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 A Trial in Painful Diabetic Peripheral Neuropathy With GRT3983Y (NCT01056315), a randomized phase 2 study. The primary outcome is Average Pain Intensity.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01056315 |
| Phase | Phase 2 |
| Condition | Painful Diabetic Neuropathy |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 553 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Grünenthal GmbH |
| Results posted | Yes |
2. Clinical Question
Population
People with painful diabetic peripheral neuropathy were the intended population. The registry record describes the condition but does not report detailed eligibility criteria, such as baseline pain requirements or restrictions on other health conditions.
Intervention
The arm description identifies GRT3983Y as the study drug. The intervention list spells the drug name GRT3938Y, while the title and arm description use GRT3983Y; the registry record does not resolve this inconsistency.
Comparator
The comparator was placebo. The official title describes a randomized, double-blind, placebo-controlled, parallel-group trial, while the registry record lists masking as triple.
Primary question
The primary efficacy question concerned the change from baseline in mean daily average pain intensity, measured on an 11-point NRS, over the last 7 days of the 12-week maintenance period, identified as Week 16. The registry record says efficacy data were not analyzed because few subjects had efficacy data when the trial ended early.
3. Trial Design
This was a randomized, multicenter, parallel-group Phase 2 trial comparing a study-drug arm with a placebo arm in people with painful diabetic peripheral neuropathy. The official title describes it as double-blind; the registry record separately classifies masking as triple. Those descriptions are both part of the record, but it does not explain who was masked or how masking was maintained.
The registry lists an enrollment of 553 and identifies Grünenthal GmbH as the sponsor. The recorded start was 2009-11, and primary completion was 2011-01. The study status is terminated. The record does not explain why the trial was terminated or provide a detailed timeline of the decision. It does state that the limited number of subjects with efficacy data at early termination prevented efficacy analysis.
The arm descriptions identify GRT3983Y and placebo. The intervention list instead spells the study drug GRT3938Y. This internal naming inconsistency is not resolved in the registry record, so the drug designation should be read with that qualification.
Random allocation is intended to make treatment groups comparable on average, while a placebo comparison helps distinguish treatment-group outcomes from changes that may occur without the active study drug. These are general design purposes, not evidence that the groups were balanced in this trial. The registry record does not report the allocation ratio, sequence-generation method, concealment procedure, or details of the multicenter sites. It also does not provide enough information to assess whether masking was successful.
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.
Before assignment: 503 participants were excluded from the trial before assignment to a treatment group because they did not meet the inclusion and or exclusion criteria.
Overall Study
| Stage | GRT3983Y | Placebo |
|---|---|---|
| STARTED | 27 | 23 |
| COMPLETED | 13 | 12 |
| NOT COMPLETED | 14 | 11 |
Analysis population for the primary outcome, as defined in the registry: Efficacy data were not analyzed because of the limited number of subjects with efficacy data at the time of the early termination of the trial.
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 | GRT3983Y | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 27 | 23 | 50 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 20 | 14 | 34 |
| Age, Categorical: >=65 years | Participants | 7 | 9 | 16 |
| Age, Continuous | years | 59.38 (SD 8.942) | 60.27 (SD 10.438) | 59.79 (SD 9.568) |
| Sex: Female, Male: Female | Participants | 12 | 8 | 20 |
| Sex: Female, Male: Male | Participants | 15 | 15 | 30 |
| Region of Enrollment: United States | participants | 27 | 23 | 50 |
6. Primary Endpoint
The registry lists the primary outcome as Average Pain Intensity, measured over Baseline; last 7 days of 12-week maintenance.
| 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 change from baseline in the mean of daily average pain intensity scores, measured on an 11-point NRS. The specified assessment was the last 7 days of the 12-week maintenance period, identified as Week 16. The endpoint therefore represents a contrast between a participant’s pain rating at baseline and their average daily ratings during the stated final assessment window. The registry record does not specify the NRS anchors or the precise calculation used to form each participant’s mean.
In general, repeated daily ratings can capture a participant’s reported pain over a period rather than relying on a single rating at one visit. A change-from-baseline measure places follow-up ratings in relation to each participant’s starting value. The placebo group can provide a reference for interpreting the observed course under the trial conditions. These are general measurement considerations; they do not establish that the endpoint was analyzed or that an effect was observed in this trial.
The registry record explicitly says efficacy data were not analyzed because the number of subjects with efficacy data at early termination was limited. It therefore reports no primary efficacy estimate, uncertainty interval, or test result. The primary endpoint was specified, but the registry record does not establish whether it was successfully assessed in a way that supports a treatment comparison.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the trial’s primary efficacy data were not analyzed. The registry record attributes this to the limited number of subjects with efficacy data at the time of early termination. Consequently, the record does not report a treatment-versus-placebo estimate for the primary endpoint, an uncertainty interval around such an estimate, or a statistical test result. No conclusion about the direction or size of an efficacy difference can be drawn from the registered primary outcome.
