Effectiveness of MORAb-003 in Women With Ovarian Cancer Who Have Relapsed After Platinum-Based Chemotherapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effectiveness of MORAb-003 in Women With Ovarian Cancer Who Have Relapsed After Platinum-Based Chemotherapy (NCT00318370), a non-randomized phase 2 study. The primary outcome is Serologic Response (Change in CA125 Level).

2. Clinical Question

3. Trial Design

This was a Phase 2, parallel, non-randomized study with no masking. The registry records an enrollment of 58 and lists Morphotek as the sponsor. The study began in 2006-05, reached primary completion in 2010-02 and is marked completed. The title describes women whose ovarian cancer relapsed after platinum-based chemotherapy; the official title specifies platinum-sensitive epithelial ovarian cancer in first relapse.

The intervention descriptions cover farletuzumab alone and farletuzumab with chemotherapy. Farletuzumab alone is described at 100 milligrams per square meter. The combination regimen is paclitaxel 175 mg/m2 or docetaxel 75 mg/m2, plus carboplatin with an AUC of 5-6 intravenously on Day 1 of a 21-day cycle, together with farletuzumab at 100 mg/m2. The registry also names a maintenance farletuzumab-only group in its safety category, but does not provide a separate arm description for it.

Because allocation was non-randomized, differences between treatment groups cannot be interpreted as if treatment assignment had been randomized. The record itself cautions that the arms are not a like-for-like control comparison. It does not report the allocation procedure, group-specific enrollment, baseline balance, or reasons for treatment selection. The primary outcome population is all participants enrolled to initial farletuzumab only; the record does not establish that this population is the same as the total enrolled population.

Several secondary outcomes are listed, including time to and duration of serologic response, overall response rate, progression-free survival and prolongation of remission. Their listing does not establish that numerical results or analysis details are available. Specific analysis methods for those outcomes are not reported in the registry record.

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.

Period 1

Reasons for not completing this period:

Period 2

Reasons for not completing this period:

Period 3

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants enrolled to initial farletuzumab only.

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 Serologic Response (Change in CA125 Level), measured over Baseline to response (up to 30 weeks).

The primary endpoint is the number of participants who achieved a serologic response, measured as a change in CA-125 from baseline. The registry defines a 50% response as a >50% decrease from baseline under modified Gynecologic Cancer Intergroup criteria. The baseline value is the higher of two pretreatment CA-125 assessments, and it must be at least 52.5 kU/L. The stated observation window runs from baseline to response, up to 30 weeks.

This is a binary endpoint at the participant level: each participant either meets the response definition or does not. Counting participants who meet a prespecified threshold can make a response outcome easier to interpret than a continuous marker change alone, while retaining a defined clinical measurement rule. That general advantage does not establish why the investigators selected this endpoint; the rationale is not reported in the registry record.

The registry identifies the primary endpoint population as all participants enrolled to initial farletuzumab only. It specifies a 95% confidence interval as the dispersion measure, but does not report the response count or interval. Without those results, the degree of observed response or its statistical precision cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information recorded for this study is limited. The primary outcome is a participant count, its stated dispersion measure is a 95% confidence interval, and its timeframe is baseline to response up to 30 weeks. The registry record does not report the observed count, the interval limits, or a detailed analysis method. The concepts below explain how such methods are generally interpreted; they do not establish which unreported procedures were used in this study.

What does a binary response measure?

A binary outcome classifies each participant according to whether a stated event or threshold was met. Here, the event is achieving the specified CA-125 response. The result would ordinarily be presented as the number of participants meeting the criterion, with a denominator for the analysis population. That count is not reported in the registry record. The endpoint definition identifies the eligible baseline measure and the required decrease, which are necessary for consistent classification. It does not give the participant-level measurements or explain how values unavailable at a scheduled assessment were handled.

What does a confidence interval convey?

In general, a confidence interval expresses uncertainty around an estimated quantity under the assumptions of the method used to construct it. For a binary response, an interval can show how imprecisely the response proportion is estimated, given the observed data and analysis method. A narrower interval generally indicates greater precision, while a wider interval indicates more uncertainty. A confidence interval is not a guarantee that the true value lies within its limits, and it does not resolve design limitations such as non-randomized allocation. Although the registry names a 95% confidence interval as the dispersion measure, its endpoints and the corresponding estimate are not reported in the registry record.

Why does the allocation design matter?

