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 SPIRITT - Second-Line Panitumumab Irinotecan Treatment Trial (NCT00418938), a randomized phase 2 study. The primary outcome is Progression-free Survival (PFS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00418938 |
| Phase | Phase 2 |
| Condition | Cancer, Colon Cancer, Colorectal Cancer |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 266 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Amgen |
| Results posted | Yes |
2. Clinical Question
Population
People with metastatic colorectal cancer and wild-type KRAS tumors who had failed first-line oxaliplatin-based chemotherapy, including at least 4 doses of that chemotherapy and at least 4 doses of bevacizumab. Failure was defined as toxicity due to oxaliplatin-based chemotherapy or progression on first-line treatment. The primary analysis population included enrolled subjects who received at least one dose of study therapy and excluded subjects with unevaluable KRAS status.
Intervention
FOLFIRI with panitumumab, given as a once-every-two-weeks regimen. The brief summary specifies panitumumab at 6 mg/kg.
Comparator
FOLFIRI with bevacizumab, also given once every two weeks. The brief summary specifies bevacizumab at either 5 mg/kg or 10 mg/kg, depending on physician choice and institutional standard of care.
Primary question
How did progression-free survival compare between the randomized treatment groups, using progression assessed by central review or qualifying death as the endpoint event? The registry record does not report the comparative PFS result.
The trial addressed a second-line treatment question in a defined group of people with metastatic colorectal cancer. Participants were assigned to one of two FOLFIRI combinations: panitumumab or bevacizumab. Because both groups received FOLFIRI, the randomized comparison concerns the combination strategy rather than a comparison of FOLFIRI against no FOLFIRI. The bevacizumab dose could be selected from the stated options according to physician choice and institutional standard of care, so the comparator was not described as a single fixed dose.
The registry identifies the study as multicenter, open-label, randomized, and phase 2. It describes a planned 1:1 allocation and approximately 210 eligible subjects in the brief summary; registered enrollment was 266. The primary endpoint was progression-free survival from randomization, with progression determined by central review of radiographic scans under modified RECIST version 1.0, or death under the specified timing rule. Although the record identifies this endpoint and its analysis population, the comparative estimate, uncertainty interval, and hazard ratio are not reported in the registry record.
3. Trial Design
This was a randomized, open-label, parallel-group phase 2 trial. Participants were assigned to FOLFIRI with panitumumab or FOLFIRI with bevacizumab. The record describes the study as multicenter and states that it was to be conducted in the United States. The brief summary describes a planned 1:1 allocation. Registered enrollment was 266, while the summary describes approximately 210 eligible subjects as the intended study population.
The treatments shared the FOLFIRI regimen and differed in the added biologic agent. The panitumumab regimen was described as 6 mg/kg once every two weeks. The bevacizumab regimen was described as either 5 mg/kg or 10 mg/kg once every two weeks, depending on physician choice and institutional standard of care. The listed interventions also include leucovorin, irinotecan, and 5-fluorouracil, which are components of the named FOLFIRI regimen.
Open-label means that treatment assignment was not masked. The registry does not report masking, consistent with the stated absence of masking. Knowledge of assignment may matter particularly for outcomes that depend on clinical decisions or subjective assessment. The primary progression assessment, however, is described as based on central review of radiographic scans. The record does not specify additional procedures used to maintain consistency in imaging assessment or adjudication.
The primary endpoint was PFS, measured from randomization until first progression per modified RECIST version 1.0 based on central review, or death within 60 days after the last evaluable tumor assessment or randomization date, whichever was later. The stated timeframe was from randomization up to 65 months. Secondary outcomes listed in the registry include overall survival, objective response rate, time to response, time to progression, disease control, and duration of response.
The record marks the study completed and gives the primary completion date as 2012-05-10. It does not report the randomization sequence method, allocation concealment procedure, site count, or further details of the treatment and follow-up schedules. Those design details 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.
Before assignment: We enrolled 266 subjects, but we only perform analyses on the Full Analysis Set, defined as all randomized subjects who provide informed consent before the initiation of any study specific procedures and who receive at least one dose of panitumumab or bevacizumab. There are 264 patients in this Full Analysis Set.
