Study of [68Ga]FAPI-46 PET in Patients With Pancreatic Ductal Carcinoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of [68Ga]FAPI-46 PET in Patients With Pancreatic Ductal Carcinoma (NCT05262855), a na phase 2 study. The primary outcome is Sensitivity of [68Ga]FAPI-46 PET Imaging to Detect PDAC, Using Histopathology as Truth Standard.

2. Clinical Question

The study was designed to assess whether the imaging result identified disease in the setting of resectable or borderline resectable pancreatic ductal adenocarcinoma. Its primary endpoint was defined at the participant level and concerned the primary lesion. A positive PET result was compared with histopathology, which served as the reference standard for classifying the lesion.

This is a diagnostic-imaging question, not a comparison of treatment outcomes. The study had a single group, was open label and non-randomized, and did not include a like-for-like control arm. The registry describes additional aims involving PET uptake and immunohistochemistry staining, diagnostic specificity, and adverse events. Those aims do not substitute for the missing primary sensitivity result.

Because the numerical endpoint result is not reported, the record does not establish the observed sensitivity or its precision. The study question can be described from its design and endpoint definition, but the magnitude of the primary finding cannot be interpreted from the registry record.

3. Trial Design

This was a phase 2, multicenter, single-arm, open-label, non-randomized study of [68Ga]FAPI-46 PET in participants with resectable or borderline resectable pancreatic ductal adenocarcinoma. The registry reports an enrollment of 63 and a completed study status. These design details describe the study structure and enrollment; they do not provide the number included in the primary endpoint analysis.

Participants received [68Ga]FAPI-46 intravenously and underwent PET/CT 15-25 minutes later. The study summary says that an initial scan was acquired after initial staging using institutional standard methods. For participants prescribed neoadjuvant therapy, a second scan was planned within 21 days before planned surgical resection. Histopathology and immunohistochemistry analyses were then compared with resected tumor specimens.

The primary endpoint concerned sensitivity for detecting pancreatic ductal adenocarcinoma, using histopathology as the reference standard. The analysis population definition required receipt of the imaging agent, an interpretable PET result for at least 1 lesion, and a corresponding histopathology result. The registry specifies Day 1 as the primary endpoint timeframe. It does not report the endpoint estimate, confidence interval bounds, or the numbers of true-positive and false-negative findings.

With no random allocation or separate control group, the study does not estimate a contrast between two assigned interventions. Its core statistical question is descriptive and diagnostic: how often PET was positive among participants whose primary lesion was confirmed by histopathology. Open-label conduct is part of the recorded design; the registry record does not report whether image interpretation or histopathology assessment was blinded.

The registry record does not report the rationale for the enrollment target, a detailed statistical analysis plan, or whether any interim analyses were conducted. The completed status indicates the study is recorded as completed, but it does not itself convey the primary endpoint result. Completion and outcome reporting are distinct: the primary numerical finding remains 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.

Before assignment: A total of 63 participants were enrolled in the study.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Efficacy Analysis Set 1 comprised of all participants who received \[68Ga\]FAPI-46, with an interpretable FAPI-46 PET image result (positive or negative) for at least 1 lesion with a corresponding histopathology result (positive or negative). Only those participants with data available at specified timepoints have been presented.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Safety Analysis Set which comprises of all participants who received any amount of \[68Ga\]FAPI-46.

6. Primary Endpoint

The registry lists the primary outcome as Sensitivity of [68Ga]FAPI-46 PET Imaging to Detect PDAC, Using Histopathology as Truth Standard, measured over Day 1.

The primary endpoint is sensitivity of [68Ga]FAPI-46 PET imaging for detecting pancreatic ductal adenocarcinoma, using histopathology as the reference standard. The endpoint is described as the proportion of participants with histopathology-confirmed disease who had a positive PET result for the primary lesion. The registry defines sensitivity as A / (A + C), where A represents true-positive findings and C represents false-negative findings.

Sensitivity addresses the frequency of positive imaging results among cases identified as positive by the reference standard. In general, it is useful when the clinical research question concerns how often an imaging method detects disease that the chosen standard identifies. It does not, by itself, describe how often a positive scan is correct across all tested participants; that is a different diagnostic property. The registry separately lists specificity as a secondary outcome.

The registry describes matching a single readable PET image to its reference histopathology assessment. This pairing matters because the endpoint is not simply a count of positive scans: the PET finding must be compared with the corresponding pathology result. The population definition also requires an interpretable image and available histopathology for at least 1 lesion.

