Radiation Therapy (RT) and Temozolomide (TMZ) in Treating Patients With Newly Diagnosed Glioblastoma or Gliosarcoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Radiation Therapy (RT) and Temozolomide (TMZ) in Treating Patients With Newly Diagnosed Glioblastoma or Gliosarcoma (NCT00304031), a randomized phase 3 study. The primary outcome is Median Overall Survival Time.

2. Clinical Question

3. Trial Design

This was a phase III, randomized, parallel-group trial with no masking. It studied patients with newly diagnosed glioblastoma or gliosarcoma and compared two schedules of adjuvant temozolomide after concurrent radiation therapy and temozolomide. The registry record lists enrollment of 1173 and a completed trial status.

The randomized comparison was between conventional adjuvant temozolomide and dose-dense adjuvant temozolomide. Both groups received concurrent radiation therapy with concurrent temozolomide, described as 75 mg/m2 for up to 49 doses. The conventional schedule was 100mg/m2 on days 1 to 5 of a 28 day cycle. The dose-dense schedule was 75mg/m2 on days 1-21 of a 28 day cycle. Both adjuvant schedules began four weeks after completion of radiation therapy.

The record also describes a group receiving concurrent treatment without randomization to either adjuvant temozolomide arm. This group is not part of the posted primary comparison between the randomized schedules. In the overall-survival results, the conventional group included 411 participants and the dose-dense group included 420 participants.

The primary outcome was median overall survival, analyzed from randomization to last follow-up. The registry describes Kaplan-Meier estimation and censoring at last contact for participants last known to be alive. Maximum follow-up at the time of analysis was 4.4 years, and the analysis took place after 647 deaths were reported. The registry record does not report the trial’s original sample-size justification or the full original statistical plan.

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: Sites were required to submit participant tumor tissue for central histologic review and MGMT (O-6-methylguanine-DNA methyltransferase) status determination in order for registered participants to continue on the study. Of 1173 participants initially registered, 1125 participants met these requirements and started protocol treatment.

Concomitant RT+TMZ (Pre-randomization)

Reasons for not completing this period:

Randomization to Adjuvant TMZ Arm

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Randomized eligible patients.

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.

Population: Eligible patients who were randomized.

6. Primary Endpoint

The registry lists the primary outcome as Median Overall Survival Time, measured over From randomization to last follow-up. Maximum follow-up at time of analysis was 4.4 years..

Overall survival measures the time from registration/randomization to death from any cause. The registry identifies this as the primary endpoint and reports median overall survival with 95% confidence intervals. Participants last known to be alive are censored at the date of their last contact, so their observed follow-up contributes information up to that point without treating them as having died.

Time-to-event outcomes are useful when the timing of an event matters and participants may have different lengths of observed follow-up. A median summarizes the time by which half of the estimated population has experienced the event, based on the survival analysis. It is not an average survival time, and it does not describe every participant’s experience.

The record states that overall survival rates were estimated with the Kaplan-Meier method. This approach uses the observed event times and accounts for censoring under its assumptions. The posted analysis reports median survival for each randomized group and a hazard ratio from a log-rank analysis. Those measures answer related but distinct questions: the medians describe each group’s estimated event-time distribution at its midpoint, while the hazard ratio summarizes the relative event rate over follow-up under the analysis framework.

7. Results Posted in the Registry

• Conventional Adjuvant TMZ vs Dose-dense Adjuvant TMZ: hazard ratio 1.03 (95% CI 0.88–1.20), reported p = 0.630 (as reported in the registry).

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Median Progression-free Survival (PFS) Time

• Endpoint type: Time to event: compared as a hazard ratio.
• Test: Hazard ratio as reported by the sponsor (Log Rank); it was not recalculated.
• Result:
  • Conventional Adjuvant TMZ vs Dose-dense Adjuvant TMZ: hazard ratio 0.87 (95% CI 0.75–1.00), reported p = 0.060 (as reported in the registry).
• Interpretation:
  • The 95% confidence interval includes no difference (a ratio of 1), so these data do not show a statistically significant difference between Conventional Adjuvant TMZ vs Dose-dense Adjuvant TMZ and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Deterioration From Baseline in MD Anderson Symptom Inventory Brain Tumor (MDASI-BT) Symptom Severity Score at Cycle 4

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Dose-dense Adjuvant TMZ: 27.5% (11/40) versus 9.8% (5/51) on control; risk difference 17.7 percentage points (95% CI 1.6 to 33.8), risk ratio 2.81 (1.06–7.42); unadjusted two-proportion z-test p = 0.028.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Dose-dense Adjuvant TMZ than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Number of Participants With Deterioration From Baseline in MD Anderson Symptom Inventory Brain Tumor (MDASI-BT) Interference Score at Cycle 4

