Efficacy and Safety of AlphaNine Versus BeneFIX in Patients With Severe Hereditary Haemophilia B: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy and Safety of AlphaNine Versus BeneFIX in Patients With Severe Hereditary Haemophilia B (NCT03091751), a na phase 2 study. The primary outcome is Mean Difference of Area Under the Curve (AUC): BeneFIX Compared to AlphaNine.

2. Clinical Question

The clinical question is pharmacokinetic rather than a direct comparison of clinical outcomes such as bleeding episodes. AUC is a summary of the measured factor IX concentration over time. The endpoint’s stated title frames the target as the mean difference in AUC for BeneFIX compared with AlphaNine, with units of IU x hour/dL.

The record describes repeated pharmacokinetic assessments with AlphaNine before the BeneFIX assessment for 13 subjects, and says that nine subjects had the BeneFIX assessment as part of a previous study. It then reports that 22 BeneFIX assessments were analyzed jointly and compared with 25 AlphaNine subjects. These population descriptions indicate that the posted comparison is not simply a randomized, between-arm treatment contrast. Details needed to determine exactly how the observations were matched or modeled are not reported in the registry record.

The registry record does not report the numerical mean AUC values, mean difference, or uncertainty interval. Therefore the direction, magnitude, and precision of the comparison cannot be established from the available outcome description.

3. Trial Design

This is a completed Phase 2 study sponsored by Grifols Biologicals, LLC. The record describes a non-randomized, multi-center study in subjects with severe hereditary haemophilia B. It lists BeneFIX as the intervention and identifies the study model as single group. Allocation is listed as NA and masking as none. These features matter because the study does not describe a randomly assigned, masked comparison between concurrent treatment groups.

The study’s stated goal was to determine and compare the pharmacokinetic and safety profiles of BeneFIX in subjects who had previously undergone two AlphaNine pharmacokinetic assessments. The primary outcome description says that 13 such subjects had a third pharmacokinetic assessment with BeneFIX. It further says that nine subjects had the BeneFIX assessment as part of a previous study, and that 22 subjects treated with BeneFIX were analyzed jointly and compared with 25 AlphaNine subjects. The registry record does not explain the full relationship among these analysis populations or how the joint comparison was carried out.

The intervention description identifies BeneFIX as recombinant factor IX, posted as lyophilized nonacog alfa with solvent for reconstitution and injection. The endpoint timeframe includes a baseline measurement before infusion and measurements at 15 and 30 minutes, 1, 3, 6, 9, 24, 48, 72, and 74 hours after a single dose infusion. The infusion followed a 7 to 15 day wash-out period.

The listed enrollment is 13, while the endpoint description reports a joint BeneFIX analysis of 22 subjects and comparison with 25 AlphaNine subjects. The record does not reconcile these figures or provide further enrollment accounting. There is no reported randomized allocation, masking, or concurrent active-control arm. The registry record does not report the protocol’s sample-size justification, detailed statistical analysis plan, interim analyses, or the exact method used to combine or compare the pharmacokinetic observations.

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

Analysis population for the primary outcome, as defined in the registry: Thirteen subjects with 2 prior pharmacokinetic assessments with AlphaNine (PK1, PK2) had a third PK assessment with BeneFIX (PK3). Nine subjects had PK3 analysis with BeneFIX as part of a previous study. In total, 22 subjects treated with BeneFIX (PK3) were analyzed jointly and compared to 25 subjects treated with AlphaNine (PK2).

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: Thirteen subjects with 2 prior pharmacokinetic assessments with AlphaNine (PK1, PK2) had a third PK assessment with BeneFIX (PK3). Nine subjects had PK3 analysis with BeneFIX as part of a previous study. In total, 22 subjects treated with BeneFIX (PK3) were analyzed jointly and compared to 25 subjects treated with AlphaNine (PK2).

6. Primary Endpoint

The registry lists the primary outcome as Mean Difference of Area Under the Curve (AUC): BeneFIX Compared to AlphaNine, measured over Baseline (prior to the infusion), and at 15 and 30 minutes, 1, 3, 6, 9, 24, 48, 72, and 74 hours following a single dose infusion of BeneFIX administered following a 7 to 15 day wash-out period..

The primary endpoint is titled “Mean Difference of Area Under the Curve (AUC): BeneFIX Compared to AlphaNine.” It concerns AUC 0-inf, a pharmacokinetic measure intended to represent exposure across the concentration-time profile. The unit is IU x hour/dL. The endpoint description identifies the reported parameter as a mean and its dispersion as a standard deviation.

