The PRONTO Study, a Global Phase 2b Study of NEOD001 in Previously Treated Subjects With Light Chain (AL) Amyloidosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The PRONTO Study, a Global Phase 2b Study of NEOD001 in Previously Treated Subjects With Light Chain (AL) Amyloidosis (NCT02632786), a randomized phase 2 study. The primary outcome is Number of Participants With Cardiac Response and Non-Response.

2. Clinical Question

The question is about a biomarker-defined category, not a direct count of symptoms, functional capacity, or survival. Cardiac response is defined using changes in N-terminal pro-brain natriuretic peptide (NT-proBNP) from baseline. A participant is considered a responder if the response criterion is met at an eligible visit after the first infusion; participants are classified as non-responders until a response is achieved. The registry record describes the outcome categories and assessment period, but the primary outcome category counts are not reported in the registry record. As a result, the direction and size of any difference between the randomized groups cannot be determined from the primary outcome information available in the record.

3. Trial Design

PRONTO is described as a global, multicenter, Phase 2b, randomized, double-blind, placebo-controlled study with two parallel groups. The trial enrolled 129 participants and is listed as completed. Its stated study population was adults with AL amyloidosis who had responded hematologically to previous treatment but continued to have cardiac dysfunction. The registry record lists NEOD001 and placebo as the interventions.

NEOD001 was administered intravenously at 24mg/kg every 28 days. The placebo group received placebo. Random allocation and parallel-group assignment mean that participants were assigned to one of the study groups and followed in that group, rather than each participant receiving both interventions in sequence. Double-blind masking is the description in the official title; the registry’s masking field says quadruple. Which additional groups, beyond participants and treatment staff, were masked is not reported in the registry record.

The study start is listed as 2016-03, and primary completion as 2018-03. The primary outcome assessment period is baseline through 12 months of treatment. The record names secondary outcomes including SF-36v2 PCS Score, 6MWT Distance, renal best response and non-response, NIS-LL Total Score, NT-proBNP Slope, and hepatic best response. The registry record does not report the detailed schedule for each secondary assessment or how these outcomes were analyzed.

Randomization can help balance measured and unmeasured prognostic factors across groups on average, while masking can reduce the influence of expectations on care and assessment. These are general design principles, not evidence that balance was achieved or that masking was maintained in this trial. Details such as the allocation ratio, randomization procedure, concealment method, and planned sample-size justification are not reported in the registry record. The total enrollment alone does not establish the precision of the primary comparison.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: ITT population

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Cardiac Response and Non-Response, measured over Baseline through 12 months of treatment.

The primary endpoint is the number of participants with cardiac response and non-response, based on NT-proBNP best response from baseline through 12 months of treatment. The record defines a response as a decrease in NT-proBNP from baseline of >30% and >300 ng/L. Progression is defined as an increase from baseline of >30% and >300 ng/L. Stable status means neither response nor progression. The best response is the most favorable category observed across eligible visits after the first infusion through the end of the study. Stable and progression are combined under non-response, and participants remain classified as non-responders until a response is achieved.

NT-proBNP is used as a biomarker related to cardiac dysfunction. In general, a biomarker can provide a measurable way to track biological change over time, but a biomarker outcome is not interchangeable with how a participant feels or functions. The registry endpoint reports categories rather than a continuous change in NT-proBNP, and it uses the best category observed across visits rather than only a single endpoint measurement. That makes the interpretation dependent on the stated thresholds, assessment timing, and rules for classifying participants.

The record identifies the ITT population for this outcome but does not report the number of participants in each response category or a between-group estimate. Those primary outcome results are not reported in the registry record, so the endpoint definition can be described but the comparative result cannot be evaluated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Randomization is a method for assigning participants to groups by chance. In general, it aims to make treatment groups comparable at the start of a trial, including with respect to factors that are not measured. Randomization does not guarantee that every factor will be balanced in a particular trial, especially when the number of participants is limited. The registry record identifies this study as randomized but does not report the randomization sequence method, allocation concealment procedure, or allocation ratio.

What does masking contribute?

Masking means that specified people do not know which intervention a participant has been assigned. In general, it can reduce the risk that knowledge of treatment assignment influences reporting, clinical management, outcome assessment, or analysis decisions. The official title describes the study as double-blind, while the registry masking field labels it quadruple. The record does not identify which groups of people were masked or report whether masking was assessed or maintained throughout follow-up.

How should a categorical outcome be understood?

The primary endpoint is a count of participants assigned to response categories, rather than a mean change in a continuous measurement. Each participant is classified using the registry’s NT-proBNP criteria: response, stable, or progression, with stable and progression combined as non-response. In general, categorical outcomes are summarized by the number of participants in each category and may be compared between groups using a statistical method appropriate to the design and data. The particular test or model used for this primary endpoint is not reported in the registry record, and the primary category counts are not reported there either.