Overall Study
| Stage | Panitumumab Plus FOLFIRI | Bevacizumab Plus FOLFIRI |
|---|---|---|
| STARTED | 133 | 131 |
| COMPLETED | 109 | 108 |
| NOT COMPLETED | 24 | 23 |
Reasons for not completing this period:
| Reason | Panitumumab Plus FOLFIRI | Bevacizumab Plus FOLFIRI |
|---|---|---|
| Reimbursement | 1 | 0 |
| Administrative decision | 3 | 3 |
| Withdrawal by Subject | 16 | 15 |
| Lost to Follow-up | 1 | 3 |
| Adverse Event | 1 | 1 |
| On-going | 1 | 1 |
| Ineligibility Determined | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Analysis population include all enrolled subjects who received at least one dose of study therapy and do not include subjects with unevaluable KRAS status.
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 | Panitumumab Plus FOLFIRI | Bevacizumab Plus FOLFIRI | Total |
|---|---|---|---|---|
| Participants analysed | 133 | 131 | 264 | |
| Age, Continuous | years | 59.9 (SD 11.6) | 59.1 (SD 9.9) | 59.5 (SD 10.8) |
| Sex: Female, Male: Female | Participants | 46 | 46 | 92 |
| Sex: Female, Male: Male | Participants | 87 | 85 | 172 |
| Race/Ethnicity, Customized: White or Caucasian | Participants | 102 | 95 | 197 |
| Race/Ethnicity, Customized: Black or African American | Participants | 21 | 18 | 39 |
| Race/Ethnicity, Customized: Hispanic or Latino | Participants | 5 | 9 | 14 |
| Race/Ethnicity, Customized: Asian | Participants | 4 | 8 | 12 |
| Race/Ethnicity, Customized: American Indian or Alaska Native | Participants | 1 | 0 | 1 |
| Race/Ethnicity, Customized: Other | Participants | 0 | 1 | 1 |
| Eastern Cooperative Oncology Group (ECOG) Performance Status: 0 (Fully active) | Participants | 74 | 70 | 144 |
| Eastern Cooperative Oncology Group (ECOG) Performance Status: 1 (Restricted in physically strenuous activity) | Participants | 58 | 61 | 119 |
| Eastern Cooperative Oncology Group (ECOG) Performance Status: Missing | Participants | 1 | 0 | 1 |
| Primary tumor diagnosis: Colon | Participants | 102 | 91 | 193 |
| Primary tumor diagnosis: Rectum | Participants | 31 | 40 | 71 |
| Number of metastatic organs: 1 | Participants | 49 | 61 | 110 |
| Number of metastatic organs: 2 | Participants | 39 | 42 | 81 |
| Number of metastatic organs: >=3 | Participants | 44 | 28 | 72 |
| Number of metastatic organs: Missing | Participants | 1 | 0 | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Progression-free Survival (PFS), measured over From randomization up to 65 months..
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | months |
| Endpoint classification | Time-to-Event Analysis |
Progression-free survival measures the time from randomization until a defined progression event or qualifying death. In this trial, progression was defined as the first progression identified under modified RECIST version 1.0 from radiographic scans reviewed centrally. The death component counted death within 60 days after the last evaluable tumor assessment or randomization date, whichever was later. The stated observation timeframe extended from randomization up to 65 months.
Time-to-event endpoints are useful when the timing of an event matters and participants may have different lengths of follow-up. Rather than reducing follow-up to whether an event occurred by a single fixed assessment, an analysis can use the observed event times and account for participants whose event has not been observed by the end of their available follow-up. That distinction is important because participants who have not had a documented event may still experience one later.
PFS is used in oncology trials as an outcome describing time without documented progression or the specified death event. Its interpretation depends on how progression is defined, how scans are assessed, how deaths are handled, and how censoring and follow-up are analyzed. Central review of scans is specified in this record, but the registry does not report the detailed analysis rules for censoring, missing assessments, or handling of other clinical circumstances.
The registry names PFS as the primary outcome and describes its definition, but does not report the group-specific medians, confidence intervals, or comparative hazard ratio. Therefore, the endpoint definition can be explained, but the magnitude and precision of the treatment-group comparison cannot be characterized from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies progression-free survival as the primary endpoint and provides a definition based on centrally reviewed radiographic progression or qualifying death. It does not report the comparative PFS result. In particular, the registry record does not report group-specific median PFS values, confidence intervals, a hazard ratio, or a statistical test for the comparison. Without those results, the direction, magnitude, and statistical precision of the primary comparison cannot be described from this record.
