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Glioblastoma Multiforme Phase 2 Registry Results NCT00515086

Study of Everolimus (RAD001) in Patients With Recurrent Glioblastoma Multiforme (GBM): Complete Statistical Analysis

The registry record describes a randomized, unmasked Phase II study of everolimus in recurrent glioblastoma, including groups with and without salvage surgery. The primary assessment concerned S6 kinase levels in the surgery group, but the record reports no primary outcome analysis.

Trial start: 2007-08  ·  Enrollment: 41  ·  Sponsor: Novartis Pharmaceuticals
Scope of this record

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 Study of Everolimus (RAD001) in Patients With Recurrent Glioblastoma Multiforme (GBM) (NCT00515086), a randomized phase 2 study. The primary outcome is Surgery Group: Percentage Change From the Baseline in S6 Kinase Levels.

41
Enrollment
Phase 2
n/a
Arms
In the primary outcome
n/a
Effect
No re-analysis shown
n/a
95% CI
See limitations
FeatureRegistry value
ClinicalTrials.gov identifierNCT00515086
PhasePhase 2
ConditionGlioblastoma Multiforme
AllocationRandomized
Design modelParallel
MaskingNone (open label)
Enrollment41
Arms in the primary outcomen/a
Lead sponsorNovartis Pharmaceuticals
Results postedYes

2. Clinical Question

Population

The study concerned participants with recurrent glioblastoma multiforme. The registry record separates participants scheduled for salvage surgical resection from those not scheduled to undergo that surgery. It does not report further eligibility details in the information recorded for this trial.

Intervention

Everolimus was given orally on a daily schedule. In the surgery group, the preoperative dose differed across the described groups: 10 mg, 5 mg, or no everolimus before surgery. After recovery, those groups received 10 mg daily until disease progression or toxicity. Participants not scheduled for surgery received 10 mg daily until progression or toxicity.

Comparator

The surgery-group regimens permit a comparison of different preoperative everolimus exposure, with the described post-surgery dose held at 10 mg daily. A separate group received 10 mg without surgery. Because surgical scheduling distinguishes that group from the surgery groups, the record does not establish that it is a directly comparable control for the surgery-group regimens.

Primary question

The main biological question was whether everolimus exposure was associated with a change in S6 kinase levels in the surgery group. The registry describes the primary assessment as inhibition of mTOR, defined as ≥75% S6 phosphorylation, measured using immunohistochemical staining of tumor tissue. The record does not report a numerical primary outcome result or an analysis comparing the treatment groups.

3. Trial Design

The registry classifies this as a Phase II, randomized, parallel-group trial with no masking. Enrollment was 41. The recorded start was 2007-08, and primary completion was 2009-08. The study status is terminated; the registry states that termination was due to slow enrollment.

Four treatment groups are described. Participants not scheduled for salvage surgery received everolimus 10 mg daily. Participants scheduled for surgery received 10 mg daily, 5 mg daily, or no everolimus during the 7 days before surgery. After recovery from surgery, each surgery group received 10 mg daily until disease progression or toxicity. Thus, the preoperative exposure differed among the surgery groups, while their described postoperative regimen was the same.

The record labels allocation as randomized but does not report the random-sequence method, allocation concealment, or how randomization related to surgical eligibility and the treatment groups. It describes participants as either scheduled or not scheduled for surgery, but does not explain how that decision was made. These details matter when interpreting comparisons: the no-surgery group is defined by surgical scheduling as well as treatment, and the registry does not establish that its members were exchangeable with the surgery groups.

The primary assessment was tissue-based and scheduled at baseline and Day 7-9 during salvage surgery. Other listed outcomes included progression-free survival in the surgery and no-surgery groups, everolimus levels in blood and brain tissue, PTEN and EGFR biomarkers, and adverse events in the surgery group. The registry lists 7 outcome measures and 0 analyses. It does not report a statistical analysis plan or explain the planned analysis populations.

