[68Ga]-NeoBOMB1 Imaging in Patients With Malignancies Known to Overexpress Gastrin Releasing Peptide Receptor (GRPR): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for [68Ga]-NeoBOMB1 Imaging in Patients With Malignancies Known to Overexpress Gastrin Releasing Peptide Receptor (GRPR) (NCT03724253), a non-randomized phase 2 study. The primary outcome is Number of Lesions Detected by [68Ga]-NeoBOMB1.

2. Clinical Question

The study was designed to explore preliminary targeting properties of [68Ga]-NeoBOMB1 in patients whose cancer types were associated with GRPR expression. The primary measure was the number of lesions identified on PET, with an intended description overall and across tumor types. The protocol description also anticipated summaries by GRPR-positive and GRPR-negative status. However, the biopsied samples for all patients were positive for GRPR, so the registry record says that presentation by GRPR expression was no longer suitable.

This is a diagnostic imaging question, not a comparison of clinical treatments. The secondary outcomes included lesion and patient-level diagnostic analyses against conventional imaging, as well as organ-level analyses against histological evidence. Those planned comparisons could address how imaging findings corresponded with other assessment methods, but the numerical results for them are not reported in the registry record. The primary question therefore concerns lesion detection as a descriptive imaging outcome; it does not, by itself, establish diagnostic accuracy or show how imaging affected patient care.

3. Trial Design

This was a Phase II, multicenter, open-label, single-dose study. It was non-randomized and had a parallel model, with no masking. The registry record lists an enrollment of 19 and describes adult participants with breast, prostate, colorectal, non-small cell lung, or small-cell lung cancer. The listed status is terminated. The study start date is 2018-07-03, and the primary completion date is 2019-06-20. The reason for termination is not reported in the registry record.

The record describes a dosimetry group and a non-dosimetry group. Both groups were to receive the recommended [68Ga]-NeoBOMB1 dose of 3 MBq/kg, plus or minus 10%, subject to a minimum of 150 MBq and a maximum of 250 MBq. The maximum peptide mass was 50 µg. The study summary characterizes the administration as a single dose. The registry record does not report the number enrolled in each group or the number who completed imaging.

Lesion counts on [68Ga]-NeoBOMB1 PET imaging acquired at Day 1 were the primary outcome. Other planned outcomes concerned treatment-emergent adverse events, lesions detected by conventional imaging, diagnostic comparisons at lesion, patient, and organ levels, and dosimetry. The primary outcome description specifies descriptive analysis only. Although conventional imaging and histological evidence appear in secondary outcome descriptions, neither is a randomized assigned control condition. Details of the procedures and statistical methods used for the secondary comparisons 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.

Before assignment: A total of 50 subjects were planned for the study (10 subjects for the dosimetry group and 40 subjects for the non dosimetry group). In total, 22 subjects were screened for eligibility and 19 subjects were enrolled (2 subjects in the dosimetry group and 17 subjects in the non dosimetry group).

Overall Study

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set (FAS). The results of the biopsied samples for all patients were positive for GRPR and thus the presentation of results according to GRPR expression were no longer suitable.

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: Full Analysis Set (FAS) = all subjects who enter the study and receive the \[68Ga\]-NeoBOMB1 dose.

6. Primary Endpoint

The registry lists the primary outcome as Number of Lesions Detected by [68Ga]-NeoBOMB1, measured over [68Ga]-NeoBOMB1 PET imaging acquired at Day 1.

The primary endpoint is the number of lesions detected by [68Ga]-NeoBOMB1 on PET imaging acquired at Day 1. The registry record describes the measure using a mean and standard deviation, and specifies the Full Analysis Set. It states that the number of lesions was to be summarized overall and by tumor type. Summaries by GRPR-positive and GRPR-negative patients were also intended, but were no longer considered suitable because the biopsied samples for all patients were positive for GRPR.

