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 AST-VAC2 Vaccine in Patients With Non-small Cell Lung Cancer (NCT03371485), a na phase 1 study. The primary outcome is Frequency and Causality of Serious Adverse Events (SAEs), Non-Serious Adverse Events (NSAEs) and Grade ≥3 Adverse Events (AEs) to AST-VAC2.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03371485 |
| Phase | Phase 1 |
| Condition | Advanced Non-small Cell Lung Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 9 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Cancer Research UK |
| Results posted | Yes |
2. Clinical Question
Population
Adults with advanced non-small cell lung cancer (NSCLC) were the intended study population. The trial enrolled 9 participants. The safety population was defined as enrolled participants who received at least one AST-VAC2 vaccination; the adverse-event summary lists 8 participants at risk.
Intervention
Participants received AST-VAC2, an allogeneic dendritic cell vaccine. The plan allowed up to six vaccinations over six weeks, with each weekly vaccination given as a split dose through two intradermal injections. The stated target dose was 1 x 10^7 viable cells, and no dose escalation was planned.
Comparator
There was no comparator group. The study used a single-group design, with no masking and allocation recorded as not applicable. The results therefore describe participants receiving AST-VAC2 rather than a contrast between treatment groups.
Primary question
The primary endpoint was the frequency and causality of serious adverse events (SAEs), non-serious adverse events (NSAEs), and Grade ≥3 adverse events (AEs) attributed to AST-VAC2. The study also aimed to learn about potential side effects, their management, and what happens to the vaccine inside the body. The registry record does not report detailed numerical results for each primary-endpoint category.
3. Trial Design
This was a completed phase I, single-group trial of AST-VAC2 in participants with advanced NSCLC. Cancer Research UK was the sponsor. The study enrolled 9 participants. Allocation was not applicable, and the trial had no masking. With no control group, its design supports description of safety observations in participants who received the vaccine, but does not provide a randomized treatment comparison.
The intervention was planned as weekly vaccination for up to six weeks, with a maximum of six vaccinations. Each vaccination was administered as a split dose through two intradermal injections, at a target dose of 1 x 10^7 viable cells. The registry record states that no dose escalation was planned. It does not report a rationale for choosing this dose or a sample-size justification.
The primary endpoint covered SAEs, NSAEs, and Grade ≥3 AEs, including whether events were considered related to AST-VAC2. The stated observation period ran from informed consent up to 2 years from the first dose; the reported median follow-up period was 402.5 days (101-770). The registry record also lists secondary outcomes concerning durable peripheral immune response, hTERT-specific T-cell changes, tumour response by immune-related response criteria, and overall survival at 2 years after the first vaccination. Numerical results for these secondary outcomes are not reported in the registry record.
The trial status is completed, with a primary completion date of 2022-08-08. Completion describes the study's status, not whether its results establish an effect. The single-group design, small enrollment, and limited outcome detail in the registry record are important when interpreting the posted safety counts.
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.
Main Trial (6 AST-VAC2 Vaccinations)
| Stage | Participants With Advanced NSCLC, to Receive AST-VAC2 |
|---|---|
| STARTED | 9 |
| COMPLETED | 8 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Participants With Advanced NSCLC, to Receive AST-VAC2 |
|---|---|
| Participant died before receiving AST-VAC2. | 1 |
2-year Follow-up
| Stage | Participants With Advanced NSCLC, to Receive AST-VAC2 |
|---|---|
| STARTED | 8 |
| COMPLETED | 3 |
| NOT COMPLETED | 5 |
Reasons for not completing this period:
| Reason | Participants With Advanced NSCLC, to Receive AST-VAC2 |
|---|---|
| Death | 5 |
Analysis population for the primary outcome, as defined in the registry: Safety Population: All enrolled participants who received at least one AST-VAC2 vaccination. This population will also be used for overall survival at 2 years post first AST-VAC2 vaccination. Participants are evaluable for survival regardless of whether they go on to receive another anti-cancer therapy.