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: Eligible participants were separated into 2 Groups: Group 1 (Surgery Group) patients were scheduled for salvage surgery and randomly assigned to one of 3 pre-surgery treatment groups: 0, 5 or 10 mg/day Everolimus for 7 days. Group 2 (No Surgery Group) patients were not scheduled for salvage surgery and received 10 mg/day Everolimus.

Overall Study

StageNo Surgery (Everolimus 10 mg)Everolimus 10 mg + SurgeryEverolimus 5 mg + SurgeryEverolimus 0 mg + Surgery
STARTED24656
COMPLETED0000
NOT COMPLETED24656

Reasons for not completing this period:

ReasonNo Surgery (Everolimus 10 mg)Everolimus 10 mg + SurgeryEverolimus 5 mg + SurgeryEverolimus 0 mg + Surgery
Adverse Event1123
Administrative1100
Withdrawal by Subject1001
Unsatisfactory therapeutic effect18332
Lost to Follow-up1000
Study drug no longer required0100
Death2000

Analysis population for the primary outcome, as defined in the registry: Study was terminated due to slow enrollment.

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.

CharacteristicUnitNo Surgery (Everolimus 10 mg)Everolimus 10 mg + SurgeryEverolimus 5 mg + SurgeryEverolimus 0 mg + SurgeryTotal
Participants analysed2465641
Age, Categorical: <=18 yearsParticipants00000
Age, Categorical: Between 18 and 65 yearsParticipants1455529
Age, Categorical: >=65 yearsParticipants1010112
Sex: Female, Male: FemaleParticipants540413
Sex: Female, Male: MaleParticipants1925228

6. Primary Endpoint

The registry lists the primary outcome as Surgery Group: Percentage Change From the Baseline in S6 Kinase Levels, measured over Baseline and Day 7-9 (during salvage surgery).

ElementRegistry entry
Result typeNumber
Measure of spreadnot applicable
UnitPercentage change in S6 kinase
Endpoint classificationnot reduced to a single comparison

The primary outcome is titled as the percentage change from baseline in S6 kinase levels for the surgery group. Its stated timeframe is baseline and Day 7-9, during salvage surgery. The description says the primary efficacy assessment concerned inhibition of mTOR, defined as ≥75% S6 phosphorylation. S6 phosphorylation was assessed by phosphor-S6 immunohistochemical staining, using tumor cells from the initial surgical resection and the salvage resection.

This is a tissue biomarker endpoint: it describes a biological measurement in tumor samples rather than a direct measure of symptoms, function, or time to disease progression. In general, a pharmacodynamic biomarker can be used to assess whether a treatment is associated with a change in a biological pathway. That rationale does not make the biomarker a substitute for a clinical outcome; the two address different questions.

The registry wording links a percentage-change title with a threshold-based description of S6 phosphorylation. It does not report the numerical change, the number of samples meeting the threshold, or an uncertainty estimate. It also does not explain how the threshold and percentage-change measure were combined in the analysis. Therefore, the endpoint definition can be described, but its observed result cannot be interpreted from the registry record.

7. Why No Re-analysis Is Shown

Reported as posted, not recalculated. Primary outcome has several categories or time points; not reduced to one comparison. A result is recalculated only when the posted data support a clean two-arm comparison, so no result is shown beyond what the sponsor posted.

8. Statistical Interpretation

Clinical Biostats interpretation

The registry record documents a study of everolimus in recurrent glioblastoma, with preoperative dosing varied among the surgery groups and a separate group not scheduled for surgery. It also records that the study was terminated due to slow enrollment. These design and conduct details set the context for interpreting the posted information, but they do not answer whether the primary biological endpoint changed.

No numerical result for the primary outcome is reported. The registry gives no treatment-group estimate for percentage change in S6 kinase levels, no count or proportion meeting the stated S6 phosphorylation threshold, and no measure of uncertainty for the primary outcome. It also lists 0 analyses. Consequently, the record does not support an estimate of the size or precision of a primary outcome difference, or a claim about statistical evidence for such a difference.

