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Colorectal Cancer Phase 2 Non-Randomized NCT02060188

CheckMate-142: Complete Statistical Analysis of Nivolumab-Based Therapy in Colorectal Cancer

An independent statistical review of the phase 2 CheckMate-142 study of nivolumab alone or nivolumab combination therapy in colorectal cancer, focusing on the registered objective response rate endpoint, trial design, statistical methodology, safety reporting, and the interpretation limits of a non-randomized study.

Trial status: COMPLETED  ·  Enrollment: 385  ·  Primary completion: 2024-10-22
Scope of this record

This page separates reported registry information from statistical interpretation. The ClinicalTrials.gov record identifies a registered binary objective-response endpoint and confirm that results have been posted, but no formal statistical analyses are included in the posted results.

Registry note: This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. View the ClinicalTrials.gov record.

1. Trial at a Glance

CheckMate-142 is a phase 2, non-randomized, parallel-design oncology study evaluating nivolumab alone or nivolumab combination therapy in colorectal cancer. The registry lists 385.0 enrolled participants, 6 arms, and one registered primary endpoint: objective response rate by investigator assessment using RECIST v1.1.

385
Enrollment
ClinicalTrials.gov registry
6
Arms
Parallel design
2
Phase
Phase 2
1
Primary Endpoint
Binary ORR
FeatureCheckMate-142
Trial nameCheckMate-142
Brief titleA Study of Nivolumab Alone or Nivolumab Combination Therapy in Colon Cancer That Has Come Back or Has Spread
PhasePhase 2
StatusCOMPLETED
AllocationNON_RANDOMIZED
Design modelPARALLEL
MaskingNONE
Primary purposeTREATMENT
Enrollment385
Arms6
Lead sponsorBristol-Myers Squibb
Sponsor typeINDUSTRY
Start2014-03-12
Primary completion2024-10-22
ClinicalTrials.gov identifierNCT02060188

2. Clinical Question

The registry describes a study of patients with colorectal cancer that includes microsatellite unstable colorectal cancer, microsatellite stable colorectal cancer, mismatch repair proficient colorectal cancer, and mismatch repair deficient colorectal cancer. The interventions listed are nivolumab, ipilimumab, cobimetinib, daratumumab, and BMS-986016.

Population

The registry conditions are Microsatellite Unstable Colorectal Cancer; Microsatellite Stable Colorectal Cancer; Mismatch Repair Proficient Colorectal Cancer; and Mismatch Repair Deficient Colorectal Cancer.

Interventions

The registry lists Ipilimumab, Nivolumab, Cobimetinib, Daratumumab, and BMS-986016 as drug interventions.

Comparator

The ClinicalTrials.gov record does not identify a randomized comparator. The allocation is explicitly recorded as NON_RANDOMIZED.

Primary question

The registered primary endpoint asks whether participants achieve a confirmed complete or partial response according to investigator-assessed RECIST v1.1 criteria.

Important registry-design distinction: the ClinicalTrials.gov record identifies the allocation as NON_RANDOMIZED, while the registered endpoint definition refers to “randomized participants.” Those are not interchangeable descriptions. This page preserves both pieces of registry information rather than resolving the discrepancy by inference.

3. Trial Design

01
Enrollment385.0 participants
02
Six ArmsParallel design
03
TreatmentDrug interventions
04
ResponseInvestigator RECIST v1.1
05
ResultsResults posted
Allocation
NON_RANDOMIZED
Design model
PARALLEL
Masking
NONE
Primary purpose
TREATMENT
STUDY · 6 ARMS

Multi-cohort treatment study

  • Six arms are listed in the registry.
  • The overall design is recorded as parallel.
  • Allocation is recorded as non-randomized.
  • Masking is recorded as none.
INTERVENTIONS

Registered drug interventions

  • Nivolumab
  • Ipilimumab
  • Cobimetinib
  • Daratumumab
  • BMS-986016

The registry extract does not provide enough arm-level information to reconstruct a complete six-arm treatment table. In particular, the available data do not establish the exact intervention composition, dose, schedule, or enrollment for every arm. Those details therefore are not inferred here.