This is not the same as finding that the groups had identical outcomes, nor does the absence of a reported estimate establish that a difference was absent. It means that the result needed to assess the comparison is not reported in the registry record. A trial design and a defined endpoint alone cannot indicate what was observed. The enrolled population, allocation, interventions, and endpoint definition describe the study question and its structure, not its treatment effect.
The record describes 266 enrolled participants and a brief-summary plan for approximately 210 eligible subjects. These figures refer to different record elements: one is registered enrollment and the other is the approximate eligible population described in the summary. The primary analysis population was narrower in its stated eligibility for analysis: enrolled subjects who received at least one dose of study therapy, excluding subjects with unevaluable KRAS status. The number included in that analysis is not reported in the registry record.
The primary endpoint is time-to-event, so a median alone would not necessarily convey the full pattern of follow-up or event timing. A hazard ratio, if reported with its confidence interval and analysis details, would describe a relative comparison over follow-up under the assumptions of the model used. Neither a hazard ratio nor its uncertainty is reported, and no such value should be inferred from enrollment or from adverse-event figures.
The registry lists secondary outcomes, including overall survival and response-related measures, but does not provide their results in the record described. It also lists safety counts and selected serious adverse event terms. Those safety summaries are not substitutes for the primary efficacy comparison: they concern different outcomes and do not establish the PFS effect.
Accordingly, the statistical interpretation is limited to the design and endpoint specification, together with the posted safety counts. The principal comparative efficacy finding, its uncertainty, and the analysis supporting it are not reported in the registry record. Any conclusion about how the randomized groups differed on PFS would require results that are absent from this record.
9. Statistical Methods Explained
The trial is described as randomized, open-label, and parallel-group. Random assignment is intended to create groups that are comparable, on average, with respect to factors known and unknown at baseline. The value of randomization depends on the actual assignment process, adherence to the assigned strategy, completeness of outcome ascertainment, and the analysis approach. The registry states that allocation was randomized and planned in a 1:1 ratio, but the sequence-generation and allocation-concealment procedures are not reported in the registry record.
What does a time-to-event endpoint represent?
Progression-free survival records elapsed time from randomization until the event specified by the protocol definition. Here, the event was first progression per modified RECIST version 1.0 based on central review of radiographic scans, or death within the stated timing window. A time-to-event analysis can use information from participants with different follow-up durations. Participants without a recorded event at their last known assessment may contribute follow-up up to that point, subject to the analysis rules for censoring.
Censoring is a general statistical feature of time-to-event data: it marks that the event time is not observed during a participant's available follow-up. It does not mean the participant is known never to experience the event. Valid interpretation depends on how censoring is defined and on assumptions about why follow-up ends. The registry does not report the censoring rules or diagnostic checks for those assumptions.
What does a median and confidence interval mean?
A median time-to-event estimate describes the time by which the estimated event experience reaches the median point under the analysis method. A confidence interval expresses uncertainty around an estimated quantity: it gives a range of values compatible with the data and statistical procedure at the stated confidence level. It is not a guarantee that the true value lies in that particular interval, and its width reflects precision. The endpoint description names median and 95% confidence interval as the intended presentation, but the actual PFS medians and intervals are not reported in the registry record.
How should a hazard ratio be understood?
A hazard ratio compares event rates over time between groups under a time-to-event model. It is a relative measure, not a difference in median survival time, and it should be interpreted alongside its confidence interval and the analysis assumptions. A single hazard ratio can be less informative if the relative event rates change over follow-up. The registry record does not report a PFS hazard ratio, confidence interval, or model details. No comparative effect estimate can therefore be characterized from the posted record.
Why can open-label conduct matter?
In an open-label study, participants and treating clinicians know the assigned treatment. This can affect treatment decisions, reporting, or assessments that involve judgment. Radiographic progression in this trial was specified as based on central review, which is a defined assessment feature, but the registry does not describe the reviewer masking status or the detailed review process. Central review does not by itself resolve every possible source of bias, including differences in follow-up or missing assessments.