The enrollment entry is 553, but that figure does not indicate how many participants contributed usable primary-outcome observations. The adverse-event summaries use their own at-risk group counts, and these should not be treated as the primary efficacy analysis population. The registry record does not give a participant flow accounting for enrollment, treatment received, follow-up, and inclusion in each analysis.
In general, an effect estimate describes the magnitude and direction of a group contrast, while a confidence interval conveys the range of values compatible with the data and analysis assumptions. Neither is reported for the primary efficacy comparison. The absence of an analyzed estimate is not the same as a result showing no difference; it leaves the primary efficacy question unanswered in this registry record.
The listed secondary outcomes cover pain ratings over the maintenance period and by week, night pain, morning and evening pain, responder thresholds, and patient-reported assessments. The registry record lists fifteen outcome measures and zero analyses. It does not provide analyzed secondary efficacy results to supplement the unavailable primary analysis. Nor does it report whether exploratory analyses were conducted outside the results recorded in the registry.
The safety information is distinct from the efficacy question. The record reports serious adverse events and other adverse events for the listed at-risk groups, but those event summaries do not recover the missing primary efficacy comparison. The serious-event terms and percentages should be interpreted within their reporting context; the record does not fully specify the denominators or term-level attribution behind those percentages.
Early termination and the limited efficacy information reduce the ability to assess both the estimated treatment effect and its precision. This is a limitation of the evidence available in the registry record, not proof that the study drug did or did not affect pain. The reason for termination, the detailed analysis plan, and any additional analyses are not reported in the registry record.
9. Statistical Methods Explained
The methods information is incomplete, so statistical interpretation must distinguish the registered design from details that are not reported. The trial is described as randomized, parallel-group, placebo-controlled, and Phase 2. The official title calls it double-blind, and the registry classification says triple masking. The record does not specify the randomization procedure, allocation concealment, masking roles, or statistical model used for an efficacy comparison.
What does randomization contribute?
General explanation: randomization assigns participants to treatment groups through a chance-based process. Its purpose is to reduce systematic differences between groups at allocation, including differences in factors that are known or unknown. It does not guarantee identical groups, particularly when few participants contribute outcome data. The registry record labels the study randomized but does not describe the method or report baseline balance for the efficacy population. No claim about the achieved balance can therefore be made from the available information.
What does the parallel-group comparison mean?
General explanation: in a parallel-group design, participants are assigned to a group and outcomes in that group are compared with outcomes in another group. A placebo arm supplies a comparator under the study conditions. The primary endpoint was a change from baseline in mean daily average pain intensity over a specified final maintenance window. A statistical analysis could compare changes between groups, but the registry record does not report the model, estimand, handling of repeated daily ratings, or adjustment variables. It also states that the efficacy data were not analyzed, so no such comparison is available to interpret.
Why does the confidence interval matter?
General explanation: an estimate alone gives a point summary of an effect, while a confidence interval communicates uncertainty due to sampling variability under the analysis assumptions. A narrow interval indicates greater precision than a wide interval, but precision does not by itself establish clinical importance. Here, the registry record does not report a primary efficacy estimate or confidence interval. It is therefore not possible to assess either the estimated effect or its precision from the primary outcome.
What can be inferred from a missing analysis?
General explanation: a missing analysis is not a null finding. A null finding would require an analyzed comparison whose estimate and uncertainty could be examined. In this record, the reason given is that few subjects had efficacy data at early termination. It does not report how many subjects had such data, the reasons data were unavailable, or whether any analyses were attempted before termination. The registered outcome’s presence alone does not establish that an analyzable result exists.
How should over-dispersion be understood?
General explanation: over-dispersion occurs when variation in data exceeds what a statistical model assumes. If present and ignored, standard errors and uncertainty estimates can be misleading. This concept can matter for count or event outcomes, but the registry record does not report a model for the adverse-event summaries or an assessment of over-dispersion. It would be inappropriate to assume that a particular model or correction was used.
What is known about multiplicity and missing data?
The registered outcomes cover multiple pain measures and assessment times, along with responder analyses and patient-reported instruments. General explanation: evaluating many outcomes or time points can increase the chance of a seemingly notable result occurring by chance if interpretation does not account for multiplicity. A prespecified hierarchy or adjustment approach can help manage that issue. The statistical plan and any multiplicity strategy are not reported in the registry record. Since efficacy data were not analyzed, there are no posted efficacy tests from which to assess multiplicity handling.
