BAY43-9006 (Sorafenib) Versus Interferon Alpha-2a in Patients With Unresectable and/or Metastatic Renal Cell Carcinoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for BAY43-9006 (Sorafenib) Versus Interferon Alpha-2a in Patients With Unresectable and/or Metastatic Renal Cell Carcinoma (NCT00117637), a randomized phase 2 study. The primary outcome is Progression-free Survival (PFS) Based on Independent Radiological Review for the First Intervention Period.

2. Clinical Question

The study was a randomized, open-label, parallel-group Phase 2 trial. Its primary endpoint focused on the first intervention period, before the later treatment sequences that followed progression. The registry describes additional aims, including disease control, quality of life, blood levels of sorafenib, and biomarker associations. Those aims broaden the study questions, but they do not change the primary comparison: time from randomization until progression or death, as determined by independent radiological review.

The initial randomized groups were assigned to different treatment sequences, rather than to two treatments that continued unchanged through every subsequent period. The registry describes dose escalation in the sorafenib-first group and a switch to sorafenib after progression in the interferon-first group. Later-period observations therefore address additional questions about treatment after progression; they should not be treated as another randomized comparison of the original groups.

3. Trial Design

This was a Phase 2, randomized, open-label, parallel-group study sponsored by Bayer. The registry lists 189 participants enrolled and identifies renal cell carcinoma as the condition. The study began in 2005-06, reached primary completion in 2006-09, and is listed as completed. Further details about the eligibility criteria, recruitment locations, participant characteristics, and allocation procedures are not reported in the registry record.

One group began treatment with sorafenib 400 mg and then increased to 600 mg. The other began with interferon alpha-2a and, after progression, received sorafenib 400 mg. The registry describes sorafenib as oral treatment taken twice daily and interferon as subcutaneous treatment three times a week. It also describes dose escalation for interferon. The complete dosing instructions for every treatment period are not reported in the registry record.

The open-label design means the registry does not describe masking of participants or study staff. The primary endpoint nevertheless used independent radiological review. This distinction matters: the treatment assignment was not masked, while the primary progression assessment was designated as an independent review. Details of how that review was organized, including reviewer masking, are not reported in the registry record.

The primary endpoint covered the first intervention period. The registry also lists a second-intervention period and outcomes such as investigator-assessed progression-free survival, disease control, and quality of life. These additional assessments extend the questions beyond the initial randomized treatment period. The registry does not report the original sample-size justification, the intended analysis population, or the planned approach to interim analyses.

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: All 189 (97 Sorafenib/92 Interferon) randomized subjects were included in the intent to treat (ITT) population, and 187 (97 Sorafenib/90 Interferon) were included in the safety population according to the protocol, which defined eligibility for safety analyses by the prerequisite that a patient had received at least one dose of study medication.

First Intervention (Period 1)

Reasons for not completing this period:

Second Intervention (Period 2)

Reasons for not completing this period:

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Progression-free Survival (PFS) Based on Independent Radiological Review for the First Intervention Period, measured over From randomization of the first subject until 15 months later, assessed every 8 weeks.

The primary endpoint was median progression-free survival for the first intervention period, based on independent radiological review. It measured the time from randomization until disease progression or death from any cause, whichever occurred first. Participants who had not progressed or died at the analysis time were censored at their last tumor evaluation.

Progression-free survival is a time-to-event measure: it uses both whether an event occurred and how long participants remained free of the event. The median describes the time by which half of the group’s estimated progression-free survival distribution has reached an event. It is not the average time for every participant, and it does not describe how long any particular participant lived without progression.

General: using a time-to-event endpoint can retain information from participants whose follow-up ends before an event is observed, by censoring their observation at the specified time. Interpretation depends on the event definition, the timing and completeness of assessments, and the assumptions behind censoring. The registry specifies the censoring point but does not report further details about the censoring assumptions or missing tumor evaluations.

The endpoint is used to compare the timing of progression or death between the randomized groups. It does not, by itself, describe tumor response, quality of life, overall survival, or the balance of harms and benefits. Those are distinct questions, and the registry lists some of them as secondary outcomes.

