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 D-cycloserine in the Management of Chemotherapy-Induced Peripheral Neuropathic Pain (NCT00301080), a randomized phase 3 study. The primary outcome is Difference in Patient-reported Pain Intensity Scores Between the 3 Arms After the Treatment Period Using the Brief Pain Inventory.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00301080 |
| Phase | Phase 3 |
| Condition | Neurotoxicity, Pain, Breast Cancer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 7 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Northwestern University |
| Results posted | Yes |
2. Clinical Question
Population
Breast cancer patients with peripheral neuropathic pain induced by paclitaxel were the intended population. The registry record describes the study as addressing chemotherapy-induced neuropathy and pain. It does not report detailed eligibility criteria or a fuller description of the patients who entered the trial.
Intervention
The intended intervention was oral D-cycloserine. The record lists a revised design with 50 mg and 200 mg doses, each administered twice per day for 12 weeks. It also records an earlier 250mg arm, administered twice per day for 4 weeks, before the design was changed.
Comparator
The comparator was placebo. The record lists an original placebo version administered twice per day for 4 weeks and a revised version administered twice per day for 12 weeks. The record describes the trial as comparing two D-cycloserine doses with each other and placebo.
Primary question
The primary question was whether patient-reported pain intensity scores on the Brief Pain Inventory differed between the 3 arms after the 12-week treatment period. No patients were analyzed for this outcome because the study design changed and the trial was terminated early.
This is a question about a between-arm difference in reported pain intensity after treatment, not simply whether participants’ scores changed from their own starting values. A comparison between arms is intended to help distinguish differences associated with the assigned study regimens from changes that could occur over time or under placebo. The registry record does not provide an estimated difference, uncertainty interval, or test result for the primary comparison, because no patients were analyzed for it.
3. Trial Design
The registry identifies this as a Phase III, randomized, double-blind, parallel-group study sponsored by Northwestern University. Its stated purpose was to examine D-cycloserine at different doses against placebo for peripheral neuropathy associated with chemotherapy. The record describes a planned comparison across 3 arms and lists pain intensity after treatment as the primary outcome.
The arm descriptions capture a change in study design. The earlier versions were placebo twice per day for 4 weeks and D-cycloserine 250mg twice per day for 4 weeks. The revised versions were placebo twice per day for 12 weeks and D-cycloserine 50 mg or 200 mg twice per day for 12 weeks. The record says that the earlier 250mg arm was the original active comparator before the design changed. It does not report how the change was implemented, when it occurred, or which revised arms enrolled participants.
Enrollment is recorded as 7. The study status is TERMINATED. The start is recorded as 2006-02 and primary completion as 2007-02. The primary outcome description gives its timeframe as from the first patient’s registration until the last patient completed the 12 weeks of intervention, approximately 1 year. No patients were analyzed for the primary outcome because of the design change followed by early termination.
The registry record does not report the randomization procedure, allocation concealment, intended recruitment target, or a detailed protocol for the analysis. The design labels describe the intended structure; they do not establish that all listed arms ran as planned or that the completed study retained the original comparison.
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.
Original Version (2 Arms & 4 Weeks)
| Stage | D-cycloserine 250mg | Placebo (Original Version) | D-cycloserine 200mg | D-cycloserine 50 mg | Placebo (Revised Version) |
|---|---|---|---|---|---|
| STARTED | 4 | 3 | 0 | 0 | 0 |
| Received an Intervention | 3 | 3 | 0 | 0 | 0 |
| Completed 4 Week Intervention | 3 | 3 | 0 | 0 | 0 |
| COMPLETED | 3 | 3 | 0 | 0 | 0 |
| NOT COMPLETED | 1 | 0 | 0 | 0 | 0 |
Reasons for not completing this period:
| Reason | D-cycloserine 250mg | Placebo (Original Version) | D-cycloserine 200mg | D-cycloserine 50 mg | Placebo (Revised Version) |
|---|---|---|---|---|---|
| Never received drug | 1 | 0 | 0 | 0 | 0 |
Revised Version (3 Arms & 12 Weeks)
| Stage | D-cycloserine 250mg | Placebo (Original Version) | D-cycloserine 200mg | D-cycloserine 50 mg | Placebo (Revised Version) |
|---|---|---|---|---|---|
| STARTED | 0 | 0 | 0 | 0 | 0 |
| COMPLETED | 0 | 0 | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 0 | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: No patients were analyzed for this outcome measure due to a change in study design followed by early termination of the study.
