Erlotinib and Chemotherapy for Patients With Stage IB-IIIA NSCLC With EGFR Mutations (ECON): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Erlotinib and Chemotherapy for Patients With Stage IB-IIIA NSCLC With EGFR Mutations (ECON) (NCT00577707), a na phase 2 study. The primary outcome is Number of Patients With Pathologic Complete Response Rate.

2. Clinical Question

3. Trial Design

ECON is listed as a phase II, single-group, open-label study sponsored by Memorial Sloan Kettering Cancer Center. The record describes it as single center. Allocation is marked not applicable, and there is no randomized control arm. The trial is recorded as completed; its listed start was 2007-11 and its primary completion was 2011-12. Enrollment is listed as 9.

Eligible participants were described as having resectable clinical stage IB-IIIA NSCLC with an activating EGFR mutation. The arm description gives the disease classification as T1-3N0-2M0. Treatment was planned in sequence: erlotinib alone for 3 weeks, then concurrent erlotinib with pemetrexed and cisplatin, followed by resection. The study summary describes postoperative erlotinib for 2 years as a secondary area of interest. The registry does not state the treatment duration of the concurrent preoperative regimen in the arm description.

The single-group structure is important when interpreting the study question. Outcomes can describe what occurred among participants receiving the study regimen, but cannot by themselves establish how those outcomes compare with chemotherapy alone. The study summary names chemotherapy alone as a motivating comparison, not as a recorded concurrent arm. Masking is listed as none, so the study is open label; details on blinded outcome assessment are not reported in the registry record.

The record lists 3 outcome measures and 0 analysis records. It does not report the primary response count, a response estimate, or an inferential comparison. The relationship between the 9 enrolled participants and the 6 participants listed as at risk in the adverse-event entries is not explained in the registry record. Enrollment therefore should not be treated as the denominator for every outcome.

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

Reasons for not completing this period:

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 Number of Patients With Pathologic Complete Response Rate, measured over Patients will undergo a CT scan of chest every 3 months for year 1 and every 4 months for year 2. In years 3 and 4, a chest CT or chest x-ray every 6 months..

The primary outcome is titled “Number of Patients With Pathologic Complete Response Rate,” and its unit is participants. It is a count outcome: it is intended to record how many participants met the definition of pathologic complete response following treatment and surgery. A pathologic response focuses on tumor findings at surgery rather than relying only on imaging or symptoms.

The registry description also provides definitions for clinical response categories, including complete response, partial response, minor response, stable disease, and progressive disease. Those definitions refer to clinical evidence, lesion measurements, and new lesions. The record does not explain how those clinical categories relate to the named pathologic complete-response endpoint, or state the pathology criteria used for the primary outcome. That distinction matters because the endpoint must be defined consistently to interpret a count as a response outcome.

Response endpoints can be useful in an early-phase study because they describe tumor response after a treatment regimen without requiring a long-term survival comparison. However, a count alone needs a clearly reported analysis denominator to be interpreted as a rate. The primary response count, denominator, and uncertainty estimate are not reported in the registry record. The listed timeframe describes chest imaging during follow-up: every 3 months for year 1, every 4 months for year 2, and a chest CT or chest x-ray every 6 months in years 3 and 4. The record does not clarify how that imaging schedule defines the timing of the primary pathologic endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group response count represent?

General statistical explanation: For a binary endpoint such as whether a participant has a response, the basic result is a count of participants meeting the definition and a denominator of participants assessed. A response rate expresses that count relative to the relevant denominator. The denominator may differ from the number enrolled if some participants were not assessed or were excluded from the analysis. In ECON, the registry names a participant count as the primary outcome but does not report the count, denominator, or analysis population.

A count without its denominator is difficult to interpret as a frequency, and a rate without an uncertainty interval can conceal how imprecise the estimate may be. A confidence interval describes a range of values compatible with the data under a specified statistical procedure; it is not a guarantee that the true value lies in that range. Different interval methods can behave differently when the available data are sparse. The registry record does not report an interval or identify an interval method for the primary endpoint.

What does the record say about statistical analyses?

The registry lists 0 analysis records. It does not report a statistical model, hypothesis test, adjustment strategy, or estimated treatment effect for the primary endpoint. It would therefore be inappropriate to attribute a particular analysis method to the investigators. Even a simple one-group response summary would require the endpoint definition and analysis denominator, neither of which is reported with a primary result.