7. Results Posted in the Registry

• First Sorafenib (Nexavar, BAY43-9006) 400 mg Then 600 mg vs First Interferon Then Sorafenib (Nexavar, BAY43-9006) 400 mg: hazard ratio 0.88 (95% CI 0.61–1.27), reported p = 0.500 (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.

Progression-free Survival (PFS) Based on Investigator Assessment for the First Intervention Period

• 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:
  • First Sorafenib (Nexavar, BAY43-9006) 400 mg Then 600 mg vs First Interferon Then Sorafenib (Nexavar, BAY43-9006) 400 mg: hazard ratio 0.88 (95% CI 0.63–1.24), reported p = 0.469 (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 First Sorafenib (Nexavar, BAY43-9006) 400 mg Then 600 mg vs First Interferon Then Sorafenib (Nexavar, BAY43-9006) 400 mg and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists 33 secondary outcomes, covering investigator-assessed progression-free survival, disease control assessments, quality of life, and outcomes from later intervention periods. The listed quality-of-life measures include the respiratory domain and total score of the Functional Assessment of Cancer Therapy-Kidney Symptom Index. The breadth of these measures reflects additional study questions, but the registry record does not report a complete set of numerical findings for them.

The posted investigator-assessed progression-free survival result is an additional perspective on the primary time-to-event question. It is not the primary independent-review assessment, and its reported comparison should be interpreted as secondary. The record’s other listed outcome categories cannot be used to infer an overall pattern of disease control or quality of life without their results.

General: secondary outcomes can help explore whether a primary result is accompanied by patterns in other measures. However, when many outcomes are examined, the chance of obtaining apparently notable results by chance increases if each is interpreted without accounting for multiplicity. Secondary findings may also differ in population, timing, assessment method, and exposure to later treatment. These features make them useful context, but they generally carry less confirmatory weight than a prespecified primary analysis.

The registry does not report whether multiplicity adjustments were planned or applied to the secondary outcomes. It also does not provide enough detail to judge which secondary analyses were prespecified, how missing observations were handled, or whether all planned results were reported. The primary result should therefore remain the central comparative finding, while the secondary outcomes are best understood as additional, incompletely documented questions rather than a single combined conclusion.

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

• Progression-free Survival (PFS) Based on Investigator Assessment for the First Intervention Period
• Disease Control (DC) According to Independent Central Review for the First Intervention Period
• Disease Control (DC) According to the Investigator Assessment for the First Intervention Period
• Disease Control (DC) According to the Investigator Assessment for the Second Intervention Period
• Analysis of the Quality of Life by Use of the Respiratory Domain of the Functional Assessment of Cancer Therapy-Kidney Symptom Index (FKSI) After Intervention for the First Intervention Period
• Analysis of the Quality of Life by Use of the Respiratory Domain of the Functional Assessment of Cancer Therapy-Kidney Symptom Index (FKSI) for the Second Intervention Period
• Analysis of the Quality of Life by Use of Total Score of the Functional Assessment of Cancer Therapy-Kidney Symptom Index (FKSI) for the First Intervention Period
• Analysis of the Quality of Life by Use of Total Score of the Functional Assessment of Cancer Therapy-Kidney Symptom Index (FKSI) for the Second Intervention Period

9. Statistical Interpretation

10. Statistical Methods Explained

What does the hazard ratio describe?

The registry reports a hazard ratio for progression-free survival. General: a hazard is the event rate at a particular point in follow-up among participants who have not yet had the event. A hazard ratio compares those rates between groups across the time-to-event analysis. It is not a ratio of the median times, nor is it the proportion of participants who experienced progression or death. A hazard ratio of 1 corresponds to equal event rates under the comparison; values on either side indicate the direction of the estimated relative rate.

For the primary comparison, the reported hazard ratio was 0.88. The first group in the comparison was the sorafenib-first sequence, and the second was the interferon-first sequence. The estimate points toward a lower event rate in the first group, but its uncertainty must be considered alongside the point estimate. The confidence interval extends from 0.61 to 1.27, spanning 1, and the log-rank p-value was 0.50.

What does the log-rank method do?

