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 Pilot Trial of Intravenous Vitamin C in Refractory Non-Hodgkin Lymphoma (NHL) (NCT00626444), a na phase 2 study. The primary outcome is Progression-free Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00626444 |
| Phase | Phase 2 |
| Condition | Non-Hodgkin Lymphoma |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sidney Kimmel Comprehensive Cancer Center at Thomas Jefferson University |
| Results posted | Yes |
2. Clinical Question
Population
The intended participants were adults with aggressive or very aggressive non-Hodgkin lymphoma confirmed by histological tumor examination. The brief summary describes disease that had failed to respond to one or more prior chemotherapy or antibody therapies given with curative intent, without progression within 60 days of the last therapy. Candidates also had to be ineligible for potentially curative treatment such as HSCT, or to have refused those alternatives. The registry record does not report the detailed inclusion and exclusion criteria.
Intervention
The intervention was intravenous vitamin C, also described as intravenous ascorbic acid. The brief summary describes dose adjustment based on plasma vitamin C level, aiming for a level in the range of 300 to 350 mg/dL. The intended schedule was 3 infusions per week, with at least 24 hours between infusions, for 10 weeks, or 30 infusions. These are protocol details; the registry record does not report how many infusions participants actually received.
Comparator
There was no comparison group. The trial is recorded as a single-group study with allocation listed as not applicable. The intervention group was intravenous vitamin C; the registry record does not describe a placebo or usual-care arm. Consequently, the design does not provide a concurrent control for distinguishing changes during the study from other influences.
Primary question
The listed primary outcome was progression-free survival, with a timeframe of 10 weeks. In broad terms, the question was whether participants remained free of disease progression over the assessment period after receiving the study intervention. The registry record does not provide an operational definition, an event count, a survival estimate, or an analysis for this outcome. It therefore does not report an answer to the primary question.
3. Trial Design
This was a phase 2, single-group trial of intravenous vitamin C in people with refractory non-Hodgkin lymphoma. The registry lists allocation as not applicable and masking as none. It records enrollment of 2 and a status of terminated. The recorded study start is 2008-02 and the primary completion date is 2011-12. The reason for termination is not reported in the registry record, so the status alone does not explain why the study ended.
The brief summary describes a treatment plan in which intravenous ascorbic acid dosing would be based on plasma vitamin C level, with a target level in the range of 300 to 350 mg/dL. Infusions were planned 3 times a week, with at least 24 hours between infusions, for 10 weeks and 30 infusions. The summary says that progression before or at the 10-week assessment, toxicity, or adverse events would lead to discontinuation. If disease had not progressed or had improved, reassessment was planned at 10-week intervals, for a total of three 10-week intervals. These statements describe the planned protocol, not documented treatment received or participant outcomes.
The registry identifies progression-free survival at 10 weeks as the primary outcome and duration of response as a secondary outcome. It records 2 outcome measures and 0 analyses. Outcome definitions beyond the brief timeframe and outcome names, as well as the statistical analysis plan, are not reported in the registry record. With no comparison arm, the study can describe experiences in the treated group if results are available, but it cannot estimate a randomized treatment contrast.
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 | Vitamin C |
|---|---|
| STARTED | 2 |
| COMPLETED | 2 |
| NOT COMPLETED | 0 |
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 | Vitamin C |
|---|---|---|
| Participants analysed | 2 | |
| Age, Continuous | years | 55.3 (SD 2.9) |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 2 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 1 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Progression-free Survival, measured over 10 weeks.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
Progression-free survival is a time-to-event outcome used to describe how long participants remain without disease progression. In general, time-to-event methods can account for the fact that participants may have different lengths of observation, including cases where follow-up ends before an event is observed. The precise event definition and handling of follow-up are study-specific. For this trial, the registry lists progression-free survival with a 10-week timeframe, but the detailed definition, time origin, assessment rules, and censoring approach are not reported in the registry record.
This endpoint is used in oncology studies because it focuses on whether disease progression has occurred during a defined period, rather than only recording a measurement at one visit. It can be informative when the clinical question concerns control of disease over time. However, interpreting it requires knowing how progression was assessed, how often assessments occurred, what counted as an event, and how incomplete observations were handled. Those details are not reported.