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Dose-dense Adjuvant TMZ: 32.5% (13/40) versus 13.7% (7/51) on control; risk difference 18.8 percentage points (95% CI 1.5 to 36.1), risk ratio 2.37 (1.04–5.38); unadjusted two-proportion z-test p = 0.032.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Dose-dense Adjuvant TMZ than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes extend beyond overall survival. The record lists progression-free survival, analyses by MGMT status, treatment response by MGMT status, adverse-event summaries, survival status by progression status at 6 months, and symptom and neurocognitive measures at cycle 10 for participants meeting the stated progression criteria. The posted results include progression-free survival and two symptom deterioration comparisons at cycle 4.

These outcomes provide additional views of the trial, but they do not have the same status as the primary endpoint. Progression-free survival is another time-to-event outcome, while cycle 4 symptom deterioration is a participant-count outcome based on scores. Their measures, follow-up, and contributing participant groups differ. As a result, each secondary finding addresses a distinct question and should not be treated as a direct confirmation or contradiction of the overall-survival analysis.

The registry record lists 25 secondary outcomes. When many outcomes are examined, some may show apparently notable results by chance alone, even if there is no underlying difference for those outcomes. This is why unadjusted secondary p-values carry less weight than a prespecified primary analysis: the chance of at least one apparently unusual result increases when many comparisons are considered, unless the analysis accounts for that multiplicity.

The posted cycle 4 analyses also involve outcome-specific numbers of participants. Those results cannot automatically be generalized to everyone randomized, because the record does not establish that all randomized participants contributed a score at that assessment. The secondary results are therefore best read as supporting context, with attention to their endpoint-specific populations, uncertainty, and multiplicity, rather than as a new primary conclusion.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Median Progression-free Survival (PFS) Time
• Median Overall Survival Time by MGMT Status
• Median Progression-free Survival Time by MGMT Status
• Best Treatment Response by MGMT Status
• Distribution of Highest Grade AE Reported as Possibly/Probably/Definitely Related to Protocol Treatment
• Overall Survival Status by Progression Status at 6 Months
• Mean MD Anderson Symptom Inventory Brain Tumor (MDASI-BT) Symptom Severity Score at Cycle 10 for Participants Without Progression After 6 Months of Adjuvant Therapy
• Mean Neurocognitive Function (NCF) Composite Score at Cycle 10 for Participants Without Progression After 6 Months of Adjuvant Therapy

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is a time-to-event measure. Each participant contributes follow-up time from registration/randomization until death or, if last known to be alive, the date of last contact. That latter observation is censored: the analysis knows the participant remained alive through that contact, but does not know the subsequent event time from the posted record.

What does Kaplan-Meier estimation contribute?

Kaplan-Meier estimation describes the probability of remaining free of the event over time while accounting for participants whose follow-up ends before the event is observed. It updates the estimate at observed event times. The median is identified from this estimated survival curve as the time at which the curve reaches its midpoint. The registry reports this method for overall survival, but the record does not give further details about diagnostics or additional modeling assumptions.

What does a hazard ratio summarize?

A hazard is the event rate at a particular point in follow-up among participants still at risk. A hazard ratio compares the hazards for two groups under the analysis definition. A value near the no-difference reference indicates that the estimated relative hazards are close to one another, while values on either side indicate different directions of relative hazard. The hazard ratio is not a ratio of the two reported medians and should not be interpreted as a direct comparison of individual survival times.

The registry reports a hazard ratio for the conventional versus dose-dense comparison and identifies the log-rank method. It does not provide enough information to reconstruct the full model specification or assess all assumptions behind the estimate. In particular, the record does not report a detailed assessment of whether the relative hazard was constant over time. The posted hazard ratio should therefore be read as the sponsor-reported summary, not as a complete description of how group outcomes may have differed at every point in follow-up.

What does the log-rank test assess?

The log-rank test compares event-time experience between groups over follow-up, taking account of the numbers at risk and the events observed at different times. The registry reports p = 0.63 for the primary comparison. A p-value summarizes the compatibility of the data with a specified null hypothesis under the test’s assumptions. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of a difference.

The reported confidence interval communicates uncertainty around the hazard-ratio estimate. If a confidence interval includes the no-difference reference, the data are compatible with that reference at the stated confidence level, as well as with other values inside the interval. The interval should be considered alongside the point estimate and the study context, rather than reduced to a binary significant/not-significant label.

