Nivolumab (BMS-936558; MDX-1106) in Combination With Sunitinib, Pazopanib, or Ipilimumab in Subjects With Metastatic Renal Cell Carcinoma (RCC) (CheckMate 016): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Nivolumab (BMS-936558; MDX-1106) in Combination With Sunitinib, Pazopanib, or Ipilimumab in Subjects With Metastatic Renal Cell Carcinoma (RCC) (CheckMate 016) (NCT01472081), a non-randomized phase 1 study. The primary outcome is Number of Participants With AEs, SAEs, and AEs Leading to Discontinuation.

2. Clinical Question

3. Trial Design

This was a phase 1, parallel-group study with nonrandomized allocation and no masking. It was registered as CheckMate 016 and concerned nivolumab combined with sunitinib, pazopanib, or ipilimumab in metastatic renal cell carcinoma. The registry lists enrollment of 194 and records the study as completed. The listed start date is 2012-02-09 and the primary completion date is 2016-02-02.

The sunitinib combination description includes nivolumab at 0.3, 2.0 (starting dose), or 5.0 mg/kg intravenously every 21 days, with sunitinib 50 mg by mouth on Days 1-28 of a 42 day cycle. The pazopanib combination description lists the same nivolumab doses and schedule, with pazopanib 800 mg by mouth daily. The record describes both combinations as continuing until progressive disease, toxicity, or discontinuation for other reasons.

The ipilimumab combinations use different dose arrangements. The listed group labels include NIVO 3+IPI 1 (MG/KG), NIVO 1+IPI 3 (MG/KG), and NIVO 3+IPI 3 (MG/KG). Descriptions refer to induction and maintenance phases, with nivolumab given on different schedules and ipilimumab administered during induction in some regimens. Detailed schedule information is not reported in the registry record for every regimen.

Because allocation was not randomized, the groups should not be read as randomized treatment comparisons. The record does not report a common control arm, a statistical comparison plan, or enough information to determine whether differences in group outcomes reflect treatment or participant characteristics.

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: 194 participants were enrolled; 153 were treated. Participants were enrolled but not treated due to the following reasons: withdrawal of consent (n=5), no longer met study criteria (n=32), administrative reason by sponsor (n=1), or other reasons (n=3)

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All treated participants

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: All treated participants

Only the first 6 of 7 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With AEs, SAEs, and AEs Leading to Discontinuation, measured over From date of first dose to date of last dose plus 100 days (assessed up to March 2016, approximately 49 months).

The primary outcome is the number of participants with adverse events, serious adverse events, and adverse events leading to discontinuation. The registry identifies the population as all treated participants and gives the timeframe as from the date of first dose to the date of last dose plus 100 days, assessed up to March 2016, approximately 49 months.

An adverse event is defined as a new unfavorable symptom, sign, or disease, or worsening of a preexisting condition, whether or not it has a causal relationship with treatment. A serious adverse event is a medical event meeting the seriousness criteria described in the registry, including events resulting in death, persistent or significant disability or incapacity, drug dependency or abuse, life-threatening events, important medical events, congenital anomalies or birth defects, or events requiring or prolonging hospitalization. Treatment-related events are described as having a certain, probable, possible, or missing relationship to study drug.

Counting affected participants is a direct way to describe how often safety events were recorded in each treatment group. It is relevant to a phase 1 study whose stated purpose includes assessing safety and identifying a dose to use. The count does not by itself describe the duration or recurrence of events, and the registry record does not report the number of events per participant for this outcome. It also does not provide a count for adverse events leading to discontinuation in the posted safety figures.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information available for interpretation is limited. The record identifies a binary outcome type and defines its meaning as participants with an event, reported as counts. The primary endpoint is a safety outcome, not a time-to-event measure or a continuous measurement. No analysis results are listed for the secondary response and progression outcomes.

What does a participant count describe?

In general, a participant count records whether each participant experienced an event during the specified observation period. A participant who experiences an event contributes to the affected count; the at-risk count gives the group denominator for that outcome. This differs from counting every occurrence: a participant with repeated events may still be represented as an affected participant rather than as multiple participants. The registry’s primary endpoint is framed as a number of participants, and the available safety figures distinguish participants at risk from participants affected.

The endpoint is described over a period beginning at first dose and ending at last dose plus 100 days, with assessment up to March 2016, approximately 49 months. This observation window matters because safety counts depend on which period is included. Participants who are followed for different lengths of time can have different opportunities for an event to be observed. The record does not report participant-level follow-up duration or an analysis adjusting for time at risk, so the counts should be read as the posted descriptive summaries rather than as event rates adjusted for observation time.

Why does nonrandomized allocation matter?

In general, random allocation helps make treatment groups comparable at the start of a study, on average, for both measured and unmeasured participant characteristics. Here, allocation is listed as nonrandomized. This means the treatment groups cannot automatically be interpreted as exchangeable. For example, clinicians or study procedures may have assigned different participants to different regimens, but the details of allocation are not reported in the registry record. Even if the event counts differ, the difference could reflect group composition, treatment, or other factors.