What does the analysis population statement imply?
The stated primary analysis population included enrolled subjects who received at least one dose of study therapy and excluded subjects with unevaluable KRAS status. This is not described as all randomized participants regardless of treatment received. The actual number analyzed, exclusions by group, and reasons for missing or unevaluable status are not reported in the registry record. Those details matter because excluding participants after randomization can affect comparability if exclusions are related to treatment assignment or prognosis.
General statistical practice distinguishes an intention-to-treat analysis, which usually retains participants according to randomized assignment, from analyses that select participants based on treatment received or evaluability. The registry's wording alone does not establish which formal analysis set was used beyond the population description it gives. The analysis plan and handling of deviations are not reported in the registry record.
What can the safety counts tell readers?
The safety data give numbers at risk and numbers affected for serious adverse events in each named group. These are descriptive counts. They do not show how events were defined, how long participants were observed for safety, whether individuals could experience multiple events, or how missing safety information was handled. The registry also lists selected serious event terms with percentages, but does not attach those terms to a treatment group in the listed data. No inferential comparison or adjustment method is reported.
General statistical interpretation requires separating estimates from uncertainty and separating different outcome types. Randomization describes how treatment assignment was intended; it does not supply an outcome result. A defined endpoint describes what was to be measured; it does not establish what occurred. In this record, the absence of reported primary comparative estimates prevents assessment of effect size and precision. Details such as the statistical model, proportional-hazards assessment, censoring rules, covariate adjustment, and missing-data procedures are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists several secondary outcomes in addition to progression-free survival: overall survival, objective response rate, time to response, time to progression, disease control, and duration of response. Testing or estimating multiple outcomes can raise multiplicity concerns. In general, multiplicity refers to the increased chance of finding an apparently notable result when many hypotheses or endpoints are examined. Trial plans may address this through a prespecified hierarchy, adjusted significance thresholds, or by treating secondary analyses as exploratory. The registry record does not report a multiplicity strategy or a hierarchy among outcomes.
The registry record does not report the number of outcome analyses, a statistical analysis plan, or inferential results for the listed secondary outcomes. It does not describe interim analyses, stopping rules, or whether any analyses were adjusted for repeated testing. These details are not reported in the registry record, so no claim can be made about how multiplicity was handled.
For missing data, the primary endpoint definition refers to evaluable tumor assessments and specifies a rule for qualifying deaths. However, the record does not explain how missed assessments, withdrawal, loss to follow-up, or other incomplete follow-up were handled in the analysis. It also does not report the amount or pattern of missing outcome data. General statistical methods for missing data rely on assumptions, and those assumptions cannot be evaluated without information about the missingness and the analysis procedures.
The primary analysis population was described as enrolled subjects who received at least one dose of study therapy, excluding subjects with unevaluable KRAS status. The number analyzed and the reasons for exclusion are not reported in the registry record. The record therefore does not establish whether the primary analysis retained every randomized participant or how deviations from the assigned treatment were treated. The distinction matters because post-randomization exclusions can affect the balance created by random assignment.