General explanation: missing outcome data can affect both the representativeness and precision of an analysis. Appropriate methods depend on why data are missing, the amount and pattern of missingness, and the estimand of interest. The registry gives a broad explanation for the lack of efficacy analysis but does not report a missing-data method, an analysis population definition, or participant-level follow-up information. The record lists an enrollment of 553; that number does not resolve these analysis questions.
What is a planning illustration?
General explanation: sample-size planning describes the number of participants an imagined future study might require under specified assumptions. Such an illustration is not an observed trial result and is not observed power. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect defined as a stated fraction of the observed effect. The registry also notes that the calculations are not the trial’s own design. Because the primary efficacy comparison was not analyzed, the record does not provide a trial efficacy estimate to support a meaningful interpretation of such an illustration. The registry record does not report the original sample-size justification or statistical plan.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists multiple secondary outcomes, including pain ratings over the maintenance period, weekly pain ratings, night pain, morning and evening pain, responder analyses using improvement thresholds, Brief Pain Inventory scores, Neuropathic Pain Symptoms Inventory scores, and Patient Global Impression of Change. The primary outcome also defines a specific assessment window. Considering multiple outcomes and assessment times raises a general multiplicity issue: if many comparisons are tested, some results may appear notable by chance. A prespecified hierarchy or adjustment can guide interpretation, but the registry record does not report whether one was planned.
The registry records fifteen outcome measures and zero analyses. It states that efficacy data were not analyzed because few subjects had efficacy data when the trial was terminated early. It does not report a missing-data strategy, details of the analysis population, or a flow of participants contributing to each outcome. The enrollment entry of 553 does not indicate how many had usable endpoint data.
In general, missing-data methods rely on assumptions about why observations are unavailable. The registry record does not report the pattern or reasons for missing efficacy observations beyond the broad statement about limited data at early termination. It also does not report sensitivity analyses to examine how different assumptions might affect an efficacy estimate. Without an analyzed primary comparison, multiplicity procedures and missing-data methods cannot be evaluated through posted efficacy results.
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 |
|---|---|---|---|
| GRT3983Y | 2 | 27 | 7.4% |
| Placebo | 1 | 23 | 4.3% |
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 |
|---|---|
| GRT3983Y | 15 of 27 |
| Placebo | 14 of 23 |
Most frequent serious adverse event terms
| Event term | Organ system | GRT3983Y | Placebo |
|---|---|---|---|
| Abdominal pain upper | Gastrointestinal disorders | 0 of 27 | 1 of 23 |
| Coronary artery disease | Cardiac disorders | 1 of 27 | 0 of 23 |
| Diabetic ketoacidosis | Metabolism and nutrition disorders | 1 of 27 | 0 of 23 |
Most frequent non-serious adverse event terms
| Event term | Organ system | GRT3983Y | Placebo |
|---|---|---|---|
| Nausea | Gastrointestinal disorders | 10 of 27 | 3 of 23 |
| Constipation | Gastrointestinal disorders | 4 of 27 | 2 of 23 |
| Dizziness | Nervous system disorders | 4 of 27 | 1 of 23 |
| Somnolence | Nervous system disorders | 4 of 27 | 1 of 23 |
| Headache | Nervous system disorders | 3 of 27 | 2 of 23 |
| Abdominal pain | Gastrointestinal disorders | 1 of 27 | 3 of 23 |
| Upper respiratory tract infection | Infections and infestations | 1 of 27 | 3 of 23 |
| Diarrhoea | Gastrointestinal disorders | 0 of 27 | 3 of 23 |
| Pruritus | Skin and subcutaneous tissue disorders | 2 of 27 | 1 of 23 |
| Cough | Respiratory, thoracic and mediastinal disorders | 0 of 27 | 3 of 23 |
Serious events with the highest arm-level rate: abdominal pain upper (4.3%), coronary artery disease (3.7%), diabetic ketoacidosis (3.7%).
The registry reports serious adverse events for the GRT3983Y arm as 2 affected among 27 at risk and for placebo as 1 affected among 23 at risk. Other adverse events are reported as 15 affected among 27 at risk in the GRT3983Y arm and 14 affected among 23 at risk in the placebo arm. These are the recorded group counts; they are not an efficacy comparison and do not establish a causal relationship between an event and treatment.
The registry lists abdominal pain upper at 4.3%, coronary artery disease at 3.7%, and diabetic ketoacidosis at 3.7% among the top serious-event terms. It does not specify the denominator or explain whether those percentages are pooled or tied to a particular arm. They should not be interpreted as rates for either group without that context. The death entries are not reported in the registry record.