How are the symptom outcomes different?

The cycle 4 symptom analyses are counts of participants with deterioration from baseline in the MD Anderson Symptom Inventory Brain Tumor symptom severity or interference score. The registry gives group-specific counts and a reported two-proportion z-test. A two-proportion test compares the observed proportions in two groups. A risk difference expresses the difference between those proportions on an absolute scale; the posted comparisons also show confidence intervals and unadjusted p-values.

These symptom analyses have outcome-specific participant counts, and those counts are much smaller than the randomized groups’ overall-survival analysis counts. The posted results therefore describe participants contributing to those particular score comparisons, not necessarily every randomized participant. The record does not report enough detail to explain why scores were unavailable for other participants, how missing scores were handled, or whether the comparisons were adjusted for other variables.

For all of these methods, the analysis result depends on the population included, outcome definitions, follow-up, and assumptions. Some of those details are recorded, including the primary population and the censoring description. Other details, including the full analysis plan and missing-data procedures, are not reported in the registry record.

11. Confidence Intervals and Precision

Precision is conveyed most directly by the 95% confidence intervals alongside the point estimates. For median overall survival, the conventional group’s estimate was 16.6 months, with an interval from 14.9 to 18.0 months. The dose-dense group’s estimate was 14.9 months, with an interval from 13.7 to 16.5 months. Each interval expresses uncertainty in its group-specific median estimate; it is not a range containing the survival times of most participants.

For the comparison, the reported hazard ratio was 1.03, with a 95% confidence interval from 0.88 to 1.20. The interval includes the no-difference reference for a hazard ratio and allows for estimates on either side of that reference. It therefore communicates uncertainty that is important even though the point estimate is close to the reference. The p-value of 0.63 is consistent with the absence of a statistically clear difference in this analysis, but it does not establish that the true effect is exactly null.

Confidence intervals are useful because they show a range of effect estimates compatible with the data and the method, rather than only a single estimate. Their interpretation depends on the analysis assumptions and does not mean there is a 95% probability that the particular interval contains the true value. The interval is also not a prediction interval for future participants.

For progression-free survival, the reported hazard ratio was 0.87 and its interval was 0.75 to 1.00. This interval reaches the no-difference reference and should be read with the reported p-value of 0.06 and the secondary status of the endpoint. The symptom outcomes have their own posted confidence intervals for risk differences; those are reported in the tables and concern the analyzed score groups, not the entire trial population.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size display is a planning illustration based on the observed effect, not the trial’s original design calculation. For time-to-event outcomes, its entries are total event counts. For the other displayed outcomes, entries are participants per arm. This distinction matters: an event target is not the same as a participant count, because participants may have different follow-up and not all will experience the event during observation.

The illustration assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It shows planning scenarios for detecting the full observed effect and smaller fractions of that effect. The original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column represents the planned probability of detecting an effect of the stated size under the illustration’s assumptions if that effect is real. The 90% power column represents a higher target probability of detection under those same assumptions. These are planning targets, not guarantees for a future study. The figures do not describe the power actually achieved in this trial and are not observed power.

Smaller effects are harder to distinguish from random variation, so the table shows that planning for a smaller fraction of the observed effect requires more events or participants. The display is most useful for comparing the scale of planning requirements across effect assumptions. It should not be interpreted as evidence that a study of the listed size would necessarily reproduce the observed result.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

d is the total number of events needed (Schoenfeld's formula) with 1:1 allocation and proportional hazards.

Worked calculation for this trial

1. Hazard ratio HR = 1.030, so ln(HR) = 0.0296.
2. d = 4 × (1.96 + 0.842)² / [ln(1.030)]² = 35,933.0, rounded up to 35,934 events in total for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
hr <- 1.03                              # observed hazard ratio
events_needed <- function(power, frac = 1) ceiling(round(4 * (z_a + qnorm(power))^2 / log(hr^frac)^2, 6))   # Schoenfeld, 1:1 allocation
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: events = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(events_needed(0.80, f), big.mark = ","), format(events_needed(0.90, f), big.mark = ",")))

# Simulation: given d total events under proportional hazards, events in the treatment arm are Binomial(d, hr / (1 + hr)).
# The score (log-rank type) statistic is (D1 - d / 2) / sqrt(d / 4).
set.seed(304031)
d    <- events_needed(0.80)
reps <- 20000
D1 <- rbinom(reps, d, hr / (1 + hr))
z  <- (D1 - d / 2) / sqrt(d / 4)
cat(sprintf("Simulated power with %s events: %.3f (%d replicates)\n", format(d, big.mark = ","), mean(abs(z) > z_a), reps))

Output from running the code

100% of observed effect: events = 35,934 (80% power), 48,105 (90% power)
 75% of observed effect: events = 63,881 (80% power), 85,519 (90% power)
 50% of observed effect: events = 143,733 (80% power), 192,417 (90% power)
Simulated power with 35,934 events: 0.801 (20000 replicates)

The simulation uses the fact that, with d events in total and proportional hazards, the number of events in the treatment arm is binomial. It is an approximation that conditions on the total number of events, and it should land close to the target power.

