This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Administration of IV Laronidase Post Bone Marrow Transplant in Hurler (NCT01173016), a na phase 1 study. The primary outcome is Percentage of Adherence to the Scheduled Weekly Infusion by the Participants.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01173016 |
| Phase | Phase 1 |
| Condition | Hurler Syndrome |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 11 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Masonic Cancer Center, University of Minnesota |
| Results posted | Yes |
2. Clinical Question
Population
Participants had Hurler syndrome, also called mucopolysaccharidosis type IH, and had previously received an allogeneic transplant. The arm description specifies that the prior transplant was more than two years earlier. The registry lists 11 participants at risk for adverse events.
Intervention
Participants received laronidase by weekly intravenous infusion for two years after transplantation. The study is described as a single-center pilot focused on the feasibility of giving the scheduled infusions.
Comparator
There was no comparison group. The registry identifies the study as single-group, with allocation listed as not applicable and no masking. Its results therefore do not provide a like-for-like comparison with another treatment or with no treatment.
Primary question
The primary question was whether weekly laronidase infusions could be delivered as scheduled over 24 months. The endpoint was each participant’s percentage adherence to scheduled weekly infusions, summarized by the median and full range. The registry record does not report the resulting median or range.
In statistical terms, this is a feasibility question about treatment delivery, not a controlled estimate of a treatment effect. Adherence describes how closely participants followed the planned infusion schedule. It does not, by itself, establish a change in health status or distinguish the effect of laronidase from other influences.
3. Trial Design
The registry describes a completed Phase 1, single-center pilot study of intravenous laronidase after allogeneic transplantation for Hurler syndrome. The study began on 2012-05-29, and primary completion was recorded as 2016-03-04. Enrollment was 11. The study is listed as completed.
There was one treatment group: participants with Hurler syndrome who had received an allogeneic transplant more than two years earlier and then received weekly laronidase for two years. The design is listed as single-group, allocation as not applicable, and masking as none. There is no control group or randomized treatment assignment described in the registry record.
The primary endpoint was percentage adherence to scheduled weekly infusions over 24 months, summarized using the median and full range. The registry also lists secondary outcomes concerning growth velocity, muscle strength, peak heart rate, joint range of motion, cardiac measures, and the relationship between the six-minute walk test and anti-laronidase antibody status. Nine outcome measures are listed overall, while the registry record does not report details of every outcome’s analysis.
Because all participants were in the same treatment group, the design can describe the experience of scheduled infusion delivery and recorded outcomes in this cohort. It cannot isolate treatment effects through comparison with a concurrent control group. Details of the protocol beyond the listed design and intervention 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.
Overall Study
| Stage | Laronidase After Transplantation |
|---|---|
| STARTED | 11 |
| COMPLETED | 10 |
| NOT COMPLETED | 1 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Laronidase After Transplantation |
|---|---|---|
| Participants analysed | 11 | |
| Age, Categorical: <=18 years | Participants | 11 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 4 |
| Sex: Female, Male: Male | Participants | 7 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Adherence to the Scheduled Weekly Infusion by the Participants, measured over 24 months.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | percentage |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was each participant’s percentage adherence to the scheduled weekly infusion, assessed over 24 months. The study description frames this measure as a way to assess the feasibility of giving weekly laronidase for two years after allogeneic transplantation. The planned summary was the median and full range across participants.
In general, adherence measures describe how much of a planned treatment schedule was followed. A median gives a central value for the participants’ adherence observations, while the full range describes the lowest and highest observations. Together, these summaries can convey both a typical level of adherence and how widely adherence varied in the group. They do not explain why any scheduled infusion was missed or delayed, and they do not show whether adherence caused a clinical outcome.
The registry record does not report the observed median or full range for this endpoint. It also does not report participant-level adherence values or details about how missed, delayed, or otherwise changed infusions were handled in the calculation. As a result, the endpoint’s definition and intended summary are available, but its numerical result and the operational details needed to interpret that result are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central statistical limitation is that the registry record describes the primary endpoint but does not report its numerical result. The median percentage adherence and full range over 24 months are not reported in the registry record. Without those values, the extent and variability of adherence cannot be characterized from the posted results. The record therefore identifies what the study intended to measure but does not permit a numerical reading of that primary outcome.
