Study to Assess the Long-term Safety of Lenvatinib Monotherapy, a Lenvatinib Combination Regimen, or a Comparator Treatment Arm to Cancer Participants in Eisai Sponsored Lenvatinib Trials: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Assess the Long-term Safety of Lenvatinib Monotherapy, a Lenvatinib Combination Regimen, or a Comparator Treatment Arm to Cancer Participants in Eisai Sponsored Lenvatinib Trials (NCT03477175), a non-randomized phase 2 study. The primary outcome is Number of Participants With Any Treatment-Emergent Serious Adverse Events (TESAEs).

2. Clinical Question

3. Trial Design

This phase 2 study was an open-label, multicenter, non-randomized, parallel roll-over study sponsored by Eisai Inc. Its stated purpose was to assess long-term safety among participants enrolled in Eisai-sponsored lenvatinib studies. The registry lists an enrollment of 40 and a status of completed. The recorded start date is 2018-08-16, and the primary completion date is 2023-12-21.

Participants who were eligible to roll over continued treatment according to the treatment they received in their parent study. Cohort A covered lenvatinib monotherapy, including participants who had crossed over from a comparator arm to receive monotherapy. Cohort B covered lenvatinib combination therapy, including participants who had crossed over from comparator treatment to the combination. Cohort C covered comparator treatment, with an exception for participants receiving placebo. The China-specific description for Cohort C is truncated in the registry record, so its full treatment details are not reported there.

The design therefore follows previously treated participants rather than assigning new treatments at random. “Parallel” describes the presence of treatment groups, but it does not make those groups exchangeable. Prior treatment, eligibility to roll over, and the parent study could distinguish participants across groups. The posted serious-event group results concern Cohort A in China and the rest of the world; the registry record does not provide corresponding serious-event group counts for Cohorts B and C.

No masking was used. The record does not report a formal sample-size justification, an interim-analysis plan, or a detailed statistical analysis plan. The study’s stated focus is long-term safety, not a controlled test of whether one regimen is more effective than another.

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: A total of 40 participants were screened and enrolled to receive study treatment in this rollover study. The study was to consist of Cohorts A, B and C; however, no participants met criteria for Cohorts B or C, so no participants were enrolled in these cohorts and hence no data were collected and reported for these cohorts. As pre-specified in statistical analysis plan (SAP), data were collected and reported by regions (China and Rest of World) in this study for all sections.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety analysis set included the group of participants who received at least 1 dose of study drug.

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: Safety analysis set included the group of participants who received at least 1 dose of study drug.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Any Treatment-Emergent Serious Adverse Events (TESAEs), measured over Up to 58.8 months in current study.

The primary endpoint is the number of participants with any treatment-emergent serious adverse event (TESAE), measured in participants and followed for up to 58.8 months in the current study. The safety analysis set includes participants who received at least 1 dose of study drug.

A treatment-emergent adverse event is defined in the registry as an event that emerged during treatment in the roll-over study after being absent before the participant signed the current study’s informed consent form, re-emerged after previously resolving, or worsened during treatment relative to the pre-consent state when the event was continuous. A serious adverse event is an untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongs an existing hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect, or is medically important for another reason.

Counting participants with at least one qualifying event gives a clear safety summary: each participant is counted as an event participant rather than as a total number of event episodes. This endpoint is used to describe serious safety experience during treatment. It does not, by itself, show the timing, duration, recurrence, or cause of events, nor does a count establish that treatment caused an event. Those details are not reported in the primary endpoint summary.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary at the participant level: a participant either had at least one treatment-emergent serious adverse event during the study or did not. The registry reports the number of participants with such events and the number at risk for two Cohort A groups. A count is direct and interpretable, but it is not a measure of the total number of event episodes. A participant with multiple serious events still contributes as a participant with an event to this endpoint.

What does the endpoint definition contribute?

The treatment-emergent definition sets a time and status rule for classifying events. It considers events that newly appear during current-study treatment, recur after resolution, or worsen relative to the pre-consent state when continuous. The serious-event definition groups events according to specified consequences or medical importance. These rules improve consistency in deciding which events meet the endpoint, but they do not establish that the study drug caused an event. The registry’s definitions describe classification, not causal attribution.

The follow-up window is stated as up to 58.8 months. “Up to” indicates the maximum timeframe stated for the endpoint; it does not mean every participant was observed for that duration. A participant count does not adjust for time under observation. In general, an event rate or time-to-event analysis can account for when events occur and for differing follow-up, but the registry record does not report such analyses for this outcome. It also does not report event dates or person-time in the group summaries.

Why does allocation matter for interpretation?

In a randomized comparison, allocation by chance is intended to make treatment groups comparable on average, subject to the conduct and size of the trial. This study was non-randomized. Participants continued treatment according to their parent-study treatment and roll-over eligibility, so group membership may be related to prior care or participant characteristics. Differences in observed counts could reflect those differences, follow-up, or other factors as well as treatment. The registry explicitly warns that the arms are not a like-for-like control comparison.