As a general statistical point, a lesion count describes how many findings an imaging assessment identifies. A mean can summarize the central tendency of such counts across participants, while a standard deviation describes their spread. These summaries can make the overall distribution easier to characterize, but they do not alone show whether identified lesions are true positives, whether lesions were missed, or how findings compare with another assessment. Those questions require appropriate reference information and diagnostic comparisons.

The endpoint is relevant to the study’s stated aim of assessing preliminary targeting properties. However, the numerical mean, standard deviation, and tumor-type summaries are not reported in the registry record. No conclusion about the observed number of lesions or its precision can therefore be drawn from the record description alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous measure in the registry’s statistical classification, summarized as a mean with standard deviation. Its underlying observations are lesion counts per participant. The specified imaging time is Day 1, when [68Ga]-NeoBOMB1 PET imaging was acquired. The outcome description says that analysis was descriptive only. The record does not provide a numerical mean, standard deviation, or interval estimate for this measure.

General explanation: A mean is the arithmetic average of observed values and provides a measure of their central location. A standard deviation describes how dispersed individual values are around that mean. These statistics answer different questions: the mean indicates a typical level in the analyzed sample, while the standard deviation indicates how variable the observations were. Neither one, on its own, establishes diagnostic sensitivity, specificity, or agreement with a reference method. Those measures require counts of relevant test outcomes and a clearly specified reference standard.

General explanation: Lesion counts may have a skewed distribution, and observations can vary substantially between participants. A mean and standard deviation remain interpretable summaries, but the underlying distribution matters when assessing how representative they are. The registry record does not report a distributional assessment or an alternative summary method. It would be inappropriate to assume that a particular model, transformation, or adjustment was used.

The Full Analysis Set is named as the primary endpoint population. The registry record does not provide its operational definition, the number of participants included, or any rules for handling participants without evaluable imaging. It also does not report whether any participants were excluded from the analysis or whether missing outcome values occurred. A population label alone does not establish how these issues were handled.

The stated primary analysis was descriptive. The record does not report an inferential test, a confidence-interval method, a model, covariate adjustment, or a statistical hypothesis for the lesion-count endpoint. Nor does it report the planned method for the secondary diagnostic comparisons. These are unknown from the registry record; they cannot be inferred from the outcome titles or from standard practice in imaging research.

General explanation: A confidence interval, when calculated, gives a range of values compatible with the data under the interval method’s assumptions. Its width reflects both variability and the amount of information available. It is not a guarantee that the true value lies in the interval, and it does not resolve problems such as an unsuitable reference standard or missing observations. No primary-outcome interval is reported in the registry record, so the precision of the lesion-count estimate cannot be evaluated from that information.

The record lists 24 outcome measures and 0 analysis entries. The number of outcome measures describes the breadth of registered outcomes; it should not be treated as the number of tests conducted or as proof that all outcomes were measured or reported. The absence of analysis entries means that the registry record does not provide a corresponding set of detailed statistical analysis descriptions. The primary endpoint’s stated descriptive approach is the available analysis information for this outcome.

A planning illustration is also described as computed from the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. For non-time-to-event outcomes, such illustrations express participants per arm; time-to-event illustrations express a total number of events. These are planning illustrations, not observed power and not the trial’s own design. The actual illustration values and the observed primary effect are not reported in the registry record information.

General explanation: A planning calculation asks how much information a hypothetical future study might need under specified assumptions. It depends on an assumed effect size, outcome variability, allocation, and statistical method. If the effect used comes from an observed result, it can be unstable, especially when the underlying study is limited in scale or has incomplete outcome information. A planning calculation is not a retrospective measure of whether the completed study had adequate power. It should not be presented as evidence that the current study did or did not detect an effect.

For diagnostic comparisons, the unit of analysis also matters. Lesions within the same participant are not necessarily statistically independent, so a method that treats each lesion as unrelated could misstate uncertainty. Patient-level and organ-level summaries answer different questions from lesion-level summaries. This is a general methodological consideration; the registry record does not state how within-participant clustering was addressed or which methods were used for the planned diagnostic analyses.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 24 outcome measures, spanning primary lesion counts, adverse events, conventional-imaging findings, diagnostic comparisons, and dosimetry. It lists 0 analysis entries. The primary endpoint description specifies descriptive analysis only, but the record does not report how multiplicity across the broader outcome set was handled. No adjustment procedure, hierarchy of confirmatory hypotheses, or prespecified distinction between exploratory and confirmatory secondary analyses is reported in the registry record.

