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 Long Term Safety Observation of Crizotinib in Chinese NSCLC Population (NCT03672643), a na phase 4 study. The primary outcome is Number of Participants With Grade 3 or 4 Adverse Events (AEs), Grade 5 AEs, AEs Lead to Treatment Discontinuation, Serious AEs (SAEs)- All Causality: Assessed by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v4.03.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03672643 |
| Phase | Phase 4 |
| Condition | ALK or ROS1-positive NSCLC |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 41 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Participants from China with advanced non-small cell lung cancer involving an ALK or ROS1 translocation or inversion event, who had previously been treated in a Pfizer-sponsored Xalkori study. The safety analysis set was defined as participants who received at least one dose of study treatment.
Intervention
Crizotinib, under an open-label study intended to allow access for people previously treated in Pfizer-sponsored studies in China.
Comparator
There was no separate comparison group. The study was single-arm, and the registry lists allocation as not applicable.
Primary question
How many participants experienced grade 3 or 4 adverse events, grade 5 adverse events, adverse events leading to treatment discontinuation, or serious adverse events, regardless of causality, during treatment and follow-up?
This is a safety-observation question rather than a randomized comparison of treatments. The registry describes an enrolled population of 41 and a safety endpoint based on participant counts. It does not identify a control group against which the frequency of events could be compared. Consequently, the registry record can describe events observed among participants receiving crizotinib in this study, but it cannot by itself establish how those events compare with outcomes under another treatment or without treatment.
The population is narrowly defined: participants had advanced non-small cell lung cancer with an ALK- or ROS1-related rearrangement and had already participated in a prior Pfizer-sponsored study of Xalkori. This context matters because the record is not a general evaluation of crizotinib in all people with lung cancer. The registry states that the study was intended to allow access to crizotinib for people treated in prior Pfizer-sponsored studies in China.
The primary question combines several safety categories. They include event severity, serious events, and events leading to treatment discontinuation. These categories can describe different aspects of safety and may overlap; the record does not report how much they overlap. The endpoint also specifies all-causality events, so its scope is broader than events judged to be caused by treatment. The record does not report a comparative efficacy question or a statistical hypothesis test.
3. Trial Design
This was a phase 4, open-label, single-arm study of crizotinib. Its official title describes long-term safety observation in patients from China with advanced non-small cell lung cancer involving an ALK or ROS1 translocation or inversion event, who had previously been treated on a study of Xalkori. The brief summary says the study was intended to allow access to crizotinib for people treated in previous Pfizer-sponsored studies in China.
The registry lists enrollment as 41. It records a start date of 2019-01-28 and a primary completion date of 2023-09-28, and the current status is terminated. The reason for termination is not reported in the registry record. The record does not report a parallel control group, random allocation, or masking; it identifies the study as single-group and open-label.
In a single-arm design, outcomes are observed in the group receiving the study intervention. Without a concurrent comparison group, observed event counts do not isolate the contribution of treatment from other influences, such as the underlying illness, prior treatment, or events that could occur over time for other reasons. The open-label design means masking was absent. For an endpoint based on reported event counts, knowledge of treatment assignment can be relevant to assessment and reporting, although the record does not describe whether or how this affected event ascertainment.
The stated safety follow-up ran from first dose through 28 days after last dose. The registry describes maximum follow-up as approximately up to 52.3 months and maximum treatment exposure as 51.3 months. These are maximum durations, not descriptions of a typical participant’s follow-up or exposure. The registry does not report the distribution of follow-up time or treatment duration across participants.
The safety analysis set included participants who received at least one dose of study treatment. The record does not report whether every enrolled participant received a dose, nor does it provide a separate participant flow or reasons for any exclusions. The sponsor is Pfizer. A more detailed account of recruitment, monitoring, or operational conduct is 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 41 Chinese participants who were previously recruited in Pfizer-sponsored Crizotinib studies (A8081005 \[NCT00932451\], A8081014 \[NCT01154140\], A8081029 \[NCT01639001\], A8081063 \[NCT01945021\]) were enrolled in the current study to continue treatment with Crizotinib.
Overall Study
| Stage | Crizotinib |
|---|---|
| STARTED | 41 |
| COMPLETED | 0 |
| NOT COMPLETED | 41 |
Reasons for not completing this period:
| Reason | Crizotinib |
|---|---|
| Adverse Event | 3 |
| Death | 2 |
| Withdrawal by Subject | 1 |
| Progressive disease | 11 |
| Global deterioration of health status | 1 |
| Refused further treatment | 7 |
| Rolled over to a continuous study for Crizotinib treatment | 16 |
Analysis population for the primary outcome, as defined in the registry: Safety analysis set included all participants who received at least one dose of the study treatment.