General statistical explanation: In a one-group study, an estimate can describe the observed outcome within that group. A claim about comparative benefit usually requires a defined comparator and an analysis that accounts for how participants entered each group. ECON has no concurrent control group in the registry design. Its stated interest in comparison with chemotherapy alone is not equivalent to a direct comparative estimate.

How should the planning illustration be understood?

The planning assumptions describe an illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The intended effect to detect is specified as a stated fraction of the observed effect. For time-to-event outcomes, the illustration concerns a total event count; for other outcomes, it concerns participants per arm. These are planning assumptions, not evidence that the study had a particular probability of detecting an effect.

The assumptions are not the same as the design recorded for ECON. ECON is single group, not an equal-allocation two-arm comparison. A hypothetical two-arm planning exercise cannot be read as the trial’s actual enrollment plan or as an observed-power calculation. The registry record does not report the trial’s own sample-size justification, and numerical planning estimates are not stated in the registry record.

Why does outcome definition matter?

General statistical explanation: A binary outcome requires a reproducible rule for classifying each participant. When different concepts are combined or left unclear, readers may not know whether the count refers to clinical response, pathologic response, or another assessment. ECON’s primary outcome title refers to pathologic complete response, while the description gives clinical response categories. Pathology criteria and the link between these definitions are not reported in the registry record. This limits interpretation independently of the missing result.

Over-dispersion is a general concern when observed variation is greater than a statistical model expects. It can arise in settings with clustering or unmodeled differences among participants. For a simple binary endpoint, the choice of model and the assumptions behind it still matter, particularly with sparse data. The registry does not report a model or enough outcome information to assess over-dispersion or other model diagnostics; no claim is made that it occurred in ECON.

Missing data methods also affect interpretation. If some participants lack an endpoint assessment, an analysis might define how they are handled, but that decision should be specified and reported. The registry record does not describe missing-data methods, analysis populations, or exclusions for the primary endpoint. Neither the enrollment figure nor the adverse-event risk entries can substitute for that information.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures, including the primary outcome and secondary outcomes concerning response after 21 days of single-agent erlotinib and response and survival with neoadjuvant treatment and adjuvant erlotinib. Considering several outcomes can raise multiplicity concerns: when many hypotheses are tested, the chance of at least one apparently notable result can increase. An analysis plan may address this by defining a primary outcome, specifying a testing sequence, or adjusting inference. No multiplicity strategy is reported in the registry record, and no analysis records are listed.

The primary endpoint result itself is not reported in the registry record. There is no denominator, estimate, uncertainty interval, or test result. The record also does not report how missing endpoint assessments were handled, whether participants were analyzed according to a defined population, or whether any participants were excluded from the primary analysis. These omissions prevent assessment of whether the reported outcome, if available elsewhere, would represent all enrolled participants or a selected subset.

The registry lists 9 enrolled participants, while the adverse-event entries list 6 at risk. It does not explain the difference, and those safety figures should not be treated as the primary endpoint denominator. Enrollment, safety follow-up, and endpoint assessment can use different populations, so their relationship needs explicit reporting rather than assumption. The record also does not state whether any interim analyses were planned or conducted.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: diarrhea (16.7%), nausea (16.7%), sodium, low (hyponatremia) (16.7%), vomiting (16.7%).

The serious-adverse-event entries list 6 participants at risk and 1 affected. The other-adverse-event entries list 6 at risk and 6 affected. These are the registry’s reported counts; the record does not explain the relationship between these safety denominators and the 9 participants enrolled. It also does not give event-level detail sufficient to determine whether an affected participant had more than one event.

The registry lists diarrhea, nausea, low sodium (hyponatremia), and vomiting among the serious adverse-event terms, each displayed as 16.7%. These entries describe what the registry reports, not a comparison with another treatment group. Because the study is single group, the safety figures cannot establish whether the regimen had more or fewer events than an alternative. The record does not report a causal assessment for each event, nor does it describe how seriousness was defined or how adverse events were collected.

Safety counts and the primary response outcome answer different questions. The adverse-event figures do not supply the missing primary response result, and they should not be used to infer treatment effectiveness. The registry record also does not clarify whether all enrolled participants contributed safety data or how missing safety information was handled.

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

This trial record describes a phase II evaluation of erlotinib with pemetrexed and cisplatin before surgery in patients with resectable, EGFR-mutated NSCLC. It identifies a pathologic complete-response count as the primary outcome and lists postoperative erlotinib as part of the study’s secondary purpose. The posted registry information establishes the intended treatment sequence and the broad clinical question, but it does not provide the primary outcome result.