Concentrations were scheduled at baseline, before infusion, and at 15 and 30 minutes, 1, 3, 6, 9, 24, 48, 72, and 74 hours after the single dose of BeneFIX. The specified wash-out period before infusion was 7 to 15 days. These measurements provide the time-course information used to characterize the AUC. In general, pharmacokinetic AUC is used to summarize exposure over time rather than relying on a concentration at a single measurement time. This is a general explanation of the measure, not a claim about the observed results.

The registry record says that BeneFIX AUC was assessed and compared with the AlphaNine pharmacokinetic parameter from the PK2 study. It does not report the numerical mean values, the calculated mean difference, or an interval estimate for that difference. Nor does the outcome description explain whether the estimate accounts for the prior assessments within participants or uses another comparison method. Thus the endpoint’s definition and measurement schedule are available, but the numerical result and its statistical precision are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: AUC is expressed on a numeric scale, and the registry identifies the target parameter as a mean. It also names standard deviation as the measure of dispersion. A mean describes the central value of a set of measurements; a standard deviation describes how spread out individual values are around that mean. Neither quantity is reported numerically for the primary comparison in the registry record.

What does AUC represent?

In general, a pharmacokinetic concentration-time curve follows measured drug or factor levels across time after administration. The area under that curve combines information across the measurement period into a summary of exposure. The planned sampling schedule in this study extended from the pre-infusion baseline through 74 hours after a single dose infusion. The outcome description names AUC 0-inf, which denotes the intended area-under-the-curve parameter. The registry record does not provide the calculation details, such as the specific interpolation method, handling of concentrations below a measurement limit, or approach to extrapolation.

AUC can be useful because a single concentration measurement may not represent the overall exposure profile. In general, however, an AUC summary depends on the timing and completeness of measurements and the method used to construct the curve. The listed sampling times describe the intended schedule; the record does not report how many measurements were available at each time or how any missing values were treated.

How should a mean difference be read?

A mean difference expresses the contrast between two group or condition means on the endpoint’s original scale. For this endpoint, the record names BeneFIX compared with AlphaNine and gives IU x hour/dL as the unit. A difference estimate would describe the direction and amount of separation between the compared AUC means. The estimate alone would not convey its precision, so it is ordinarily considered alongside an uncertainty interval and the analysis method. Those numerical result details are not reported in the registry record.

A confidence interval is, in general, a range of estimates compatible with the data and the assumptions of the analysis at the stated confidence level. A narrow interval indicates greater statistical precision than a wide interval, while neither width nor location alone establishes clinical importance. The registry record does not state a confidence interval for the primary endpoint or identify an interval confidence level. No numerical interval should therefore be inferred.

Why do study design and analysis population matter?

Random assignment can, in general, help make treatment groups comparable with respect to factors known and unknown at baseline. This record describes a non-randomized, single-group study with no masking and allocation listed as NA. It also describes prior AlphaNine assessments and a later BeneFIX assessment for some subjects, alongside a joint BeneFIX analysis compared with AlphaNine subjects. The analysis may depend on whether observations are paired within participants, drawn from distinct groups, or handled by another approach. The registry record does not report enough detail to identify the method, so no particular model should be assumed.

Repeated measures within one person are often correlated rather than independent. In general, an analysis that accounts for within-person correlation can differ from an analysis that treats observations as independent. The record does not say how repeated pharmacokinetic assessments were incorporated. It also does not report covariate adjustment, transformations, assumptions about the distribution of AUC, or diagnostic checks.

What does dispersion add?

Reporting a mean with a standard deviation gives information about the spread of the observations as well as their average. For continuous outcomes, distributions can be asymmetric or include unusually high values. In general, such features can affect how well a mean and standard deviation summarize the data and which inferential method is appropriate. The registry record does not provide the underlying distribution, individual values, or a description of diagnostic assessment, so the suitability of any particular model cannot be evaluated.

Over-dispersion is a general issue when variability is greater than a statistical model assumes. If a model understates variability, its uncertainty estimates may be too small. This concept is not evidence that over-dispersion occurred in this trial; the record does not report a model or a variability assessment that would establish it.

What can planning calculations tell the reader?

The planning illustration assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They specify that the target effect is a stated fraction of the observed effect. Such calculations, in general, estimate how many participants per arm might be needed under those assumptions to detect a chosen effect size. They are planning illustrations rather than observed results, and they are not the trial’s reported sample-size justification.