What is an estimate and what does its uncertainty mean?

In general, an effect estimate describes the observed contrast between groups, while a confidence interval describes a range of values that are compatible with the data under the assumptions of the analysis. A narrow interval indicates greater statistical precision than a wide interval; neither an estimate nor an interval by itself establishes clinical importance. The registry record does not report a primary between-group estimate, confidence interval, or p-value, so the magnitude and precision of the primary comparison cannot be assessed from the available record.

What role does the ITT population play?

The record identifies the ITT population for the primary outcome. In general, an intention-to-treat approach preserves the comparison created by randomization by analyzing participants in their assigned groups. The exact population rules, exclusions, and treatment of participants with missing outcomes are not reported in the registry record. The record also does not state whether additional populations were used for supportive or sensitivity analyses.

Why do missing data and follow-up matter?

When an outcome depends on measurements over time, missing visits can affect which participants have an evaluable best response. In general, the impact depends on why data are missing, how much information is missing, and the assumptions used by the analysis. For a best-response endpoint, both the available measurements and the opportunity to observe a response can matter. The registry record does not report missing-data methods, imputation, sensitivity analyses, or rules for participants who stopped treatment or follow-up early. It is therefore not possible to assess whether missingness could have influenced the primary comparison.

How should planning illustrations be read?

In general, sample-size calculations describe the number of participants that might be needed under specified assumptions about an effect, significance level, allocation, and statistical model. They are planning illustrations, not observed trial outcomes and not a measure of the probability that a treatment effect is real. A calculation based on an observed effect is especially dependent on that observed estimate and on the assumptions used. The registry record does not report the trial’s own sample-size justification or statistical plan, so any planning illustration should not be mistaken for evidence about the trial’s design rationale or results.

The record lists seven outcome measures and seven analyses, but does not report the full statistical analysis plan. It also does not report the statistical procedure for the primary comparison, covariate adjustment, interim analyses, or a prespecified strategy for interpreting secondary outcomes. These details are important for assessing analytic choices, but should not be inferred from the design description or endpoint definition.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary outcome and several secondary outcomes, including measures of physical health status, walking distance, renal response, neurologic function, NT-proBNP slope, and hepatic response. When a study evaluates multiple outcomes or performs multiple comparisons, there is a general possibility that some results will appear notable by chance. Statistical plans sometimes address this issue through a prespecified hierarchy, adjustment procedure, or distinction between confirmatory and exploratory analyses. Which, if any, approach was used for PRONTO is not reported in the registry record. The record also does not report whether there were interim analyses or how any such analyses would affect interpretation.

Missing data can matter because the primary endpoint uses repeated NT-proBNP assessments and assigns a best-response category over time. In general, incomplete follow-up may change which observations are available to classify a participant. The importance of this depends on the amount and reasons for missingness and the analysis assumptions. The registry record does not report the extent of missing primary outcome data, the rules for handling missing visits, imputation methods, or sensitivity analyses. These omissions limit assessment of how robust any unreported primary comparison would be to missing data.

The primary outcome population is identified as ITT. The record does not describe the operational definition of that population, numbers analyzed, exclusions, or any additional analysis populations. It also does not report a complete statistical analysis plan, including the model or test for the primary outcome. Consequently, the registry record does not support a full assessment of multiplicity control, missing-data assumptions, or the analysis population beyond the stated ITT label.

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: pneumonia (6.3%), cardiac failure (4.8%), acute kidney injury (4.8%), pyrexia (3.2%), atrial fibrillation (3.0%).

The safety record lists serious adverse events for NEOD001 24 mg/kg as 14 participants affected among 66 at risk, and for placebo as 15 among 63 at risk. Other adverse events are listed as 58 among 66 at risk for NEOD001 and 52 among 63 at risk for placebo. Deaths are listed as 3 and 6, respectively. These are descriptive counts, not adjusted comparisons. The registry record does not give information about exposure-adjusted rates, event timing, or a causal assessment for individual events.

The listed serious-event terms include pneumonia (6.3%), cardiac failure (4.8%), acute kidney injury (4.8%), pyrexia (3.2%), atrial fibrillation (3.0%), and bradycardia (3.0%). These percentages describe the registry’s listed terms; the record does not specify a comparison or causal attribution for each term in this summary. A term’s presence in the list does not establish that the event was caused by a study intervention.

Raw counts can be useful for describing what was recorded, but they do not account for differences in exposure duration, baseline risk, or chance variation. They also do not establish whether an observed difference is statistically precise. Detailed definitions, event-level information, and a formal comparative safety analysis are not reported in the registry record.