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) included all participants who had been enrolled in the study, regardless of whether treatment was received.
| Characteristic | Unit | Crizotinib |
|---|---|---|
| Participants analysed | 41 | |
| Age, Continuous | Years | 58.0 (SD 12.14) |
| Sex: Female, Male: Female | Participants | 24 |
| Sex: Female, Male: Male | Participants | 17 |
| Race/Ethnicity, Customized: Race: Asian | Participants | 41 |
| Race/Ethnicity, Customized: Ethnicity: Not Hispanic or Latino | Participants | 41 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Grade 3 or 4 Adverse Events (AEs), Grade 5 AEs, AEs Lead to Treatment Discontinuation, Serious AEs (SAEs)- All Causality: Assessed by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v4.03, measured over From first dose of study treatment up to 28 days after last dose (maximum follow up approximately up to 52.3 months; maximum exposure to treatment was 51.3 months).
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants with selected adverse-event outcomes: grade 3 or 4 events, grade 5 events, events leading to treatment discontinuation, and serious adverse events. The registry specifies that events are assessed using NCI CTCAE version 4.03 and that the endpoint includes all causality. An adverse event is defined as an untoward medical occurrence associated with use of the study intervention, whether or not it is considered related to that intervention.
The grade definitions distinguish severity. Grade 3 denotes a severe event; grade 4 denotes life-threatening consequences for which urgent intervention is indicated; and grade 5 denotes death related to an adverse event. The registry also defines serious adverse events by outcomes or circumstances such as death, immediate risk of death, inpatient hospitalization or its prolongation, persistent or significant disability, congenital anomaly or birth defect, or another important medical event. Events leading to treatment discontinuation are included among adverse events.
Counting participants is useful for describing how many people experienced an event in the safety analysis set. It gives a direct, interpretable safety summary, but it does not describe the total number of event episodes, their duration, or their timing. The registry record does not report those details for the primary endpoint. It also does not report a breakdown of the endpoint count by each named category, so the categories should not be treated as mutually exclusive or added together.
Because the endpoint is all-causality, it includes events whether or not they were judged to be related to crizotinib. This broad approach can capture the overall burden of events observed during the study, while leaving treatment attribution unresolved. The endpoint is therefore used to characterize safety experience, not to prove that treatment caused a particular event or that an event was unrelated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes safety outcomes in a single group receiving crizotinib. Its adverse-event summary lists serious adverse events for 13 of 41 participants at risk, other adverse events for 8 of 41 participants at risk, and 3 deaths. These figures are descriptive counts in the registry record. They are not results of a randomized comparison, and the record does not establish that the listed deaths were caused by treatment. The primary endpoint itself specifies all-causality events.
The serious-event terms appearing most often in the registry summary include Disease progression at 4.9%, and Crohn's disease, Gastrointestinal haemorrhage, Impaired gastric emptying, Obstruction gastric, and Pancreatitis acute, each at 2.4%. These percentages describe the posted serious-event terms. The record does not provide further context about the individuals affected, event timing, recurrence, or whether a participant could appear under more than one term. The terms should not be interpreted as evidence that crizotinib caused them.
No statistical analyses are listed in the registry record. It does not report confidence intervals, hypothesis tests, adjusted estimates, or a comparative treatment effect. As a result, the event counts do not support a formal estimate of uncertainty or a claim of a statistically detectable difference. A count is informative about what was recorded in this study, but its precision cannot be fully assessed without additional statistical summaries and a clear definition of the event denominator and analysis for each outcome.
General statistical context: a confidence interval expresses a range of values compatible with data and a specified statistical method. It helps show how uncertain an estimate is, rather than indicating that the range contains a guaranteed value. No confidence intervals are reported for these safety counts in the registry record. The sample size alone does not supply that missing uncertainty estimate, and no estimate should be reconstructed from counts without making assumptions about the endpoint and analysis.
The single-arm design also limits causal interpretation. The study has no concurrent control group, so the observed event counts cannot determine what event experience would have been under a different treatment or in the absence of crizotinib. The population had advanced disease and prior study treatment, but the record does not provide enough detail to separate these influences from treatment effects. Nor does it report an efficacy analysis that could be set alongside the safety findings.
The study is marked terminated, but the reason is not reported in the registry record. Termination status alone does not establish why the study ended or imply a particular safety conclusion. The registry states maximum follow-up and maximum treatment exposure, but these maxima do not describe the experience of every participant. The distribution of exposure, the number with complete follow-up, and details of missing safety information are not reported in the registry record.