4. Trial Population and Disease Definitions

The registry lists four colorectal-cancer condition categories. These definitions are important statistically because the biological classification of participants can affect how response rates are interpreted, particularly in a study that is not randomized.

Registered conditionRole in the trial record
Microsatellite Unstable Colorectal CancerOne of the conditions listed in the registry.
Microsatellite Stable Colorectal CancerOne of the conditions listed in the registry.
Mismatch Repair Proficient Colorectal CancerOne of the conditions listed in the registry.
Mismatch Repair Deficient Colorectal CancerOne of the conditions listed in the registry.

No baseline demographic table, baseline disease-characteristic table, or subgroup-specific response estimates are included in the ClinicalTrials.gov record. Those sections are therefore not reconstructed on this page.

5. Primary Endpoint

EndpointRegistered definition / time frameType
Objective Response Rate (ORR) by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 Per Investigator Assessment Time Frame: From date of randomization to the date of objectively documented progression or the date of subsequent systemic cancer therapy, whichever occurs first (Up to approximately 127 months) Binary

The registry defines objective response rate as the number of randomized participants who achieve a best overall response (BOR) of confirmed complete response (CR) or confirmed partial response (PR), based on investigator assessments using RECIST v1.1, divided by the number of all randomized participants.

The registry-reported definition continues beyond the available extract with the definition of complete response and related response criteria, but the ClinicalTrials.gov record terminate partway through that text. The endpoint is therefore presented using the registry wording available in the ClinicalTrials.gov record rather than completing the definition from an external source.

Binary endpoint structure
ORR = number with confirmed CR or confirmed PR ÷ number of randomized participants

Conceptually, ORR is a proportion. Unlike a hazard ratio, it does not describe an instantaneous event rate over time. It classifies each participant according to whether the prespecified response criterion was achieved.

6. Results Availability and Planned Analysis

Results are posted, but no formal statistical analyses are reported in the ClinicalTrials.gov record used for this page. The registry extract reports “Results Posted: Yes,” while no formal statistical analyses were posted. No treatment-effect estimate, confidence interval, or p-value is therefore reported here.

What the registry reports

The available results information establishes that outcome measures have been posted and that the registered primary endpoint is a binary objective response rate based on investigator assessment using RECIST v1.1.

What a formal analysis would normally involve

For a binary response endpoint, the statistical analysis would ordinarily begin with the number and proportion of participants achieving the prespecified response definition. Depending on the design and prespecified estimand, an analysis could also provide a confidence interval for the response proportion and, where a formal comparator or benchmark is defined, a hypothesis test against that prespecified reference.

For a non-randomized multi-arm study, the statistical interpretation is different from that of a randomized comparative trial. Response proportions can describe activity within cohorts, but differences between cohorts may reflect differences in patient characteristics, disease classification, eligibility, treatment selection, follow-up, or other factors rather than treatment effects alone.

No formal efficacy result posted:The presence of posted outcome measures is not equivalent to the presence of a formal comparative statistical analysis.

7. How to Analyze Objective Response Rate

Objective response rate is naturally expressed as a binomial proportion. If x participants meet the confirmed CR or PR definition among n participants in the analysis set, the estimated response rate is:

Response-rate estimator
p̂ = x / n

The numerator is the number of participants meeting the prespecified response definition, while the denominator is determined by the analysis population specified for the endpoint.

Confidence intervals

A confidence interval is important because a response proportion calculated from a finite number of participants is an estimate rather than a known population parameter. For a binomial endpoint, an exact or score-based interval may be preferable to a simple normal approximation, particularly when the sample size is modest or the observed response proportion is close to 0 or 1.

Why the analysis population matters

The registered endpoint definition uses all randomized participants as its denominator. Yet the overall trial allocation is recorded as non-randomized. That creates an important interpretive issue: the precise analysis population used for the posted result should be verified against the underlying registry results and statistical analysis plan rather than inferred from the trial's general enrollment number.

