This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Safety and Activity of PolyPEPI1018 Plus Atezolizumab in Colorectal Cancer. (NCT05243862), a na phase 2 study. The primary outcome is The Incidence and Severity Treatment Related Adverse Events.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05243862 |
| Phase | Phase 2 |
| Condition | Colorectal Cancer Metastatic |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 18 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Treos Bio Limited |
| Results posted | Yes |
2. Clinical Question
Population
Participants had relapsed or refractory microsatellite-stable metastatic colorectal cancer. The study description says they had progressed on 2 or 3 prior regimens. The registry does not report further eligibility details in the record.
Intervention
Participants received PolyPEPI1018 CRC Vaccine by subcutaneous injection in combination with atezolizumab by intravenous injection. The registry describes both as administered every 3 weeks. The vaccine description specifies 0.2 mg per peptide, 6 peptides total, and Montanide ISA51VG adjuvant; the atezolizumab description specifies 1200mg/20mL.
Comparator
There was no separate comparator group in this single-group study. Allocation is listed as NA, and the record does not describe randomization. The results therefore do not provide a like-for-like control comparison with another treatment or with no treatment.
Primary question
The primary endpoint concerns the incidence and severity of treatment-emergent adverse events, including related events and serious adverse events. The registry also lists secondary outcomes covering objective response, duration of response, progression-free survival, overall survival, and immune responses. The posted safety counts describe adverse events; results for those secondary outcomes are not reported in the registry record.
3. Trial Design
This is a multicenter, open-label phase II study of PolyPEPI1018 vaccine combined with atezolizumab in participants with relapsed or refractory microsatellite-stable metastatic colorectal cancer. The registry lists the study as completed and reports enrollment of 18 participants. Its dates are start 2022-06-02 and primary completion 2024-07-08.
The design is single-group, with allocation listed as NA and masking listed as none. Participants received the combination rather than being assigned to separate treatment groups. Thus, the study can describe what was observed among people who received the combination, but it cannot use a randomized concurrent control group to distinguish treatment effects from other explanations for outcomes.
The intervention description specifies administration every 3 weeks. PolyPEPI1018 was described as a CRC vaccine solution with 0.2 mg per peptide, 6 peptides total, and Montanide ISA51VG adjuvant, given by subcutaneous injection. Atezolizumab was described as an injectable solution, 1200mg/20mL, given by intravenous injection.
The stated study aim was to determine safety, tolerability, immunogenicity, and initial clinical activity in participants who had progressed on 2 or 3 prior regimens. The registry lists objective response rate, duration of response, progression-free survival, overall survival, PEPI listing, and effector and memory T cell immune responses among secondary outcomes. Outcome results for these measures are not reported in the registry record. The registry record also does not report a sample-size justification, interim-analysis plan, or detailed statistical analysis plan.
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.
Overall Study
| Stage | PolyPEPI1018 Plus Atezolizumab |
|---|---|
| STARTED | 18 |
| COMPLETED | 0 |
| NOT COMPLETED | 18 |
Reasons for not completing this period:
| Reason | PolyPEPI1018 Plus Atezolizumab |
|---|---|
| Death | 9 |
| Withdrawal by Subject | 4 |
| discontinued study treatment, but completed the 90-day safety follow-up | 5 |
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.
| Characteristic | Unit | PolyPEPI1018 Plus Atezolizumab |
|---|---|---|
| Participants analysed | 18 | |
| Age, Continuous | years | 55.7 (SD 11.4) |
| Sex: Female, Male: Female | Participants | 12 |
| Sex: Female, Male: Male | Participants | 6 |
| Race/Ethnicity, Customized: Not Hispanic/Latino – Asian | Participants | 1 |
| Race/Ethnicity, Customized: Not Hispanic/Latino – Black or African American | Participants | 2 |
| Race/Ethnicity, Customized: Not Hispanic/Latino – White | Participants | 11 |
| Race/Ethnicity, Customized: Not Hispanic/Latino – Other | Participants | 2 |
| Race/Ethnicity, Customized: Not Hispanic/Latino – Not reported | Participants | 2 |
| Body mass index | kg/m2 | 29.468 (SD 6.8428) |
| ECOG Performance Status: ECOG = 0 | Participants | 10 |
| ECOG Performance Status: ECOG = 1 | Participants | 8 |
6. Primary Endpoint
The registry lists the primary outcome as The Incidence and Severity Treatment Related Adverse Events, measured over From 1st dose until 90-Days after last dose, up to 7.5 months..