The open-label design means masking was absent. For an outcome involving adverse-event recognition and reporting, awareness of treatment can be relevant in general. However, the registry record does not describe event adjudication, reporting procedures, or any steps used to limit assessment bias. It is not possible to state how much, if at all, open-label conduct affected the recorded results.

What can the reported counts establish?

The counts establish how many participants in the named groups were recorded as having the endpoint under the registry’s stated definitions. They do not establish the chance of an event for a new patient, the comparative effect of lenvatinib versus another treatment, or whether an event was caused by treatment. General measures such as a confidence interval can communicate uncertainty around an estimate, while an adjusted analysis can address measured differences between groups. Neither a confidence interval nor an adjusted analysis is reported for these group results in the registry record.

For binary outcomes, statistical methods may compare event proportions or model the probability of an event. Such methods need a defined comparison and assumptions about the data and design. Here, the registry lists 0 analyses, and no inferential model or test is reported. The posted counts should therefore be treated as descriptive rather than as evidence from a statistical test.

How should planning calculations be understood?

General sample-size planning asks how many participants would be needed to detect a specified effect under stated assumptions. The planning assumptions for any illustration associated with these results are a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect defined as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not evidence that the study was designed around those assumptions. The registry record does not report that these were the study’s own design assumptions or provide a sample-size justification. No planning output should be interpreted as an observed trial result.

In general, assumptions matter: a smaller target effect, a different allocation, or different error-rate choices can change a planning requirement. But an illustrative calculation cannot repair the non-randomized design, create an unreported comparator analysis, or establish that the study had adequate power for a safety question. In the absence of a reported inferential analysis, the central statistical reading remains descriptive: the recorded participant counts and their defined safety context.

10. Exact Estimates for Each Arm

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

R code and output

arm    <- c("Cohort A, China: Lenvatinib Monotherapy", "Cohort A, Rest of the World: Lenvatinib Monotherap")
n      <- c(19, 21)
events <- c(7, 14)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Cohort A, China: Lenvatinib Monotherapy  19  7  36.8  16.3  61.6  19.1  59.0  19.1  59.2
ARM  Cohort A, Rest of the World: Lenvatinib Monotherap  21  14  66.7  43.0  85.4  45.4  82.8  45.1  82.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures and 0 analyses. A multiplicity strategy addressing the interpretation of multiple outcomes or comparisons is not reported in the registry record. Without a reported analysis plan, it is not possible to determine whether outcomes were prioritized beyond the listed primary endpoint, whether any adjustment for multiple testing was intended, or how secondary findings were to be interpreted.

Missing-data methods are not reported in the registry record. The safety analysis set is defined as participants who received at least 1 dose of study drug, but the record does not explain how missing adverse-event information, withdrawal, incomplete follow-up, or differing exposure duration was handled. Nor does it report how many participants had incomplete safety follow-up. These omissions matter because the event counts describe recorded observations; they do not demonstrate that every participant was observed for the full timeframe of up to 58.8 months.

The registry enrollment is 40. The serious-event summaries separately give 19 participants at risk in Cohort A, China, and 21 in Cohort A, rest of the world. The record does not explain the relationship between those group summaries and every aspect of the safety analysis set, or provide corresponding serious-event counts for the other cohorts in this summary. No imputation, sensitivity analysis, or missingness model is reported. Accordingly, the available counts should be read as the posted group summaries rather than as a complete account of all possible outcomes or follow-up patterns.

12. Safety Results

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

Deaths

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: pneumonia (9.5%), urinary tract infection (9.5%), large intestine polyp (5.3%), covid-19 (5.3%), spinal compression fracture (5.3%).

The registry reports serious adverse events in 7 of 19 participants in Cohort A, China, and 14 of 21 participants in Cohort A, rest of the world. It also lists 2 deaths in the China cohort and 5 in the rest-of-the-world cohort. These are descriptive counts. Because treatment allocation was non-randomized and the registry cautions that the arms are not like-for-like controls, the counts do not support a causal or comparative conclusion.

The listed serious-event terms and percentages are pneumonia, 9.5%; urinary tract infection, 9.5%; large intestine polyp, 5.3%; COVID-19, 5.3%; spinal compression fracture, 5.3%; and bone pain, 5.3%. The registry record does not identify a cohort for each listed term in this summary or establish that any event was caused by treatment. The percentages should be read as reported, not recalculated or interpreted as a comparison across cohorts.

The endpoint counts participants with at least one qualifying serious event, not the total number of events or their timing. The posted summaries do not report event duration, recurrent episodes, causes of death, or time-adjusted event rates.

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

The results describe long-term safety experience recorded for participants who rolled over from Eisai-sponsored lenvatinib studies. They show the numbers of participants with serious adverse events in two named lenvatinib-monotherapy cohorts, along with reported counts for deaths and other events. The primary endpoint uses a registry-defined treatment-emergent period and a defined serious-event classification, providing a consistent frame for interpreting the counts.