Randomization is a design method used to reduce systematic differences between treatment groups. This study is recorded as non-randomized, with no masking. The registry warns that its arms are not a like-for-like control comparison. In general, non-randomized comparisons can be affected by confounding: characteristics associated with treatment selection may also be associated with the outcome. Adjustment methods can sometimes address measured differences, but the record does not report whether any adjustment was planned or performed. It also does not report the allocation procedure or group-specific baseline characteristics. No causal interpretation of an arm contrast can therefore be established from the design description alone.

How should the planning illustrations be read?

The sample-size assumptions describe planning illustrations computed from an observed effect, not the trial's own design. They specify a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. For time-to-event outcomes, the stated method uses a total number of events based on Schoenfeld; other outcomes are expressed as participants per arm. These are planning conventions, not observed trial findings. A planning illustration does not show that the study had a particular probability of detecting an effect, and it is not observed power. The registry does not report that these assumptions formed the original sample-size justification.

What is not available about the analyses?

The registry lists seven outcome measures and records no analysis entries. It does not report the statistical tests, model specifications, covariate adjustments, handling of repeated measurements, or criteria for selecting an analysis population beyond the stated primary population. Detailed methods for the secondary outcomes are also not reported in the registry record. No interim analysis plan, stopping rule or multiplicity procedure is reported. These omissions limit the ability to reproduce an analysis or assess whether the reported endpoint definition was applied consistently. General statistical principles cannot fill in those study-specific details.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Far Only")
n      <- c(21)
events <- c(2)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Far Only  21  2  9.5  1.2  30.4  2.7  28.9  2.9  29.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary CA-125 response outcome and secondary outcomes covering time to serologic response, duration of serologic response, overall response rate, progression-free survival and prolongation of remission. The record does not report how testing across multiple outcomes was handled. It does not state whether a hierarchy of hypotheses was used, whether significance levels were adjusted, or whether secondary outcomes were intended to be descriptive. Without that information, the risk of chance-positive findings across multiple statistical tests cannot be assessed from the registry record.

Missing-data procedures are not reported. The record does not describe how participants without a post-baseline CA-125 assessment were classified, whether incomplete follow-up affected response assessment, or how missing values were treated for the secondary outcomes. In general, missing outcome data can affect estimates when the chance that a value is missing is related to treatment or outcome status. The registry does not provide enough detail to determine whether missingness occurred or how it was addressed.

The stated primary endpoint population is all participants enrolled to initial farletuzumab only. No further analysis-population definitions are reported, such as separate populations for safety or secondary efficacy analyses. The safety record uses a combined group label that includes Far Only, Chemo Plus Far and Maintenance Far Only; it should not be assumed to define the primary efficacy population. The registry also does not report participant flow between treatment groups or explain the relationship between the enrollment figure and the safety population. These details are needed to understand which participants contributed to each analysis.

12. 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: abdominal pain (3.7%), diarrhoea (3.7%), large intestinal obstruction (3.7%), subileus (3.7%), febrile neutropenia (3.7%).

The safety category is labeled “Far Only and Chemo Plus Far and Maintenance Far Only.” For that combined category, the record reports 54 participants at risk for serious adverse events and 20 participants affected. For other adverse events, it reports 54 participants at risk and 54 affected. The record does not separate these figures by treatment group, so they cannot be used to compare the arms.

Six serious adverse event terms are listed with a reported frequency of 3.7% each: Abdominal Pain, Diarrhoea, Large intestinal obstruction, Subileus, Febrile neutropenia and Thrombocytopenia. The record does not provide event counts for these individual terms or clarify whether a participant could contribute to more than one term. These term-level percentages should not be added together to estimate a total; adverse event categories can overlap in general.

The deaths value is not reported in the registry record. The safety figures describe the recorded population and categories, not a randomized comparison or a complete account of each participant's clinical course. The registry does not report further details such as event timing, duration, attribution or treatment-group-specific safety results.

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

The record establishes what the study set out to evaluate: farletuzumab alone or in combination with chemotherapy, with a primary endpoint based on CA-125 response. It also supplies the response threshold, baseline rule and observation timeframe. Those details help define what a response would mean under the study's endpoint criteria. They do not tell readers how many participants responded.

The registry record does not report the primary outcome result, its confidence interval, or numerical results for the listed secondary outcomes. Accordingly, it does not show the size or precision of a response estimate, and it cannot support a conclusion about whether one treatment approach had better outcomes than another. An outcome definition is not an outcome result.