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 | Participants With Advanced NSCLC, to Receive AST-VAC2 |
|---|---|---|
| Participants analysed | 9 | |
| Age, Continuous | years | 56 (53 to 62) |
| Sex: Female, Male: Female | Participants | 7 |
| Sex: Female, Male: Male | Participants | 2 |
| Race and Ethnicity Not Collected | Participants | — |
| Region of Enrollment: United Kingdom | participants | 9 |
6. Primary Endpoint
The registry lists the primary outcome as Frequency and Causality of Serious Adverse Events (SAEs), Non-Serious Adverse Events (NSAEs) and Grade ≥3 Adverse Events (AEs) to AST-VAC2, measured over From the time of informed consent up to 2 years from the first dose of AST-VAC2, a median (range) of 402.5 days (101-770)..
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Adverse Events |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint counts SAEs, NSAEs, and Grade ≥3 AEs, both overall and when considered related to AST-VAC2. This is a safety-focused endpoint: it records the frequency and seriousness of adverse events and includes an assessment of whether the study doctors judged an event to be causally related to vaccination. The endpoint description says that events were categorized using Medical Dictionary for Regulatory Activities version 25.0 and graded under National Cancer Institute Common Terminology Criteria for Adverse Events version 4.02, or the protocol-specific grading system for injection-site reactions.
For this endpoint, related events were those judged possible, probable, or highly probable in their causal relationship to AST-VAC2. All AEs and SAEs were collected until 30 days after the last vaccination; only related AEs and SAEs were collected after that point. The stated overall timeframe extended from informed consent up to 2 years after the first dose, with a median (range) of 402.5 days (101-770).
Counting events and grading severity can help describe the range of safety observations in an early-phase trial. The registry record defines these measures but does not report the full endpoint counts by event type, grade, or causal relationship. The adverse-event summary includes participant counts for serious events and an other-adverse-event category; those figures do not replace the complete endpoint breakdown.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted safety summary lists 8 participants at risk for serious adverse events and 0 participants affected in that category. It also lists 8 participants at risk and 8 affected in the other-adverse-event category, alongside 6 deaths. These are participant-level summary counts. The registry record does not provide event-level details, grades, timing, or a full account of causal attribution for these categories. In particular, the death count should not be read as a count of deaths caused by AST-VAC2: the record does not state that these deaths were attributed to vaccination.
The trial enrolled 9 participants, while the adverse-event summary lists 8 at risk. The safety population is defined as participants who received at least one vaccination, but the registry record does not explain the difference between the enrollment total and the adverse-event denominator. That distinction matters because the counts describe the participants included in the safety summary, not necessarily everyone enrolled.
Because this was a single-group study, there is no concurrent control group to indicate how often similar events might have occurred without AST-VAC2. The observed counts therefore describe what was recorded among participants in this trial; they do not estimate a comparative treatment effect. Nor do the counts alone establish whether any particular event was caused by vaccination. The endpoint definition includes doctor-assessed causality, but detailed related-event results are not reported in the registry record.
The study is phase I and enrolled a small group. In general, safety observations from a small group can identify events that occurred during follow-up, but they provide limited precision about how frequently uncommon events occur in a wider population. A count of zero in the serious-event summary does not establish that the underlying risk is zero. The registry record does not provide confidence intervals or other uncertainty estimates for the safety counts.
The record lists immune-response, tumour-response, and survival outcomes as secondary outcomes, but it does not report numerical results for them. No conclusions about those outcomes can be drawn from the posted results. Likewise, the available safety summary does not supply the full primary endpoint breakdown required to assess the frequency of NSAEs and Grade ≥3 AEs separately or the number judged related to AST-VAC2.
Any planning calculations based on an observed effect are illustrations, not observed power and not evidence that the trial was designed to detect that effect. The registry record does not report a trial-specific sample-size justification. Taken together, the posted information supports a limited descriptive reading of the safety summary, not a broad conclusion about comparative safety, efficacy, or causation.
9. Statistical Methods Explained
The trial's primary endpoint is based on adverse-event counts and categories. Interpreting such an endpoint requires attention to what is counted, which participants contribute to the denominator, how severity is graded, and how causality is assessed. These are general statistical considerations; details specific to this trial are stated where the registry record reports them.