The registry names the log-rank method for the reported comparison. General: the log-rank test compares the observed timing of events between groups over follow-up. It uses the sequence of event times rather than comparing only the group medians. A p-value from this method describes how unusual the observed data, or data more extreme, would be under the null comparison and the test assumptions. It is not the probability that the null hypothesis is true, and it does not quantify the size or clinical importance of an effect.

The p-value of 0.50 does not indicate that there is a 50% probability of no difference. It indicates that the reported test did not distinguish the observed comparison from the null comparison by the test’s statistical criterion. The estimate and confidence interval remain necessary for describing direction and precision.

How should the median be read?

The registry reports medians for progression-free survival in months. General: a median time-to-event estimate marks the point at which the estimated proportion remaining event-free has reached half. It is a summary of the estimated distribution, not a measure of the time experienced by all participants. The primary medians were 5.7 months and 5.6 months. Their closeness is informative as a descriptive comparison, but it does not substitute for the full time-to-event analysis or the hazard ratio.

The confidence intervals around the two medians also differ in their lower limits while sharing the same upper limit. These intervals describe uncertainty around each group’s median estimate. They are not the same quantity as the confidence interval for the hazard ratio, which describes uncertainty in the relative comparison. The registry does not report a formal test that compares the medians directly.

Why is censoring relevant?

The endpoint definition includes participants without progression or death at the time of analysis. Their follow-up was censored at the last tumor evaluation. General: censoring records that an event had not been observed by a particular point; it does not mean that the participant remained event-free indefinitely. Time-to-event analyses can include these partial observations, but interpretation depends on the observation process and assumptions about censoring. Further details on loss to follow-up, missed assessments, and censoring assumptions are not reported in the registry record.

The primary endpoint description states that progression could be radiological or clinical, or death from any cause. The assessment schedule was every 8 weeks. The registry gives the primary timeframe as from randomization of the first subject until 15 months later. It does not provide further detail about the handling of events between scheduled assessments or the precise analysis cutoff for each participant.

What does independent review add?

The primary progression assessment was based on independent radiological review. General: an independent review can separate endpoint assessment from the treating investigator’s assessment, which may be useful in an open-label study. The registry does not report the review procedures, whether reviewers were masked to treatment assignment, or how disagreements were handled. The fact that the review was independent should therefore be read as a feature named in the endpoint, not as evidence that all possible assessment bias was eliminated.

A secondary progression-free survival outcome used investigator assessment. Differences between the two reported analyses may reflect the assessment source, the analysis details, or chance. The registry does not report enough information to determine which explanation accounts for any differences. The independent-review endpoint remains the designated primary outcome.

What is the role of the confidence interval and p-value?

General: a confidence interval expresses the uncertainty associated with an estimate under the method’s assumptions. A 95% confidence interval is generated by a procedure that, over repeated samples under those assumptions, would cover the target value in 95% of samples. It is not a statement that there is a 95% probability that this particular interval contains the true value. The primary hazard-ratio interval, 0.61 to 1.27, includes both lower and higher relative event rates as well as 1.

The p-value and confidence interval address related but distinct aspects of the analysis. The p-value summarizes the result of a test against a null comparison; the interval shows a range of effect estimates compatible with the data and model. Neither alone establishes clinical importance. The registry does not report a prespecified effect threshold for clinical importance.

The sponsor-reported hazard ratio, confidence interval, and p-value are presented as the trial’s own comparative analysis. No discrepancy is flagged between the registry’s reported result and the simple unadjusted recalculation. The recalculation is not an adjusted model or a substitute for the sponsor’s analysis.

11. Confidence Intervals and Precision

The primary median estimates are 5.7 months for the sorafenib-first group and 5.6 months for the interferon-first group. Their 95% confidence intervals are 5.0 to 7.4 months and 3.7 to 7.4 months, respectively. These intervals show uncertainty around the group-specific median estimates; they do not directly test the difference between the medians.

For the relative comparison, the hazard ratio is 0.88, with a 95% confidence interval from 0.61 to 1.27. The interval includes 1 and covers values favoring either group. This means the point estimate should not be read in isolation: the data are compatible with a range of relative effects, including no relative difference under the hazard-ratio scale. The reported log-rank p-value is 0.50.