In general, a confidence interval describes the range of effect values compatible with the data and the statistical method used. It helps distinguish a precisely estimated effect from one that remains uncertain. No confidence interval for the primary outcome is reported in this registry record, so its precision cannot be assessed. A p-value, if reported, would address a different question about compatibility with a specified null hypothesis; the record does not report a primary-outcome p-value or test.

The adverse-event entries give counts of participants affected and counts at risk for each group. Those entries describe recorded safety events, not the primary tumor biomarker result. The listed serious-event terms and their percentages do not establish a treatment effect, and the record does not give the context needed to compare risks reliably across groups. In particular, the group definitions differ by surgery scheduling and preoperative treatment.

Progression-free survival, tissue and blood drug levels, biomarkers, and adverse events appear among the listed outcomes. Numerical results or analyses for these outcomes are not reported in the registry record. The absence of reported analyses should not be mistaken for evidence of no effect; it means that the posted registry information does not permit those effects to be estimated. The record supports a description of the trial design, its endpoint definition, its termination reason, and the posted adverse-event counts, but not a conclusion about efficacy or a comparative treatment effect.

9. Statistical Methods Explained

The registry identifies randomized allocation and a parallel-group design, but gives no details of the allocation procedure. It also states that the study was unmasked. In general, randomization is intended to reduce systematic differences between groups at the point of allocation, while masking can reduce the influence of expectations on care or outcome assessment. These features do not by themselves ensure comparable groups in every respect, and the registry does not describe how randomization was implemented or whether outcome assessors were masked.

What does the tissue endpoint measure?

The primary endpoint concerns a change in S6 kinase levels and is described in terms of mTOR inhibition assessed through S6 phosphorylation. The registry says that phosphor-S6 immunohistochemical staining was used on tumor cells from the initial and salvage resections. In general, a biomarker measurement is an observation of a biological feature. A change in such a measure can be informative about biological activity, but it is not automatically equivalent to a change in a clinical outcome.

The record defines inhibition using a ≥75% S6 phosphorylation threshold, while the endpoint title refers to percentage change from baseline in S6 kinase levels. Those descriptions may refer to related aspects of the assessment, but the registry does not explain their exact analytical relationship. It does not report the observed values, the number of participants with evaluable paired tissue, or how tissue results were summarized. Without those details, the endpoint's operational definition and result cannot be fully reconstructed.

What can a group comparison establish?

In general, a group comparison estimates how outcomes differ between the groups being compared. Its interpretation depends on how participants entered each group, what treatment each group received, when outcomes were measured, and how missing observations were handled. The record describes three preoperative everolimus regimens among participants scheduled for surgery, followed by 10 mg daily after recovery. It also describes a no-surgery group receiving 10 mg daily. Because surgery scheduling distinguishes this group, its comparison with the surgery groups may reflect differences beyond the preoperative dose. The registry does not provide enough detail to assess the allocation process or the comparability of these groups.

The study is labeled randomized, but the record does not state whether the surgery and no-surgery cohorts were randomized together, whether randomization occurred within the surgery group, or how the three preoperative regimens were assigned. Those are important design details, not matters that can be filled in by assumption. The record also does not report adjusted analyses, stratification factors, or the statistical model used for any outcome.

How should uncertainty be assessed?

In general, a point estimate gives a single summary of an observed effect, while an uncertainty interval indicates how much the estimate could vary because of sampling uncertainty under the stated method. A narrow interval generally indicates more precision than a wide interval, though interpretation also depends on the outcome and design. The registry reports no primary-outcome estimate or uncertainty interval, so neither effect magnitude nor precision can be judged. It does not report a hypothesis test for the primary outcome.

The registry's sample-size assumptions describe planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such illustrations are not evidence that the trial was designed with those assumptions, and they are not observed power. The registry does not report the trial's own sample-size justification. More generally, calculations based on an observed effect are sensitive to the estimate used; they should not be treated as a substitute for an analysis of the trial outcome or as a measure of the reliability of an observed finding.