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the incidence and severity of treatment-emergent adverse events. The registry describes assessment of all such events, related events, all serious adverse events, and related serious adverse events, using National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. The listed timeframe runs from the first dose until 90-Days after the last dose, up to 7.5 months.
The endpoint is expressed as a count of participants. This means the focus is on how many participants experienced an event, rather than on a comparison of event rates between randomized groups. The registry’s safety results list 18 participants at risk, with 4 affected by serious adverse events and 18 affected in the other-adverse-event count. These counts do not, by themselves, describe event severity distributions or establish whether an event was considered related to treatment.
Safety endpoints are used to characterize harms observed during and after exposure to a study treatment. Including both occurrence and severity helps distinguish the simple presence of an event from its graded seriousness. The record’s stated assessment period defines the window for this endpoint; it does not establish that all possible longer-term effects were captured.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry reports safety counts for 18 participants in the PolyPEPI1018 plus atezolizumab group. It records 4 participants affected by serious adverse events and 18 participants in the other-adverse-event count. It also records 9 deaths. These are descriptive counts from a small, single-group study, not estimates from a randomized comparison. They should be read as observations in this study population, not as evidence of how the combination compares with another option.
The listed serious-event terms include Disease progression at 11.1%, and Abdominal pain, Ascites, Intestinal obstruction, Nausea, and Rectal haemorrhage at 5.6% each. The registry record does not establish from these terms alone whether an event was considered related to study treatment. Nor does it clarify in the listed results whether participants could contribute to more than one term. These percentages should therefore be read as the registry’s reported term frequencies, not added together or treated as mutually exclusive categories.
The primary endpoint includes treatment-emergent events, treatment-related events, serious events, and related serious events. The aggregate safety counts do not provide separate counts for each of those endpoint components. In particular, the registry record does not report the number of participants with related adverse events or the number with related serious adverse events. The reported primary endpoint description and the posted safety counts therefore do not support a complete reconstruction of every planned safety measure.
No numerical results for objective response, duration of response, progression-free survival, overall survival, or immune-response outcomes are reported in the registry record. The study’s stated interest in initial clinical activity and immunogenicity is not itself an outcome result. Without those results, the record does not permit statistical interpretation of activity or immune response.
There is also no comparator group, so changes over time or event counts cannot be attributed to the combination by comparison with a control arm. In an open-label study, participants and study personnel know which treatment is being given; general statistical interpretation recognizes that this can affect how subjective outcomes are assessed or reported. The registry record does not describe any procedures intended to address that issue. Overall, the posted results offer a limited descriptive account of safety events in the enrolled group, while comparative effects and the listed secondary outcomes are not established by the record.
9. Statistical Methods Explained
What kind of result is reported?
The primary endpoint is a count of participants experiencing adverse events, so it is a binary outcome at the participant level: a participant either meets the specified event definition during the assessment period or does not. General statistical explanation: binary outcomes are often presented as counts and proportions. Counts preserve the direct observed information, while a proportion expresses the count relative to the number assessed. The registry’s safety record gives at-risk and affected counts, but it does not report confidence intervals or a formal inferential analysis for these results.
What does a confidence interval add?
General statistical explanation: a confidence interval describes the precision of an estimated quantity under a specified statistical model. It reflects that an estimate based on a finite sample is uncertain; it is not a guarantee that the true value lies within a particular interval. No confidence intervals are reported for the safety counts in the registry record, so their precision cannot be assessed from interval estimates in this record.
Why does the single-group design matter?