Overall, the posted results describe adverse-event experience in a defined cohort. They should be read as descriptive registry findings, not as a comparative estimate or a causal conclusion. The record’s limited statistical reporting and the absence of a control group are central to interpreting what these counts can and cannot establish.
9. Statistical Methods Explained
The study design determines which statistical conclusions are supported. This registry record describes an open-label, single-arm study: outcomes were observed in a group receiving crizotinib, without a concurrent randomized control group. The main safety outcome is a count of participants with specified adverse events. Such a count answers a descriptive question about the observed group. It does not, on its own, estimate a treatment contrast.
What does a participant count represent?
A participant count records whether people experienced an outcome during the period being assessed. It differs from an event count, which can include repeated episodes in the same person. The primary endpoint is explicitly expressed as participants with events. The record does not provide a full breakdown of primary endpoint counts by event category, so it is not possible to determine from the registry record how many participants fell into each category or how much overlap there was among categories.
Counts are most interpretable alongside a clearly specified denominator and observation period. The registry defines the safety analysis set as participants who received at least one dose, and the endpoint timeframe extends from first dose through 28 days after last dose. The adverse-event summary reports at-risk counts of 41 for its serious and other-event summaries. The record does not provide participant-level exposure time or the distribution of time at risk. A count over longer observation can reflect more opportunity for events to be observed; the maximum follow-up value does not resolve that issue for each participant.
Why distinguish severity from seriousness?
Severity grades describe the intensity or clinical severity of an adverse event under the stated NCI CTCAE system. Seriousness is defined by outcomes or circumstances, including death, life-threatening risk, hospitalization, significant disability, congenital anomaly or birth defect, or an important medical event. These are related but not interchangeable classifications. An event can be severe without meeting a seriousness criterion, and an event can be serious for reasons other than its severity grade. The registry’s primary endpoint includes both grade-based categories and serious adverse events, so those labels should not be collapsed into one measure.
The endpoint includes all-causality events. This means the event count does not depend on a finding that treatment caused the event. That choice can make a safety summary broader, but it also means the count cannot be read as a count of treatment-attributed harm. The registry does not report separate causal assessments for these primary endpoint categories.
What can be concluded without a comparator?
In general, a randomized comparison helps estimate how outcomes differ between assigned groups while reducing some sources of confounding. No such comparison is present in this single-arm study. Describing the observed safety experience remains possible, but contrasting it with a hypothetical alternative requires information that this design does not provide. Differences from external populations would also require careful consideration of eligibility, follow-up, outcome definitions, and other characteristics; the registry record does not make such a comparison.
The registry lists no statistical analyses. In particular, it does not report confidence intervals, p-values, adjusted models, or a formal comparison. General statistical interpretation: a p-value assesses how compatible data are with a specified null model under the assumptions of a test; it does not quantify the probability that a treatment works or that a finding is true. A confidence interval describes uncertainty in an estimate under a chosen method. Neither is listed for the registry safety results, so statistical significance and precision cannot be assessed from the record.
How should planning illustrations be read?
The planning assumptions describe illustrations based on an 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. Such calculations are planning illustrations, not observed power and not a design feature of this single-arm registry study. The registry record does not report the trial’s own sample-size justification or a two-arm allocation. No sample-size illustration should be read as evidence that the study had a particular probability of detecting a treatment effect.
General statistical context: normal approximations simplify calculations by using a smooth reference distribution. Their usefulness depends on whether the approximation is appropriate for the data and design. Binary outcomes such as participant event counts can be sparse, and a simple approximation may not capture all uncertainty, particularly when events are uncommon. This is a general consideration, not a statement that a particular approximation was used to analyze the registry outcomes; no outcome analysis is listed.
Likewise, over-dispersion is a general issue in count data when observed variation exceeds what a chosen model expects. It can lead a model to understate uncertainty if ignored. The primary endpoint is a participant count, not a reported rate model, and the registry record does not describe a model or an over-dispersion assessment. This concept therefore provides background, not a claim about the study’s analysis.
The record also does not state whether there were planned interim analyses, a prespecified statistical analysis plan, or any adjustment for multiple testing. These details are not reported in the registry record. They should not be inferred from the endpoint description or from the fact that the registry lists more than one outcome measure.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 2 outcome measures and 0 analyses. It does not report a multiplicity strategy or explain how statistical interpretation would be handled across outcomes. Multiplicity is a general concern when several hypotheses are tested: repeated testing can increase the chance of at least one apparently unusual result under a setting where no effects are present. This concern is most relevant to inferential testing; the record lists no tests, p-values, or analysis results to evaluate. A correction method or testing hierarchy is not reported in the registry record.
