Nab-Pac+Cis+Gem in Pts w Previously Untreated Metastatic PDA: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Nab-Pac+Cis+Gem in Pts w Previously Untreated Metastatic PDA (NCT01893801), a na phase 1, phase 2 study. The primary outcome is Complete Response Rate.

2. Clinical Question

The trial's stated objective was to evaluate preliminary efficacy and safety of the three-drug regimen in this population. The primary endpoint description sets out an expected complete response level and a staged enrollment rule, but those design statements are not observed results. A separate result note says one patient achieved complete response 32 days after the last dose, after having a best response of partial response before that assessment. The note also says that the patient's best response was identified as “C,” but the entry is incomplete. This patient-level description does not establish the study's complete response rate or resolve how that observation was classified in the endpoint analysis.

3. Trial Design

This was a phase 1b/2 pilot study, recorded as completed, with a single treatment group and no masking. The registry lists enrollment of 25 and a study start of 2013-05, with primary completion in 2016-04. The treatment group received nab-paclitaxel, cisplatin and gemcitabine. The study description calls the trial open-label and says treatment was evaluated for preliminary efficacy and safety.

Because there was no separate control group, the design can describe outcomes observed among treated participants but cannot isolate the regimen's effect from other explanations through a randomized comparison. There is no like-for-like control arm in the registry record. The study therefore answers a different question from a controlled trial: it documents outcomes and safety observations in a treated group, rather than estimating a comparative treatment effect.

The primary outcome description says the study aimed to treat 25 individual patients and evaluate complete response using CT and tumor-marker criteria. It also describes a planned enrollment decision based on complete responses among the first 10 patients, and a stopping condition tied to intolerable adverse events or absence of clinical benefit among the first 6 patients. These are protocol statements in the endpoint description; they do not demonstrate that a stopping rule was triggered or establish the final endpoint result.

The registry lists treatment-related toxicities, percentage change in CA 19-9, overall survival and progression-free survival as secondary outcomes. It does not report numerical results for these outcomes in the record summarized by the posted results. The timing, analysis methods and detailed assessment procedures for those secondary endpoints are not reported in the registry record. Nor are the details of the statistical plan, including any planned interim analyses beyond the enrollment rule described in the primary outcome text.

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

Analysis population for the primary outcome, as defined in the registry: Best Response on study was assessed for patients with at least one evaluation for response while evaluable during the study. One patient achieved CR 32 days after the last dose on therapy and had a best response of PR prior to this assessment. The patient is identified as having a best response of CR in this table.

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.

6. Primary Endpoint

The registry lists the primary outcome as Complete Response Rate, measured over 1 yr..

The primary endpoint is complete response rate, recorded as a count of participants and assigned a 1 yr. timeframe. In general, a response rate describes how many participants meet a defined response category among the population assessed. It is not the same as the amount of tumor change in every participant, nor does the endpoint title alone tell the reader which analysis population was used or how missing evaluations were handled.

The registry defines complete response using CT assessment under RECIST 1.1 criteria and normalization of CA 19-9, or CA 125 or CEA for participants who do not express CA 19-9. The description further specifies a marker level that had been at least > 2x ULN before treatment. It says a confirmatory PET scan would be obtained when a complete response was documented. These criteria combine imaging and marker information, so a response classification depends on the stated assessment rules rather than on a single measurement alone.

Complete response is used as a categorical measure of tumor response. It can communicate whether a participant met a stringent response definition, but it does not by itself describe response duration, survival, toxicity, or the overall balance of outcomes. Those questions require their own endpoints and results. The registry record does not report the study-level complete response count or rate, the denominator used for that calculation, or a confidence interval. The individual response note is not enough to reconstruct those values.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Complete response is a binary outcome at the participant level: a participant either meets the registry's stated complete response definition or does not. In general, binary endpoints are often summarized as counts and proportions. The count conveys how many participants met the definition; the proportion relates that count to a specified analysis population. Both components matter. An enrollment total is not automatically the denominator, particularly when the outcome description limits assessment to participants with an evaluable response assessment.

What the response definition contributes

The registry describes a composite assessment based on CT findings under RECIST 1.1 criteria and tumor-marker normalization. CA 19-9 is specified, with CA 125 or CEA used for people who do not express CA 19-9. A confirmatory PET scan is described after a complete response is documented. In general, explicit endpoint criteria help make a classification reproducible: they state what evidence counts and reduce the risk that a response category is assigned differently across participants. The registry record does not provide the full assessment charter, adjudication procedures or participant-level assessment data, so those details cannot be evaluated.

The outcome timeframe is listed as 1 yr. A timeframe defines the period relevant to endpoint assessment, but its interpretation also depends on when assessments were scheduled, how late or missed assessments were handled, and how a response first observed near or after treatment was classified. Those operational details are not reported in the registry record. The note about a response 32 days after the last dose illustrates why timing and classification rules matter, but it does not specify the full study rule or establish the final analysis classification.