What does a count endpoint describe?
A count endpoint records how many events, or how many participants with events, are observed during a defined period. Those are not interchangeable quantities: one participant can experience more than one event. The registry record's adverse-event summary gives participants at risk and participants affected for its listed categories, while the primary endpoint description refers to numbers of SAEs, NSAEs, and Grade ≥3 AEs. The complete event counts for each primary-endpoint category are not reported in the registry record, so the summary cannot be used to reconstruct them.
Counts also depend on the observation period and the population included. Here, the stated endpoint timeframe extends from informed consent up to 2 years after the first AST-VAC2 dose, and the reported median (range) is 402.5 days (101-770). The endpoint description says all AEs and SAEs were collected until 30 days after the last vaccination, while only related events were collected thereafter. This means event collection differed by period and causal assessment. Further details about the handling of incomplete follow-up are not reported in the registry record.
Why distinguish seriousness, severity, and causality?
Seriousness and severity describe different aspects of an adverse event. Seriousness is a regulatory and clinical classification; severity grades the intensity of an event. An event can be severe without meeting a definition of serious, or serious without being among the most severe grades. The primary endpoint separately identifies SAEs and Grade ≥3 AEs, reflecting that these categories are not synonyms. The record says events were graded under the stated criteria, or under a protocol-specific grading system for injection-site reactions.
Causality is a judgment about whether an event may be related to the intervention. The registry record says study doctors assessed the causal relationship and counted events as related when classified as possible, probable, or highly probable. Such an assessment is not, by itself, proof that vaccination caused the event. In a single-group study, causal interpretation is especially limited because the record lacks a concurrent control group for comparison.
How should denominators be read?
A denominator identifies the participants included in a particular summary. The study enrolled 9 participants, and the safety population is defined as enrolled participants who received at least one vaccination. The adverse-event summary lists 8 participants at risk. These figures should be kept distinct: the registry record does not explain the difference between the total enrolled and the adverse-event denominator. Counts describe the stated group and should not be silently generalized to all enrolled participants.
In general, a larger denominator can provide more information about how frequently an event occurs, while a small denominator leaves greater uncertainty about the frequency in a broader population. A confidence interval, when reported, describes statistical uncertainty around an estimate under specified assumptions. No confidence intervals for the adverse-event counts are reported in the registry record, so the precision of those counts cannot be quantified from the posted information.
What can a single-group design establish?
A single-group design can describe outcomes observed in participants receiving an intervention. Without a comparator, it cannot directly estimate how those outcomes differ from what would have occurred under another treatment or no study intervention. Background illness, other care, and events that can occur independently of treatment may also be relevant to interpretation, but the registry record does not provide a comparative analysis that separates these possibilities.
The trial's secondary outcomes include durable peripheral immune response, fold changes in hTERT-specific T cells across three peptide-pool assays, tumour response under immune-related response criteria, and overall survival at 2 years after first vaccination. These measures address different questions. Immune assays characterize measured immune responses; tumour response and survival are clinical outcomes. The registry record lists them but does not report their numerical results or the statistical analyses used to evaluate them.
What do the planning assumptions mean?
General sample-size calculations can illustrate how many participants might be needed under stated assumptions to detect a chosen effect with a chosen level of statistical power. The planning assumptions described for such illustrations include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a fraction of an observed effect. For time-to-event illustrations, the stated quantity is a total number of events; other illustrations are expressed as participants per arm. These are planning conventions, not features of this single-group trial's observed results. The registry record does not report the trial's own sample-size justification, and planning illustrations must not be described as observed power.
For event counts, over-dispersion is a general concern when counts vary more than a simple model assumes. In such settings, a model that assumes a fixed, simple count distribution may understate uncertainty. Whether over-dispersion was assessed or modeled in this trial is not reported in the registry record. No model specification or inferential analysis for the primary endpoint is reported.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists multiple secondary outcomes: durable peripheral immune response; hTERT-specific T-cell fold changes for three peptide pools; tumour response by immune-related response criteria; and overall survival at 2 years after the first vaccination. Testing or interpreting several outcomes raises a general multiplicity issue: the more questions examined, the greater the chance that at least one apparent finding could arise by chance when results are assessed statistically. Whether the trial specified a hierarchy, adjustment method, or other approach to multiplicity is not reported in the registry record. Numerical results and analysis details for the secondary outcomes are also not reported.
