Safety Study of MM-121 in Combination With Multiple Anticancer Therapies in Patients With Advanced Solid Tumors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety Study of MM-121 in Combination With Multiple Anticancer Therapies in Patients With Advanced Solid Tumors (NCT01447225), a non-randomized phase 1 study. The primary outcome is To Evaluate the Safety and Tolerability of Escalating Doses of the MM-121 Anticancer Therapies.

2. Clinical Question

3. Trial Design

This was a Phase 1, non-randomized, unmasked, parallel study of MM-121 combined with multiple anticancer therapies in patients with advanced solid tumors. The registry identifies Merrimack Pharmaceuticals as the sponsor and records the study as completed. The listed enrollment is 43.

Participants were assigned to combination arms involving gemcitabine, carboplatin, pemetrexed, or cabazitaxel. The registry describes escalating MM-121 doses in each combination. The schedules differed: the gemcitabine combination was given on Day 1 and Day 8 of every 3 week cycle, while the other listed combinations were administered on Day 1 of every 3 week cycle. The carboplatin regimen is described as carboplatin at AUC 6, and the pemetrexed regimen as pemetrexed at 500 mg/m2. These descriptions do not establish that the arms had otherwise comparable participants or treatment exposure.

Allocation was non-randomized and masking was absent. Consequently, the arm-specific safety figures are descriptive rather than results of a controlled, randomized comparison. The registry records a study start of 2011-10 and primary completion of 2013-11. The primary outcome timeframe ran from the first dose to 30 days after treatment termination, with the longest stated timeframe of 88.1 weeks. Further details of allocation decisions, dose-escalation rules, and the statistical plan are not reported in the registry record.

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.

Only the first 6 of 10 groups are shown.

Overall Study

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 To Evaluate the Safety and Tolerability of Escalating Doses of the MM-121 Anticancer Therapies, measured over From date of first dose to 30 days after termination, the longest 88.1 weeks.

The primary outcome concerns the number of participants reporting adverse events. The registry frames the endpoint as an evaluation of the safety and tolerability of escalating MM-121 doses with the listed anticancer therapies. The stated observation period begins on the date of first dose and continues to 30 days after termination; the longest timeframe is 88.1 weeks.

Counting participants who report events is useful in early-phase research because it gives a direct description of how often safety events were recorded among those treated. It does not, on its own, describe the number of separate events per participant, their duration, or their severity. A participant may report more than one event, so participant counts and event counts answer different questions. The registry also presents serious adverse event information separately from other adverse events.

In general, safety outcomes help characterize tolerability during dose escalation and can inform decisions about further study. They do not establish comparative safety without a suitable comparison design. The detailed safety and tolerability results are described in the adverse events and serious adverse events portion of the registry posting. The primary outcome record does not provide a single aggregate count or an inferential estimate for the primary question.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count describe?

A participant count records how many people in a defined group met the outcome definition. For adverse events, a count of participants affected differs from a count of events: one participant may experience multiple events, and an event may be recorded more than once across different terms or reporting categories. A participant-level count is therefore not a measure of total event burden, duration, or severity.

The registry gives arm-specific risk sets and affected-participant counts for serious and other adverse events. Interpreting these counts requires keeping the denominator attached to its own arm and outcome category. The serious adverse event figures and the other adverse event figures describe different outcome categories; they should not be added together. The record does not provide a combined count of participants with any adverse event across the study, and no such total should be inferred by adding the arm counts.

Why is design important for comparisons?

In general, random assignment helps balance measured and unmeasured characteristics between treatment groups, on average. When allocation is non-randomized, differences in baseline health, treatment selection, exposure, or follow-up can contribute to differences in observed outcomes. This means an arm-to-arm contrast may reflect those factors as well as the treatments themselves.

This study had a parallel design, but its arms combined MM-121 with different anticancer therapies and used different schedules. The parallel structure means that separate groups received separate regimens; it does not make those groups interchangeable controls. Because allocation was non-randomized and masking was absent, the observed counts are best treated as descriptions of the registry’s reported groups rather than causal estimates of the effect of a particular combination.

What does uncertainty mean?

In general, a confidence interval expresses the range of effect estimates that are reasonably compatible with the data and the assumptions of the analysis. It conveys statistical uncertainty in a way that a point estimate alone cannot. The registry information summarized for the primary safety outcome does not report a confidence interval or an inferential estimate. The precision of a contrast between arms therefore cannot be assessed from the listed counts alone.