The study’s single-group structure also shapes what can be inferred. There is no concurrent comparator, and the design is not a randomized comparison. Any observed change in a secondary measure would be a description of the treated group over time, not a controlled estimate of what would have happened under a different treatment or without laronidase. The registry lists several secondary outcomes but does not provide enough analysis detail to establish that every measure was evaluated at the same times or in the same participants.
The adverse-event record reports that 1 of 11 participants was affected by a serious adverse event and that 7 of 11 were affected by other adverse events. Syncope and seizure are each listed among the most frequent serious adverse-event terms, at 9.1%. These figures describe events recorded for the treatment group. They do not establish that laronidase caused the events, and the registry does not provide event timing, participant-level overlap, or additional context for attribution. Deaths are not reported in the registry record.
In general, a small pilot cohort can provide descriptive information about the experience of delivering a regimen and about events recorded during follow-up. Estimates from a small group are limited in how precisely they represent a broader population, especially when the registry does not provide confidence intervals or participant-level detail. A lack of a reported numerical primary result is distinct from a result of zero: it means the endpoint value cannot be read from the registry record.
Overall, the posted information supports a description of the design, planned endpoint, and reported adverse-event counts. It does not supply the primary adherence summary or a comparative treatment-effect estimate. The statistical interpretation should remain at that descriptive level.
9. Statistical Methods Explained
What does the primary summary represent?
The study planned to summarize adherence using a median and a full range. In general, the median is a measure of the center of a set of observations: it indicates the value around which observations are ordered, without being pulled as strongly by unusually high or low values as an arithmetic mean can be. The full range gives the minimum and maximum observations. It can show the span of participant experiences, but it does not show how observations are distributed between those extremes.
For an adherence endpoint, those summaries would describe the observed percentages across participants. They would not explain the reasons for differences in adherence or establish whether adherence influenced any clinical outcome. The registry record states the planned summary and timeframe, but the actual median and full range are not reported in the registry record. Participant-level values and calculation details are also not reported in the registry record.
What can a single-group design estimate?
In general, a single-group study can describe outcomes observed among participants receiving the intervention. It does not directly estimate a contrast between that intervention and an alternative. Without a comparison group, changes over time may reflect multiple influences, including the course of the condition, prior treatment, follow-up, or other factors. The design does not separate those influences from the intervention’s effects.
Here, the registry lists a single group receiving weekly laronidase after a prior allogeneic transplant. Allocation is not applicable, and masking is listed as none. These design features mean that a randomized, masked comparison is not described. The registry explicitly identifies the study as a pilot focused on feasibility of scheduled infusions; the primary endpoint is adherence rather than a comparative efficacy measure.
How should a confidence interval be understood?
In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the statistical method used. A narrower interval indicates greater precision for that estimate, while a wider interval indicates less precision. An interval does not remove limitations arising from study design, incomplete reporting, or a small and selected group. No confidence interval for the primary adherence endpoint is reported in the registry record.
When a result and its uncertainty interval are both available, they can help readers distinguish the estimated value from the precision with which it is known. In this record, the primary endpoint’s numerical summary is absent, so neither its magnitude nor its precision can be assessed from the posted results. The absence of a reported interval should not be interpreted as evidence of no uncertainty.
What does the adverse-event summary say statistically?
The registry reports the number of participants at risk and the number affected for serious and other adverse events. Such counts are descriptive: they indicate how many participants in the listed group were recorded as affected. A percentage attached to an event term describes its reported frequency in the record, but without further information it does not establish cause, severity beyond the classification given, duration, or timing.
In general, adverse-event frequencies from a small group are imprecise as estimates of frequency in a wider population. Participants may also experience more than one event, so categories and event terms should not automatically be treated as mutually exclusive. The registry does not report participant-level event overlap or the details needed to determine whether the serious-event terms occurred in the same or different participants.
What is not available about the analysis?
The registry record does not report the statistical analysis plan, sample-size justification, handling of missing outcome data, or rules for inclusion in each analysis. It also does not report whether any interim analyses were conducted. Those omissions matter because analysis choices can affect how an estimate is calculated and how much confidence readers can place in it. They should not be filled in by assumption.