Missing-data handling is also not reported in the registry record. The safety analysis set is defined as participants who received at least one dose, but the record does not describe how incomplete follow-up, withdrawal, or missing event assessments were handled. It does not report the number of participants with complete safety follow-up or whether any endpoint information was missing. Consequently, the posted counts cannot establish whether all eligible observation time was captured.
Analysis populations can affect interpretation. Here, the stated safety population includes participants who received at least one dose. The registry does not provide a separate intention-to-treat population, per-protocol population, or population-specific analysis. It also does not state whether the population used for the primary safety endpoint differed from the safety analysis set.
These omissions matter because event counts depend on outcome definitions, observation windows, and the availability of assessments. The stated timeframe is from first dose through 28 days after last dose, but participant-level follow-up and handling of gaps are not described. The record does not report imputation methods, sensitivity analyses, or a prespecified plan for missing data. None of these methods should be assumed to have been used.
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 |
|---|---|---|---|
| Crizotinib | 13 | 41 | 31.7% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Crizotinib | 3 of 41 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Crizotinib | 8 of 41 |
Most frequent serious adverse event terms
| Event term | Organ system | Crizotinib |
|---|---|---|
| Disease progression | General disorders | 2 of 41 |
| Crohn's disease | Gastrointestinal disorders | 1 of 41 |
| Gastrointestinal haemorrhage | Gastrointestinal disorders | 1 of 41 |
| Impaired gastric emptying | Gastrointestinal disorders | 1 of 41 |
| Obstruction gastric | Gastrointestinal disorders | 1 of 41 |
| Pancreatitis acute | Gastrointestinal disorders | 1 of 41 |
| Anal abscess | Infections and infestations | 1 of 41 |
| Herpes zoster | Infections and infestations | 1 of 41 |
| Pneumonia | Infections and infestations | 1 of 41 |
| Postoperative wound infection | Infections and infestations | 1 of 41 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Crizotinib |
|---|---|---|
| Neutrophil count decreased | Investigations | 8 of 41 |
| White blood cell count decreased | Investigations | 3 of 41 |
Serious events with the highest arm-level rate: disease progression (4.9%), crohn's disease (2.4%), gastrointestinal haemorrhage (2.4%), impaired gastric emptying (2.4%), obstruction gastric (2.4%).
The registry’s adverse-event summary lists serious adverse events for 13 of 41 participants at risk, other adverse events for 8 of 41 participants at risk, and 3 deaths. These are descriptive figures. The summary does not establish that every listed event was caused by crizotinib, and the primary endpoint explicitly includes all-causality events. The record does not report a separate causal attribution for the listed counts.
The registry lists Disease progression at 4.9% among the serious-event terms, and Crohn's disease, Gastrointestinal haemorrhage, Impaired gastric emptying, Obstruction gastric, and Pancreatitis acute at 2.4% each. The record does not explain whether these terms represent first events, all episodes, or participant-level categories, nor does it provide event timing or participant detail. Percentages for terms should not be converted into additional counts or added together.
Seriousness and severity are distinct concepts. The primary endpoint includes severity grades as well as serious events, but the adverse-event summary does not provide the full grade-specific breakdown. The 3 deaths in the summary should not be interpreted as 3 grade 5 adverse events: the record does not say that these deaths were related to an adverse event or provide that classification. More detailed information is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The results provide a descriptive account of safety events recorded in a single-arm study of crizotinib among participants with advanced ALK- or ROS1-positive non-small cell lung cancer who had previously been treated in Pfizer-sponsored studies in China. The registry’s summary includes serious adverse events for 13 of 41 participants at risk, other adverse events for 8 of 41 participants at risk, and 3 deaths. These observations are relevant to understanding what was recorded in this cohort during the defined study period.
They do not establish that crizotinib caused each event. The endpoint includes all-causality events, and the record does not report treatment-attributed results for the counts. The listed deaths also cannot be assumed to be treatment-related or to meet the primary endpoint’s grade 5 definition, which specifies death related to an adverse event. The record does not provide the information needed to make those classifications.
The findings also do not show whether the event experience was higher or lower than it would have been under another treatment. The study has no randomized comparator, and no comparative statistical analysis is listed. Differences in disease status, prior treatment, follow-up, and other factors cannot be separated from treatment effects using these registry figures alone. No efficacy conclusion is supported by the safety counts, and an efficacy analysis is not reported in the registry record.