Small early-phase groups commonly yield imprecise estimates, and an absence of a reported statistical test is not evidence that the groups are equivalent. A formal analysis would need a defined estimand, outcome definition, analysis population, and method for handling follow-up and missing observations. These details are not reported in the registry record. The record lists 0 analyses, so there is no posted inferential result to interpret for the primary question.

How should planning calculations be understood?

In general, a sample-size calculation describes the amount of information a future study might need under stated assumptions about an effect, error rates, allocation, and statistical method. It is a planning exercise, not a measure of the probability that a completed study found a true effect. Sample sizes derived from an observed effect are especially dependent on that estimate and should not be described as observed power.

The stated planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. These are assumptions for a planning illustration, not evidence that this trial was designed or conducted using those conditions. The actual trial was non-randomized and had several different combination arms. A planning calculation under equal allocation between two arms does not convert its observed safety counts into a randomized comparison.

What can secondary outcomes add?

Secondary outcomes can describe questions beyond the primary safety objective. The registry lists objective response rate, pharmacokinetics, pharmacokinetics (AUClast), and immunogenicity. In general, pharmacokinetic outcomes characterize drug exposure, while immunogenicity concerns immune responses to a therapeutic product. These outcomes require their own definitions, analysis populations, and methods. Their presence in the registry does not mean that results or analyses are reported.

Multiplicity arises when a study evaluates multiple outcomes or comparisons. In general, testing many hypotheses can increase the chance of at least one apparently notable result unless the analysis plan accounts for that testing. The registry record does not report a multiplicity strategy, a hierarchy of outcomes, or inferential analyses. It is therefore not possible to determine whether or how multiplicity was addressed. The descriptive adverse event counts remain useful as observations, but they do not support claims of statistical significance or comparative effect.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 11 outcome measures, including the primary safety and tolerability outcome and secondary outcomes for objective response rate, pharmacokinetics, AUClast, and immunogenicity. It lists 0 analyses. A statistical analysis plan, prespecified hierarchy of outcomes, and method for controlling multiplicity are not reported in the registry record. Without those details, it is not possible to tell whether any formal adjustment or prioritization was planned or used.

Missing-data handling is also not reported in the registry record. The record does not describe how participants who discontinued treatment, lacked follow-up, or had incomplete outcome assessments were handled for the primary outcome or secondary outcomes. The stated primary timeframe extends from first dose to 30 days after termination, with the longest timeframe of 88.1 weeks, but the record does not explain how differences in observation time were incorporated into analyses.

The analysis populations are not reported in the registry record. The arm-specific adverse event risk sets are given, but the registry information summarized does not specify whether those sets represent all enrolled participants, participants who received treatment, or another defined population. No conclusions about imputation, censoring, protocol deviations, or sensitivity analyses can be made from the posted results. These omissions limit assessment of precision and of how complete the reported safety observations are.

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: thrombocytopenia (18.2%), cellulitis (10.0%), device related infection (10.0%), erysipelas (10.0%), acute coronary syndrome (10.0%).

The serious adverse event figures are participant counts within the listed arm-specific risk sets. The record reports 9 of 11 participants affected for MM-121 plus gemcitabine, 7 of 11 for MM-121 plus carboplatin, 3 of 10 for MM-121 plus pemetrexed, and 2 of 11 for MM-121 plus cabazitaxel. Read each count with its own arm and denominator; they are not results of a randomized comparison.

The top serious adverse event terms include thrombocytopenia at 18.2%, and cellulitis, device related infection, erysipelas, acute coronary syndrome, and atrial fibrillation at 10.0% each. These listed terms describe reported events, not mutually exclusive groups of participants. The registry record does not report enough detail to combine these percentages or infer how many participants experienced multiple terms.

In general, a serious adverse event category and an event’s frequency are distinct descriptions. The participant counts do not communicate severity beyond the serious-event classification, duration, causal attribution, or the number of separate episodes. Further definitions and details are not reported in the registry record summarized.

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

The registry record describes a completed Phase 1 study that evaluated escalating MM-121 doses in combination with several anticancer therapies in patients with advanced solid tumors. Its primary focus was safety and tolerability, and the posted safety figures show that serious and other adverse events were recorded in the listed arms. The record also names several serious event terms and provides arm-specific participant counts.