The endpoint description specifies a 90% confidence interval, but the numerical sensitivity estimate and interval bounds are not reported in the registry record. Without those results, neither the observed detection proportion nor the precision of that estimate can be assessed. The stated endpoint and its definition explain what was intended to be measured, not what the study found.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The main statistical method described for the primary outcome is a diagnostic sensitivity calculation. The study compares a PET classification with a histopathology classification for a corresponding primary lesion. Histopathology is treated as the reference standard. The registry defines sensitivity as A / (A + C), with A representing true-positive findings and C representing false-negative findings. In general, a true positive is a finding classified as positive by both the test and reference standard; a false negative is a reference-positive finding classified as negative by the test.

What does sensitivity describe?

Sensitivity describes the proportion of reference-positive cases that the test identifies as positive. Its denominator is restricted to cases positive according to the reference standard, rather than all participants who underwent imaging. In general, that makes sensitivity a measure of detection among known positive cases. It does not describe the probability that a positive test is correct, and it does not capture every aspect of diagnostic performance. The registry lists specificity as a separate secondary outcome, reflecting a different question about results among reference-negative cases.

For this study, the primary endpoint is defined for participants with histopathology-confirmed pancreatic ductal adenocarcinoma and a positive PET result for the primary lesion. The registry says that sensitivity was calculated by comparing positive and negative PET findings with corresponding histopathology results, using a single readable PET image matched to its reference assessment. The primary endpoint timeframe is Day 1. The registry record does not report the observed counts needed to inspect the calculation or the resulting estimate.

Why match PET and histopathology?

A diagnostic measure depends on a meaningful pairing between the test and reference assessment. Matching the PET image to corresponding histopathology aims to ensure that both assessments concern the same lesion. If results from unrelated lesions or mismatched assessments were combined, the resulting classifications could answer a different question. The registry describes this matching approach but does not report additional operational details about image review, adjudication, or blinding.

The primary analysis population is described as participants who received [68Ga]FAPI-46 and had an interpretable PET result, positive or negative, for at least 1 lesion with a corresponding histopathology result, positive or negative. This is an analysis-set definition, not the same as overall enrollment. It identifies who could contribute to the endpoint under the stated criteria. The registry does not report the number meeting those criteria, the number with unavailable pathology, or the number with an uninterpretable scan.

What does a confidence interval add?

The registry specifies a 90% confidence interval for the primary endpoint. In general, a confidence interval expresses sampling uncertainty around an estimate under the method used to construct it. It is not a guarantee that the true value lies within a particular interval, and it does not remedy potential bias or limitations in the study design. The interval’s width helps readers judge precision: a broad interval signals less precision than a narrow one. Neither the primary estimate nor its interval bounds are reported in the registry record, so precision cannot be evaluated for this study.

The registry entry does not identify the specific confidence-interval calculation method. That matters because interval methods can differ, especially when the underlying estimate is a proportion and the available number of observations is limited. The method and its assumptions are not reported in the registry record. They should not be inferred from the stated confidence level alone.

What can the single-arm design estimate?

Because the study is single group and non-randomized, there is no randomized comparator arm. The primary analysis is therefore not a between-group treatment contrast. It estimates a diagnostic property against a reference standard within the eligible analysis population. In general, this design can address whether PET results correspond with pathology classifications, but it cannot isolate a causal effect of assigning one imaging strategy rather than another.

Open-label status means the study is recorded as unmasked. It does not by itself establish that every assessment was unblinded, nor does the record give enough detail to determine whether image readers or pathology assessors were kept unaware of other findings. Those procedures can matter because diagnostic classification involves assessment. The registry record does not report those details.

Why can over-dispersion matter in other analyses?

General statistical note: over-dispersion occurs when observed variability is greater than a statistical model expects. It can make standard errors too small if the model assumes less variability than is present, leading to confidence intervals that are too narrow and tests that appear more precise than warranted. It is particularly relevant to some count or clustered-data models. The primary endpoint is described as a proportion, and the registry does not report a model-based analysis or an over-dispersion assessment. No claim about over-dispersion can therefore be made for this study.

The registry lists a correlation analysis between PET uptake, expressed as SUVmax, and immunohistochemistry staining intensity, expressed as an H-score. It also lists secondary sensitivity and specificity outcomes using H-score as the reference standard. Those methods address questions distinct from the primary histopathology-based sensitivity endpoint. The registry record does not report the statistical procedures, estimates, or uncertainty measures for those secondary analyses.