A valid comparative analysis would need to address the study question, the allocation process, the outcome definition, and relevant participant characteristics. The registry record does not report such an analysis for the posted safety counts. It also lists no analyses in the record. Accordingly, the counts should not be converted into claims of statistical significance or causal treatment effects.

What would uncertainty estimates add?

In general, a confidence interval describes the range of values reasonably compatible with an estimate under a specified statistical model. It communicates precision as well as the estimate itself. A count alone does not show how uncertain an underlying event probability may be, and estimates based on small groups are generally less precise than estimates from larger groups. No confidence intervals for the posted safety counts are reported in the registry record.

Similarly, a p-value is a measure, under a statistical model and null hypothesis, of how unusual data at least as extreme as those observed would be. It does not measure the probability that a treatment is effective or that a result is due to chance. The registry does not report p-values or a hypothesis test for these safety figures. Without a reported comparison model and its assumptions, statistical significance cannot be inferred from the raw counts.

How should the planning illustration be understood?

The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes planning for a stated fraction of the observed effect. For time-to-event outcomes, its stated convention is total events; for other outcomes, it is participants per arm. Such values are planning illustrations, not observed trial results and not observed power. They do not establish that the trial was designed around those assumptions. The trial’s own sample-size justification is not reported in the registry record.

In general, a planning calculation asks what study size could be needed to detect an assumed effect under selected model assumptions. It is not evidence that the planned effect occurred, and it cannot substitute for reporting the estimate and its uncertainty. No sample-size justification or statistical plan is reported in the registry record. The illustration should therefore be read as a separate planning aid, not as a result of the trial.

What do the severity grades mean?

The record defines Grade 1 as mild, Grade 2 as moderate, Grade 3 as severe, and Grade 4 as potentially life-threatening or disabling. These grades describe severity, whereas seriousness is defined using regulatory-style event criteria such as hospitalization or life-threatening consequences. In general, severity and seriousness are related but distinct classifications. The posted group counts do not provide a full grade-by-grade breakdown, so the overall counts cannot show how events were distributed across grades.

10. Multiplicity, Missing Data and Analysis Populations

The study lists multiple secondary outcomes: best overall response rate, objective response rate, duration of response, progression-free survival at Week 24, and progression-free survival. The registry also identifies a primary safety outcome that combines adverse events, serious adverse events, and events leading to discontinuation. When a study examines multiple outcomes or comparisons, the chance of at least one apparently notable result can increase if each is tested separately. General methods for addressing this include prespecifying a hierarchy, adjusting significance thresholds, or treating analyses as exploratory. The analysis plan used for this study is not reported in the registry record, so it is not possible to determine whether or how multiplicity was addressed.

Results for the listed secondary outcomes are not reported in the registry record. The record also reports no analyses. It is therefore not possible to assess whether those outcomes were analyzed, whether estimates were adjusted, or whether results were omitted. No missing-data approach, censoring rules, or imputation method is reported in the registry record.

The primary endpoint describes all treated participants, but the registry does not provide enough detail to determine how participants with incomplete safety follow-up were handled. The posted safety groups give at-risk and affected counts, but do not explain the handling of missing observations or variations in time under observation. Death counts are not reported in the posted safety figures, and the endpoint title’s discontinuation component is not accompanied by reported counts.

These omissions limit interpretation of both precision and completeness. In general, missing outcome information can bias a summary if the participants with missing data differ systematically from those observed. The direction and size of any such effect cannot be assessed without details about missingness and the analysis population. The registry record does not report the statistical analysis plan, interim analyses, or sample-size justification.

11. 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: pyrexia (33.3%), myocardial ischaemia (16.7%), diplopia (16.7%), autoimmune colitis (16.7%), diarrhoea (16.7%).

The safety figures report, for each treatment group, participants at risk and participants affected by serious adverse events and other adverse events. For example, the sunitinib plus nivolumab group lists 19 of 33 participants affected by serious adverse events and 33 of 33 affected by other adverse events. The analogous figures are 13 of 20 and 20 of 20 for pazopanib plus nivolumab; 29 of 47 and 47 of 47 for NIVO 3+IPI 1 (MG/KG); 30 of 47 and 46 of 47 for NIVO 1+IPI 3 (MG/KG); and 4 of 6 and 6 of 6 for NIVO 3+IPI 3 (MG/KG).

These are participant counts, not counts of every episode. They are presented by treatment group and should be read descriptively. The groups were not randomized, have different regimens, and have different denominators; raw counts do not provide a fair standalone comparison of risk. No confidence intervals or adjusted comparisons are reported in the registry record. The listed serious-event terms and percentages provide additional description, but the record does not supply group-specific term counts alongside those percentages. Adverse-event discontinuation counts and deaths are not reported in the posted safety figures.