The study is listed as single-group, with allocation NA and no masking. General statistical explanation: a treatment contrast is most directly estimated by comparing outcomes between groups assigned to different strategies. Without a concurrent comparison group, an observed event count describes the enrolled participants, but there is no randomized group contrast to estimate the difference associated with treatment assignment. Other factors, including the illness and events that would occur over time without the study treatment, cannot be separated from treatment effects using these counts alone. The record does not provide a control-group result or a causal comparison.
Open-label status means the study was not masked. General statistical explanation: knowledge of treatment assignment can influence reporting, clinical assessment, or decisions about whether an event is recorded, especially when judgment is involved. That is a potential consideration, not evidence that any particular event count was biased. The registry record does not describe blinded assessment or other methods for limiting such influence.
How should the safety categories be read?
The endpoint description distinguishes all treatment-emergent adverse events from events considered related, and all serious adverse events from serious events considered related. These are different classifications: timing after treatment and seriousness do not alone establish treatment relatedness. The posted group counts provide 4 affected participants in the serious-event count and 18 in the other-adverse-event count, but do not provide separate related-event counts. General statistical explanation: counts in overlapping categories should not be added unless the categories are explicitly mutually exclusive. The registry record does not state that the listed serious-event terms are mutually exclusive, so their percentages should not be summed.
The primary endpoint timeframe is from first dose until 90-Days after last dose, up to 7.5 months. General statistical explanation: a defined observation window makes clear which events are intended to be counted, but a window also limits what the endpoint can describe. Events outside that interval are not represented by an endpoint restricted to that interval. The registry record does not report more detailed participant-level follow-up or exposure duration.
What can be inferred from the registry analyses?
The registry lists 10 outcome measures and 0 analyses. The record therefore does not report inferential analyses for the outcomes in the form of analysis results. No p-values, confidence intervals, adjusted estimates, or analysis populations are reported in the registry record. General statistical explanation: an inferential result depends on a defined estimand, analysis method, and assumptions; a count alone is descriptive and does not supply those elements.
The record includes a sample-size planning illustration based on an observed effect and states assumptions of a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also distinguishes total events for time-to-event planning from participants per arm for other planning. These assumptions describe an illustration, not the design rationale for this single-group trial. Planning counts are not observed power and do not establish that a study was adequately powered. The registry record does not report the trial’s own sample-size justification, a prespecified effect to detect, or its statistical plan.
General statistical explanation: over-dispersion matters when variability in observed data exceeds what a chosen model expects; ignoring it can make uncertainty appear too small. The registry record does not report a model-based analysis of these safety data, so over-dispersion is not an established feature of the posted results and no model correction can be assessed.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 10 outcome measures, including a primary safety endpoint and secondary measures of response, duration of response, progression-free survival, overall survival, and immune response. It reports 0 analyses. The registry record does not report a multiplicity strategy, such as a hierarchy among outcomes or an adjustment for testing multiple hypotheses. Without analysis results and a stated plan, it is not possible to assess how the many listed outcomes were handled statistically or how any inferential findings should be interpreted. No outcome-specific p-values are reported in the registry record.
Missing-data methods and analysis populations are not reported in the registry record. The enrollment count is 18, but the record does not state the number included in each outcome analysis, whether all enrolled participants were assessed throughout the endpoint window, or how withdrawals and incomplete follow-up were handled. The count of participants at risk in the safety summary is 18, but that does not supply details about missing observations for other outcomes or timepoints.
General statistical explanation: missing outcome data can affect interpretation when the people with observed results differ from those without results. The direction and magnitude of any effect depend on why data are missing and on the analysis assumptions; they cannot be inferred from an enrollment count alone. Similarly, multiplicity concerns the interpretation of several statistical tests, not simply the number of outcomes listed. Because the record does not provide analyses or a multiplicity plan, no conclusion about adjusted error rates or missing-data sensitivity can be drawn.