Finally, a sample-size calculation would concern planning assumptions and a target design, not observed diagnostic performance. The registry record does not report the study’s sample-size justification or the assumptions used to set enrollment. The enrollment figure is not an endpoint result and should not be treated as evidence of precision or as observed power.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("68Ga-FAPI-46 PET/CT")
n      <- c(58)
events <- c(0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  68Ga-FAPI-46 PET/CT  58  0  0.0  0.0  6.2  0.0  6.2  0.0  6.1

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures and reports zero analyses. The primary outcome is sensitivity of [68Ga]FAPI-46 PET using histopathology as the reference standard. Listed secondary outcomes concern correlation of PET uptake with H-score, sensitivity and specificity using H-score as the reference, and treatment-emergent adverse events. The record does not report a multiplicity adjustment, a hierarchy among secondary outcomes, or a plan for controlling the chance of false-positive findings across multiple analyses. Those procedures are not reported in the registry record.

Multiplicity is a general concern when several outcomes or comparisons are evaluated. If many statistical tests are conducted, the chance of at least one apparently notable result can increase unless the analysis plan addresses that issue. Whether and how this matters depends on which tests were conducted, their relationship, and whether any were designated as primary or exploratory. The registry identifies a primary endpoint, but it does not provide enough information to determine the analysis strategy for the full set of outcomes.

The primary analysis population requires an interpretable PET result and corresponding histopathology for at least 1 lesion. This definition makes availability of paired assessments relevant to inclusion. The registry record does not report how many participants lacked a readable scan, lacked corresponding pathology, or otherwise did not enter the analysis set. It also does not describe imputation, sensitivity analyses for missing data, or rules for handling multiple lesions beyond the stated matching approach.

The outcome description says that only participants with data available at specified points were considered, but the remaining text of that population description is incomplete in the registry record. Additional eligibility details for the analysis cannot be established from that entry. The endpoint estimate and interval are also not reported, preventing evaluation of the analysis results themselves.

In general, missing outcome data can affect an estimate when the participants with observed results differ systematically from those without them. The direction and size of any such effect depend on the missingness pattern and analytic assumptions. Since the record does not give missing-data counts or handling methods, the impact cannot be assessed. These omissions are distinct from multiplicity: one concerns incomplete observations, while the other concerns interpretation across multiple outcomes or tests.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: adenocarcinoma pancreas (1.7%).

The registry reports safety figures for the [⁶⁸Ga]FAPI-46 PET/CT group. It lists 58 participants at risk for serious adverse events and 1 participant with a serious adverse event. For other adverse events, it lists 58 at risk and 3 affected. The registry also records 3 deaths. These are descriptive counts in the posted record; the associated observation period and detailed event-level context are not reported.

The listed serious adverse event term is “Adenocarcinoma pancreas,” with a reported percentage of 1.7%. This is the registry’s term and percentage; it should not be read as establishing that the imaging agent caused the event. The record does not report a causal attribution for this term in the information available for this analysis.

Adverse-event counts answer a different question from the primary diagnostic endpoint. They do not indicate sensitivity, and they do not establish a comparison with an untreated or alternative-imaging group. The study is single arm, so these figures describe events in the study group rather than a relative safety contrast.

In general, safety counts require context about timing, severity definitions, event collection, and attribution to intervention. The registry gives the at-risk and affected counts, but fuller details about timing and the relationship of the deaths to study procedures are not reported in the registry record. The counts should therefore be read as recorded safety observations, not as estimates of comparative risk or proof of causation.

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

The registry record establishes the study’s purpose and the definition of its primary diagnostic endpoint. It describes a phase 2, multicenter study in resectable or borderline resectable pancreatic ductal adenocarcinoma, with [68Ga]FAPI-46 PET findings compared with histopathology. It also records that the study is completed and that enrollment was 63. These registry entries describe the study, but they do not reveal the observed sensitivity.

The record does not report the primary sensitivity estimate or its 90% confidence interval. As a result, readers cannot determine from this record how often PET was positive among participants whose primary lesion was confirmed by histopathology, or how precise that estimate was. The absence of those values is not evidence that sensitivity was high or low. It means the numerical endpoint result is not reported in the registry record.

The study’s design also sets boundaries on interpretation. It is non-randomized and single arm, so it does not compare assigned imaging strategies. Histopathology functions as the reference standard for the diagnostic question, not as a control group. The result, if reported, would describe diagnostic performance in the analyzed population and under the study’s assessment procedures; it would not by itself establish a causal effect on treatment decisions or clinical outcomes.