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 Participants (Original Version) |
|---|---|---|
| Participants analysed | 7 | |
| Age, Customized: 40-50 years | participants | 1 |
| Age, Customized: 51-60 years | participants | 2 |
| Age, Customized: 61-70 years | participants | 4 |
| Sex: Female, Male: Female | Participants | 3 |
| Sex: Female, Male: Male | Participants | 4 |
| Region of Enrollment: United States | participants | 7 |
6. Primary Endpoint
The registry lists the primary outcome as Difference in Patient-reported Pain Intensity Scores Between the 3 Arms After the Treatment Period Using the Brief Pain Inventory, measured over From the date that the first patient is registered until the last patient completes the 12 weeks of study intervention (approximately 1 year).
| 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 was the difference in patient-reported pain intensity scores between the 3 arms after the treatment period, using the Brief Pain Inventory. The planned treatment period was 12 weeks. The record does not report a unit, summary parameter, or measure of dispersion for this outcome.
The Brief Pain Inventory is used to collect patients’ reports about pain intensity. As a general statistical point, a patient-reported endpoint can represent an experience that may not be fully captured by clinical or laboratory measures. Comparing scores between assigned arms is relevant because the clinical question concerns whether reported pain intensity differs across the study regimens after treatment. The registry does not specify which Brief Pain Inventory score or scoring summary was to form the primary analysis, so the precise endpoint definition cannot be expanded beyond the description in the record.
The outcome was not analyzed: the registry states that no patients were analyzed because of a change in study design followed by early termination. Consequently, the record contains no primary outcome estimate or uncertainty measure with which to assess the size or precision of an arm difference. The absence of an estimate is not evidence that the arms had the same outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main interpretive fact is that the registry reports no patient analysis for the primary pain outcome. The trial was terminated, and the record attributes the absence of a primary analysis to a change in study design followed by early termination. Therefore, there is no posted between-arm estimate of pain intensity after treatment, no confidence interval, and no statistical test result for that endpoint. A treatment effect cannot be inferred from the primary outcome record.
The recorded enrollment is 7, but that figure does not establish how many participants contributed to any particular outcome or arm. The registry does not provide an analyzed population for the primary endpoint, participant flow, or outcome-level denominators. It would be inappropriate to treat the enrollment figure as the number analyzed or to assume how participants were distributed across the original and revised arms.
As a general statistical point, an estimate describes the observed contrast, while a confidence interval communicates uncertainty around that estimate under the analysis assumptions. Neither is reported for the primary outcome. Without them, readers cannot assess whether the data were compatible with a range of potentially important differences. There is also no reported primary p-value to interpret. The missing result cannot be recast as a null finding or as evidence that D-cycloserine and placebo produced equivalent scores.
The posted adverse-event figures are limited to two groups labelled Placebo (Original Version) and D-cycloserine 250mg. In each group, 3 participants are listed as at risk for serious adverse events and 0 as affected; the corresponding figures for other adverse events are also 3 at risk and 0 affected in each group. These entries describe only the listed groups and do not supply a full account of safety for the revised regimen or the full intended population. Deaths are not reported in the registry record.
The record also lists secondary measures covering pain relief, neuropathic pain, pain interference, and opioid medication use. It does not provide analysis results for them. The registry’s outcome listings therefore describe what the study intended to assess, not evidence of observed benefit or harm on those measures.
Any sample-size illustrations associated with the results should be understood as planning scenarios, not results from this trial. The stated assumptions use a fraction of an observed effect, but the primary outcome has no posted analyzed effect from which to infer the trial’s observed precision. Such planning values are not observed power and are not the study’s own sample-size justification.
9. Statistical Methods Explained
The registry describes a randomized, double-blind, parallel-group design. In general, randomization assigns participants to study arms using a chance-based process, which is intended to reduce systematic differences between groups at the start of a trial. Double blinding means that treatment assignment is masked for specified parties, but the record does not identify exactly who was masked or how masking was maintained. A parallel design assigns participants to an arm rather than having each participant receive every regimen in sequence. These general descriptions explain the design labels; they do not confirm the practical conduct of the trial after its design changed.
What would an arm comparison estimate?
For the primary question, an analysis would compare patient-reported Brief Pain Inventory pain intensity after the 12-week treatment period across the 3 intended arms. In general, the comparison could be expressed as differences between arm-level summaries, with an uncertainty interval describing the precision of those differences. The registry does not specify the exact score summary, statistical model, contrast structure, or adjustment factors. It reports no patients analyzed for this endpoint, so no arm comparison estimate is available.
What does a confidence interval communicate?
As a general statistical explanation, a confidence interval gives a range of values compatible with the observed data under the model and its assumptions. A narrower interval indicates greater precision than a wider interval, but it does not by itself establish clinical importance. In this record, no interval is reported for the primary outcome. There is therefore no basis for describing the primary effect as precise or imprecise from an outcome estimate, because there is no analyzed estimate to evaluate.
Why does the design change matter?