The registry record also does not report interim analyses, stopping rules, or a detailed protocol for handling outcome data. These omissions limit assessment of how the reported results relate to prespecified analytic decisions.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| PolyPEPI1018 Plus Atezolizumab | 4 | 18 | 22.2% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| PolyPEPI1018 Plus Atezolizumab | 9 of 18 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| PolyPEPI1018 Plus Atezolizumab | 18 of 18 |
Most frequent serious adverse event terms
| Event term | Organ system | PolyPEPI1018 Plus Atezolizumab |
|---|---|---|
| Disease progression | General disorders | 2 of 18 |
| Abdominal pain | Gastrointestinal disorders | 1 of 18 |
| Ascites | Gastrointestinal disorders | 1 of 18 |
| Intestinal obstruction | Gastrointestinal disorders | 1 of 18 |
| Nausea | Gastrointestinal disorders | 1 of 18 |
| Rectal haemorrhage | Gastrointestinal disorders | 1 of 18 |
| Vomiting | Gastrointestinal disorders | 1 of 18 |
Most frequent non-serious adverse event terms
| Event term | Organ system | PolyPEPI1018 Plus Atezolizumab |
|---|---|---|
| Injection site reaction | General disorders | 13 of 18 |
| Fatique | General disorders | 9 of 18 |
| Pyrexia | General disorders | 8 of 18 |
| Nausea | Gastrointestinal disorders | 6 of 18 |
| Headache | Nervous system disorders | 5 of 18 |
| Dyspnoea | Respiratory, thoracic and mediastinal disorders | 5 of 18 |
| Abdominal pain | Gastrointestinal disorders | 4 of 18 |
| Vomiting | Gastrointestinal disorders | 4 of 18 |
| Constipation | Gastrointestinal disorders | 4 of 18 |
| Decrease appetite | Metabolism and nutrition disorders | 4 of 18 |
Serious events with the highest arm-level rate: disease progression (11.1%), abdominal pain (5.6%), ascites (5.6%), intestinal obstruction (5.6%), nausea (5.6%).
The safety summary lists 18 participants at risk in the PolyPEPI1018 plus atezolizumab group. It records 4 participants affected by serious adverse events, 18 in the other-adverse-event count, and 9 deaths. These are participant counts; they should not be read as counts of every event episode. A participant may experience more than one event, and the registry record does not explain whether the listed event terms overlap.
The serious-event terms are reported as Disease progression at 11.1%, with Abdominal pain, Ascites, Intestinal obstruction, Nausea, and Rectal haemorrhage each at 5.6%. These are registry-listed frequencies. The record does not establish from this summary whether each term was considered treatment-related, nor does it provide a detailed severity breakdown for each term. The primary endpoint description refers to both all events and related events, but the summary does not provide separate related-event counts.
The 9 deaths are listed in the safety information, but the registry record does not report their causes or establish that they were related to treatment. The serious-event count and death count are separate summary values; the record does not state how they overlap. Because this is an open-label, single-group study, these figures describe observed events among participants who received the combination and do not offer a comparative risk estimate.
12. What the Result Does, and Does Not, Mean
The registry record establishes that this completed phase II study enrolled 18 participants in a single group receiving PolyPEPI1018 plus atezolizumab. It reports safety counts, including 4 participants affected by serious adverse events, 18 in the other-adverse-event count, and 9 deaths. It also lists several serious-event terms with their reported percentages. These findings provide descriptive information about events recorded among the study participants during the stated safety assessment period.
They do not establish whether the combination caused any particular event. The registry’s distinction between treatment-emergent and treatment-related events matters: an event occurring after treatment is not automatically an event attributed to treatment. Separate counts for related events are not reported in the registry record. The death count likewise does not establish cause or treatment relatedness.
The results also do not establish comparative safety or clinical activity. There is no randomized comparator group, and numerical results for the listed secondary outcomes are not reported in the registry record. The study’s aim to assess initial clinical activity and immunogenicity is a statement of purpose, not evidence that an outcome was observed or that a treatment effect was demonstrated.