Missing-data methods are not reported in the registry record. In general, missing outcome observations can affect estimates, particularly when the reasons for missingness are related to participants' health or outcomes. The posted information does not describe the extent or pattern of missing data, imputation, or sensitivity analyses. The endpoint's collection windows are described, but they do not establish how incomplete follow-up was handled analytically.
The safety population is defined as all enrolled participants who received at least one AST-VAC2 vaccination. The record also says this population was used for overall survival at 2 years after the first vaccination, and that participants were evaluable for survival regardless of whether they went on to receive another anti-cancer treatment. The adverse-event summary lists 8 participants at risk, while total enrollment was 9; the reason for that denominator is not reported in the registry record. No analysis population details beyond those stated are reported.
The registry record does not report a statistical analysis plan, interim analyses, or inferential results for the primary endpoint. Absence of these details should not be filled in by assumption.
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 |
|---|---|---|---|
| Participants With Advanced NSCLC, to Receive AST-VAC2 | 0 | 8 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Participants With Advanced NSCLC, to Receive AST-VAC2 | 6 of 9 |
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 |
|---|---|
| Participants With Advanced NSCLC, to Receive AST-VAC2 | 8 of 8 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Participants With Advanced NSCLC, to Receive AST-VAC2 |
|---|---|---|
| Injection site reaction | General disorders | 8 of 8 |
| Fatigue | General disorders | 6 of 8 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 3 of 8 |
| Cough | Respiratory, thoracic and mediastinal disorders | 2 of 8 |
| Influenza like illness | General disorders | 2 of 8 |
| Musculoskeletal chest pain | Musculoskeletal and connective tissue disorders | 2 of 8 |
| Myalgia | Musculoskeletal and connective tissue disorders | 2 of 8 |
| Anaemia | Blood and lymphatic system disorders | 1 of 8 |
| Axillary pain | General disorders | 1 of 8 |
| Bone Pain | Musculoskeletal and connective tissue disorders | 1 of 8 |
The adverse-event summary lists 0 participants affected by serious adverse events among 8 participants at risk. Its other-adverse-event category lists 8 affected among 8 at risk, and the summary lists 6 deaths. These are the posted participant counts; they are not a complete event-level description of the primary endpoint.
The primary endpoint distinguishes serious events, non-serious events, and Grade ≥3 events, and also considers whether events were judged related to AST-VAC2. The registry record does not provide the full counts by these endpoint categories, severity grade, or causal relationship. The summary's other-adverse-event label should not be treated as a complete substitute for the separate NSAEs and Grade ≥3 AE results.
The 6 deaths are reported as a count in the adverse-event summary. The record does not state that they were caused by AST-VAC2 or identify their causes. The serious-event count of 0 should likewise be read as a description of this safety summary, not evidence that serious events cannot occur. The at-risk denominator is 8, whereas enrollment was 9; the registry record does not explain the difference.
12. What the Result Does, and Does Not, Mean
The posted results describe a completed phase I, single-group study of AST-VAC2 in participants with advanced NSCLC. The adverse-event summary records 0 participants affected by serious adverse events among 8 at risk, 8 affected in the other-adverse-event category among 8 at risk, and 6 deaths. These counts are descriptive observations from the trial. They do not, on their own, establish causation or show how outcomes compare with another intervention.
The primary endpoint was intended to characterize adverse events by frequency, seriousness, severity, and assessed relationship to AST-VAC2. Yet the registry record does not report a complete numerical breakdown for SAEs, NSAEs, Grade ≥3 AEs, or related events. Consequently, the summary counts do not answer every part of the primary safety question. The record also does not report numerical results for the listed immune, tumour-response, and survival outcomes.