No progression-free survival estimate, event count, confidence interval, or statistical test is reported in the registry record. The 10-week timeframe should therefore be read as the listed assessment period, not as evidence that participants remained progression-free for that length of time.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a small, single-group phase 2 study, with enrollment of 2 and a terminated status. It identifies progression-free survival at 10 weeks as the primary outcome, but records 0 analyses and supplies no efficacy results. There is no reported progression-free survival estimate, event count, confidence interval, or p-value. Duration of response is named as a secondary outcome, but no result for it is reported either. The absence of posted results means the clinical outcome cannot be assessed from this record.
Even if outcome observations were available, a single-group design would limit what could be concluded about treatment effects. Without a concurrent comparator, an observed course of disease could not be separated cleanly from the disease’s natural course, prior treatment, selection of participants, or other care received during follow-up. Those are general limitations of uncontrolled comparisons, not findings about what happened to these participants. The registry record does not report information that would allow those influences to be evaluated.
The enrollment of 2 also means that any descriptive estimate based on the participants would be highly sensitive to each individual observation. In general, small samples produce imprecise estimates, and uncertainty can be substantial even when a point estimate is calculable. Here, no point estimate or interval is posted, so precision cannot be quantified. The recorded enrollment should not be confused with a reported efficacy analysis or interpreted as a sample-size justification; the justification is not reported in the registry record.
The protocol summary describes discontinuation in the event of progression, toxicity, or adverse events, and reassessment at 10-week intervals if disease had not progressed or had improved. The registry does not report whether those planned assessments occurred, how many participants were assessed at each time, or how discontinuation and missing observations were handled analytically. Thus, it is not possible to determine whether the outcome timeframe was completed for any participant or whether the endpoint was analyzed as planned.
The safest statistical reading is narrow: the record documents an intended intervention, a single-group design, enrollment of 2, termination, and named outcomes. It does not report results that establish the direction, magnitude, or precision of the primary outcome. The serious and other adverse-event counts are separately listed, but they do not supply missing efficacy results and should be read as safety reporting rather than as a comparison of treatment effects.
9. Statistical Methods Explained
What does a single-group design allow?
In a single-group study, participants receive the intervention under study, and outcomes are recorded without a concurrent control group. This design can document what was observed among enrolled participants, provided that outcome data and analysis methods are reported. It does not create a like-for-like comparison between intervention and control groups. General statistical interpretation therefore distinguishes descriptive observations from causal effects: an outcome occurring after treatment does not, by itself, show what would have happened to the same participants without treatment.
That distinction matters in this record because allocation is listed as not applicable, masking as none, and the model as single group. There is no randomized comparison. The registry record does not report an analysis that estimates a treatment effect against a control. It also does not describe a statistical plan that would support another type of comparison. Because the posted record has no outcome analyses, even a descriptive estimate of progression-free survival is unavailable.
How should progression-free survival be understood?
Generally, progression-free survival is a time-to-event measure. It is intended to represent the time until a defined disease-progression event, and sometimes includes death as an event; the exact definition depends on the protocol. Time-to-event analysis can use information from participants whose event has not been observed by the end of follow-up, subject to assumptions and a specified censoring approach. A reader needs the event definition, time origin, assessment schedule, and censoring rules to interpret an estimate properly.
The registry names progression-free survival as the primary outcome and gives a 10-week timeframe. It does not state the operational definition, time origin, event-assessment procedures, censoring rules, or analysis method. It also provides no estimate, event count, or uncertainty interval. The general features of time-to-event analysis explain what this endpoint can measure, but they cannot fill in those trial-specific details.
What does the posted analysis record show?
The record lists 2 outcome measures and 0 analyses. It names progression-free survival as primary and duration of response as secondary, but reports no numerical results for either. A confidence interval would ordinarily communicate the range of values reasonably compatible with the observed data under a specified method. Without an estimate, interval, event count, or analysis description, the precision of the primary outcome cannot be evaluated. No significance test or inferential result is reported.
Enrollment of 2 is important context for precision. As a general principle, each observation has substantial influence when a study includes very few participants, and a time-to-event estimate may be especially difficult to interpret if event and follow-up information are not reported. This does not justify reconstructing outcomes from the safety counts. Those counts concern adverse-event categories, not progression-free survival.