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

The posted results establish that safety events were recorded among participants in each listed treatment group. They provide counts of participants affected by serious and other adverse events, together with the at-risk group counts, and the registry lists several serious-event terms with percentages. Those summaries describe the observations recorded in this study; they are not, by themselves, estimates of comparative treatment effects.

The design is phase 1 and nonrandomized, with no masking. The treatment groups receive different combinations and dose schedules. Without random assignment and a reported comparative analysis, differences between the groups cannot be attributed solely to their regimens. The record also does not report confidence intervals for the safety counts, so the precision of group-specific estimates is not available from these results.

The registry’s stated purpose includes determining safety, effectiveness, and a dose to use. However, the posted outcome information available in the record centers on safety. Although response and progression outcomes are listed as secondary outcomes, their results are not reported in the registry record. The primary outcome title includes events leading to discontinuation, but those counts are also not reported. Thus the available results do not provide a complete account of effectiveness or all components of the primary endpoint.

These limitations mean the counts should not be used to claim that a combination is superior, safer, or more effective than another. They also do not establish what would happen in a different population or setting. The registry record does not report the analysis plan, participant-level follow-up details, missing-data handling, or a sample-size justification, all of which would help assess how robustly the summaries answer the study questions.

In general, a descriptive safety summary is useful for seeing the kinds and frequency of events recorded during a study, while a causal comparison requires a design and analysis capable of separating treatment effects from other explanations. The record supports the former, limited interpretation; it does not report enough information to support the latter.

13. Why This Trial Matters Statistically

This study illustrates a common statistical distinction in early-phase research: describing safety within treatment groups is not the same as estimating comparative effects between treatments. The registry reports counts of affected participants for several nivolumab combinations, but allocation was nonrandomized. This makes it important to avoid treating the groups as though they were randomized arms with a shared baseline profile.

The endpoint is also a reminder that outcome definitions shape interpretation. The primary outcome refers to participants with adverse events, serious adverse events, and events leading to discontinuation. Those components have different meanings: an event may be unfavorable without meeting the seriousness criteria, and a serious event is not necessarily treatment-related. The registry’s definition allows events with a missing relationship to study drug to be classified as treatment-related, alongside certain, probable, or possible relationships. A count alone cannot distinguish these categories unless the record reports them separately.

The record lists response and progression outcomes as secondary measures, but their results are not reported in the registry record. This makes completeness of outcome reporting a statistical concern, not merely a presentation detail. A reader cannot determine from the listed outcomes alone whether analyses were performed, what estimates they produced, or how uncertainty and multiple outcomes were handled.

Finally, the record’s planning illustration is distinct from the trial’s observed results and from its original design justification. Understanding that distinction prevents a planning calculation from being mistaken for evidence about the precision or power of the completed study. Overall, the registry highlights why design, outcome definitions, analysis reporting, and uncertainty estimates all matter when interpreting early-phase clinical evidence.

14. Limitations

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

The nonrandomized allocation is a central limitation for comparisons between regimens. The record does not describe how participants were assigned to groups or report an adjusted analysis. Because groups received different combination regimens, the posted counts cannot isolate a treatment effect from differences in the participants or their care.

The available safety summaries are limited to affected participant counts and at-risk group counts. The registry does not report confidence intervals, a comparative model, or participant-level follow-up information for these results. It also does not report deaths in the posted safety figures, or counts for the primary endpoint component concerning adverse events leading to discontinuation.

Although secondary response and progression outcomes are listed, their results are not reported in the registry record. The record does not report its statistical analysis plan, the handling of missing data, interim analyses, or sample-size justification. These gaps prevent assessment of analysis choices, outcome completeness, and the precision of estimates beyond the reported counts.

The detailed regimen descriptions for ipilimumab combinations are not complete for every group in the registry record. The group sizes also differ, including a group with 6 participants, which limits the stability of descriptive summaries for that group. In general, estimates based on fewer observations have greater uncertainty, but the registry does not provide uncertainty intervals to quantify it. These limitations call for interpreting the posted safety figures as descriptive observations rather than as definitive comparisons among combinations.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Nivolumab (BMS-936558; MDX-1106) in Combination With Sunitinib, Pazopanib, or Ipilimumab in Subjects With Metastatic Renal Cell Carcinoma (RCC) (CheckMate 016) — NCT01472081.
• Registry record last updated 2021-12-02; status last verified 2021-11.
• Results first posted 2019-08-02.
• 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.

18. Record Summary

NCT01472081, CheckMate 016, is a completed phase 1, parallel, nonrandomized study with no masking. It examined nivolumab combined with sunitinib, pazopanib, or ipilimumab in participants with metastatic renal cell carcinoma. Registry enrollment is 194. The recorded start date is 2012-02-09, and the primary completion date is 2016-02-02.

The primary outcome concerns participants with adverse events, serious adverse events, and adverse events leading to discontinuation. The posted safety figures provide serious and other adverse-event counts by treatment group. Response and progression outcomes are listed as secondary outcomes, but their results are not reported in the registry record. The nonrandomized design, absent uncertainty estimates, and missing analysis details constrain comparative interpretation.