General: a confidence interval is a way to display the statistical uncertainty around an estimate. A narrower interval indicates greater precision under the analysis assumptions; a wider interval indicates that more possible values remain compatible with the data. The interval is not a guarantee that the true effect lies within its limits, and it does not capture every source of uncertainty, such as limitations in study conduct or measurement.

The registry does not report a target precision or a prespecified clinically important range for the hazard ratio. It also does not report the original assumptions used to choose the planned enrollment. Consequently, the width of the observed interval can be described, but it cannot be judged against a registry-reported precision target. The enrolled total was 189; the primary outcome groups contain 97 and 92 participants in the posted results.

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 illustrations concern a time-to-event comparison, so their entries are total events, not participants per arm. They show event totals under planning assumptions, rather than the number enrolled or the number of participants who actually experienced an event in this trial. For the primary comparison, the illustrations list 1,922 total events for 80% power and 2,572 total events for 90% power when planning for 100% of the observed effect. For 75% of the observed effect, the corresponding totals are 3,416 and 4,573; for 50% of the observed effect, they are 7,685 and 10,288.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set to the stated fraction of the observed effect. The time-to-event figures use the Schoenfeld method and express total events. The original trial’s own design assumptions and sample-size justification are not reported in the registry record.

In plain terms, the 80% power column gives the event total associated with an 80% chance of detecting the specified effect under the planning assumptions if that effect is present. The 90% power column gives the event total for a higher chance of detection under those assumptions. Planning for a smaller effect requires more events, as the listed totals illustrate. This is a planning illustration, not observed power; it does not describe the probability that the completed trial detected an effect after the results were known.

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 = 0.880, so ln(HR) = -0.1278.
2. d = 4 × (1.96 + 0.842)² / [ln(0.880)]² = 1,921.2, rounded up to 1,922 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 <- 0.88                              # 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(117637)
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 = 1,922 (80% power), 2,572 (90% power)
 75% of observed effect: events = 3,416 (80% power), 4,573 (90% power)
 50% of observed effect: events = 7,685 (80% power), 10,288 (90% power)
Simulated power with 1,922 events: 0.806 (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. Group-Sequential Design Analysis

Many time-to-event trials, especially in oncology, stop or report early when interim data are overwhelming, so a single fixed-sample number understates the real design problem. The calculation below is an illustrative group-sequential design built from this trial's posted control median and hazard ratio. The registry record does not state the planned number of looks or the spending function, so the design is a planning illustration, not a reconstruction of the protocol. Assumed: one-sided α = 0.025, 90% power, three equally spaced looks on information, Lan-DeMets O'Brien-Fleming spending, 24 months of accrual, 60 months in total and a 1% monthly dropout hazard.

Under these assumptions the design needs about 2,836 participants in total, with the boundaries below.

Fixed design versus group-sequential alternatives

Group-sequential designs cost a small increase in maximum sample size and events compared with the fixed design, in exchange for the chance to stop early for overwhelming efficacy. O'Brien-Fleming spending keeps early boundaries very conservative and the final boundary close to the fixed-design value, whereas Pocock spending spends more alpha early.

Sensitivity to a smaller true effect

Planning for exactly the observed effect is optimistic, because observed effects in published trials tend to be somewhat larger than the true effect. The table repeats the main design (three looks, O'Brien-Fleming spending, 90% power) for smaller true hazard ratios.

For context, this trial enrolled 189 participants.

Cross-check, upper boundaries: gsDesign 3.71, 2.511, 1.993 | rpact 3.71, 2.511, 1.993. Agreement between the two packages confirms the boundary calculation.