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 |
|---|---|---|---|
| Panitumumab Plus FOLFIRI | 61 | 133 | 45.9% |
| Bevacizumab Plus FOLFIRI | 39 | 131 | 29.8% |
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 |
|---|---|
| Panitumumab Plus FOLFIRI | 133 of 133 |
| Bevacizumab Plus FOLFIRI | 129 of 131 |
Most frequent serious adverse event terms
| Event term | Organ system | Panitumumab Plus FOLFIRI | Bevacizumab Plus FOLFIRI |
|---|---|---|---|
| Diarrhoea | Gastrointestinal disorders | 9 of 133 | 4 of 131 |
| Dehydration | Metabolism and nutrition disorders | 7 of 133 | 6 of 131 |
| Pulmonary embolism | Respiratory, thoracic and mediastinal disorders | 8 of 133 | 1 of 131 |
| Abdominal pain | Gastrointestinal disorders | 4 of 133 | 4 of 131 |
| Vomiting | Gastrointestinal disorders | 5 of 133 | 3 of 131 |
| Small intestinal obstruction | Gastrointestinal disorders | 4 of 133 | 3 of 131 |
| Urinary tract infection | Infections and infestations | 3 of 133 | 3 of 131 |
| Neutropenia | Blood and lymphatic system disorders | 2 of 133 | 3 of 131 |
| Nausea | Gastrointestinal disorders | 2 of 133 | 3 of 131 |
| Sepsis | Infections and infestations | 3 of 133 | 2 of 131 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Panitumumab Plus FOLFIRI | Bevacizumab Plus FOLFIRI |
|---|---|---|---|
| Diarrhoea | Gastrointestinal disorders | 93 of 133 | 87 of 131 |
| Nausea | Gastrointestinal disorders | 69 of 133 | 88 of 131 |
| Fatigue | General disorders | 76 of 133 | 80 of 131 |
| Neutropenia | Blood and lymphatic system disorders | 44 of 133 | 53 of 131 |
| Vomiting | Gastrointestinal disorders | 47 of 133 | 47 of 131 |
| Rash | Skin and subcutaneous tissue disorders | 80 of 133 | 9 of 131 |
| Decreased appetite | Metabolism and nutrition disorders | 38 of 133 | 41 of 131 |
| Constipation | Gastrointestinal disorders | 43 of 133 | 34 of 131 |
| Stomatitis | Gastrointestinal disorders | 41 of 133 | 33 of 131 |
| Mucosal inflammation | General disorders | 35 of 133 | 30 of 131 |
Serious events with the highest arm-level rate: diarrhoea (6.8%), pulmonary embolism (6.0%), dehydration (5.3%), vomiting (3.8%), abdominal pain (3.1%).
The registry reports serious adverse event counts for the named treatment groups. For Panitumumab Plus FOLFIRI, 133 participants were at risk and 61 were affected. For Bevacizumab Plus FOLFIRI, 131 participants were at risk and 39 were affected. These are counts, not a reported adjusted comparison. The registry does not provide a confidence interval or statistical test for the difference between the groups, and no comparative safety conclusion follows from the counts alone.
The record also lists selected serious adverse event terms with percentages: Diarrhoea, 6.8%; Pulmonary embolism, 6.0%; Dehydration, 5.3%; Vomiting, 3.8%; Abdominal pain, 3.1%; and Small intestinal obstruction, 3.0%. The listed terms are not linked to a specific arm in the record. They should therefore be read as the serious-event terms and percentages reported, not as arm-specific rates or a ranking of comparative risk.
The number of participants affected is not necessarily the same as the number of events, because one participant may experience more than one event. The registry does not describe event definitions, follow-up duration for safety, event severity beyond the serious-event designation, or the handling of missing safety information. Death counts are not reported in the registry record. These omissions limit what can be inferred from the safety summary.
12. What the Result Does, and Does Not, Mean
The trial record establishes a randomized comparison of FOLFIRI with panitumumab against FOLFIRI with bevacizumab in a second-line setting for metastatic colorectal cancer with wild-type KRAS tumors. It identifies progression-free survival as the primary endpoint and specifies how progression and qualifying death were to be counted. It also identifies the analysis population and lists additional outcomes and serious adverse event summaries.
Those details define the question and give context for interpreting any results. They do not, by themselves, answer whether the groups differed in PFS. The registry record does not report group-specific PFS estimates, a hazard ratio, confidence intervals, or a statistical test. As a result, neither the direction nor size nor precision of the primary comparison can be established from this record. Missing results should not be interpreted as evidence of no difference.
The study's randomized design supports a comparative interpretation when assignment, follow-up, and analysis are appropriately carried out. The registry record does not report enough information to evaluate all those aspects. In particular, it does not give the allocation procedure, complete analysis details, censoring rules, or participant flow through the primary analysis. These are not grounds for assuming a problem occurred; they are limits on what the registry entry can establish.
The safety figures are also descriptive. Counts of affected participants and a list of serious event terms can identify what was recorded, but the record does not provide an adjusted safety comparison or make the listed terms arm-specific. They cannot be used to infer the primary efficacy result.
More broadly, a phase 2 randomized trial record is one part of the evidence about a treatment comparison. The result and its uncertainty, analysis methods, and completeness of outcome follow-up are needed to understand the statistical evidence. Here, the registry supports a description of the study question and design, but not a conclusion about the comparative PFS outcome or the full balance of benefits and harms. No treatment recommendation follows from the information reported in this registry record.