In general, adverse-event counts depend on how events were defined, collected, and coded, and group counts alone do not provide a complete assessment of risk. The record does not report event timing, severity detail beyond the serious-event classification, or treatment attribution for each event. These safety figures also do not replace the missing efficacy analysis.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, placebo-controlled Phase 2 trial was conducted for painful diabetic peripheral neuropathy and that it was terminated. Its registered primary endpoint was change from baseline in mean daily average pain intensity on an 11-point NRS during the last 7 days of the 12-week maintenance period, identified as Week 16.
It does not establish whether GRT3983Y changed pain intensity relative to placebo. The record says efficacy data were not analyzed because the number of subjects with efficacy data was limited at the time of early termination. There is no reported primary treatment-effect estimate, confidence interval, or p-value. The lack of an analyzed result should not be read as evidence that the groups were the same, nor as evidence that one group was better.
The safety entries describe serious and other adverse events among the listed at-risk groups, as well as selected serious-event terms. They do not resolve the efficacy question, and incomplete information about the term-level percentages limits interpretation. The death entries are not reported in the registry record.
More broadly, a trial’s design and registered endpoints describe what investigators intended to evaluate, while conclusions depend on analyzed data and transparent reporting of methods and uncertainty. The registry record does not report why the trial ended early, the detailed statistical plan, the analysis populations, or the missing-data approach. It also uses inconsistent spellings for the study drug in different registry fields. Those gaps limit what can be concluded from the record, without implying an outcome that was not reported.
13. Why This Trial Matters Statistically
This trial illustrates an important distinction in clinical-trial interpretation: a registered primary outcome is not the same as an analyzed primary result. The record specifies a pain-intensity endpoint and a placebo comparison, but it also states that efficacy data were not analyzed because few subjects had efficacy data when the trial ended early. Without an estimate and its uncertainty, readers cannot judge the direction, magnitude, or precision of an efficacy contrast.
The distinction matters because enrollment and analysis populations are not interchangeable. The registry lists an enrollment of 553, while the adverse-event summaries identify smaller at-risk groups and the primary efficacy population is not quantified. The record does not provide participant flow or explain how many subjects contributed to each outcome. Readers therefore need to avoid treating the enrollment entry as the denominator for every analysis.
The trial also highlights why outcome multiplicity and missing data are relevant statistical concerns. The registered outcomes include several pain measures, time windows, and patient-reported instruments. A planned analysis strategy is needed to guide interpretation across multiple outcomes, but the statistical plan is not reported. The record also does not describe how missing efficacy observations were handled; it reports that efficacy data were not analyzed.
Finally, the registry contains inconsistent spellings of the study drug and differing descriptions of masking. Such reporting details do not determine the study’s results, but they affect how clearly the design can be understood. In general, transparent reporting of endpoint definitions, analysis populations, methods, and uncertainty is essential for readers assessing what a trial can and cannot establish.
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 principal limitation is that the registry record reports no efficacy analysis. It attributes this to the limited number of subjects with efficacy data when the trial was terminated early. There is consequently no posted primary effect estimate or uncertainty interval, and no basis in this record for judging the observed efficacy contrast.
The reason for early termination is not reported in the registry record. Nor does the record provide a detailed account of when participants stopped treatment or follow-up, how many contributed to each endpoint, or why efficacy data were limited. The enrollment entry cannot answer those questions. The record also does not describe an analysis population, missing-data methods, or sensitivity analyses.
Statistical methods are insufficiently detailed for independent evaluation. The randomization procedure, allocation concealment, efficacy model, adjustment strategy, and multiplicity plan are not reported in the registry record. Although the study is called double-blind in the official title and triple-masked in the registry classification, the masked roles and procedures are not specified.
The reporting also contains a drug-name inconsistency: the title and arm description use GRT3983Y, while the intervention list uses GRT3938Y. The record does not explain the difference. Safety summaries include at-risk counts and event counts, but do not fully define the denominators behind the listed serious-event percentages or report death entries. These limitations concern interpretation of the registry record and do not establish unreported trial results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Trial in Painful Diabetic Peripheral Neuropathy With GRT3983Y — NCT01056315.
- Registry record last updated 2019-10-28; status last verified 2019-10.
- Results first posted 2012-05-03.
- 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
NCT01056315 is a randomized, multicenter, placebo-controlled, parallel-group Phase 2 trial in painful diabetic peripheral neuropathy, sponsored by Grünenthal GmbH. The registry lists enrollment of 553, a start of 2009-11, primary completion in 2011-01, and terminated status. The official title describes double-blinding; the registry lists triple masking.
The primary endpoint was change from baseline in mean daily average pain intensity on an 11-point NRS over the last 7 days of the 12-week maintenance period, identified as Week 16. The registry states that efficacy data were not analyzed because few subjects had efficacy data at early termination. It lists fifteen outcome measures and zero analyses. Safety information includes serious and other adverse-event counts, but does not provide a primary efficacy result. The study-drug spelling differs between registry entries.