Those observations do not establish that MM-121 caused a particular event, that one combination is safer than another, or that the treatments improve outcomes. The arms were non-randomized, used different companion therapies and schedules, and were not like-for-like control groups. The registry does not report an inferential comparison for the primary safety question, and it lists no analyses. It also does not provide a single aggregate primary-endpoint estimate in the information summarized.

The presence of objective response rate, pharmacokinetic, and immunogenicity outcomes in the registry does not establish what those outcomes showed. Results for those outcomes are not reported in the registry record summarized. The safety counts cannot be used as a substitute for efficacy or exposure results.

In general, early-phase safety observations can characterize events recorded during exposure and help frame questions for later research. The precision and interpretation of such observations depend on group size, follow-up, outcome definitions, and complete analysis reporting. The registry record does not provide all of those details. The appropriate conclusion is therefore limited to the descriptive safety information recorded for these combination groups, not a broader judgment of benefit or comparative safety.

13. Why This Trial Matters Statistically

This study illustrates a common statistical challenge in early-phase combination research: a safety question is studied across several regimens, but the groups are not randomized controls. The arm-specific adverse event counts can describe what was observed within each group, yet differences between groups cannot be attributed solely to MM-121 or to the accompanying therapy. Treatment selection, patient characteristics, and exposure may also matter, and relevant details are not reported in the registry record.

It also shows why the outcome definition matters. A count of participants reporting adverse events is not the same as a count of event episodes, an assessment of severity, or a comparison of time at risk. Separate reporting of serious adverse events and other adverse events makes it important not to combine distinct categories or interpret repeated event terms as separate participants.

For clinical researchers and statisticians, the record highlights the value of transparent reporting of analysis populations, missing-data handling, outcome definitions, follow-up, and planned comparisons. Without such information, readers can describe the posted counts but cannot assess inferential precision or reproduce an analysis. The registry’s listing of secondary outcomes alongside 0 analyses also illustrates that a registered outcome is not, by itself, a reported finding.

The study’s statistical contribution is therefore descriptive: it records safety observations across different MM-121 combinations during an early-phase investigation. Its design and reporting do not support a causal ranking of the regimens or a conclusion about efficacy.

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 principal limitation for interpretation is the non-randomized design. The listed arms had different companion therapies and schedules, so arm-level differences are not controlled comparisons. The registry record also states that masking was absent. These features limit causal interpretation of differences in adverse event counts.

The primary outcome is described as the number of participants reporting adverse events, but a single aggregate result for that endpoint is not reported in the registry information summarized. Arm-specific safety figures are available, while definitions of the analysis populations and methods for missing observations are not reported in the registry record. The record does not provide confidence intervals or hypothesis tests for the primary outcome.

The stated observation period extends from first dose to 30 days after termination, with the longest timeframe of 88.1 weeks. The record does not explain whether follow-up duration was similar across participants or how time at risk was considered in analyses. That matters when interpreting event counts, since counts alone do not account for differences in exposure or observation time.

The registry lists secondary outcomes but reports 0 analyses. Details of the statistical plan, multiplicity handling, dose-escalation rules, and the population used for each outcome are not reported in the registry record. The top serious adverse event terms are listed with percentages but without additional detail in the information summarized. Together, these limitations mean that the results are best interpreted descriptively, without inferring a comparative treatment effect or a definitive safety profile.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Safety Study of MM-121 in Combination With Multiple Anticancer Therapies in Patients With Advanced Solid Tumors — NCT01447225.
• Registry record last updated 2016-09-14; status last verified 2016-09.
• Results first posted 2016-09-14.
• 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

NCT01447225 is a completed Phase 1 study of MM-121 in combination with multiple anticancer therapies in patients with advanced solid tumors. The design was non-randomized, unmasked, and parallel. The registry records 43 enrolled participants and lists combinations with gemcitabine, carboplatin, pemetrexed, and cabazitaxel.

The primary outcome concerned safety and tolerability of escalating MM-121 doses, measured by participants reporting adverse events. The stated timeframe was from first dose to 30 days after termination, with the longest timeframe of 88.1 weeks. Secondary outcomes included objective response rate, pharmacokinetics, AUClast, and immunogenicity. The registry lists 11 outcome measures and 0 analyses.

Arm-specific serious and other adverse event counts are reported, but they are descriptive and do not form randomized comparisons. The registry record does not report an inferential analysis of the primary question, analysis populations, missing-data methods, or a multiplicity strategy.