Any planning calculation based on an observed effect can be sensitive to the size and uncertainty of that estimate. The record does not report a protocol-based sample-size rationale, and planning illustrations do not establish observed power. The registry record also does not report the primary estimate needed to independently judge the effect on which the illustration is based. The calculations should therefore not be interpreted as evidence that the trial did or did not detect a particular biological or clinical effect.

Finally, no inferential test, confidence interval method, missing-data method, or adjustment strategy is specified for the primary outcome in the registry record. The endpoint’s name and summary-statistic labels do not substitute for a complete analysis plan. The available methodological details support describing what was measured and the broad design, but not reconstructing the statistical procedure or its assumptions.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("BeneFIX")
n   <- c(22)
m   <- c(10.41)
sp  <- c(563.081)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  BeneFIX  22  10.410  563.081  -239.246  260.066

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists five outcome measures and five analyses. It identifies the AUC mean difference as the primary endpoint, but does not describe the full set of other outcome measures or explain how they relate to the primary question. The registry record does not report whether a multiplicity adjustment was planned for multiple outcomes, analyses, comparisons, or time points.

Multiplicity is a general statistical concern when several hypotheses are tested. The more opportunities there are to declare a result noteworthy, the greater the chance of at least one apparently unusual finding when no true effect exists. Methods that control this concern require a prespecified testing strategy. No such strategy is reported in the registry record, so it is not possible to determine whether or how multiplicity was addressed. The count of listed outcomes and analyses alone does not establish that all were tested in the same way or that a correction was required or applied.

The record gives a detailed intended sampling schedule for the AUC assessment, but does not report completeness of concentration measurements, missing outcome data, reasons for missingness, or a missing-data handling method. It does not state whether analyses used all available measurements, imputed values, excluded incomplete profiles, or followed another approach. These details matter because incomplete pharmacokinetic profiles can affect an AUC estimate.

Analysis populations are also not fully described. The record refers to 13 subjects with prior AlphaNine assessments and a BeneFIX assessment, nine subjects whose BeneFIX assessment was part of a previous study, a joint BeneFIX analysis of 22 subjects, and 25 AlphaNine subjects. The registry record does not report a formal definition of the analysis populations, a flow of participants through the analyses, or whether all enrolled subjects contributed to the primary endpoint. It also does not specify an intention-to-treat, per-protocol, or other named analysis population. No assumptions about missing data or population selection should be inferred from the counts alone.

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.

The serious adverse event record lists 22 BeneFIX subjects at risk and 0 with a serious adverse event. It also lists 22 at risk for other adverse events and 0 affected, with 0 deaths. No serious adverse event terms are listed. These figures describe the registry’s recorded counts for the BeneFIX group; they do not provide a detailed account of event definitions, observation time, severity grading beyond the serious-event category, or how events were collected.

A recorded count of 0 means that no event was listed in that category for the stated group in this record. It does not establish that the risk is absent, nor does it rule out uncommon events or events not captured in the registry summary. The record does not give a follow-up duration for the safety counts or explain whether the 22 subjects in the safety listing correspond exactly to the primary endpoint population.

The safety figures should also be kept distinct from the pharmacokinetic comparison. They do not show whether the AUC values differed, and the absence of listed serious events does not answer the endpoint question. Conversely, an AUC comparison alone would not describe the full safety profile. These counts are a limited registry summary, not a complete characterization of safety.

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

The trial asks a focused pharmacokinetic question: how the mean AUC for BeneFIX compares with the AlphaNine measure in people with severe hereditary haemophilia B. It describes the product, assessment schedule, wash-out period, and broad comparison populations. It does not provide the numerical primary outcome estimate in the registry record. As a result, the posted information does not establish the size, direction, or precision of the AUC contrast.

That absence is important for interpretation. Without the group means or a mean difference, it is not possible to describe the observed separation on the IU x hour/dL scale. Without an uncertainty interval or a reported analysis, it is not possible to assess how precise the estimate was or what values are compatible with the data under the analysis assumptions. The result cannot be classified as evidence of a difference, similarity, equivalence, or lack of difference from the available outcome description.

The study’s design also sets limits on what the comparison can mean. It was non-randomized, unmasked, and described as single group. AlphaNine assessments serve as the comparison in the endpoint description, but the record does not provide enough detail to establish whether the comparison is paired, adjusted, or based on separate groups. The estimate should therefore not be interpreted as a randomized causal effect or assumed to remove all differences between the compared observations.