General explanation: When several outcomes or comparisons are examined, the chance of at least one apparently unusual result can increase if each is tested separately at a conventional threshold. Multiplicity procedures can address that issue, but their relevance depends on the study’s aims and whether formal tests are planned. Here, the primary outcome is described as descriptive, and no testing strategy for the other outcomes is reported. It is therefore not possible to determine how multiplicity was addressed, or whether inferential testing was performed.

The Full Analysis Set is named for the primary endpoint, but the record does not define the set or report how many participants contributed data. It does not describe missing-data handling, imputation, exclusions, or sensitivity analyses. The number of enrolled participants does not establish that each participant had an evaluable scan or contributed to every outcome. Such details are not reported in the registry record.

The record notes that biopsied samples for all patients were positive for GRPR, making summaries by GRPR-positive and GRPR-negative status unsuitable. This is a limitation to that planned stratification, but it does not establish what alternative analyses were conducted. The registry record does not report further analysis-population details or a revised plan for the intended expression-based summaries.

11. 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: leukopenia (100.0%), hyponatraemia (100.0%).

The safety figures are presented by cancer-type group. For serious adverse events, the registry lists 0 affected among 5 at risk in the breast group, 0 among 5 in the prostate group, 0 among 5 in the colorectal group, 0 among 3 in the non-small cell lung cancer group, and 1 among 1 in the small-cell lung cancer group. The record lists 0 deaths in each group. These counts describe the registry’s stated at-risk and affected figures; they do not explain event timing, duration, severity beyond the serious classification, or causal attribution.

For other adverse events, the registry lists 0 affected among 5 at risk in the breast group, 1 among 5 in the prostate group, 3 among 5 in the colorectal group, 3 among 3 in the non-small cell lung cancer group, and 1 among 1 in the small-cell lung cancer group. The serious-event terms Leukopenia and Hyponatraemia are each listed at 100.0%. The denominator underlying those term percentages is not reported in the registry record, so they should not be read as percentages of all enrolled participants.

General explanation: Counts in small groups can be highly sensitive to individual events and do not, by themselves, support stable comparisons between cancer types. The registry record does not report a comparative safety analysis or establish that an event was caused by the imaging agent. These figures should be read as reported event counts, not as comparative evidence.

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

The registry record establishes that [68Ga]-NeoBOMB1 was studied as a PET imaging agent in a Phase II, open-label, non-randomized, single-dose study of adults with malignancies associated with GRPR expression. It identifies the number of lesions detected at Day 1 as the primary outcome and describes descriptive summaries by tumor type. The registry record does not report the numerical primary results. It therefore does not show the observed lesion counts or their variability.

The listed secondary outcomes describe intended assessments against conventional imaging and histological evidence, along with safety and dosimetry measures. Outcome descriptions alone do not show whether the imaging findings agreed with those methods or how diagnostic performance varied. Numerical results for those outcomes are not reported in the registry record. The registry information also does not provide the detail needed to assess precision, missing data, or the analysis methods for these comparisons.

General explanation: Detecting a lesion is not equivalent to confirming that it is malignant or establishing that no lesions were missed. Diagnostic performance depends on how positive and negative findings are defined and compared with an appropriate reference. A lesion-count endpoint can describe imaging yield, but it cannot alone establish sensitivity, specificity, or clinical utility.

The study was non-randomized and did not assign a control treatment group. Conventional imaging appears as a planned secondary comparison, but that does not make it a randomized control condition. The registry record also notes that all biopsied samples were positive for GRPR, leaving no suitable positive-versus-negative expression presentation as originally contemplated. These design and reporting features constrain what can be concluded.