The stated analysis population requires an interpretable image and paired histopathology. Without the number included and information about participants who did not meet those criteria, it is not possible to assess how closely the analysis set reflects the enrolled population. Likewise, details about blinding, missing-data handling, and the statistical analysis plan are not reported in the registry record.

Secondary outcomes and safety counts provide additional areas of planned or recorded assessment, but they cannot replace the missing primary result. The registry reports counts for adverse events and deaths, while the numerical results for the listed imaging secondary outcomes are not reported in the record. Overall, the registry makes the question and measurement approach identifiable, but does not support a numerical conclusion about the primary diagnostic finding or its precision.

14. Why This Trial Matters Statistically

This study raises a useful statistical distinction between evaluating a diagnostic test and comparing treatments. Its primary endpoint is sensitivity against histopathology, a reference-standard question about whether imaging identifies reference-positive disease. A single-arm design can address that type of question without a randomized treatment comparator, but the interpretation depends on how test and reference results are paired and on who contributes to the analysis.

The registry specifies a paired assessment using a readable PET image matched to reference histopathology. It also defines an analysis population that requires an interpretable image and a corresponding pathology result. These criteria make the denominator more specific than overall enrollment. Reporting the number of participants who met those criteria, along with the endpoint estimate and its confidence interval, would help readers judge both the observed result and its precision. Those numerical results are not reported in the registry record.

The design also illustrates why a completed study status is not equivalent to a reported endpoint. Enrollment and completion describe study conduct; they do not show the numerator, denominator, sensitivity estimate, or uncertainty interval. The confidence level is specified, but without the estimate and interval bounds, readers cannot assess precision.

Finally, the record contains multiple outcome domains: diagnostic sensitivity, other imaging measures, and adverse events. Keeping those questions distinct is important. Diagnostic agreement, correlation with staining intensity, and safety counts are not interchangeable outcomes, and a single-arm study cannot yield a randomized comparison of imaging strategies. The statistical value of the record is therefore in clarifying the intended measurement and analysis population while making clear which results remain unreported.

15. 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 interpreting the primary endpoint is that its estimate and 90% confidence interval are not reported in the registry record. The true-positive and false-negative counts are also not reported, so the calculation cannot be checked from the posted information. The endpoint definition is available, but a definition alone cannot establish the magnitude or precision of the result.

The analysis population depends on having an interpretable PET image and corresponding histopathology for at least 1 lesion. The record does not report how many enrolled participants met those conditions or how many were omitted from the primary analysis. Without those counts, the potential effect of exclusions or unavailable assessments cannot be evaluated. The description of the analysis population is also incomplete after the phrase referring to data available at specified points.

The registry does not report the image-reading or pathology-assessment procedures in enough detail to assess blinding, adjudication, or reader variability. It also does not report missing-data methods, a detailed statistical analysis plan, the specific confidence-interval method, or the rationale for the enrollment target. These should be treated as unreported details, not assumed to have followed a particular approach.

The single-arm, non-randomized design has no concurrent control group. It can describe the diagnostic comparison with histopathology but cannot provide a randomized contrast between imaging strategies. The registry’s completed status does not resolve this limitation or supply the missing numerical findings. These constraints are specific to interpreting the posted record and do not, by themselves, establish the direction or size of any bias.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study of [68Ga]FAPI-46 PET in Patients With Pancreatic Ductal Carcinoma — NCT05262855.
• Registry record last updated 2026-05-29; status last verified 2026-05.
• Results first posted 2026-05-29.
• 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.

19. Record Summary

NCT05262855 is a completed phase 2, multicenter, single-arm, open-label, non-randomized study of [68Ga]FAPI-46 PET/CT in participants with resectable or borderline resectable pancreatic ductal adenocarcinoma. The registry reports enrollment of 63. Participants received [68Ga]FAPI-46 intravenously followed by PET/CT 15-25 minutes later.

The primary endpoint was sensitivity for detecting pancreatic ductal adenocarcinoma using histopathology as the reference standard, with a 90% confidence interval specified. The analysis population required an interpretable PET result and corresponding histopathology for at least 1 lesion. The primary estimate, interval bounds, and analysis-set count are not reported in the registry record.

Other listed outcomes include PET uptake and H-score correlation, sensitivity and specificity using H-score, and adverse events. The record reports 1 participant with a serious adverse event among 58 at risk, 3 with other adverse events among 58 at risk, and 3 deaths. These figures are descriptive and do not constitute a comparative safety analysis.