General statistical explanation: a descriptive count can be informative about what occurred in a study group, but its precision and interpretation depend on sample size, follow-up, event definitions, and completeness of data. The registry record does not supply confidence intervals, detailed analysis populations, or missing-data methods for these results. Thus, the safety counts should be understood as the posted observations, without extending them to a broader population or interpreting them as a causal estimate.
The record is therefore useful for identifying the study design, endpoint definitions, and reported safety observations, while leaving major questions unresolved. It does not provide the analysis needed to quantify comparative effects, and it does not report results for the secondary clinical and immune outcomes.
13. Why This Trial Matters Statistically
This trial is statistically notable because it combines a defined safety endpoint with a single-group, open-label phase II design. That structure is relevant to interpretation: it can describe events recorded among participants receiving the combination, but it does not provide a randomized contrast. The registry’s safety results should therefore be treated as descriptive rather than as comparative estimates.
The endpoint also separates several concepts that are easy to conflate. Treatment-emergent events are assessed within a specified period after dosing, while related events reflect an attribution judgment; serious events are a distinct classification. The record describes all of these categories in the primary endpoint, yet the posted summary does not report separate counts for every component. Recognizing those distinctions prevents an event count from being mistaken for a count of events caused by treatment.
The study enrolled 18 participants, and the registry reports 4 affected by serious adverse events, 18 in the other-adverse-event count, and 9 deaths. Those observations are important to read in context rather than as stand-alone comparative risks. No confidence intervals or inferential analyses are reported in the registry record, and no numerical results are provided for the listed secondary clinical and immune outcomes.
More broadly, the record illustrates why statistical interpretation depends on both results and design. A list of outcomes or a planning illustration does not substitute for reported endpoint analyses. The planning assumptions described in the record are not evidence of observed power or of the study’s own sample-size justification. A careful reading separates the stated aims, the design, the safety observations, and the results that are not reported.
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 single-group design is the central limitation for comparative interpretation. With allocation listed as NA and no separate comparator, the registry results cannot estimate how safety or other outcomes differed from a control group. The open-label design also means masking was absent. The registry record does not describe blinded outcome assessment or other procedures for reducing assessment-related influence.
The study enrolled 18 participants. Safety counts from this group are descriptive, and the registry record does not report confidence intervals or other measures of uncertainty for them. The record also does not provide separate counts for all treatment-emergent events, related events, all serious events, and related serious events, although each category appears in the primary endpoint description.
Although the registry lists secondary outcomes for objective response, duration of response, progression-free survival, overall survival, PEPI listing, and effector and memory T cell responses, their numerical results are not reported in the registry record. It lists 10 outcome measures and 0 analyses. This prevents assessment of those outcomes, of the analyses used, and of how multiple outcomes were handled.
The record does not report analysis populations, missing-data methods, a sample-size justification, interim analyses, or a detailed statistical plan. It also does not provide information sufficient to determine how the 9 deaths overlap with serious adverse events or whether listed event terms overlap. These limitations restrict conclusions to the study design and posted descriptive safety observations; they do not support causal or comparative claims.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Activity of PolyPEPI1018 Plus Atezolizumab in Colorectal Cancer. — NCT05243862.
- Registry record last updated 2026-08-07; status last verified 2026-07.
- Results first posted 2026-08-07.
- 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.
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18. Record Summary
The registry describes a completed, multicenter, open-label phase II study of PolyPEPI1018 plus atezolizumab in relapsed or refractory microsatellite-stable metastatic colorectal cancer. The single-group study enrolled 18 participants, with allocation listed as NA and masking listed as none. The stated aim covered safety, tolerability, immunogenicity, and initial clinical activity.
The primary endpoint concerns the incidence and severity of treatment-emergent adverse events, including related and serious events, from first dose until 90-Days after last dose, up to 7.5 months. The safety summary reports 4 participants affected by serious adverse events, 18 in the other-adverse-event count, and 9 deaths. The registry record does not report numerical results for the listed secondary outcomes or inferential analyses, and it does not provide a randomized comparator.