The terminated status is a record status, not a result. The registry record does not report why the study was terminated. Neither that status nor the enrollment figure establishes whether the study met its objectives, whether findings were favorable, or whether any imaging approach should be used in practice. No treatment recommendation follows from the information reported.

13. Why This Trial Matters Statistically

This study is statistically informative because it illustrates the difference between a clearly named endpoint and a reported estimate. The registry specifies a primary lesion-count measure, its descriptive summary, and the imaging time point. Yet the numerical summary is not reported in the registry record. Without the estimate and a measure of uncertainty, readers cannot assess the magnitude or precision of the observed imaging findings.

The study also spans several cancer types and includes planned summaries by tumor type. Such stratification can be important when performance may differ across clinical contexts, but the record does not report the numerical subgroup results or the number analyzed in each subgroup. The enrollment figure alone cannot resolve those questions. Nor can the planned GRPR-expression comparison be evaluated: all biopsied samples were positive, so the record says that presentation by expression status was no longer suitable.

The distinction between descriptive outcomes and diagnostic comparisons is another important lesson. A mean lesion count can characterize imaging findings, while a comparison with conventional imaging or histological evidence asks a different question. Each analysis requires its own outcome definition, reference method, and statistical approach. The registry outcome descriptions identify several such questions, but their results and methods are not reported in the registry record.

Finally, planning calculations should remain separate from evidence about a completed study. The described planning illustrations rely on specified assumptions and an observed effect; they are not observed power. Interpreting them as if they were trial findings would confuse a hypothetical design exercise with the study’s actual results. The record offers an opportunity to distinguish study design, outcome definitions, observed data, and inferential precision, while also showing how missing result detail limits statistical interpretation.

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 record lists the study as terminated, but the reason for termination is not reported in the registry record. It lists enrollment of 19, but does not report the analyzed number for the primary endpoint, completion of imaging, or participant flow by cancer type and study group. The numerical primary endpoint results are also not reported, preventing assessment of the observed lesion counts and their precision.

The study was open-label and non-randomized, with no randomized control condition. Although conventional imaging and histological evidence were named for secondary diagnostic comparisons, their numerical results and analysis details are not reported in the registry record. The available description does not establish how imaging findings were adjudicated or how any within-participant dependence among lesions was addressed.

The planned expression-based presentation was no longer suitable because all biopsied samples were positive for GRPR. This prevents the intended contrast between positive and negative expression categories in the reported approach. The record does not report the number of biopsied samples, the distribution of biopsies across tumor types, or a revised analysis plan.

The registry names the Full Analysis Set but does not define it or describe missing-data procedures, exclusions, or sensitivity analyses. It also lists 24 outcome measures but 0 analysis entries, leaving multiplicity handling and detailed statistical methods unreported. Safety counts are presented by tumor type, but the record does not report comparative safety analyses or causal attribution. These limitations concern what can be interpreted from the registry record; they do not establish why results or methods are absent.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: [68Ga]-NeoBOMB1 Imaging in Patients With Malignancies Known to Overexpress Gastrin Releasing Peptide Receptor (GRPR) — NCT03724253.
• Registry record last updated 2020-10-23; status last verified 2020-10.
• Results first posted 2020-10-23.
• 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

NCT03724253 is a Phase II, multicenter, open-label, non-randomized, single-dose study of [68Ga]-NeoBOMB1 in adults with malignancies associated with GRPR expression. The registry lists enrollment of 19, a start date of 2018-07-03, a primary completion date of 2019-06-20, and status terminated. The primary endpoint was the number of lesions detected by PET at Day 1, summarized descriptively using a mean and standard deviation.

The study included dosimetry and non-dosimetry groups, with the same recommended dose described for both. Secondary outcomes included adverse events, conventional imaging comparisons, histology comparisons, and dosimetry measures. All biopsied samples were positive for GRPR, so expression-based presentation was no longer suitable. Numerical results for the primary endpoint and the diagnostic comparisons are not reported in the registry record. The reason for termination and key analysis details are also not reported.