The record lists two sets of arm descriptions with different doses and treatment durations. The original versions describe a 250mg D-cycloserine arm and a placebo arm, both for 4 weeks. The revised versions describe 50 mg and 200 mg D-cycloserine arms and placebo for 12 weeks. This makes it important to distinguish planned regimens from the arms represented in posted results. The adverse-event entries refer to the original placebo and 250mg groups, while the primary outcome description refers to comparison between the 3 arms after 12 weeks. The registry does not report how participants or data were handled across the change.
As a general statistical point, a change in design can affect which comparisons remain meaningful and which participants contribute to each analysis. It can also complicate interpretation if treatment durations, doses, or comparator conditions differ. The record does not give enough information to determine whether the intended analysis was revised, whether any transition rules were used, or whether outcomes from different design periods were combined.
What are the planning assumptions?
The sample-size assumptions described in the record are a planning illustration based on an observed effect, not the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event tables, the stated quantity is the total number of events using the Schoenfeld approach; other planning values are participants per arm. These conventions describe hypothetical planning calculations. They do not establish that the trial used those assumptions when it was designed or analyzed.
In general, a planning calculation asks how much information might be needed to detect a chosen effect under specified assumptions. Its output depends on those assumptions and is not a measure of what the trial actually observed. A sample-size illustration is not observed power. Since no primary effect estimate is posted for this trial, planning scenarios based on an observed effect should not be read as a trial-specific demonstration of the study’s achieved ability to detect an effect.
What methods are not documented?
The registry record does not report the primary analysis model, handling of missing endpoint data, planned covariates, interim analyses, multiplicity adjustment, or a detailed statistical analysis plan. It also does not report a sample-size justification for the original or revised design. These omissions prevent a fuller appraisal of the planned inferential procedures. They do not establish that a method was or was not used; they mean that the method is not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The record lists a primary outcome and secondary outcomes covering self-reported overall pain relief, neuropathic pain measures, pain interference, and opioid medication use. It also records 5 outcome measures. The secondary descriptions refer to several instruments and comparisons, but the registry does not provide a complete analysis plan or report analysis results for these measures.
As a general statistical point, testing multiple outcomes or contrasts creates multiple opportunities to observe apparently notable results by chance. A prespecified approach to multiplicity can help define how evidence is evaluated across several comparisons. Whether and how such an approach was planned is not reported in the registry record. The trial’s randomized, double-blind design labels do not answer that question.
The primary endpoint has no analyzed participants according to the registry, due to a design change followed by early termination. The record does not explain how missing endpoint values would have been handled, whether an intention-to-treat population was defined, or how analyses would account for participants who did not complete treatment. It also does not report outcome-specific denominators, participant flow, or the population used for any secondary analysis. The number of analyses is recorded as 0, but the registry does not give further detail about the analysis record or explain that entry.
These gaps matter because the interpretation of a treatment comparison depends not only on its endpoint, but also on which participants contribute data and how missing observations and multiple comparisons are addressed. None of those unreported details can be reconstructed from the listed outcomes. The primary result should therefore be read as unavailable, rather than as a completed analysis with a nonsignificant finding.
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 |
|---|---|---|---|
| Placebo (Original Version) | 0 | 3 | 0.0% |
| D-cycloserine 250mg | 0 | 3 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Placebo (Original Version) | 0 of 3 |
| D-cycloserine 250mg | 0 of 3 |
The registry lists adverse-event figures for Placebo (Original Version) and D-cycloserine 250mg. For each group, 3 participants are listed as at risk for serious adverse events, and 0 as affected. For other adverse events, each group is likewise listed with 3 at risk and 0 affected. These are counts for the groups and categories named in the record; they are not estimates of comparative risk for all intended regimens.
The adverse-event record does not list any serious adverse-event terms. Deaths are not reported in the registry record. The entries concern the original arms, which were described as 4-week regimens. They should not be extended to the revised 12-week placebo, 50 mg, or 200 mg regimens, for which corresponding adverse-event figures are not presented in this record.
As a general statistical point, a zero count in a small recorded group does not demonstrate that an event is impossible or that two treatments have equal safety. Counts are most informative when the relevant population, follow-up period, and completeness of reporting are clear. Here, the registry’s early termination, design change, and limited safety entries constrain what can be concluded. The figures document what was reported for the named original groups, not a comprehensive safety comparison.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the study was intended to compare D-cycloserine regimens with placebo for paclitaxel-induced peripheral neuropathic pain in breast cancer patients. It also establishes that the trial was randomized, double-blind, and parallel-group, and that the design changed before early termination. Those details describe the study’s intent and status, not an observed treatment effect.
The primary outcome is explicitly reported as having no patients analyzed. There is no posted estimate of the difference in Brief Pain Inventory pain intensity between the intended arms after treatment, and no interval or test result is reported. Thus, the registry record does not show whether pain scores differed, how large any difference might have been, or how precise an estimate would have been. It also does not show that the treatments had equivalent outcomes or that there was no effect.