The study's non-randomized design also limits what a comparison between treatment groups could establish. The registry itself cautions that the arms are not a like-for-like control comparison. In general, observed differences in such groups may reflect differences in participant characteristics or treatment selection as well as any treatment effect. The record does not provide enough information to evaluate or adjust for those possibilities.

Safety information is reported for a combined category spanning Far Only, Chemo Plus Far and Maintenance Far Only, rather than separately by treatment group. It therefore describes events in that combined registry category, not comparative safety. The listed serious adverse event terms and their percentages are not a substitute for detailed event-level results, which are not reported.

The record can be read as a description of a completed Phase 2 study and its planned outcome framework. It cannot, on its own, establish the magnitude, precision or cause of any treatment-related outcome. Those limits reflect the results and analysis details not reported in the registry record, not evidence that an outcome did or did not occur.

14. Why This Trial Matters Statistically

This study illustrates why a precise endpoint definition is important in clinical research. A CA-125 response is not simply a general decrease: the registry specifies a threshold, a rule for selecting the baseline value and a minimum baseline level. Those criteria determine how participants are classified and make clear what the primary measure is intended to count. Without the observed count and confidence interval, however, a clearly defined endpoint still cannot answer how often the response occurred.

It also illustrates the distinction between describing treatment groups and making a fair treatment comparison. The study is non-randomized, and the registry explicitly cautions that the arms are not a like-for-like control comparison. In general, treatment comparisons require attention to how participants entered each group, what differences existed at baseline, and how analyses handled those differences. The registry does not report these details.

The record also highlights the importance of keeping analysis populations distinct. The primary endpoint applies to participants enrolled to initial farletuzumab only, while the safety label combines several treatment categories. Treating those populations as interchangeable would obscure what each result represents. The registry does not provide enough information to reconcile their membership.

Finally, the entry shows why outcome listings, safety summaries and planning calculations should be interpreted according to what they actually contain. A listed secondary outcome is not a reported result, and a sample-size planning illustration is not observed power or evidence of an effect. The record is useful for identifying the design and measurement framework, while its missing numerical efficacy results and analysis details sharply limit statistical conclusions.

15. 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 for statistical interpretation is that the registry record does not report the primary response count or its 95% confidence interval. It also does not report numerical results for the listed secondary outcomes. Without those estimates, neither outcome magnitude nor precision can be assessed.

The non-randomized allocation is a design limitation for between-arm comparisons. The registry explicitly says the arms are not a like-for-like control comparison. Group sizes, treatment-selection procedures and baseline characteristics are not reported in the record. It is therefore not possible to assess group comparability or determine whether any adjustment for differences was made.

The registry does not report the protocol rationale for the enrollment target, detailed statistical analysis methods, multiplicity handling, missing-data procedures or interim analyses. It also does not specify how the primary response was analyzed when outcome assessments were incomplete. These gaps prevent a full evaluation of analysis choices and potential bias.

The primary endpoint population is restricted to all participants enrolled to initial farletuzumab only, while the safety information is grouped across Far Only, Chemo Plus Far and Maintenance Far Only. The record does not explain the relationship between these populations or provide treatment-specific safety figures. It also does not report a death count. The listed serious adverse event percentages lack term-specific counts and further event details.

These limitations describe what is unavailable in the registry record. They should not be interpreted as evidence that a particular analysis, event or outcome did not occur; the relevant details are simply not reported there.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effectiveness of MORAb-003 in Women With Ovarian Cancer Who Have Relapsed After Platinum-Based Chemotherapy — NCT00318370.
• Registry record last updated 2015-09-09; status last verified 2015-09.
• Results first posted 2012-02-15.
• 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.

19. Record Summary

NCT00318370 is a completed Phase 2, parallel, non-randomized study sponsored by Morphotek. It enrolled 58 and began in 2006-05, with primary completion in 2010-02. The study evaluated farletuzumab alone and in combination with chemotherapy in the setting of platinum-sensitive epithelial ovarian cancer in first relapse.

The primary endpoint was the number of participants meeting a modified GCIG CA-125 response definition, from baseline to response up to 30 weeks. The primary analysis population is described as all participants enrolled to initial farletuzumab only. The registry record does not report the primary outcome result or its confidence interval.

The record lists secondary efficacy outcomes and provides safety figures for a combined treatment-category label. It cautions that the non-randomized arms are not a like-for-like control comparison. Analysis methods, missing-data procedures and multiplicity handling are not reported in the registry record.