Without the number of participants meeting the primary endpoint and the corresponding analysis denominator, the response frequency cannot be described. The registry also supplies no uncertainty interval or inferential result. Absence of these results from the registry record is not evidence that no participant responded, and it is not evidence of a particular treatment effect.

The single-group design further limits interpretation. It can, in principle, describe outcomes among participants treated in the study, but it cannot make a direct comparison with chemotherapy alone because no such arm is recorded. The study’s stated interest in whether the combination might be better than chemotherapy alone is a rationale, not a comparative result.

The safety entries offer a limited description of reported adverse-event counts and terms. They do not establish comparative safety, and the record does not explain how the safety population relates to enrollment. The clinical response definitions also do not resolve how the named pathologic endpoint was assessed. A clear endpoint definition, analysis denominator, result, and uncertainty estimate would be needed to interpret the primary outcome quantitatively. The record summary should therefore be read as a description of trial design and available registry information, not as a conclusion about efficacy or comparative benefit.

13. Why This Trial Matters Statistically

ECON illustrates why design and endpoint reporting are central to statistical interpretation. The clinical question concerns a combined preoperative regimen and a pathologic response outcome, but the registry design is single group. The record can describe what was planned and which population was targeted; it does not establish a comparison with chemotherapy alone. The difference between a motivating comparison and a comparison actually supported by the design is important when interpreting early-phase studies.

The primary endpoint is named as a count of participants with pathologic complete response, yet the registry description supplies clinical response categories and does not state pathology criteria. A clearly defined outcome is necessary for consistent classification and for understanding what an estimate represents. Here, the missing result and denominator compound the ambiguity: readers cannot quantify the outcome or assess its precision.

The record also demonstrates why enrollment, safety counts, and endpoint-analysis populations should not be assumed to match. Enrollment is listed as 9, while safety entries use 6 participants at risk. The reason is not reported. Without explicit analysis populations, a count can be detached from the people it is meant to describe.

Finally, planning assumptions should be separated from observed evidence. A hypothetical two-arm sample-size illustration using an observed effect is not the design of this single-group study and is not observed power. Together, these distinctions show how design, outcome definitions, denominators, uncertainty, and planning assumptions each affect what a registry record can support.

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 primary endpoint result is not reported in the registry record. The count, denominator, response-rate estimate, and uncertainty interval are absent, so the main outcome cannot be quantitatively assessed. The registry lists 0 analysis records and does not provide a statistical model, testing procedure, or analysis population.

The endpoint wording is also incomplete for interpretation. The primary outcome title refers to pathologic complete response, while the description provides clinical response definitions. Pathology criteria and the relationship between the clinical definitions and the primary endpoint are not reported. The listed imaging follow-up schedule does not resolve the timing or assessment procedure for the pathologic outcome.

The single-group design has no concurrent comparator, despite the study summary’s interest in comparing the combination with chemotherapy alone. Therefore, the recorded design does not support a direct comparative estimate. The record does not report blinding of outcome assessment, missing-data handling, or participant exclusions from outcome analyses.

Enrollment is listed as 9, but the adverse-event entries list 6 at risk; the registry does not explain this difference. The safety terms are reported without event-level details or a comparative group. The record also does not report the trial’s sample-size justification, any interim analyses, or a multiplicity strategy. These limitations constrain interpretation of both efficacy and safety information in the registry.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Erlotinib and Chemotherapy for Patients With Stage IB-IIIA NSCLC With EGFR Mutations (ECON) — NCT00577707.
• Registry record last updated 2018-01-10; status last verified 2017-12.
• Results first posted 2015-11-20.
• 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

ECON (NCT00577707) is a completed, open-label, single-center phase II study sponsored by Memorial Sloan Kettering Cancer Center. The registry lists 9 participants enrolled, with a study start of 2007-11 and primary completion of 2011-12. Participants were described as having resectable stage IB-IIIA NSCLC with activating EGFR mutations.

The planned regimen began with erlotinib for 3 weeks, followed by concurrent erlotinib, pemetrexed, and cisplatin before resection. The study summary also describes postoperative erlotinib for 2 years. The primary outcome is titled as a count of participants with pathologic complete response, but its result and analysis denominator are not reported in the registry record. The record lists 3 outcome measures and 0 analysis records. Serious-adverse-event entries list 6 at risk and 1 affected; other-adverse-event entries list 6 at risk and 6 affected. No concurrent comparator is recorded.