The absence of a control group means there is no within-trial comparison for estimating what would have happened under a different treatment or without the vaccine. The absence of reported confidence intervals or detailed analyses also means the precision of the event estimates cannot be assessed from the registry record. With enrollment of 9 participants and 8 at risk in the adverse-event summary, the observations concern a small group and cannot precisely characterize uncommon events in a broader population.
These limitations do not make the recorded counts meaningless: they describe the safety observations included in the registry summary. But they set boundaries on interpretation. The counts should not be read as proof of vaccine-related harm or safety, and they do not establish a treatment effect. The record's stated safety focus, trial design, denominators, and missing outcome detail all matter when deciding what the posted results can support.
13. Why This Trial Matters Statistically
Early-phase trials commonly focus on safety characterization and on collecting information that can guide further study. This trial's primary endpoint was structured around adverse-event frequency, seriousness, severity, and causal assessment. Statistically, such a design makes careful definitions and denominators essential: readers need to know what was counted, in which population, over what period, and how events were classified.
The AST-VAC2 study illustrates why participant counts and event counts should not be conflated. The adverse-event summary reports participants affected in its listed categories, while the primary endpoint refers to numbers of events across several classifications. The record's distinction between the 9 participants enrolled and 8 at risk in the safety summary also shows why denominators need to be read alongside every result. The registry record does not explain that difference.
It also illustrates the limits of causal interpretation in an uncontrolled study. A single-group design can record events during treatment and follow-up, but it cannot provide a randomized comparison that distinguishes treatment-associated outcomes from background occurrences. Doctor-assessed relatedness adds structured information, but does not replace a comparator or prove causality.
Finally, the record shows the importance of complete reporting. It defines the primary endpoint and lists several secondary outcomes, but does not report detailed primary-event counts or numerical secondary results. Clear statistical interpretation depends not only on design but also on the availability of outcome breakdowns, analysis methods, and uncertainty estimates. Without those details, conclusions should remain limited to the descriptive information recorded.
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.
Enrollment was 9, and the adverse-event summary lists 8 participants at risk. The registry record does not explain why the summary denominator differs from enrollment. This limits interpretation of how the safety counts relate to the full enrolled group.
The study had a single group, no masking, and no comparator. As a result, the posted observations do not provide a treatment contrast, and event occurrence cannot be attributed to AST-VAC2 solely from these counts. The record's causal assessments are based on study doctors' judgments, with related events defined as possible, probable, or highly probable; detailed results under that definition are not reported.
The primary endpoint includes several categories, but full counts by seriousness, severity, and relationship to AST-VAC2 are not reported in the registry record. The summary's other-adverse-event count does not supply the complete breakdown of NSAEs and Grade ≥3 AEs. The listed death count has no reported cause or causal attribution in the summary.
The record reports a median follow-up of 402.5 days (101-770) for the stated endpoint timeframe, but does not report missing-data handling, censoring details, confidence intervals, or the statistical analysis methods used. It also does not provide numerical results for the listed immune, tumour-response, or survival outcomes. The trial-specific sample-size justification is not reported in the registry record. Together, these gaps limit assessment of precision, completeness, and the scope of conclusions supported by the posted information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: AST-VAC2 Vaccine in Patients With Non-small Cell Lung Cancer — NCT03371485.
- Registry record last updated 2024-08-09; status last verified 2024-03.
- Results first posted 2024-08-09.
- 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
NCT03371485 is a completed phase I, single-group study of AST-VAC2 in participants with advanced NSCLC, sponsored by Cancer Research UK. The trial enrolled 9 participants and planned up to six weekly vaccinations, administered as split intradermal doses. Its primary endpoint concerned the frequency and causality of serious, non-serious, and Grade ≥3 adverse events.
The adverse-event summary lists 8 participants at risk for serious events, with 0 affected; its other-adverse-event category lists 8 at risk and 8 affected, and it reports 6 deaths. The registry record does not provide full primary-endpoint breakdowns, causal attribution for the deaths, or numerical results for the listed secondary outcomes. The single-group design and limited outcome detail constrain comparative and causal interpretation.