8. Statistical Methodology

Binary outcome analysis

The primary endpoint is explicitly classified as Binary. A binary endpoint records whether each participant satisfies a prespecified condition. Here, the condition is achieving a confirmed complete response or confirmed partial response according to investigator assessment using RECIST v1.1.

Binary-data framework
X ~ Binomial(n, p)

In a simple binomial formulation, X represents the number of responders among n analyzed participants and p represents the underlying response probability.

Confidence intervals for a proportion

The uncertainty around an ORR estimate should be communicated with a confidence interval rather than relying only on the point estimate. The interval quantifies sampling uncertainty under the chosen statistical method; it does not describe the range of response probabilities for individual participants.

Comparative testing

A comparative hypothesis test requires a clearly specified comparison. In a randomized two-arm trial, that comparison could be a difference in response probabilities, a response-rate ratio, or another prespecified effect measure. In a non-randomized multi-arm study, the meaning of a between-cohort comparison depends critically on how treatment assignment and the populations being compared were defined.

Investigator assessment

The registered endpoint specifies investigator assessment. This matters because response classification is an assessment process rather than a purely administrative outcome. Any statistical interpretation of ORR must therefore retain the endpoint's prespecified assessment framework rather than treating response as an unspecified binary event.

RECIST v1.1

The endpoint explicitly references Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Thus, the binary response variable is constructed from a standardized radiographic response framework rather than from an unspecified clinical judgment.

9. Statistical Methods Explained

Why is ORR a binary endpoint?

Each participant is ultimately classified according to whether the prespecified response criterion is met. Confirmed CR or confirmed PR qualifies as response under the registered definition; participants who do not satisfy that definition do not contribute to the responder numerator. This makes the primary endpoint naturally suitable for binomial-proportion methods.

What does ORR measure?

ORR measures the proportion of participants achieving the specified objective tumor response. It is a measure of response frequency, not a direct measure of overall survival, progression-free survival, duration of response, or quality of life.

Why is the confidence interval important?

Two studies can have the same observed response proportion but different statistical precision if their analysis populations differ in size. A confidence interval makes that uncertainty visible. A narrow interval indicates greater precision under the specified statistical framework; a wider interval indicates greater uncertainty.

Why does a p-value not measure the size of an ORR?

A p-value addresses compatibility with a specified null hypothesis under the chosen statistical model. It does not tell the reader how large the response rate is, how clinically important a response is, or what proportion of individual patients will respond. Those questions require the response estimate and its uncertainty, together with clinical context.

Why is non-randomization important?

Randomization helps balance measured and unmeasured prognostic factors between treatment groups in expectation. Because the registry records CheckMate-142 as non-randomized, a difference in response between treatment cohorts cannot automatically be interpreted as a causal treatment effect. Patient selection and cohort composition can contribute to observed differences.

Why should the registry's denominator be checked carefully?

The registered endpoint definition states that the response rate is calculated using randomized participants as the denominator, while the overall allocation is recorded as non-randomized. That apparent inconsistency makes verification of the actual analysis population especially important before interpreting a posted ORR.

10. Safety Results

Safety information reported in the registry extractAffected / at risk
Serious adverse events by arm Cohort 1: Nivolumab Monotherapy: 46/74; Cohort 2: Nivolumab 3 mg/kg + Ipilimumab: 72/119; Cohort 3: Nivolumab 3 mg/kg Q2W with Ipi: 22/45; MSS Nivolumab 3 mg/kg + Ipilimumab 1 mg/: 8/10; Non-MSI-H: Nivolumab 1 mg/kg + Ipilimuma: 3/3; Non-MSI-H: Nivolumab 1 mg/kg + Ipilimuma: 9/10; Cohort 4: Nivoluma

The serious-adverse-event data also illustrate why denominators matter. A count such as “46/74” communicates both the number of affected participants and the number at risk. A count without its denominator would not provide enough information to compare event frequency across cohorts.

11. Interpretation of a Non-Randomized Multi-Arm Study

Within-cohort description

An ORR can describe the observed frequency of response within a defined cohort, provided the analysis population and response rules are clearly specified.

