isolate the contribution of EL625 from the other drugs, the natural course of disease, patient selection, or other influences. It also cannot directly estimate what would have happened to a comparable group receiving another regimen. This is a limitation of the design, not a statistical adjustment that can be resolved from the registry record.
The endpoint criteria are specified in considerable detail, including thresholds for partial response and conditions required for complete response. That detail helps define what counts as a response. It does not establish how consistently assessments were made, whether assessors were blinded, how missing assessments were handled, or how many participants met each category. Masking is listed as none, but the record does not explain assessment procedures or any safeguards for outcome classification.
Progression-free survival and overall survival are named as secondary outcomes. Their values, event counts, follow-up duration, and statistical analyses are not reported in the registry record. The record also lists 0 analyses. This means the registry entry does not offer inferential results such as a confidence interval or p-value for the primary outcome; it should not be read as evidence of a statistically demonstrated effect or as evidence that no response occurred.
Safety information is available as counts for the all-patient group: 8 patients are listed as affected by serious adverse events, and 20 as affected by other adverse events. These counts describe reported events in the registry entry; they do not establish that the study treatment caused them. The listed serious-event terms include febrile neutropenia at 15.0%, with several other terms at 5.0%. The record does not provide context sufficient to compare these figures with another regimen or to assess all dimensions of safety.
Overall, the posted information permits a cautious account of the design, endpoint definition, and reported safety counts. It does not permit a quantified estimate of the primary response outcome, an uncertainty assessment for that outcome, or a comparative efficacy conclusion. The terminated status and lack of reported analyses further limit what can be inferred, but neither fact supplies a reason for termination or an unreported clinical result.
9. Statistical Methods Explained
The registry describes a single-group phase II study. This design observes outcomes among patients receiving one treatment strategy. In general, a single-group study can describe the frequency of a measured outcome in that group, but it does not create a concurrent untreated or alternative-treatment group. It therefore cannot separate treatment-associated outcomes from other explanations in the way a randomized comparison is intended to do. The record lists allocation as NA and masking as none; it does not report a statistical plan that would add a comparative design.
What does a response count represent?
The primary outcome is a count of patients whose best qualifying category is complete response or partial response, as described in the endpoint definition. In general, counts are easiest to interpret when the denominator and analysis population are clear. The registry defines the response population as patients completing at least 2 cycles, but does not report how many patients completed that exposure or the number included in the response assessment. The enrollment of 20 is not automatically the denominator for this endpoint.
The record specifies that assessments occurred every 3 cycles. Repeated assessment can matter because response status may change over treatment. In general, interpretation of a repeated-measure endpoint depends on the rule for selecting or summarizing assessments, such as whether a response at any assessment or at a specified assessment is counted. That rule, the timing of individual assessments, and the handling of participants without an assessment are not reported in the registry record. The provided response criteria define categories but do not fill in those analysis details.
What would uncertainty estimates add?
In general, a confidence interval expresses the range of values compatible with the observed data under a statistical model and procedure. For a response count or proportion, an interval can communicate that the estimate is uncertain, particularly when the analyzed group is limited. The registry record does not report a primary response result, denominator, confidence interval, or p-value. No uncertainty estimate can therefore be interpreted from the record itself.
A p-value, in general, evaluates how compatible data are with a specified null hypothesis under the assumptions of a test. It is not a measure of the size or clinical importance of an effect. In this study, no primary analysis or hypothesis test is reported in the registry record. With a single group and no comparator, a test against a reference value would require that reference and its rationale to be specified; neither is reported.
How should planning illustrations be read?
In general, sample-size calculations describe how many participants might be needed under chosen assumptions to detect a specified effect with a stated error rate and power. They are prospective planning tools, not observed outcomes and not proof that a study had a particular probability of success. The planning assumptions associated with this record describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect defined as a stated fraction of the observed effect. They also distinguish total events for time-to-event calculations from participants per arm for other calculations.
Those assumptions are illustrative rather than the trial’s own design: the trial itself is listed as single-group, not as an equal-allocation, two-arm study. The record does not report the trial’s sample-size justification. It also does not report the primary response result or an observed effect estimate in the registry entry, so any planning illustration based on an observed effect should not be mistaken for a result from a randomized comparison or an original design specification. It is not observed power.
What does over-dispersion mean in general?
In general, over-dispersion occurs when count outcomes vary more than a statistical model assumes. A model that ignores it can give uncertainty estimates that are too narrow. This is relevant to some count outcomes, but the record does not report a count-model analysis, a dispersion estimate, or a finding of over-dispersion. The primary endpoint is described as a participant count, and no inferential model is specified in the registry record.
What does the listed analysis count tell the reader?