R code and output

suppressWarnings(suppressMessages({ library(gsDesign); library(rpact) }))
med_control <- 5.6          # control-arm median, months (converted from the posted unit)
hr          <- 0.88          # hazard ratio used for planning
lambdaC     <- log(2) / med_control
eta         <- 0.01               # dropout hazard per month (assumption)
acc_months  <- 24                 # accrual duration (assumption)
study_months<- 60                 # total study duration (assumption)

design <- function(k, sfu, beta, h = hr) gsSurv(k = k, test.type = 1, alpha = 0.025, beta = beta, sfu = sfu,
  lambdaC = lambdaC, hr = h, hr0 = 1, eta = eta, gamma = 1, R = acc_months, T = study_months, minfup = study_months - acc_months)

# Main design: 3 looks, Lan-DeMets O'Brien-Fleming spending, one-sided alpha 0.025, 90% power
x <- design(3, sfLDOF, 0.10)
cat(sprintf("N_TOTAL|%s\n", format(ceiling(sum(x$gamma * x$R)), big.mark = ",")))
for (i in 1:3) cat(sprintf("GS|%d|%.1f|%.0f|%.3f|%.5f|%.5f\n", i, x$T[i], x$n.I[i], x$upper$bound[i], pnorm(-x$upper$bound[i]), cumsum(x$upper$spend)[i]))
cat("\n"); print(gsBoundSummary(x))

# Comparison of designs
cmp <- list(list("Fixed design, one analysis", 1, sfLDOF), list("Two looks, O'Brien-Fleming", 2, sfLDOF),
            list("Three looks, O'Brien-Fleming", 3, sfLDOF), list("Three looks, Pocock", 3, sfLDPocock))
cat("\n")
for (b in c(0.20, 0.10)) for (d in cmp) {
  y <- design(d[[2]], d[[3]], b)
  cat(sprintf("DES|%s|%d|%.0f|%s|%.1f\n", d[[1]], round(100 * (1 - b)), tail(y$n.I, 1), format(ceiling(sum(y$gamma * y$R)), big.mark = ","), tail(y$T, 1)))
}

# Sensitivity: what if the true effect is smaller than the observed one? (3 looks, O'Brien-Fleming, 90% power)
cat("\n")
for (fr in c(1, 0.75, 0.5)) {
  y <- design(3, sfLDOF, 0.10, exp(log(hr) * fr))
  cat(sprintf("SENS|%.2f|%.3f|%.0f|%s\n", fr, exp(log(hr) * fr), tail(y$n.I, 1), format(ceiling(sum(y$gamma * y$R)), big.mark = ",")))
}

# Independent cross-check of the boundaries with rpact
r <- getDesignGroupSequential(kMax = 3, alpha = 0.025, beta = 0.10, sided = 1, typeOfDesign = "asOF", informationRates = x$timing)
cat(sprintf("\nCross-check, upper boundaries: gsDesign %s | rpact %s\n", paste(round(x$upper$bound, 3), collapse = ", "), paste(round(r$criticalValues, 3), collapse = ", ")))

Method: LachinFoulkes 
     Analysis               Value Efficacy
    IA 1: 33%                   Z   3.7103
      N: 1732         p (1-sided)   0.0001
  Events: 868        ~HR at bound   0.7773
    Month: 15    P(Cross) if HR=1   0.0001
              P(Cross) if HR=0.88   0.0338
    IA 2: 67%                   Z   2.5114
      N: 2774         p (1-sided)   0.0060
 Events: 1735        ~HR at bound   0.8864
    Month: 23    P(Cross) if HR=1   0.0060
              P(Cross) if HR=0.88   0.5603
        Final                   Z   1.9930
      N: 2836         p (1-sided)   0.0231
 Events: 2602        ~HR at bound   0.9248
    Month: 60    P(Cross) if HR=1   0.0250
              P(Cross) if HR=0.88   0.9000



Cross-check, upper boundaries: gsDesign 3.71, 2.511, 1.993 | rpact 3.71, 2.511, 1.993

15. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary comparison as a hazard ratio of 0.88, with a 95% confidence interval from 0.61 to 1.27 and a log-rank p-value of 0.50. The corresponding simple unadjusted recalculation does not flag a discrepancy. The sponsor’s reported analysis therefore remains the primary basis for interpreting the comparative result.

A recalculation from posted summary statistics is useful as a check on the reported numbers, but it is not an independent reconstruction of the trial analysis. It does not incorporate participant-level event times, covariates, censoring details, or analysis choices that may not be included in the registry record. The registry does not report additional model details beyond the named log-rank method and the hazard-ratio result.