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

The registry record describes a randomized, placebo-controlled study of NEOD001 in previously treated adults with AL amyloidosis and persistent cardiac dysfunction. It specifies an NT-proBNP-based primary endpoint, its response thresholds, the assessment period, and the grouping of stable status and progression as non-response. It also reports selected safety counts and several secondary outcomes. These details establish what the study set out to assess and provide context for reading its recorded safety information.

The primary cardiac response category counts and a comparative estimate are not reported in the registry record. Therefore, the posted information does not establish whether the groups differed on the primary endpoint, how large any difference was, or how precisely it was estimated. The endpoint definition cannot substitute for an outcome result, and enrollment alone cannot establish the statistical precision of a treatment comparison.

The safety counts describe events recorded in the study groups, but are not on their own proof of cause or evidence of a treatment effect. They do not account for all potential differences in follow-up or exposure, and the registry record does not include a detailed comparative safety analysis in the information.

In general, results from a trial apply most directly to the population, interventions, and outcome definitions studied. PRONTO’s stated population had AL amyloidosis, a hematologic response to previous treatment, and persistent cardiac dysfunction. The record does not support extending conclusions to populations outside that description. Because the comparative primary results and important analysis details are not reported in the registry record, this information supports a description of the study and its measures, not a conclusion about clinical benefit or lack of benefit.

13. Why This Trial Matters Statistically

PRONTO raises a statistical question that is common in clinical research: how to assess an intervention using a biomarker-based response definition observed over multiple visits. The endpoint does not simply compare a single measurement at one time. It classifies participants according to their most favorable NT-proBNP category over the specified assessment period, with a response determined by thresholds for both relative and absolute change. The meaning of the outcome therefore depends on the classification rules as well as the observed data.

The study also illustrates why outcome definitions and outcome results need to be distinguished. A detailed endpoint definition makes clear what would count as response or non-response, but it does not reveal how many participants met each definition or how groups compared. Without those counts or a comparative estimate, the central statistical question remains unanswered by the registry record.

Randomization and masking are important design features because they can support a fair comparison and reduce certain biases. Yet an assessment of a trial also requires information about the analysis method, missing observations, multiplicity, and uncertainty around estimates. Those details are not reported in the registry record. The listed safety counts add descriptive information, but do not replace a comparative efficacy analysis or establish causation.

For biostatisticians and clinical researchers, the record underscores the importance of linking the protocol-defined estimand, analysis population, missing-data strategy, and reported results. It also shows why a completed study status and an enrollment figure are not enough to assess the strength or precision of the primary finding. Here, the trial question and measurement framework are described, while the primary comparative result and several key analytic details 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 most consequential limitation of the available registry information is that the primary outcome category counts and a between-group estimate are not reported in the registry record. As a result, the observed cardiac response comparison cannot be described or assessed for precision. The endpoint is defined in detail, but its comparative result is unavailable in the record.

The primary endpoint uses NT-proBNP best response across visits, which makes classification dependent on the outcome thresholds and the available assessment history. The record does not report the detailed visit schedule, the number of participants with measurements at each visit, or how missing values and early discontinuation were handled. It is therefore not possible to evaluate the influence of incomplete follow-up on the endpoint.

The registry identifies an ITT population but does not report its operational definition or the numbers included in each analysis. It does not report the primary statistical method, any covariate adjustment, the confidence interval, or the p-value for a group comparison. A sample-size justification, full statistical analysis plan, multiplicity strategy, and interim analysis information are also not reported in the registry record.

Safety information is presented as counts and selected event terms, without a detailed account of event timing, duration of exposure, or comparative analysis. These data are descriptive and cannot establish causality. The record also does not report details that would clarify which groups were included in the quadruple masking description. These limitations constrain interpretation of both efficacy and safety from the registry information alone.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The PRONTO Study, a Global Phase 2b Study of NEOD001 in Previously Treated Subjects With Light Chain (AL) Amyloidosis — NCT02632786.
• Registry record last updated 2019-04-05; status last verified 2019-04.
• Results first posted 2019-04-05.
• 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

PRONTO (NCT02632786) is listed as a completed, randomized, Phase 2b, parallel-group study with 129 enrolled participants. It compared intravenous NEOD001 at 24mg/kg every 28 days with placebo in adults with AL amyloidosis who had a hematologic response to previous treatment and persistent cardiac dysfunction. The study start is listed as 2016-03, with primary completion in 2018-03.

The primary endpoint was the number of participants with cardiac response and non-response based on NT-proBNP best response from baseline through 12 months of treatment. The registry record defines the response categories and identifies the ITT population, but does not report primary outcome category counts or a comparative estimate. Selected adverse-event counts and secondary outcomes are listed. The detailed statistical plan, missing-data methods, multiplicity strategy, and primary comparative result are not reported in the registry record.