14. Analyses Reported by the Sponsor

The posted primary comparison reports a hazard ratio of 1.03, a 95% confidence interval from 0.88 to 1.20, and p = 0.63 using the log-rank method. The table and explanatory text present that sponsor-reported result as the principal comparison. No discrepancy between the posted sponsor analysis and the simple recalculation is flagged, so there is no conflicting result to resolve.

A recalculation from summary statistics can be a useful check, but it cannot replace an analysis based on participant-level follow-up and the trial’s complete analysis procedures. In this time-to-event setting, the sponsor’s reported hazard ratio and log-rank result are the relevant analysis because those are the reported trial analyses; the record does not provide participant-level data with which to reproduce them fully.

For the cycle 4 symptom outcomes, the registry reports two-proportion z-tests. The displayed unadjusted recalculations are summary-statistic comparisons and should be understood in that limited sense. The reported analyses remain the sponsor’s analyses. These secondary comparisons also require caution because the registry lists multiple outcomes and does not report a multiplicity adjustment for the posted results.

15. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and 25 secondary outcomes. Testing or estimating many outcomes creates a multiplicity issue: the more comparisons examined, the greater the opportunity for chance variation to produce a seemingly notable result. The record does not report whether a formal multiplicity adjustment was used for the secondary analyses, whether a hierarchy of testing was specified, or how the listed outcomes were prioritized beyond identifying the primary outcome.

Accordingly, the p-values for secondary outcomes should be treated as unadjusted unless the posted record says otherwise. They can help describe the data and identify questions for further study, but they are less conclusive than a primary analysis with a defined role in the trial. The record does not report a detailed statistical analysis plan that would clarify the intended interpretation of every secondary comparison.

Missing-data methods are also not reported in the registry record for the symptom score analyses. The cycle 4 comparisons include 51 participants in the conventional group and 40 in the dose-dense group, but the record does not explain why these are the available analysis counts, how missing scores were handled, or whether participants with unavailable assessments differed from those included. No missing-data procedure should be assumed.

For the primary survival outcome, the record does report that participants last known to be alive were censored at last contact. It also defines the primary analysis population as randomized eligible patients. The exact handling of other analysis populations, exclusions, protocol deviations, or sensitivity analyses is not reported in the registry record. The record likewise does not report interim analyses or a stopping rule, so no claims about those procedures can be made.

16. 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: platelet count decreased (11.9%), neutrophil count (7.0%), leukopenia nos (6.0%), convulsions nos (5.7%), lymphopenia (5.5%).

The safety display separates serious adverse events from other adverse events and gives the numbers at risk and affected in each listed group. In the nonrandomized no-adjuvant group, 105 of 285 participants at risk had a serious adverse event and 216 of 285 had another adverse event. In the conventional group, the corresponding counts were 131 of 409 and 376 of 409. In the dose-dense group, they were 142 of 420 and 392 of 420.

These are counts from the posted safety summary, not a randomized efficacy comparison. The no-adjuvant group was not randomized to either adjuvant schedule, so its safety figures should not be treated as a directly comparable randomized control group. The registry also lists serious-event terms including platelet count decreased, neutrophil count, leukopenia NOS, convulsions NOS, lymphopenia, and thrombosis, with percentages shown in the safety table. The record does not establish that those term-specific percentages can be assigned to a particular randomized comparison from the summary alone.

Adverse-event counts do not by themselves show causation, severity over time, or the balance of benefits and harms. The registry lists a secondary outcome for highest-grade adverse events reported as possibly, probably, or definitely related to protocol treatment, but the summary does not provide a complete account of individual event timing or management.

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

The primary result describes a randomized comparison of two adjuvant temozolomide schedules after concurrent radiation therapy and temozolomide. In the posted analysis, the estimated median overall survival values were 16.6 months and 14.9 months, while the reported hazard ratio was 1.03 with a 95% confidence interval from 0.88 to 1.20 and p = 0.63. This is a result about the comparison as analyzed, with uncertainty around the estimate.