What does the absence of analyses imply?

The record lists 0 analyses. This means that the registry entry does not present an analysis method or a formal inferential result for the listed outcomes. It does not establish that no analyses were ever conducted outside the registry record. The record also does not describe a plan for handling repeated measurements, multiple endpoints, or differences in follow-up. Without those methods, a reader cannot determine whether reported outcome summaries, if available elsewhere, would be adjusted or unadjusted, or how their uncertainty should be interpreted.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 7 outcome measures, including a tissue-based primary assessment, progression-free survival in the surgery and no-surgery groups, drug levels, biomarkers, and adverse events. When a study examines multiple outcomes or time points, the opportunity for chance findings can increase if results are interpreted without regard to multiplicity. In general, multiplicity procedures can control the overall chance of false-positive conclusions or clarify which analyses are confirmatory and which are exploratory.

The registry record does not report a multiplicity adjustment, an ordering or hierarchy of secondary outcomes, or a statistical plan specifying which comparisons were primary. It also does not give analysis results for the listed secondary outcomes. The primary outcome is not reduced to a single comparison in the registry's posted analysis information. There is therefore no basis for determining whether any reported result was adjusted for multiple testing or whether the listed outcomes were intended as confirmatory or exploratory.

Missing-data methods are not reported in the registry record. The entry does not state how unavailable tumor tissue, incomplete follow-up, or missing outcome measurements were handled. It does not report the number of participants contributing data to the primary endpoint or identify an analysis population such as all randomized participants or an evaluable subset. These omissions prevent assessment of whether the analyzed participants differed from those enrolled or whether missing observations could affect interpretation.

General statistical methods cannot resolve these gaps. An analysis population, missing-data strategy, and multiplicity approach need to be specified or reported; none can be inferred from the outcome names or the treatment descriptions alone.

11. Safety Results

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

ArmParticipants with serious adverse eventsParticipants at riskPercentage
Everolimus 10 mg + Surgery1616.7%
Everolimus 5 mg + Surgery1520.0%
Everolimus 0 mg + Surgery2633.3%
No Surgery (Everolimus 10 mg)62425.0%
Participants with at least one serious adverse event
Serious adverse events by armEverolimus 10 mg + Surgery16.7%Everolimus 5 mg + Surgery20.0%Everolimus 0 mg + Surgery33.3%No Surgery (Everolimus 10 mg)25.0%% of participants with at least one serious adverse event

Other (non-serious) adverse events

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

ArmParticipants affected of at risk
Everolimus 10 mg + Surgery6 of 6
Everolimus 5 mg + Surgery5 of 5
Everolimus 0 mg + Surgery6 of 6
No Surgery (Everolimus 10 mg)20 of 24

Most frequent serious adverse event terms

Event termOrgan systemEverolimus 10 mg + SurgeryEverolimus 5 mg + SurgeryEverolimus 0 mg + SurgeryNo Surgery (Everolimus 10 mg)
Gait DisturbanceGeneral disorders0 of 60 of 50 of 62 of 24
Myocardial infarctionCardiac disorders0 of 60 of 50 of 61 of 24
PyrexiaGeneral disorders0 of 60 of 51 of 60 of 24
Bacterial DiarrhoeaInfections and infestations0 of 60 of 50 of 61 of 24
MeningitisInfections and infestations0 of 60 of 51 of 60 of 24
Perirectal AbscessInfections and infestations0 of 60 of 51 of 60 of 24
Pneumocystis Jiroveci PneumoniaInfections and infestations0 of 60 of 50 of 61 of 24
Wound infection StaphylococcalInfections and infestations1 of 60 of 50 of 60 of 24
HypercholesterolaemiaMetabolism and nutrition disorders0 of 60 of 50 of 61 of 24
HypertriglyceridaemiaMetabolism and nutrition disorders0 of 60 of 50 of 61 of 24