Counts, proportions and uncertainty

For a binary outcome, a count by itself does not show how precisely the underlying response frequency has been estimated. A confidence interval is a range of values compatible with the observed data under a stated statistical method. In general, the interval reflects sampling uncertainty: with limited observations, plausible response frequencies can span a broad range. A confidence interval is not a guarantee that a particular value is correct, and its interpretation depends on the method and assumptions used.

No study-level complete response count, rate or confidence interval is reported in the registry record. A recalculated rate or interval cannot be recovered from the incomplete patient-level note because the relevant denominator and endpoint classification are not reported. No statistical analysis plan for the primary outcome is reported in the registry record. Thus, the estimation method, confidence level and any adjustment or sensitivity analysis cannot be described.

Single-group interpretation

The design is single-group, with no separate comparator. In general, an outcome frequency in a single group is descriptive: it records what happened among the assessed participants. A treatment effect, in contrast, requires a comparison that estimates what would have happened under another condition. Without a control group, changes over time or observed responses cannot be separated from other influences, such as participant characteristics, disease course, assessment practices or care outside the trial. This is a design limitation, not a defect that can be fixed by calculating a different response proportion.

Likewise, a p-value from a comparison cannot be interpreted when no comparison is reported. The registry lists no analyses, and no analysis results are reported. It is therefore not appropriate to infer statistical significance, a comparative effect size or evidence against a null hypothesis from the enrollment number or the patient-level response note.

Safety summaries

Adverse-event summaries use different units from the primary response endpoint. The registry group summary reports counts of participants affected by serious and other adverse events, while the listed serious event terms carry percentages. In general, a participant count and an event count are not interchangeable: one participant may experience more than one event, and a given event term may occur more than once in one participant. Without event-level definitions and denominators for each term, the listed summaries should not be expanded into claims about the number, timing or recurrence of events.

Seriousness is a classification of an adverse event, not proof that the study treatment caused it. Establishing attribution requires information about how events were assessed and reported. The record does not provide that detail. Deaths are separately listed in the group summary; that count alone does not state cause, timing, relationship to treatment or whether deaths occurred during a defined follow-up period.

Planning statements are not analysis results

The primary outcome description includes an expected response level and rules for continuing or discontinuing enrollment. These statements describe intended study conduct. They are not observed efficacy results, and they do not supply a statistical estimate. The registry record does not report the design assumptions or a formal sample-size justification. Any general sample-size illustration elsewhere should be understood as planning context rather than observed power or a substitute for an outcome analysis. No study-specific calculation can be inferred from the registry entries.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and several secondary outcomes: treatment-related toxicities, percentage change in CA 19-9, overall survival and progression-free survival. A study that assesses multiple outcomes raises a general multiplicity issue: the more statistical claims considered, the greater the opportunity for chance findings if each is interpreted as confirmatory without adjustment. This concern depends on which outcomes were formally tested, the testing strategy and the intended role of each endpoint. Those details are not reported in the registry record.

The record lists no analyses, and it does not report a multiplicity adjustment or a hierarchy for interpreting the secondary outcomes. It is therefore not possible to tell whether any statistical testing was planned, whether outcomes were exploratory, or whether adjustments were made. The outcomes should not be treated as a set of confirmatory findings on the basis of their listing alone.

Missing-data handling is also not reported in the registry record. The primary outcome description limits response assessment to patients with at least one response evaluation while evaluable during the study, but it does not state how participants without an evaluable response were counted or whether any imputation or sensitivity analyses were used. The evaluable population size is not reported. For the secondary outcomes, the record does not specify the analysis populations or missing-data procedures.

In general, analysis populations determine which participants contribute to an estimate, while missing-data methods determine how unavailable measurements affect that estimate. Both can influence interpretation. Because the relevant details and endpoint results are absent, the posted results do not support a reconstruction of the primary analysis or an assessment of how missing outcomes may have affected it.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: fever (8.0%), platelet count decreased (8.0%), dehydration (8.0%), stroke (8.0%), acute cryptosporidiosis (4.0%).

The group summary records serious adverse events affecting 12 participants and other adverse events affecting 24 participants. It also lists 21 deaths. Serious-event terms include fever, platelet count decreased, dehydration and stroke, each reported at 8.0%, and acute cryptosporidiosis and lung infection, each reported at 4.0%. These are registry summaries for the treatment group, not comparisons between treatment arms.

In general, adverse-event percentages describe the reporting frequency according to the registry's underlying definition and denominator. A percentage does not, by itself, tell how many separate episodes occurred or whether a participant had more than one event. The record does not report enough event-level detail to determine recurrence, timing, duration, management or the denominator used for each listed term.