The result does not establish that the schedules are identical. A non-significant test does not prove no effect, and a confidence interval spanning the no-difference reference remains compatible with a range of relative effects. Nor does this record establish equivalence or non-inferiority: those require a design and analysis aimed at those specific claims, and such a design is not reported.

The result also does not establish that either schedule is preferable for an individual participant. The registry analysis is a group-level comparison, and it does not provide individualized predictions. This page describes the posted statistical results and does not offer medical advice.

Secondary outcomes add context but should not be used to replace the primary outcome. They differ in measurement, timing, and analysis population, and many secondary outcomes are listed. Their findings are subject to uncertainty and the possibility of chance patterns across multiple comparisons. Safety summaries describe reported events but do not, on their own, establish causation or a complete comparison of risks.

The appropriate reading is therefore bounded: the record reports no statistically clear difference in the primary overall-survival comparison between the two randomized schedules, while leaving uncertainty about the range of effects compatible with the data. It does not answer every question about treatment, long-term outcomes, subgroups, or an individual patient.

18. Why This Trial Matters Statistically

This trial illustrates why a clinical trial result should be read through its design, endpoint, and uncertainty together. The comparison was randomized between two adjuvant schedules, which makes the primary comparison more interpretable than a comparison with the separate group that was not randomized to either adjuvant arm. Keeping those groups distinct is important when describing what the study tested.

It also demonstrates the value of separating a primary outcome from secondary outcomes. Overall survival was the primary endpoint, while progression-free survival and multiple other outcomes posted additional perspectives. A secondary result may be informative, but it does not automatically supersede the primary result, particularly when many outcomes are listed and adjustment for multiplicity is not reported.

The survival analysis highlights the difference between a point estimate and its precision. The hazard ratio gives a compact relative comparison, while its confidence interval shows that the estimate is uncertain. The p-value alone cannot communicate the size of the range of effects compatible with the analysis, and a result that is not statistically significant does not establish that the groups are equivalent.

Finally, the record shows why the details of analysis populations and missing assessments matter. The primary outcome population is identified, and censoring is described, but the available symptom-score groups are smaller and missing-data procedures are not reported. Clear statistical interpretation depends not only on the headline result but also on knowing who contributed to each analysis and what the record leaves unresolved.

19. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record does not report the trial’s original sample-size justification or the assumptions used to plan enrollment. The sample-size display on this page is a planning illustration based on observed effects and should not be confused with the original design calculation.

The record does not report a complete statistical analysis plan, including whether interim analyses were conducted, whether any stopping rules applied, or how all secondary outcomes were prioritized. It lists many secondary outcomes but does not report a multiplicity adjustment in the information. This limits how strongly isolated secondary p-values can be interpreted.

For the cycle 4 symptom analyses, the record gives smaller analysis counts than the overall randomized groups but does not explain the availability of scores, the handling of missing assessments, or whether missingness could affect interpretation. Detailed analysis-population information for all outcomes is not reported. The summary also does not provide participant-level data, so the reported time-to-event results cannot be independently reconstructed from the posted group summaries alone.

Follow-up for the primary analysis had a maximum of 4.4 years, and the analysis was conducted after 647 deaths were reported. The record does not provide a longer-term result in this summary. It also does not report the full assumptions or diagnostics underlying the hazard-ratio analysis, so the hazard ratio should be read as the reported summary rather than a complete account of how relative hazards may have varied through follow-up.

Finally, the group described as receiving no adjuvant temozolomide was not randomized to either adjuvant arm. Its safety results should not be used as if they formed a randomized comparator for the primary treatment question.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Radiation Therapy (RT) and Temozolomide (TMZ) in Treating Patients With Newly Diagnosed Glioblastoma or Gliosarcoma — NCT00304031.
• Registry record last updated 2020-06-09; status last verified 2020-05.
• Results first posted 2014-04-30.
• 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.

23. Record Summary

This completed phase III randomized parallel-group trial compared conventional with dose-dense adjuvant temozolomide after concurrent radiation therapy and temozolomide in newly diagnosed glioblastoma or gliosarcoma. The primary outcome was median overall survival in randomized eligible patients, estimated by Kaplan-Meier methods with censoring at last contact for participants last known to be alive.

The posted primary comparison reported a hazard ratio of 1.03, a 95% confidence interval from 0.88 to 1.20, and p = 0.63. Median overall survival was 16.6 months in the conventional group and 14.9 months in the dose-dense group. The result does not show a statistically clear difference, but it does not establish equivalence. Secondary and safety results require attention to their outcome-specific populations, uncertainty, and the multiplicity of outcomes listed in the registry record.