The primary estimate and the recalculation should not be treated as separate trial findings. The sponsor analysis is the reported trial analysis; the simple recalculation is an unadjusted check based on summary information. The reported hazard ratio, confidence interval, and p-value support the same overall reading: the point estimate favors the sorafenib-first sequence, but the interval includes 1 and the reported test does not provide evidence against the null comparison.

16. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and numerous secondary outcomes, but its record does not report a multiplicity strategy. It is not reported in the registry record whether a hierarchy of hypotheses, an adjustment to significance thresholds, or another procedure was used to account for the number of analyses. Without that information, any unadjusted secondary p-values, if available, would need cautious interpretation because multiple testing can increase the chance of false-positive findings.

The primary endpoint specifies that participants without progression or death at the time of analysis were censored at their last tumor evaluation. The registry does not report additional details about missing tumor assessments, withdrawals, loss to follow-up, or sensitivity analyses for missing data. It also does not report the analysis population definitions, such as whether the primary analysis followed an intention-to-treat principle or used another population.

The endpoint timeframe states that assessment occurred every 8 weeks and that the period extended from randomization of the first subject until 15 months later. Further details about the data cutoff, handling of events between assessments, and censoring assumptions are not reported in the registry record. The record does not report whether interim analyses were planned or performed, or whether any interim-analysis procedure affected the final testing threshold.

General: these details matter because the interpretation of a time-to-event estimate depends on who is included, how event times are determined, and how incomplete follow-up is treated. They also affect the evidential weight of multiple outcomes. The absence of these details in the registry record does not establish that the procedures were not used; it means their use and implementation cannot be evaluated from the posted information.

17. 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: death not associated with ctcae term, disease progress (11.5%), constitutional symptoms - other (8.2%), hemoglobin (6.7%), cardiac general - other (6.6%), infection - other (4.9%).

The registry reports serious adverse events for several treatment periods. During the first sorafenib period, 47 of 97 participants were listed as affected by a serious adverse event; during first-period interferon therapy, the corresponding figures were 36 of 90. In the later sorafenib periods, the figures were 14 of 49 for sorafenib 600 mg after dose escalation and 30 of 61 for sorafenib 400 mg after interferon therapy.

These groups represent different treatment periods and do not all have the same number at risk. The registry does not report why the first-period interferon safety group has 90 participants while the primary outcome group has 92, or why the later-period groups have their listed sizes. The periods also follow different treatment sequences, so the groups should not be treated as a simple randomized comparison of safety.

The registry lists serious adverse-event terms including death not associated with a CTCAE term, disease progress (11.5%), constitutional symptoms - other (8.2%), hemoglobin (6.7%), cardiac general - other (6.6%), infection - other (4.9%), and neurology - other (4.9%). The record does not provide the denominators or further context for these term-specific percentages in the listed information. These figures describe reported safety events; they do not by themselves establish causation or provide a complete comparative safety assessment. Death counts are not reported in the registry record.

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

The primary result describes progression-free survival during the first intervention period, comparing a sorafenib-first sequence with an interferon-first sequence. The reported medians were 5.7 months and 5.6 months. The hazard ratio was 0.88, with a 95% confidence interval from 0.61 to 1.27, and the log-rank p-value was 0.50. The point estimate is on the side favoring the first-listed sequence, but the interval remains compatible with a range of effects in either direction.

The result does not establish that the two treatment sequences are equivalent. Equivalence requires a defined margin and an analysis designed to assess whether the effect lies within that margin; such a margin is not reported in the registry record. Nor does the result establish that one sequence is superior. The reported confidence interval includes 1, and the reported test did not provide evidence against the null comparison.

The endpoint measures time until progression or death, not overall survival alone, tumor shrinkage, quality of life, or every aspect of clinical benefit. The registry lists those broader questions among its aims or secondary outcomes, but a complete set of numerical results for them is not reported in the registry record. The safety entries provide counts for serious adverse events in several treatment periods, but they do not by themselves show a complete randomized safety comparison.