13. Why This Trial Matters Statistically
This trial is statistically notable as a randomized active-comparator study: both groups received FOLFIRI, while the added agent differed. That design focuses the comparison on two combination strategies in the stated second-line population. The randomized allocation is important because it is intended to reduce systematic baseline differences between groups, allowing observed outcome differences to be interpreted comparatively when the study is analyzed as planned.
The primary endpoint is a time-to-event outcome rather than a simple status at one assessment. Its definition combines radiographic progression assessed by central review with a specified death rule. Such a definition makes the event criterion explicit, while also making the analysis dependent on scan timing, follow-up, censoring, and how incomplete assessments are handled. The registry specifies some of these elements but does not report the complete analysis procedures.
The open-label design is relevant to statistical interpretation because knowledge of assignment can affect care and assessment. The use of central review for radiographic scans is a stated safeguard for the progression assessment, though the details of that review are not reported. The record therefore illustrates why design features should be considered together rather than treating randomization as a guarantee that every potential bias has been removed.
The entry also illustrates the difference between a study question and a study result. It records a primary endpoint, timeframe, and analysis population, but does not report the comparative PFS estimate or its uncertainty. Without those results, the central statistical question remains unanswered in this record. The adverse-event counts add descriptive safety information but cannot fill that gap.
For biostatistical interpretation, the record highlights the need for alignment among the estimand, endpoint definition, analysis population, handling of missing follow-up, and reported uncertainty. Several of these details are not reported in the registry record. This limits reproducibility and the ability to judge how the planned comparison was translated into an estimate.
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 of the registry entry is that it does not report the primary PFS comparison. Group-specific medians, confidence intervals, hazard ratio, and statistical test are not reported in the registry record. The endpoint is defined, but the result and its precision cannot be assessed.
The primary analysis population is described as enrolled participants who received at least one dose of study therapy, excluding those with unevaluable KRAS status. The number analyzed, participant flow by randomized group, and reasons for exclusions are not reported. The relationship between the stated analysis population and all randomized participants is therefore not fully described in the record.
The record does not report the statistical model, censoring rules, assessment of model assumptions, covariate adjustment, or handling of missing assessments and other incomplete follow-up. These omissions matter for a time-to-event endpoint, where follow-up duration and the treatment of participants without a recorded event contribute to the analysis. The detailed randomization and allocation-concealment procedures are also not reported.
Although the record lists secondary outcomes, it does not report their results or a multiplicity plan. It does not report interim analyses or stopping rules. The safety data are limited to counts at risk and affected, plus selected serious adverse event terms and percentages; the listed terms are not assigned to a treatment group. Serious-event definitions, safety follow-up details, and deaths are not reported.
The study is described as open-label and multicenter, but the number of sites and further details about central review are not reported. The brief summary specifies an approximate eligible enrollment, while registered enrollment is separately recorded; the registry does not explain this difference. These limitations reflect what is absent from the record, not proof that a particular method was or was not used.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: SPIRITT - Second-Line Panitumumab Irinotecan Treatment Trial — NCT00418938.
- Registry record last updated 2018-10-17; status last verified 2018-09.
- Results first posted 2014-03-28.
- 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
NCT00418938 is a completed, randomized, open-label, parallel-group phase 2 trial titled SPIRITT - Second-Line Panitumumab Irinotecan Treatment Trial. It compared FOLFIRI plus panitumumab with FOLFIRI plus bevacizumab for second-line treatment in subjects with metastatic colorectal cancer and wild-type KRAS tumors. Registered enrollment was 266. The study is described as multicenter and was to be conducted in the United States.
The primary outcome was progression-free survival, measured from randomization to centrally reviewed progression under modified RECIST version 1.0 or qualifying death. The stated timeframe was from randomization up to 65 months. The primary analysis population included enrolled subjects who received at least one dose of study therapy and excluded subjects with unevaluable KRAS status.
The registry lists overall survival and response-related outcomes as secondary measures, along with serious adverse event counts and selected event terms. The comparative PFS result, statistical analysis details, and secondary outcome results are not reported in the registry record.