The registry lists nine outcome measures overall and one analysis, but that count alone does not explain the statistical procedures, outcome-specific denominators, or whether all planned analyses were completed. The listed secondary outcomes include functional, growth, joint, and cardiac measures, as well as a relationship involving the six-minute walk test and antibody status. Detailed results and analysis methods for these outcomes are not reported in the registry record.
Any sample-size illustration based on a fraction of an observed effect would be a planning illustration, not a description of the trial’s design or observed statistical power. The stated assumptions for such illustrations include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Those assumptions do not describe this single-group study. The registry record does not report its own sample-size justification, and planning calculations should not be mistaken for evidence about the trial’s power or the likelihood of a particular result.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists nine outcome measures overall, including a primary adherence endpoint and secondary outcomes related to growth, muscle strength, peak heart rate, joint range of motion, cardiac function and structure, and the six-minute walk test in relation to anti-laronidase antibody status. The registry record does not report a multiplicity adjustment or a plan for prioritizing secondary analyses.
In general, when many outcomes or statistical tests are examined, the chance of finding at least one apparently notable result by chance can increase. Methods for addressing multiplicity may include prespecifying a primary outcome, adjusting significance thresholds, or treating secondary analyses as exploratory. Which approach is appropriate depends on the study’s aims and analysis plan. The registry record does not report enough detail to determine what approach, if any, was used for the listed outcomes.
Missing-data handling is also not reported in the registry record. The record does not specify how participants with incomplete adherence information or unavailable secondary outcome measurements were handled, whether analyses used all enrolled participants, or how outcome-specific denominators were determined. These details affect the interpretation of any summary because the analyzed participants may differ from the enrolled group.
The registry lists one analysis, but does not explain its scope or give a statistical analysis plan. Interim analyses are not reported in the registry record. These absences should not be taken to mean that a particular method was or was not used; they mean the details cannot be established from the registry record. The primary endpoint’s numerical summary is also not reported, so its missing-data handling and precision cannot be evaluated from the posted results.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Laronidase After Transplantation | 1 | 11 | 9.1% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Laronidase After Transplantation | 7 of 11 |
Most frequent serious adverse event terms
| Event term | Organ system | Laronidase After Transplantation |
|---|---|---|
| Syncope | Nervous system disorders | 1 of 11 |
| Seizure | Nervous system disorders | 1 of 11 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Laronidase After Transplantation |
|---|---|---|
| Hypertension | Vascular disorders | 3 of 11 |
| Sinus Tachycardia | Cardiac disorders | 3 of 11 |
| Allergy Reaction/Hypersensitivity | Immune system disorders | 1 of 11 |
| Fever | General disorders | 1 of 11 |
| Headache | Nervous system disorders | 1 of 11 |
| Hives | Immune system disorders | 1 of 11 |
| Pain, Right Shoulder | General disorders | 1 of 11 |
| Hypotension | Cardiac disorders | 1 of 11 |
Serious events with the highest arm-level rate: syncope (9.1%), seizure (9.1%).
The registry lists 11 participants at risk for adverse events. It reports that 1 participant was affected by a serious adverse event and 7 participants were affected by other adverse events. Syncope and seizure are each listed among the top serious adverse-event terms, with a reported frequency of 9.1% for each. Deaths are not reported in the registry record.
These are descriptive counts and reported percentages for the study group. They do not establish whether an event was caused by laronidase, and they do not show when it occurred, how long it lasted, or how it was managed. The registry does not report whether the serious-event terms occurred in the same participant or in different participants. It also does not provide enough detail to infer how the event terms relate to the overall count of participants with serious events.
In general, event percentages from a small study group have limited precision and should be read as observations in that group, not as stable estimates of frequency elsewhere. The record’s adverse-event summary does not support a causal comparison because there is no control group. The figures describe what was recorded, rather than establishing a treatment-related risk.
12. What the Result Does, and Does Not, Mean
The study addresses a practical and clearly defined question: whether weekly intravenous laronidase could be given after allogeneic transplantation for Hurler syndrome, with adherence to scheduled infusions measured over 24 months. Its single-center, single-group pilot design is suited to describing the planned regimen and the experience recorded in the study group. The primary endpoint is a feasibility measure, not a direct comparison of clinical outcomes between treatment strategies.