Most frequent non-serious adverse event terms

Event termOrgan systemEverolimus 10 mg + SurgeryEverolimus 5 mg + SurgeryEverolimus 0 mg + SurgeryNo Surgery (Everolimus 10 mg)
FatigueGeneral disorders3 of 62 of 52 of 68 of 24
HyperglycaemiaMetabolism and nutrition disorders6 of 62 of 52 of 65 of 24
LeukopeniaBlood and lymphatic system disorders2 of 60 of 53 of 66 of 24
ConstipationGastrointestinal disorders3 of 64 of 51 of 62 of 24
NeutropeniaBlood and lymphatic system disorders2 of 61 of 52 of 64 of 24
ThrombocytopeniaBlood and lymphatic system disorders3 of 61 of 52 of 63 of 24
HeadacheNervous system disorders1 of 62 of 51 of 64 of 24
Mucosal inflammationGeneral disorders2 of 61 of 53 of 61 of 24
HypertriglyceridaemiaMetabolism and nutrition disorders1 of 62 of 51 of 63 of 24
insomniaPsychiatric disorders2 of 61 of 51 of 63 of 24

Serious events with the highest arm-level rate: convulsion (20.0%), pyrexia (16.7%), meningitis (16.7%), perirectal abscess (16.7%), wound infection staphylococcal (16.7%).

Do not overextend the safety comparison. Serious-adverse-event counts are safety observations, not efficacy outcomes, and should not be combined with the primary result into a single benefit-risk number.

The registry reports serious adverse event-affected participants and participants at risk by group. In the Everolimus 10 mg + Surgery group, 1 participant was affected among 6 at risk. In the Everolimus 5 mg + Surgery group, 1 was affected among 5 at risk. In the Everolimus 0 mg + Surgery group, 2 were affected among 6 at risk. In the No Surgery (Everolimus 10 mg) group, 6 were affected among 24 at risk. These are the registry's group-specific counts; they should not be combined into a single total or treated as a causal comparison.

For other adverse events, the record lists 6 affected among 6 at risk in each surgery group, and 20 affected among 24 at risk in the no-surgery group. Serious-event terms listed include Convulsion (20.0%), Pyrexia (16.7%), Meningitis (16.7%), Perirectal Abscess (16.7%), Wound infection Staphylococcal (16.7%), and Lethargy (16.7%). The registry record does not report the denominator or attribution details for those term percentages. A participant may have experienced more than one event, so event terms should not be read as mutually exclusive categories.

Deaths are not reported in the registry record. The counts describe the posted safety entries; they do not by themselves establish that an event was caused by treatment or permit a reliable comparison between groups with different surgery status and preoperative regimens.

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

The registry record establishes that a Phase II randomized, unmasked study was conducted in recurrent glioblastoma and that its primary assessment focused on a tissue biomarker in the surgery group. It also records the intended preoperative dosing regimens, the postoperative everolimus regimen, the study's termination due to slow enrollment, and group-specific adverse-event counts. These registry entries describe the trial and its posted information.

The record does not report the primary endpoint result. It therefore does not show the magnitude or direction of a change in S6 kinase levels, how many participants met the stated S6 phosphorylation threshold, or how precisely any effect was estimated. Without a reported analysis, it cannot establish whether the biomarker differed between treatment groups. The same limitation applies to the listed progression-free survival, drug-level, and other biomarker outcomes, for which numerical results are not reported.

In general, a biological endpoint and a clinical endpoint answer different questions. A tissue measure can reflect a biological response, while progression-free survival concerns time until a clinical event defined by the study. Evidence about one should not be substituted for evidence about the other. The registry does not provide enough outcome data to assess either endpoint's treatment effect.

The reported adverse-event counts are descriptive. They do not establish causation, and differences in counts between groups cannot be interpreted as treatment effects without accounting for group assignment, follow-up, and the reasons participants entered the surgery or no-surgery groups. The registry does not report those analytical details or uncertainty estimates.