Between-cohort comparison

Observed differences between non-randomized cohorts can reflect treatment as well as differences in the populations receiving each intervention.

Confounding

Without random allocation, measured and unmeasured prognostic factors may differ between treatment groups and complicate causal interpretation.

Endpoint scope

ORR captures tumor response according to the registered RECIST v1.1 framework. It does not by itself establish durability of response or a time-to-event benefit.

This distinction is central to the statistical reading of CheckMate-142. A response rate is a useful descriptive endpoint, but the inferential question changes depending on whether the analysis is estimating activity within a cohort, comparing cohorts, or testing against a prespecified benchmark.

12. Registered Design Features and What They Imply Statistically

Design featureRegistry informationStatistical implication
AllocationNON_RANDOMIZEDTreatment-group differences cannot automatically be attributed to treatment because assignment is not randomized.
Design modelPARALLELThe study is organized into parallel treatment cohorts rather than a crossover design.
MaskingNONEThe registry records an unmasked study; the primary endpoint is investigator assessed.
Primary purposeTREATMENTThe registry classifies the principal purpose as treatment.
Arms6The study contains multiple treatment cohorts, making arm-specific denominators and analysis populations important.
Primary endpointBinary ORRThe principal registered outcome is naturally analyzed as a response proportion.

13. Multiplicity and Multiple Arms

The trial has 6 arms, but the ClinicalTrials.gov record does not provide a multiplicity strategy. Consequently, this page does not assume a particular familywise-error procedure, hierarchical testing sequence, adjustment method, or number of confirmatory pairwise comparisons.

This is an important distinction. Multiple treatment cohorts can generate many possible comparisons, but the existence of several arms does not by itself establish that every possible comparison was intended to be confirmatory. The appropriate interpretation depends on the prespecified statistical analysis plan.

Multiplicity concept
More formal tests → greater need to define the error-control strategy prospectively

If several hypotheses are tested within one confirmatory family, the probability of at least one false-positive conclusion can exceed the nominal level unless the testing strategy accounts for multiplicity.

14. Interim Analysis, Bayesian Methods, and Missing Data

The ClinicalTrials.gov record does not report an interim-analysis strategy, alpha-spending method, Bayesian model, missing-data imputation method, or formal multiplicity procedure.

Methodological topicWhat can be established from the ClinicalTrials.gov record
Interim analysisNo interim-analysis method is reported.
Alpha spendingNo alpha-spending method is reported.
Bayesian methodsNo Bayesian statistical method is reported.
Missing-data / imputationNo missing-data or imputation method is reported.
MultiplicityNo formal multiplicity strategy is reported.
StratificationNo statistical stratification factors are reported.

These omissions do not mean that such methods were necessarily absent from the complete protocol or statistical analysis plan. They mean only that the ClinicalTrials.gov record does not document them, so they should not be presented as established features of the analysis.

15. Analysis Populations

The registered primary endpoint definition specifies “randomized participants” as its denominator, but the overall trial allocation is recorded as NON_RANDOMIZED. The ClinicalTrials.gov record does not provide a complete definition of the actual efficacy analysis population.

Population conceptStatus in the ClinicalTrials.gov record
Randomized populationReferenced in the registered endpoint definition, although overall allocation is recorded as non-randomized.
Efficacy analysis populationNot separately defined in the ClinicalTrials.gov record.
Safety populationArm-level serious-adverse-event affected/at-risk information is reported, but a complete population definition is not.
Per-protocol populationNot reported.

For a binary response endpoint, changing the denominator can materially change the estimated ORR. Therefore, a response percentage should always be interpreted alongside the population from which the numerator and denominator were derived.

16. Clinical Biostats Interpretation of the Primary Endpoint

What the estimate would mean

An ORR estimate would represent the proportion of participants in the specified analysis population who achieved a confirmed complete response or confirmed partial response according to investigator assessment using RECIST v1.1.

What it would not mean

ORR would not mean that the same proportion of participants were cured, remained progression-free for a specified period, or experienced a particular survival benefit. Response is one clinical endpoint with a specific definition.