The most important limit on interpretation is that the registry record does not report the primary endpoint’s median adherence or full range. Consequently, the posted results do not quantify how closely participants followed the weekly schedule or how much adherence varied. This is not evidence that adherence was high, low, or absent; the numerical summary is simply not reported in the registry record.
The adverse-event counts provide descriptive information for the 11 participants at risk. They do not establish causation, comparative safety, or the frequency expected in a wider population. The absence of a control group also means that the study cannot determine whether any observed outcome changes were due to laronidase rather than other influences.
More generally, a pilot study can help characterize a regimen and identify questions for further study, but conclusions depend on the outcomes actually reported and the methods used to analyze them. Here, the registry record does not report the statistical analysis plan, missing-data approach, or sample-size justification. It also does not provide a comparative treatment-effect estimate. Readers can therefore use the record to understand the study’s design and stated endpoints, while recognizing that the main numerical adherence result and several analysis details are unavailable.
13. Why This Trial Matters Statistically
This trial is statistically notable for the distinction between feasibility and treatment-effect questions. Its primary endpoint was adherence to scheduled weekly infusions over 24 months. That choice asks whether a regimen was followed as planned; it does not by itself estimate whether the intervention changes a clinical outcome. Keeping those questions separate helps avoid reading a feasibility study as though it were a controlled efficacy comparison.
The single-group design is central to that distinction. Without a comparison group, the study can describe outcomes and events recorded among participants who received laronidase, but it cannot estimate a treatment contrast against another approach. This remains true even if clinical measures were collected over time: change within one group is not equivalent to a randomized between-group effect.
The record also illustrates why endpoint definitions and endpoint results are different kinds of information. It specifies that adherence was to be summarized by the median and full range, but those numerical results are not reported in the registry record. Readers can identify the intended measure yet cannot judge its observed level or variability. A clearly described endpoint does not substitute for a reported estimate.
Finally, the adverse-event summaries are useful as descriptive observations but do not establish causality or comparative risk. The lack of reported analysis details further limits assessment of precision, missing data, and multiplicity. These points make transparent reporting particularly important: design, endpoint, analysis, and result each contribute distinct information to a 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 registry record describes a single-center pilot with one treatment group and no like-for-like control comparison. Participants had a prior allogeneic transplant, specified in the arm description as more than two years earlier, and received weekly laronidase for two years. The study’s findings, as reported, therefore concern this defined group and regimen; the record does not establish how results would compare under another treatment or in a different population.
Enrollment was 11, and the primary adherence result is not reported in the registry record. The median and full range, as well as participant-level adherence observations, are unavailable. Without these values, readers cannot assess either the typical adherence level or its variation. The record also does not explain how incomplete adherence information was handled.
The statistical analysis plan, sample-size justification, interim analyses, and analysis populations are not reported in the registry record. Outcome-specific denominators and detailed results for the secondary measures are likewise not available in the listed information. The number of outcomes listed does not reveal how many participants contributed to each outcome or how analyses were conducted.
For safety, the record provides participant counts and selected serious-event terms, but not event timing, participant-level overlap, or causal attribution. Deaths are not reported in the registry record. These reporting limitations constrain interpretation of both the feasibility endpoint and the adverse-event summaries. They do not support conclusions about unreported outcomes or methods.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Administration of IV Laronidase Post Bone Marrow Transplant in Hurler — NCT01173016.
- Registry record last updated 2020-03-20; status last verified 2020-03.
- Results first posted 2020-03-20.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry describes a completed Phase 1, single-center, single-group pilot study of weekly intravenous laronidase after allogeneic transplantation for Hurler syndrome. Enrollment was 11. The study began on 2012-05-29, and primary completion was recorded as 2016-03-04.
The primary endpoint was percentage adherence to scheduled weekly infusions over 24 months, summarized by the median and full range. Those numerical results are not reported in the registry record. The record lists nine outcome measures overall and secondary outcomes concerning growth, strength, fitness, joint movement, cardiac measures, and antibody status in relation to the six-minute walk test.
For adverse events, 1 of 11 participants was affected by a serious event and 7 of 11 by other events. Syncope and seizure are each listed at 9.1% among serious-event terms. The registry record does not report deaths or the analysis details needed to establish causal or comparative conclusions.