What are the sample-size illustrations?
The stated planning assumptions describe illustrations based on an observed effect, not the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. For time-to-event illustrations, the stated quantity is the total number of events using the Schoenfeld approach; other illustrations are expressed as participants per arm.
These are planning calculations, not observed power and not a record of participants analyzed. Their assumptions refer to a two-arm comparison, whereas this trial is recorded as single group with allocation not applicable. The registry record does not provide an observed effect from which to assess such illustrations, nor does it report a sample-size justification for the trial itself. Any planning figure should therefore be read as hypothetical under its stated assumptions, not as evidence that the study was designed to detect a particular effect or that it achieved a particular power.
Why do outcome definitions and follow-up matter?
General statistical interpretation depends on the link between a protocol’s planned assessments and the observations actually collected. The brief summary describes a 10-week initial treatment period and further reassessments at 10-week intervals under specified circumstances. It does not report how many participants completed treatment, whether assessments took place, or the length and completeness of follow-up. Without those details, the relationship between the planned schedule and the reported endpoint cannot be assessed.
The registry record also does not report the statistical methods used for the primary outcome, the analysis population, or how missing data were handled. These omissions leave important aspects of the analysis unverifiable. No method should be inferred from the endpoint name alone, and no unreported estimate should be recreated from unrelated counts.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies progression-free survival as the primary outcome and duration of response as a secondary outcome. It does not report a statistical analysis plan, a hierarchy of hypotheses, or a method for controlling multiplicity. In general, testing several outcomes can increase the chance of finding an apparently unusual result by chance; prespecified outcome priorities and adjustment strategies can help readers understand how such testing was handled. No such approach is reported in the registry record, and no outcome analyses are listed.
Missing-data handling is also not reported. The brief summary describes stopping the protocol following progression, toxicity, or adverse events, but does not say how incomplete outcome observations would be treated in an analysis. The record does not report numbers assessed at follow-up visits, reasons for missing observations, censoring rules, or sensitivity analyses. It is therefore not possible to determine whether missingness was considered or how it might affect any estimate.
The analysis populations are not reported in the registry record. It is not stated whether analyses were intended to include everyone enrolled, only participants who received treatment, or another defined group. The enrollment is recorded as 2, but this does not establish how many participants contributed data to any particular outcome. With 0 analyses recorded, there is no reported analysis population or account of exclusions to evaluate.
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 |
|---|---|---|---|
| Vitamin C | 0 | 2 | 0.0% |
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 |
|---|---|
| Vitamin C | 2 of 2 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Vitamin C |
|---|---|---|
| Abdominal pain | General disorders | 1 of 2 |
| Back pain | General disorders | 1 of 2 |
| Induration at IV site | General disorders | 1 of 2 |
| Lightheadedness | General disorders | 1 of 2 |
| Nausea | General disorders | 1 of 2 |
| Pain at IV site | General disorders | 1 of 2 |
| Viral illness | General disorders | 1 of 2 |
The registry lists a Vitamin C group with 2 participants at risk for serious adverse events and 0 affected. For other adverse events, it lists 2 at risk and 2 affected. These are the posted counts; they should be read as separate registry categories, not combined or used to infer an unreported rate. No serious adverse-event terms are listed. The death count is not reported in the registry record.
In general, adverse-event counts describe events recorded during a study and do not, by themselves, establish that the intervention caused them. Their interpretation depends on definitions, collection methods, observation time, severity criteria, and attribution procedures. Those details are not reported in the registry record. The count for other adverse events does not indicate the number or type of events per participant, and the record does not list their terms.
These safety figures are not a substitute for progression-free survival results. They describe the registry’s adverse-event reporting fields and do not provide a controlled safety comparison. Given the small enrollment, the counts also offer limited information about the range of possible adverse experiences. No broader safety conclusion can be drawn from the posted figures alone.
12. What the Result Does, and Does Not, Mean
The record establishes that a phase 2 study of intravenous vitamin C in refractory non-Hodgkin lymphoma was registered as a single-group trial, enrolled 2, and is marked terminated. It describes a planned regimen and names progression-free survival at 10 weeks as the primary outcome. It also lists duration of response as a secondary outcome and provides adverse-event counts for the Vitamin C group.