Why the confidence interval matters

A confidence interval around ORR would describe statistical uncertainty around the estimated response proportion under the selected binomial framework. It would not describe the probability that an individual participant will respond.

Why the p-value matters differently

If a formal hypothesis test were specified, its p-value would quantify evidence against a particular null hypothesis under the chosen model. It would not measure the magnitude of ORR or establish clinical importance by itself.

Why non-randomization matters

Because allocation is recorded as non-randomized, a difference in observed response between cohorts would require caution. Differences in participant characteristics or treatment selection could contribute to the observed result.

17. Limitations

18. Why This Trial Matters Statistically

CheckMate-142 is a useful statistical teaching case because it demonstrates how the interpretation of a clinical-trial result depends not only on the endpoint but also on allocation, cohort structure, analysis populations, and the prespecified inferential framework.

ConceptHow it appears in CheckMate-142
Binary endpointObjective response rate is the registered primary endpoint type.
RECIST-based responseORR is based on investigator assessment using RECIST v1.1.
Non-randomized designAllocation is explicitly recorded as NON_RANDOMIZED.
Multi-arm studyThe registry lists 6 arms.
Denominator selectionThe endpoint definition specifies randomized participants, creating an important population-definition issue because the study is recorded as non-randomized.
Confidence intervalsA proportion estimate should be interpreted together with its statistical uncertainty when a formal analysis is available.
MultiplicityMultiple arms can create multiple potential comparisons, but the ClinicalTrials.gov record does not specify an error-control strategy.
Safety denominatorsSerious adverse events are reported as affected/at-risk counts for several cohorts.
Results interpretationResults are posted, but the registry-reported statistical-analysis array contains no formal analyses.

19. Trial Timeline

2014-03-12

Study start

The registry lists 2014-03-12 as the study start date.

Phase 2

Clinical development phase

The trial is recorded as phase 2 with treatment as its primary purpose.

385

Enrollment

The registry lists enrollment of 385.0 participants across 6 arms.

2024-10-22

Primary completion

The registry lists 2024-10-22 as the primary completion date.

COMPLETED

Current registry status in the ClinicalTrials.gov record

The trial is recorded as COMPLETED, with results posted in the ClinicalTrials.gov record.

20. Four Questions a Statistician Should Ask Before Reading the ORR

1. What is the denominator?

Confirm exactly which participants are included in the analysis population and reconcile that definition with the registered wording referring to randomized participants.

2. What is the response definition?

Confirm that the response classification follows the registered investigator-assessed RECIST v1.1 framework and the required confirmation rules.

3. Is there a comparator?

Determine whether the reported analysis is descriptive within a cohort or makes a prespecified comparison. the ClinicalTrials.gov record records non-randomized allocation.

4. What uncertainty is reported?

Look for a confidence interval and the method used to construct it. A response percentage without uncertainty provides an incomplete statistical picture.

21. Statistical Concepts in This Trial

Learn more about the methods used in this trial:

22. Related Statistical Calculators

Explore calculators that support the statistical concepts behind this trial:

23. Sources

Continue through Clinical Biostats

Connect this trial's response endpoint, clinical-trial design, and safety concepts with broader statistical tutorials and practical calculators.

24. Record Summary

CheckMate-142 is a phase 2, non-randomized, parallel-design oncology study with 385.0 enrolled participants, 6 arms, and a registered binary primary endpoint measuring objective response rate by investigator assessment using RECIST v1.1. The registry reports results as posted, but the ClinicalTrials.gov record contains no formal analysis records. The statistically appropriate interpretation is therefore to distinguish the registered endpoint and design from any efficacy conclusion that would require a verified result, analysis population, confidence interval, and prespecified comparison framework.

Clinical Biostats methodology: A trial-results page should reconstruct the statistical question without filling gaps in the evidence. For CheckMate-142, that means preserving the registry's non-randomized design, recognizing the registered ORR definition, identifying the denominator issue, and avoiding unsupported effect estimates when formal statistical analyses are not present in the ClinicalTrials.gov record.