These observations do not establish that lenvatinib caused the reported events. A temporal event definition identifies when an event is counted, not why it occurred. Cancer participants may have health events for reasons unrelated to a study treatment, and the registry’s event counts do not adjudicate cause. The record also does not report the causes of death in these group summaries.

The counts do not establish that one cohort had a higher or lower underlying risk than another. Cohort A participants in China and the rest of the world were not randomly assigned to geographic groups, and the study did not use random allocation to treatment. Group differences can reflect participant mix, parent-study history, exposure duration, or other factors not reported in the registry record. No adjusted comparison or inferential analysis is reported.

The findings also cannot be taken as an estimate of safety for every person treated with lenvatinib, for every regimen, or for every duration of use. The study concerns roll-over-eligible participants from prior sponsored studies, and the reported serious-event summaries cover only the two Cohort A groups described. Results for combination and comparator cohorts are not included in these group summaries.

In general, a safety count is useful for describing what was observed in a defined study population. Its interpretation depends on the participants included, the event definitions, completeness and duration of follow-up, and the design used to compare groups. The registry record leaves several of these analytic details unreported. The defensible conclusion is limited to the descriptive counts and event terms recorded, not a judgment that a treatment is beneficial, harmful, or equivalent to a comparator.

14. Why This Trial Matters Statistically

Long-term safety monitoring addresses a different statistical question from a short-term efficacy comparison. It focuses on the accumulation and classification of adverse events during ongoing treatment, including events considered serious under explicit criteria. A roll-over study can describe safety experience among participants who remain eligible to continue from earlier sponsored trials, extending observation beyond the parent-study treatment period.

The design also illustrates why the purpose of an analysis must match the strength of its conclusions. The study is open-label and non-randomized, and its groups follow treatment histories from parent studies. These features can be appropriate context for descriptive safety reporting, but they limit causal comparisons. The registry itself warns that the arms are not like-for-like controls. Recognizing that distinction prevents descriptive counts from being mistaken for a comparative treatment effect.

The endpoint’s participant-level definition is another useful statistical feature. It answers how many participants had at least one serious event, rather than how many episodes occurred. That is a clear summary for a safety record, while leaving other questions—such as timing, recurrence, severity pattern, and time at risk—unanswered by the count alone.

The record also demonstrates the importance of transparent analysis reporting. It lists 4 outcome measures but 0 analyses, and does not report a formal sample-size justification, missing-data methods, or multiplicity strategy. Without those details, readers can describe the posted observations but cannot assess an unreported inferential plan or its assumptions. The value of the record is therefore in documenting a long-term safety context and explicit event counts, while making the limits of comparison visible.

15. Limitations

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

Several limitations specific to this study affect interpretation. Participants were roll-over eligible and continued treatment related to their parent-study regimen. They are therefore a selected group with prior exposure to treatment or comparator arms, not a newly enrolled population assigned to treatments for this study. The registry does not report enough detail to characterize selection into roll-over or how prior study experience differed across cohorts.

Allocation was non-randomized, masking was absent, and the registry cautions against treating the arms as like-for-like controls. Comparisons across groups could be confounded by differences in treatment history, participants, parent studies, follow-up, or other unreported factors. The serious-event summaries cover Cohort A in China and the rest of the world; corresponding serious-event group counts for Cohorts B and C are not reported in this summary. The comparator arm description for China is also incomplete in the registry record.

The primary outcome is a participant count over a timeframe of up to 58.8 months. The group summaries do not provide event timing, person-time, duration of exposure, recurrent-event detail, or the completeness of follow-up. They therefore cannot show how risk varied over time or adjust for unequal observation. The death counts are not accompanied by causes or attribution in these summaries, and the registry does not specify the meaning of the other-event category.

Finally, no statistical analyses are listed. The registry record does not report an inferential comparison, confidence intervals, missing-data methods, multiplicity strategy, or formal sample-size justification. These gaps constrain the conclusions to descriptive reporting and prevent evaluation of comparative precision or robustness.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study to Assess the Long-term Safety of Lenvatinib Monotherapy, a Lenvatinib Combination Regimen, or a Comparator Treatment Arm to Cancer Participants in Eisai Sponsored Lenvatinib Trials — NCT03477175.
• Registry record last updated 2025-01-07; status last verified 2023-04.
• Results first posted 2025-01-07.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT03477175 is a completed phase 2, open-label, multicenter, non-randomized, parallel roll-over study sponsored by Eisai Inc. It enrolled 40 participants and assessed long-term safety among cancer participants continuing lenvatinib monotherapy, a lenvatinib combination regimen, or comparator treatment from Eisai-sponsored lenvatinib trials. The study start date was 2018-08-16, and the primary completion date was 2023-12-21.

The primary endpoint was the number of participants with any treatment-emergent serious adverse event, with follow-up up to 58.8 months. The safety analysis set included participants who received at least 1 dose. The registry lists 4 outcome measures and 0 analyses. Serious-event counts are reported for Cohort A in China and the rest of the world. Because allocation was non-randomized, the registry cautions that the arms are not like-for-like controls. The record does not report a formal sample-size justification, missing-data methods, or a multiplicity strategy.