Accordingly, the posted record supports an account of the design and selected safety entries, but not a conclusion that everolimus did or did not alter the primary endpoint or clinical outcomes. That limitation reflects what is reported in the registry record, not proof that an effect was absent.

13. Why This Trial Matters Statistically

This trial is statistically notable because it combines a biological endpoint measured in tumor tissue with treatment groups defined by preoperative exposure and surgery scheduling. The endpoint description links a percentage-change title to a threshold for S6 phosphorylation. Clear operational definitions are essential for interpreting a biomarker analysis, particularly when the registry does not provide the numerical measurements or analysis method.

The design also highlights why group definitions matter. The surgery groups differed in preoperative everolimus exposure, while the no-surgery group was defined by not being scheduled for salvage surgery. The registry labels allocation randomized, but does not explain the scope or implementation of randomization. Without that detail, readers should not assume that every contrast isolates only the effect of a preoperative dose.

The record lists 7 outcomes but 0 analyses. This distinction matters: listing an outcome identifies a question of interest, while an analysis provides an estimate and a method for quantifying uncertainty. Without reported estimates, uncertainty intervals, and a stated multiplicity approach, readers cannot judge the strength or precision of evidence across the listed questions.

Finally, the registry states that the trial was terminated because of slow enrollment. That is relevant context for interpreting a record with enrollment of 41 and no posted outcome analyses. It does not, on its own, establish why results are absent or what the findings would have been. The statistical lesson is to distinguish the study's intended questions, its recorded conduct, and the evidence actually reported.

14. Limitations

The main limitation for interpretation is that the registry record contains no numerical primary outcome result and lists 0 analyses. There is no estimate of percentage change in S6 kinase levels, no reported count meeting the S6 phosphorylation threshold, and no uncertainty measure. The registry therefore does not support an assessment of the magnitude, direction, or precision of the primary endpoint.

The endpoint description does not fully clarify how the percentage-change title relates to the stated ≥75% S6 phosphorylation definition. The record identifies the tissue source and staining method, but does not report sample availability, endpoint summaries, or rules for handling non-evaluable tissue. It also does not report analysis populations or missing-data methods.

Although the trial is classified as randomized, the registry does not describe sequence generation, concealment, or how randomization related to surgical eligibility and the three surgery-group regimens. The no-surgery group differs by surgical scheduling, and the record does not explain how that scheduling decision was made. The extent to which comparisons isolate the preoperative dose is consequently unclear.

The registry does not report a statistical analysis plan, model, adjustment strategy, multiplicity procedure, or outcome-specific uncertainty. It lists several secondary outcomes but no numerical results for them. The safety entries are descriptive; term-level denominators and event attribution details are not reported, and deaths are not reported in the registry record.

Finally, the study was terminated due to slow enrollment. The record does not report a sample-size justification or explain the implications of termination for the planned analyses. These limitations are specific to the information recorded for this trial and prevent reconstruction of its inferential results.

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18. Record Summary

The registry record describes NCT00515086, a Phase II randomized, parallel-group, unmasked study of everolimus in recurrent glioblastoma multiforme. Enrollment was 41. The recorded start was 2007-08, primary completion was 2009-08, and the study status is terminated due to slow enrollment.

The primary assessment concerned percentage change from baseline in S6 kinase levels in the surgery group, with tissue assessed at baseline and Day 7-9 during salvage surgery. The description defines mTOR inhibition using a ≥75% S6 phosphorylation threshold. Everolimus dosing varied before surgery across the surgery groups; after recovery, those groups received 10 mg daily. Participants not scheduled for surgery received 10 mg daily.

The registry lists 7 outcome measures and 0 analyses. It reports group-specific adverse-event counts but no numerical primary outcome result or analysis. The record does not report the statistical plan, analysis populations, missing-data methods, or multiplicity procedures.

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