The endpoint concerns pharmacokinetic exposure. It is not itself a measure of bleeding events, long-term safety, quality of life, or other clinical outcomes. The registry lists no serious adverse events, other adverse events, or deaths in the BeneFIX safety group, but those counts do not establish that no safety risks exist, and they do not fill the gap in the primary outcome result.

Overall, the record supports a description of the study question and design, but not a conclusion about the numerical pharmacokinetic result. It also does not establish whether any observed exposure contrast, if estimated, would be clinically important. Interpretation requires the actual outcome values, uncertainty, and analysis details, none of which are reported in the registry record.

14. Why This Trial Matters Statistically

This study is statistically notable because its comparison is built around pharmacokinetic measurements collected over time, rather than a simple randomized comparison of two concurrent arms. The endpoint combines measurements from baseline through 74 hours after a single dose into an AUC summary. Such a summary can be useful for comparing exposure profiles, but its interpretation depends on how concentration measurements are converted into area and how the observations are linked across participants.

The record describes a design with prior AlphaNine assessments and a later BeneFIX assessment for some participants, while also reporting a joint BeneFIX analysis and an AlphaNine comparison population. This makes clarity about analysis populations and dependence between observations especially important. Repeated measurements from the same person are not generally independent, and a paired comparison can answer a different statistical question from a comparison between distinct groups. The registry record does not report enough methodological detail to determine the approach used.

The record also illustrates why design counts and analysis counts need to be read separately. Listed enrollment is 13, while the endpoint description gives additional population details and reports a joint analysis involving 22 BeneFIX subjects and a comparison with 25 AlphaNine subjects. Those figures are not fully explained. The distinction matters when interpreting who contributed to the endpoint and whether the analyzed group represents the enrolled group.

Finally, the case highlights the difference between a defined endpoint and a reported result. The measure, unit, and timing are stated, but the numerical estimate and its uncertainty are not reported. Statistical reasoning needs both the method and the result: without them, no assessment of effect size, precision, or robustness is possible. The record’s planning assumptions are illustrations, not a substitute for a study-specific design justification or outcome analysis.

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 primary limitation for interpretation is that the registry record does not report the numerical AUC result. It supplies the endpoint name, unit, parameter type, dispersion type, and measurement schedule, but not the means, mean difference, standard deviations, confidence interval, or p-value. The direction, magnitude, and precision of the primary comparison therefore cannot be evaluated.

The study is described as non-randomized, unmasked, and single group, with allocation listed as NA. The endpoint uses AlphaNine pharmacokinetic information as a comparator, but the registry record does not explain whether the analysis was paired, based on independent groups, or adjusted for differences between participants or assessments. This limits causal interpretation and makes it difficult to assess whether the comparison is like-for-like.

The record’s participant accounting is incomplete. It lists enrollment of 13 and describes 13 subjects with prior AlphaNine assessments and a later BeneFIX assessment, nine subjects whose BeneFIX assessment was part of a previous study, a joint BeneFIX analysis of 22 subjects, and a comparison with 25 AlphaNine subjects. It does not reconcile these figures or specify exactly which participants contributed to each analysis. It also does not report exclusions, missing measurements, or reasons for missingness.

Further details are not reported in the registry record, including the statistical model, method for calculating AUC, handling of incomplete concentration-time profiles, covariate adjustment, confidence interval procedure, and multiplicity strategy. The safety summary gives event counts but not follow-up duration or broader event-collection details. The record does not report the protocol’s sample-size justification or interim-analysis plan. These omissions restrict assessment of precision, potential bias, and the completeness of the safety and efficacy interpretation.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy and Safety of AlphaNine Versus BeneFIX in Patients With Severe Hereditary Haemophilia B — NCT03091751.
• Registry record last updated 2017-07-25; status last verified 2017-06.
• Results first posted 2017-07-25.
• 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

This completed Phase 2 study examined BeneFIX pharmacokinetics and safety in severe hereditary haemophilia B. It was non-randomized, unmasked, and described as a single-group study. The primary endpoint was the mean difference in AUC for BeneFIX compared with AlphaNine, measured in IU x hour/dL after a single dose infusion and a 7 to 15 day wash-out period.

The registry describes prior AlphaNine assessments and a joint BeneFIX analysis, but does not fully reconcile the participant counts or explain the comparison method. Although the endpoint and sampling schedule are stated, the numerical AUC means, mean difference, and uncertainty are not reported in the registry record. The listed BeneFIX safety group had 0 serious adverse events, 0 other adverse events, and 0 deaths among 22 at risk. These counts are limited safety information and do not establish absence of risk.