The record lists 0 analyses. This indicates that no analysis results are recorded in the registry entry; it does not establish that investigators performed no analyses outside the registry. The statistical analysis plan, methods for secondary outcomes, adjustment for multiple outcomes, and procedures for missing data are not reported in the registry record. Without those details and endpoint results, an independent assessment of model assumptions, uncertainty, and robustness is not possible from the registry information.
10. Multiplicity, Missing Data and Analysis Populations
The record names one primary outcome—number of patients with an overall response—and two secondary outcomes, progression-free survival and overall survival. Considering more than one outcome can create multiplicity: in general, the chance of a false-positive finding across a family of tests can increase if many hypotheses are tested without an adjustment or an explicitly chosen testing strategy. The registry record does not report whether multiplicity was considered, whether any adjustment was planned, or whether a hierarchy among outcomes was specified. It also reports 0 analyses, so there are no registry-recorded inferential results to interpret in light of multiplicity.
The primary outcome population is patients completing at least 2 cycles. The record does not report how many participants completed those cycles, how many had an evaluable response, or how missing response assessments were handled. In general, excluding participants with missing outcomes can affect interpretation if the reasons for missingness are related to prognosis or treatment experience. Other approaches to missing data also require assumptions and analysis details. None are reported in the registry record, so the extent and potential influence of missing outcome data cannot be assessed.
The registry lists enrollment of 20 and provides safety counts for all patients, but this does not establish the denominator used for efficacy analyses. The analysis population, any exclusions, and whether participants were analyzed according to a prespecified population are not reported in the registry record. The record also does not describe interim analyses, stopping boundaries, or a complete statistical analysis plan. Their use or absence should not be inferred from the entry.
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 |
|---|---|---|---|
| All Patients | 8 | 20 | 40.0% |
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 |
|---|---|
| All Patients | 20 of 20 |
Most frequent serious adverse event terms
| Event term | Organ system | All Patients |
|---|---|---|
| Febrile neutropenia (fever of unknown origin without clinically or microbiologically documented infe | Blood and lymphatic system disorders | 3 of 20 |
| Neutrophils / granulocytes (ANC / AGC) | Investigations | 1 of 20 |
| Cognitive disturbance | Nervous system disorders | 1 of 20 |
| Hypoxia | Respiratory, thoracic and mediastinal disorders | 1 of 20 |
| Ulceration | Skin and subcutaneous tissue disorders | 1 of 20 |
| Hemolysis (e.g., immune hemolytic anemia, drug-related hemolysis) | Blood and lymphatic system disorders | 1 of 20 |
| Syncope (fainting) | Nervous system disorders | 1 of 20 |
| Cystitis | Renal and urinary disorders | 1 of 20 |
Most frequent non-serious adverse event terms
| Event term | Organ system | All Patients |
|---|---|---|
| Platelets | Investigations | 14 of 20 |
| Fatigue (asthenia, lethargy, malaise) | General disorders | 11 of 20 |
| Hemoglobin | Blood and lymphatic system disorders | 10 of 20 |
| Leukocytes (total WBC) | Investigations | 8 of 20 |
| Nausea | Gastrointestinal disorders | 8 of 20 |
| Constipation | Gastrointestinal disorders | 7 of 20 |
| Febrile neutropenia (fever of unknown origin w/oclinically or microbiologically documented infe | Blood and lymphatic system disorders | 7 of 20 |
| Dyspnea (shortness of breath) | Respiratory, thoracic and mediastinal disorders | 7 of 20 |
| Neutrophils / granulocytes (ANC / AGC) | Investigations | 6 of 20 |
| Pain - Head / headache | Nervous system disorders | 6 of 20 |
Serious events with the highest arm-level rate: febrile neutropenia (fever of unknown origin without clinically or microbiologically documented infe (15.0%), neutrophils / granulocytes (anc / agc) (5.0%), cognitive disturbance (5.0%), hypoxia (5.0%), ulceration (5.0%).
The adverse-event record lists an all-patient group. For serious adverse events, 20 are listed as at risk and 8 as affected. For other adverse events, 20 are listed as at risk and 20 as affected. These are the posted counts; the registry record does not specify a safety follow-up timeframe or provide additional detail about the definitions and collection procedures.
The listed serious-event terms include febrile neutropenia, shown with 15.0%. The accompanying label is truncated in the registry record. Neutrophils / granulocytes (ANC / AGC), cognitive disturbance, hypoxia, ulceration, and hemolysis are each listed with 5.0%. The percentages are quoted as recorded and should not be treated as a complete account of event frequency or severity across all possible terms.