The enrollment entry of 7 is not a substitute for an outcome analysis. The record does not provide analyzed counts by arm, participant flow, or results for the listed secondary measures. The adverse-event counts are restricted to the original placebo and 250mg groups and cannot establish safety for the revised arms or provide a comprehensive comparison.
As a general statistical distinction, absence of an estimate is different from an estimate near zero. A near-zero estimate would still require an uncertainty measure to show what effects remain compatible with the data. In this record, there is no primary estimate to interpret at all. Any sample-size planning illustrations are hypothetical calculations under stated assumptions; they are not evidence that this trial achieved a particular power or detected an effect.
The most defensible reading is therefore limited: the trial was designed to address a clinically relevant comparison, but the registry does not provide an analyzed primary outcome with which to answer it. The missing result should not be converted into a claim of efficacy, lack of efficacy, or equivalence.
13. Why This Trial Matters Statistically
This trial illustrates why a study’s design labels and intended outcomes must be separated from its analyzed results. Randomization and double blinding can support a rigorous comparison when the trial is conducted and analyzed as planned, but those features alone do not produce an interpretable treatment estimate. Here, the registry reports no analysis of the primary pain endpoint after a design change and early termination.
The changing arm descriptions make the distinction especially important. The original schedule involved a 250mg dose and placebo for 4 weeks, whereas the revised descriptions involved two different D-cycloserine doses and placebo for 12 weeks. Without a reported account of how the design transition was handled, readers cannot assume that the original and revised regimens form a single coherent comparison or that the listed arms all contributed to the intended primary analysis.
Statistically, incomplete outcome reporting is not the same as a negative trial. A null or nonsignificant result would require an analysis estimate and its uncertainty; neither is reported for the primary endpoint. Similarly, low adverse-event counts in the original groups do not settle safety questions for the revised regimens. These distinctions prevent overinterpretation in either direction.
The record also shows why planning calculations must be kept separate from trial findings. Planning values based on an effect and assumptions can illustrate hypothetical information needs, but they do not replace an observed estimate, establish observed power, or explain why a trial ended. The stated planning illustration is not reported as the trial’s own design justification.
For clinical researchers, this is a useful case in reading registry entries carefully: identify the intended estimand, check whether it was analyzed, establish which treatment versions the data represent, and distinguish missing evidence from evidence of no difference. In this record, the intended question remains unanswered by the posted primary outcome results.
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 consequential limitation is that no patients were analyzed for the primary endpoint. The registry attributes this to a change in study design followed by early termination, but does not provide a primary estimate or explain the operational details behind the change. It does not report the reason for termination beyond this statement, the timing of the design change, or how the change affected enrollment and analysis.
The listed arm descriptions span different doses and treatment durations. The record does not clarify which participants received each regimen, how assignments were made after the revision, or whether any results were collected under the revised design. The adverse-event figures are attached to the original placebo and 250mg groups only. Consequently, the safety entries cannot be generalized to the revised schedules on the basis of this record.
Important outcome details are absent. The primary endpoint has no reported unit, summary parameter, or dispersion measure, and the precise Brief Pain Inventory score to be analyzed is not specified. The registry does not report participant flow, outcome-specific denominators, baseline results, missing-data methods, or analysis populations. It also does not report results for the listed secondary measures.
The record identifies a Phase III randomized, double-blind, parallel study, but it does not describe the randomization method, masking procedures, or statistical analysis plan. The sample-size assumptions are described as planning illustrations rather than the trial’s own design, and no sample-size justification is reported in the registry record. These limitations mean that neither the intended comparison nor the completeness of the available data can be assessed from the registry entries alone.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: D-cycloserine in the Management of Chemotherapy-Induced Peripheral Neuropathic Pain — NCT00301080.
- Registry record last updated 2013-12-02; status last verified 2013-11.
- Results first posted 2013-12-02.
- 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
NCT00301080 is a Phase III randomized, double-blind, parallel-group study sponsored by Northwestern University. It was designed to study D-cycloserine for paclitaxel-induced peripheral neuropathic pain in breast cancer patients, with placebo as comparator. The record lists a design change from original 4-week placebo and 250mg regimens to revised 12-week placebo, 50 mg, and 200 mg regimens.
Enrollment is recorded as 7. The study status is TERMINATED; its start is recorded as 2006-02 and primary completion as 2007-02. The primary outcome was pain intensity on the Brief Pain Inventory after treatment. The registry reports that no patients were analyzed for this outcome following the design change and early termination. It provides no primary effect estimate or analysis result.
Adverse-event entries are limited to the original placebo and 250mg groups. Results for the revised regimens and for the listed secondary outcomes are not reported in the registry record.