Seriousness should not be read as treatment causality. The registry does not report the attribution method or whether each event was judged related to treatment. The death count likewise does not specify cause or relationship to the regimen. Because the trial has no comparator group, these summaries cannot establish whether event frequencies were higher or lower than under another treatment. They describe reported safety observations, with important context and attribution details not reported in the registry record.

12. What the Result Does, and Does Not, Mean

The registry record establishes the study's basic design and intended question: a completed, single-group phase 1b/2 pilot study of nab-paclitaxel, cisplatin and gemcitabine in patients with previously untreated metastatic pancreatic ductal adenocarcinoma. It identifies complete response rate as the primary endpoint and describes imaging and tumor-marker criteria. It also records safety summaries and lists additional outcomes.

It does not report a study-level complete response rate, the endpoint denominator, or a confidence interval. The note describing one patient's complete response after treatment, preceded by a best response of partial response, is not sufficient to calculate the endpoint result. Its final classification text is incomplete. Overall survival, progression-free survival and the secondary marker outcome are listed but their numerical results are not reported in the registry record.

The single-group design means the observations cannot be interpreted as a randomized comparison. A response observed in the group does not, on its own, show what would have happened under a different treatment or establish that the regimen caused the outcome. Similarly, the safety counts describe reported events but do not establish treatment attribution or comparative safety.

In general, a pilot study can provide descriptive information and help frame questions for further evaluation, but its role depends on its design and the completeness of its results. The registry record does not report a formal statistical plan, a sample-size justification or enough primary outcome data to assess precision. The information supports a careful account of the design and the recorded safety counts; it does not support a numerical estimate of primary efficacy or a comparative conclusion.

13. Why This Trial Matters Statistically

This trial is statistically instructive because it distinguishes a clearly stated endpoint from a reported endpoint result. The registry defines complete response using imaging and tumor-marker criteria, and identifies a 1 yr. timeframe. Yet the study-level count, rate, denominator and uncertainty interval are not reported in the registry record. A detailed endpoint definition is valuable, but it cannot substitute for results needed to estimate the outcome.

The record also shows why the analysis population matters. Enrollment is 25, while the endpoint description refers to patients with at least one evaluation for response while evaluable during the study. Those are not necessarily the same analysis set. Because the evaluable population count is not reported, the response frequency cannot be reconstructed from the enrollment total or from the isolated patient-level note.

The single-group design provides another important lesson. Descriptive outcomes can characterize what was recorded among treated participants, but a comparison is needed to estimate a treatment contrast. The safety summaries should likewise be read as observations in one group, not as evidence of relative risk or causality. These distinctions remain important even when the study has a defined endpoint and a completed status.

Finally, the planned enrollment rules and expected response statement are not observed results. Separating design intentions from analysis findings prevents a protocol target from being mistaken for evidence about outcomes. The record's limitations make transparent reporting of denominators, classifications, analysis methods and uncertainty especially important for interpretation.

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 registry record is incomplete for evaluating the primary endpoint. Although it names complete response rate and provides an endpoint definition, it does not report the study-level count, rate, denominator or confidence interval. The patient-level note is truncated after stating that the participant's best response was identified as “C,” leaving the classification text unresolved. The number of participants who met the endpoint's evaluability description is also not reported.

The single-group design has no concurrent comparator, limiting causal and comparative interpretation. The record does not report a statistical analysis plan, a formal sample-size justification, detailed analysis populations, missing-data methods or multiplicity procedures. These omissions prevent assessment of how the endpoint was analyzed and how uncertainty or multiple outcomes were handled.

Secondary outcomes are listed without numerical results in the registry record. Safety summaries do not include sufficient detail on event timing, recurrence, duration, attribution or cause of death. The record also does not explain the denominator underlying each serious-event percentage or provide event-level data. These limitations apply to interpretation of the posted record; they do not establish that analyses or information were absent from other study materials.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Nab-Pac+Cis+Gem in Pts w Previously Untreated Metastatic PDA — NCT01893801.
• Registry record last updated 2019-05-29; status last verified 2019-05.
• Results first posted 2019-05-29.
• 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.

18. Record Summary

The registry describes a completed phase 1b/2 open-label pilot study with a single group receiving nab-paclitaxel, cisplatin and gemcitabine. Enrollment was 25. The study start is recorded as 2013-05 and primary completion as 2016-04. The population was patients with previously untreated metastatic pancreatic ductal adenocarcinoma.

Complete response rate was the primary endpoint, with a stated timeframe of 1 yr. The registry provides response criteria but does not report a study-level response rate or its analysis denominator. Treatment-related toxicities, percentage change in CA 19-9, overall survival and progression-free survival are listed as secondary outcomes; their numerical results are not reported in the registry record.

The group safety summary records 12 participants with serious adverse events, 24 with other adverse events and 21 deaths. The single-group design does not provide a randomized comparator, and the available record does not establish treatment causality or comparative effects.