It does not report the primary outcome result, a response result, a confidence interval, a p-value, or the analysis used for either outcome. As a result, the direction and magnitude of any change in disease status cannot be determined from the registry record. Nor can the precision of an efficacy estimate be assessed. The record does not report why the trial was terminated, whether the planned assessments were completed, or how many participants contributed to an efficacy analysis.
Even a reported outcome in this design would need cautious interpretation. Without a comparator, the study would not establish how outcomes differed from those under another treatment or no study intervention. General limitations of single-group studies include difficulty separating the intervention’s contribution from other influences on participants’ outcomes. The registry record provides no control group or adjusted comparison to address that problem.
The adverse-event figures show the counts recorded in the registry, but do not establish causality or offer a comparative estimate of safety. The study’s enrollment and missing analysis details limit how broadly those counts can be interpreted. Overall, the registry documents a trial design and selected reporting fields, but does not provide posted efficacy results from which to assess the primary question.
13. Why This Trial Matters Statistically
Statistically, this trial illustrates the difference between a registered research question and a reported result. The registry names progression-free survival at 10 weeks as the primary outcome, but lists 0 analyses and provides no estimate or uncertainty interval. Without those results, readers cannot assess either the observed outcome or its precision. A clearly named endpoint is not itself evidence of an effect.
The single-group structure is also an important interpretive feature. It can support descriptive reporting of participants’ experiences when results are available, but it lacks a concurrent control for a treatment contrast. That limits causal interpretation independently of the small enrollment. The recorded enrollment of 2 further underscores why individual observations and complete outcome reporting would be essential for interpreting any descriptive estimate.
The record also demonstrates why protocol descriptions should be distinguished from completed study procedures. It outlines an intended infusion schedule, criteria for discontinuation, and planned reassessments. It does not report whether those procedures occurred as planned, or how the primary endpoint was analyzed. Statistical interpretation needs the outcomes actually observed and methods used, not just the planned schedule.
Finally, the record’s sample-size assumptions are described as planning illustrations based on an observed effect, with assumptions for a two-arm calculation. Those illustrations are not observed power and do not describe this single-group trial’s own design justification. Keeping planning calculations separate from observed trial results helps prevent hypothetical sample-size scenarios from being mistaken for evidence about the study’s findings.
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 trial-specific details needed for interpretation are not reported in the registry record. These include the reason for termination, the operational definition of progression-free survival, the method of outcome assessment, the analysis plan, and the analysis population. The record also does not report whether the planned 10-week assessments occurred or how many participants had outcome data. These gaps prevent verification of how the listed primary endpoint relates to the observations collected.
The brief summary describes intended eligibility requirements and treatment procedures, but the record does not provide the full inclusion and exclusion criteria. It also does not report actual treatment exposure, including the number of infusions received. The protocol’s planned dose targeting and reassessment schedule should not be mistaken for documented treatment delivery or completed follow-up.
The study has no comparator, is recorded as unmasked, and has enrollment of 2. These features constrain interpretation of descriptive outcomes and preclude a randomized comparison. The registry does not provide efficacy analyses, so the practical effect of these limitations cannot be evaluated against outcome estimates. Safety reporting is also limited: serious-event terms are absent, other-event terms are not listed, and the death count is not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pilot Trial of Intravenous Vitamin C in Refractory Non-Hodgkin Lymphoma (NHL) — NCT00626444.
- Registry record last updated 2025-05-16; status last verified 2025-05.
- Results first posted 2014-12-10.
- 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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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry describes a phase 2, single-group trial of intravenous vitamin C in adults with refractory non-Hodgkin lymphoma. Allocation is listed as not applicable and masking as none. Enrollment is recorded as 2, and the study status is terminated. The recorded start is 2008-02, and primary completion is 2011-12.
The intended intervention was intravenous ascorbic acid, with dosing based on plasma vitamin C level. Progression-free survival at 10 weeks is the primary outcome; duration of response is listed as secondary. The registry records 2 outcome measures and 0 analyses. No efficacy results, statistical analysis plan, or reason for termination are reported in the registry record.
For the Vitamin C group, the registry lists serious adverse events for 0 of 2 participants and other adverse events for 2 of 2. No serious-event terms are listed, and the death count is not reported.