Precision is also uncertain. The record does not provide confidence intervals or other measures of statistical uncertainty for the event counts. The reported enrollment and at-risk counts do not substitute for uncertainty estimates, particularly when follow-up duration and missing outcome information are not described in detail. The maximum follow-up and maximum treatment exposure are not typical durations and should not be applied to every participant.
Accordingly, the appropriate reading is limited: the posted results describe adverse events recorded in the study population under the registry’s definitions. They do not establish causality, comparative safety, or a treatment effect. The registry record does not report the reason for termination, a detailed statistical analysis, or enough participant-level follow-up information to resolve these uncertainties.
13. Why This Trial Matters Statistically
This study is statistically notable because it addresses long-term safety observation in a defined population while using a single-arm design. The population had advanced non-small cell lung cancer involving ALK or ROS1 and had previously been treated in Pfizer-sponsored studies. That context makes careful attention to eligibility and prior treatment important when interpreting the observed safety experience.
A single-arm study can document events in people receiving a treatment and can contribute descriptive safety information. Its central statistical limitation is that it does not provide a concurrent counterfactual: the outcomes that would have occurred for comparable participants under another treatment or without the study intervention. Without that comparison, event counts cannot isolate a treatment effect. This distinction is important for all-causality safety outcomes, which include events not judged to be related to treatment.
The endpoint also illustrates why safety measures need careful definition. It combines grade-based events, treatment discontinuation events, and serious adverse events. Severity and seriousness refer to different features, and categories can overlap. A participant-count endpoint is not the same as a count of event episodes. Interpreting any summary therefore depends on knowing the event definitions, analysis population, observation period, and how overlap was handled; some of these details are not reported in the registry record.
Finally, the registry lists no statistical analyses. Without inferential estimates or uncertainty measures, the findings remain descriptive. This does not make the observations uninformative, but it constrains the strength and scope of conclusions. The study is most appropriately read as a record of observed safety events in its enrolled population, rather than as a comparative test or a causal assessment.
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.
Several limitations specific to this registry record constrain interpretation. The study is single-arm and open-label, with no randomized comparator. The event counts therefore cannot show how safety outcomes differ from those under another treatment, and open-label assessment may be relevant to how events were recognized or recorded. The registry does not describe event-adjudication procedures or methods to reduce assessment bias.
The enrolled population was selected: participants had advanced disease involving an ALK or ROS1 event and had previously been treated in a Pfizer-sponsored study. The results should not be assumed to describe other populations. The record does not give further detail on participant characteristics, prior treatment histories, or how those factors relate to the observed events.
The primary endpoint combines several event categories, but the registry does not report a complete category-specific breakdown or the extent of overlap. The adverse-event summary lists serious and other events and deaths, but does not establish causality for those figures. Its serious-event terms are not accompanied by event timing, recurrence, or participant-level descriptions. The record also does not clarify whether every listed term reflects a unique participant.
Although maximum follow-up is approximately up to 52.3 months and maximum treatment exposure was 51.3 months, the distribution of observation time is not reported. Thus, the maxima cannot describe typical follow-up or comparable time at risk across participants. The record does not describe missing data, withdrawals, or completeness of endpoint assessments.
The study status is terminated, but the reason is not reported in the registry record. No statistical analyses are listed, and confidence intervals, hypothesis tests, adjusted estimates, multiplicity procedures, and a detailed statistical analysis plan are not reported. These are limits of the available record and should not be filled in by assumption.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Long Term Safety Observation of Crizotinib in Chinese NSCLC Population — NCT03672643.
- Registry record last updated 2024-11-08; status last verified 2024-09.
- Results first posted 2024-11-08.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT03672643 is a phase 4, open-label, single-arm study of crizotinib for long-term safety observation in participants from China with advanced non-small cell lung cancer involving an ALK or ROS1 translocation or inversion event who had previously been treated on a study of Xalkori. The registry lists enrollment as 41, sponsor Pfizer, and study status terminated. The reason for termination is not reported in the registry record.
The primary outcome counts participants with grade 3 or 4 adverse events, grade 5 adverse events, events leading to treatment discontinuation, or serious adverse events, assessed using NCI CTCAE version 4.03 and including all causality. The timeframe is from first dose through 28 days after last dose. The safety analysis set includes participants who received at least one dose.
The registry’s adverse-event summary lists serious adverse events for 13 of 41 participants at risk, other adverse events for 8 of 41 participants at risk, and 3 deaths. The registry lists no statistical analyses. The findings are descriptive and do not provide a randomized comparison or establish treatment causality.