In general, serious adverse events are a classification distinct from the general experience of an adverse event; a serious event is not simply another way of saying that a symptom was severe. These counts do not by themselves establish causation, because the registry record does not provide a causal assessment for each event. They also do not allow comparison with another treatment group, since the study had no comparator arm. Deaths are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record establishes that a phase II, single-group study evaluated EL625 with rituximab, fludarabine, and cyclophosphamide in persistent chronic lymphocytic leukemia or small lymphocytic lymphoma. It also establishes how the primary response endpoint was defined and identifies progression-free survival and overall survival as secondary outcomes. The safety entry reports counts of patients affected by serious and other adverse events.
It does not establish the primary response result. The number of patients achieving complete or partial response, the response denominator, and an uncertainty interval are not reported in the registry record. Nor does it provide progression-free survival or overall survival results. Consequently, a reader cannot use this registry entry alone to quantify the response experience, judge its precision, or assess the secondary outcomes.
The single-group design also means that the posted information cannot provide a direct treatment comparison. Even if an outcome count were available, the absence of a concurrent comparator would limit attribution of that outcome to EL625 or to any one component of the combination. No statement that the treatment works or does not work follows from an unreported primary result.
Likewise, safety counts do not prove that the combination caused the reported events. They describe what is listed for the all-patient group, without a comparator, detailed event narratives, or a reported follow-up window. The record’s TERMINATED status does not explain why the study ended and does not substitute for an outcome analysis. Overall, the registry supports a description of the study question, treatment, endpoint definition, and recorded safety counts, while leaving the central efficacy results and much of the analysis context unavailable.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of why endpoint definitions and endpoint results must be considered separately. The registry gives detailed criteria for complete and partial response, including clinical findings, blood counts, bone-marrow findings, and a duration requirement for a hematologic parameter. That specificity helps readers understand what the investigators intended to count. Yet without the response count and its denominator, the endpoint definition alone cannot answer how many patients met the criteria or how uncertain that estimate might be.
The case also illustrates the limits of a single-group design. A treated-group description can be useful for documenting outcomes and safety in the setting studied, but causal interpretation requires caution when no comparison arm is present. The registry lists no allocation scheme and no masking, and all patients received the same combination. No statistical method can create the missing concurrent comparison from the information in this record.
The specified response population creates another important interpretive point: enrollment and endpoint denominator are not necessarily the same. The record reports enrollment of 20 and defines the response population by completion of at least 2 cycles, but does not report how many patients qualified for analysis. A clear distinction between enrollment, treatment exposure, and evaluable outcomes is essential when reading clinical trial results.
Finally, the record lists secondary survival outcomes and safety findings but does not report analyses for them. This makes transparent reporting of outcome values, analysis populations, uncertainty, and missing-data handling especially important. The study’s registry entry therefore illustrates both the value of an explicit clinical outcome definition and the substantial limits imposed when results and statistical methods are absent.
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 most important trial-specific limitation in the registry record is that the primary response result is not reported. Although the endpoint definition is detailed, neither the response count nor the number of patients evaluated is available. Since the outcome population is defined as patients completing at least 2 cycles, the enrollment of 20 cannot be assumed to be the denominator.
The study is single-group, with no separate comparator. The record therefore does not support a direct comparison with another regimen or an estimate of the incremental contribution of EL625 to the combination. Allocation is listed as NA, and masking as none. The record does not describe procedures for outcome assessment or whether assessors had other safeguards against bias.
The study status is TERMINATED, but the reason for termination is not reported in the registry record. It is also not reported whether all planned assessments were completed, how long patients were followed, or how many participants contributed to the secondary survival outcomes. Progression-free survival and overall survival are named, but their results and analysis methods are absent.
The record lists 0 analyses and does not describe a statistical analysis plan, a sample-size justification, missing-data procedures, multiplicity handling, or an analysis population beyond the stated primary endpoint population. Safety data provide counts and selected event terms, but no follow-up timeframe is reported, and deaths are not reported in the registry record. These gaps limit assessment of efficacy, precision, safety context, and the robustness of any interpretation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: EL625 in Persistent Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma — NCT00636155.
- Registry record last updated 2012-11-28; status last verified 2012-11.
- Results first posted 2012-08-22.
- 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
NCT00636155 is a phase II, single-group study of EL625, listed as cenersen sodium, combined with rituximab, fludarabine, and cyclophosphamide in persistent chronic lymphocytic leukemia or small lymphocytic lymphoma. Enrollment is 20; the study status is TERMINATED. The primary outcome is the number of patients with complete or partial response, assessed every 3 cycles, among patients completing at least 2 cycles.
Progression-free survival and overall survival are listed as secondary outcomes. The registry record reports 0 analyses and does not report the primary response count, survival results, or the reason for termination. In the all-patient safety group, 8 are listed as affected by serious adverse events and 20 by other adverse events. These counts describe the posted safety information and do not establish causation or a comparative treatment effect.