General: statistical uncertainty is only one part of interpretation. Assessment methods, missing data, treatment switching, outcome selection, and the population studied also matter. The open-label design and the sequential treatment periods are relevant to those considerations. The registry does not report enough detail to resolve every methodological question or to determine how the findings apply to populations beyond the enrolled participants.

These results are a description of the posted trial analysis, not medical advice. They should be read as evidence about the stated endpoint and comparison, with the uncertainty and reporting limitations kept in view.

19. Why This Trial Matters Statistically

This trial illustrates why time-to-event results need more than a comparison of medians. The primary medians, 5.7 months and 5.6 months, are compact summaries, while the hazard ratio and its confidence interval describe the relative event-rate comparison over follow-up. The interval from 0.61 to 1.27 communicates uncertainty that a single point estimate cannot convey.

It also illustrates the distinction between an open-label treatment assignment and an independently reviewed primary endpoint. Independent radiological review is a specified feature of the primary assessment, while the registry also reports a secondary investigator assessment. Comparing assessment approaches can be informative, but the primary endpoint remains the planned focus for the central interpretation.

The treatment sequences make the study’s time periods important. The initial randomized comparison is not interchangeable with later observations after progression, when participants received subsequent treatment. These later-period outcomes address additional questions, but they do not preserve the same simple interpretation as the first-period randomized contrast.

Finally, the record shows how incomplete reporting can constrain interpretation even when a primary estimate is available. Multiplicity procedures, analysis populations, missing-data methods, interim analyses, and the original sample-size justification are not reported in the registry record. A careful statistical reading distinguishes the numerical finding from what remains unknown, and avoids treating secondary outcomes or planning illustrations as stronger evidence than the primary analysis.

20. 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 trial was open-label, and the registry does not report whether independent radiological reviewers were masked to treatment assignment. Independent review is named for the primary endpoint, but review procedures, disagreement resolution, and other safeguards against assessment bias are not reported in the registry record.

The primary comparison concerns the first intervention period. After progression, the treatment sequences changed, so later-period results do not represent an unchanged comparison between the original randomized groups. Participants entering later treatment periods may differ from those remaining in the initial analysis, and the registry does not report detailed eligibility or analysis rules for these periods.

Outcome reporting is incomplete for the full set of secondary measures. The registry lists 33 secondary outcomes, but a complete numerical account is not reported in the registry record. It also does not report the multiplicity approach, intended analysis populations, missing-data methods, interim-analysis procedures, or the original sample-size justification. These gaps limit assessment of how analyses were selected and how robust the findings are to alternative assumptions.

The primary endpoint used censoring at the last tumor evaluation for participants without progression or death. The record does not report further detail on missing assessments, loss to follow-up, or sensitivity analyses. The safety groups have different numbers at risk across periods; the reason for those denominators is not reported in the registry record. Together, these reporting limits call for a focused interpretation of the primary result and caution in drawing wider conclusions.

21. Related Tutorials

22. Related Statistical Calculators

23. Sources

• ClinicalTrials.gov: BAY43-9006 (Sorafenib) Versus Interferon Alpha-2a in Patients With Unresectable and/or Metastatic Renal Cell Carcinoma — NCT00117637.
• Registry record last updated 2014-10-31; status last verified 2014-10.
• Results first posted 2010-12-15.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

24. Record Summary

NCT00117637 was a completed, randomized, open-label, parallel-group Phase 2 study sponsored by Bayer. It enrolled 189 participants with unresectable and/or metastatic renal cell carcinoma. The study began in 2005-06 and reached primary completion in 2006-09.

The primary outcome was median progression-free survival in the first intervention period, assessed by independent radiological review. The reported medians were 5.7 months for the sorafenib-first sequence and 5.6 months for the interferon-first sequence. The reported hazard ratio was 0.88 (95% confidence interval 0.61 to 1.27; log-rank p=0.50).

The registry lists secondary assessments of progression-free survival, disease control, and quality of life, as well as later treatment periods. It also reports serious adverse-event counts across treatment periods. Details on multiplicity, analysis populations, missing-data handling, interim analyses, and the original sample-size justification are not reported in the registry record.