Study to Assess the Efficacy and Safety of VX-210 in Subjects With Acute Traumatic Cervical Spinal Cord Injury: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Assess the Efficacy and Safety of VX-210 in Subjects With Acute Traumatic Cervical Spinal Cord Injury (NCT02669849), a randomized phase 2, phase 3 study. The primary outcome is Change in Upper Extremity Motor Score (UEMS).

2. Clinical Question

The registry describes the study’s purpose as assessing VX-210 efficacy and safety in acute traumatic cervical spinal cord injury. It also identifies neurological recovery and daily function as secondary areas of interest. The primary measure focuses on hand and arm motor control, which the registry describes as particularly relevant to people with cervical spinal cord injury.

The posted primary results report group means and standard deviations, alongside a sponsor analysis using a mixed-effects model for repeated measure. These answer related but not identical statistical questions: the simple comparison of group summaries is unadjusted, while the registry’s reported model result is the sponsor’s stated analysis. The registry record does not explain the model specification or give the original design assumptions, so those details cannot be inferred from the result alone.

3. Trial Design

This was a Phase 2b/3, randomized, quadruple-masked, parallel-group, placebo-controlled, multicenter study sponsored by Vertex Pharmaceuticals Incorporated. The condition listed was cervical spinal cord injury, and the intervention groups included VX-210 and placebo. Enrollment was 70. The registry lists the study status as terminated, with a start date of 2016-07 and primary completion in 2018-11.

The primary outcome was change in Upper Extremity Motor Score (UEMS), measured from baseline at 6 months post-treatment. The primary comparison in the posted results is VX-210 9 mg versus placebo. The placebo group had 29 participants in the primary outcome summary, and the VX-210 9 mg group had 32. These analysis counts are not the same thing as the study’s overall enrollment.

The primary population description says that the overall number analyzed included randomized subjects who received study drug. It also says that, following a protocol amendment, the 3 mg arm was no longer planned for assessment on any primary or secondary outcome measure. The 3 mg group nevertheless appears in the safety results. The registry does not give further details about the amendment or explain its timing.

The registry lists nine secondary outcomes, including measures of self-care, upper-extremity capabilities, strength and prehension, responder outcomes, and VX-210 plasma concentration measures. Numeric results are posted for three secondary measures: the SCIM III Self-Care Subscore, CUE-T Score and GRASSP Quantitative Prehension Score. The registry record does not report the original sample-size justification, the trial’s planned statistical analysis details beyond the reported model name, or the reason for termination.

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 70 participants were randomized, out of which 67 participants received the study drug.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The "Overall Number of Participants Analyzed" included all randomized subjects who received study drug. As per the amended protocol, the 3 mg arm was no longer planned to be assessed for any primary or secondary outcome measure.

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: Overall number of Baseline participants includes all randomized participants who received study drug.

6. Primary Endpoint

The registry lists the primary outcome as Change in Upper Extremity Motor Score (UEMS), measured over From baseline at 6 months post-treatment.

UEMS is a measure of upper-extremity motor function. The registry describes it as selectively focused on hand and arm control, which is relevant to people with cervical spinal cord injury. Its scale ranges from 0 to 50, with higher scores indicating better hand and arm movement.

The primary endpoint is change in UEMS from baseline at 6 months post-treatment. Measuring change compares participants’ scores at follow-up with their own baseline scores, rather than treating a single follow-up score as the full outcome. The registry’s stated timeframe therefore asks about change over the specified follow-up period; it does not, by itself, establish whether any observed difference is important to participants.

The registry reports group means and standard deviations for this outcome. Those summaries describe the average change and the spread of individual results in each group. The posted results also include a sponsor-reported least-squares mean difference from a mixed-effects model for repeated measure. The record does not give a definition of a clinically important difference for UEMS, so statistical estimates should not be treated as establishing clinical importance.

General: a continuous score can help describe the degree of function captured by a scale, while a group average can conceal variation among participants. Interpreting a mean difference therefore requires attention both to the scale’s meaning and to the uncertainty around the group comparison.

7. Results Posted in the Registry

• VX-210 9 mg: mean 8.69 versus 8.90 on control; difference -0.21 (95% CI -4.50 to 4.08), standardized effect d = -0.02; z-test p = 0.924.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Spinal Cord Independence Measure (SCIM) III Self-Care Subscore

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • VX-210 9 mg: mean 5.90 versus 6.20 on control; difference -0.30 (95% CI -3.72 to 3.12), standardized effect d = -0.04; z-test p = 0.864.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between VX-210 9 mg and the control. The interval gives the range of effects that remain compatible with the data.

Capabilities of Upper Extremity Test (CUE-T) Score

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • VX-210 9 mg: mean 42.80 versus 39.60 on control; difference 3.20 (95% CI -16.75 to 23.15), standardized effect d = 0.08; z-test p = 0.753.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between VX-210 9 mg and the control. The interval gives the range of effects that remain compatible with the data.

Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) Quantitative Prehension Score

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • VX-210 9 mg: mean 20.10 versus 18.90 on control; difference 1.20 (95% CI -9.09 to 11.49), standardized effect d = 0.06; z-test p = 0.819.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between VX-210 9 mg and the control. The interval gives the range of effects that remain compatible with the data.

The three secondary outcomes with numeric results are the SCIM III Self-Care Subscore, CUE-T Score and GRASSP Quantitative Prehension Score. Across these measures, the unadjusted estimates vary in direction and all three confidence intervals span no difference. Taken together, the posted summaries do not show a consistent, precisely estimated separation between VX-210 9 mg and placebo across these functional measures.

This broad pattern is compatible with the uncertainty in the primary UEMS comparison: neither the primary nor these secondary results precisely establish the direction or size of a group difference. The secondary outcomes address related but distinct aspects of function, so they should not be treated as interchangeable with UEMS. The registry lists additional secondary outcomes, including responder and plasma concentration measures, but numeric summaries for those measures are not included among the posted secondary results.

The secondary recalculations are unadjusted. The registry does not report sponsor model analyses for these three outcomes, nor does it report an adjustment for testing multiple outcomes. General: when several outcomes are examined, the chance of observing an apparently notable result by chance can increase. A multiplicity procedure can account for that family of comparisons, but none is reported. Accordingly, individual unadjusted secondary p-values should be interpreted cautiously and carry less weight than a prespecified primary analysis.

The registry record does not state whether the secondary analyses were confirmatory or exploratory, or how they were prioritized. Their results are useful for describing the posted outcome pattern, but they do not independently settle the primary question or establish a treatment effect.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Spinal Cord Independence Measure (SCIM) III Self-Care Subscore
• Capabilities of Upper Extremity Test (CUE-T) Score
• Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) Quantitative Prehension Score
• Percentage of American Spinal Injury Association Impairment Scale (AIS) Grade Responders
• Percentage of Motor Level Responders
• Time to Reach Maximum Observed Plasma Concentration (Tmax) of VX-210
• Maximum Observed Plasma Concentration (Cmax) of VX-210
• Area Under Plasma Concentration Time Curve (AUC) of VX-210

9. Statistical Interpretation

10. Statistical Methods Explained

What does the mean difference represent?

The primary outcome is continuous, and the registry reports a mean for each group. The unadjusted mean difference compares the VX-210 9 mg group’s mean change with the placebo group’s mean change. Its estimate is -0.21 units. A negative value indicates that the VX-210 9 mg group’s posted mean was lower than the placebo group’s posted mean on this comparison; it does not describe every participant or establish why the groups differed.

General: a mean is an average, and a mean difference is a contrast between two averages. It is a compact description, but it does not show the full distribution of participant outcomes. The standard deviation describes the spread of observations around a group mean; it is not the uncertainty interval for the mean difference.

Why are two analyses reported?

The simple recalculation uses the posted group summaries to form an unadjusted comparison. The registry’s sponsor-reported analysis instead uses a mixed-effects model for repeated measure and reports a least-squares mean difference. The model-based estimate is -0.69, with a 95% confidence interval from -5.08 to 3.69. The recalculated estimate is -0.21, with a 95% confidence interval from -4.498 to 4.078.

General: a repeated-measures model is designed to analyze measurements collected over time and account for their relationship within a participant. A least-squares mean is a model-based estimate, rather than simply the arithmetic mean of the posted group values. The registry does not report the model’s detailed specification, the handling of missing measurements, or which covariates were included. Those choices cannot be inferred from the method name alone.

The two estimates should not be treated as if they came from identical procedures. The recalculation is an unadjusted summary-statistics comparison, whereas the sponsor result comes from the stated repeated-measures model. The record does not explain the difference between their estimates. The registry’s sponsor analysis remains the reported trial analysis; the recalculation is a supplementary descriptive check.

How should a confidence interval be read?

The unadjusted 95% confidence interval for the primary mean difference runs from -4.498 to 4.078. The sponsor-reported 95% interval runs from -5.08 to 3.69. Each interval expresses uncertainty around its corresponding estimate. In both cases, values indicating a difference in either direction are compatible with the interval, including no difference.

General: a confidence interval is a range of values reasonably compatible with the data and the statistical procedure used. It is not a guarantee that the true value lies within the particular interval, nor does it assign a probability to each value inside it. A narrow interval generally indicates greater precision than a wide interval. Width depends on factors including sample size, outcome variability and the analysis method.

What does a p-value add?

The unadjusted recalculation reports p = 0.924. The sponsor analysis reports p = 0.752. A p-value is interpreted in relation to a specified statistical model and null hypothesis. Neither value measures the size or importance of a difference, and neither is the probability that a treatment effect is true. The registry does not report the full analysis plan, so the p-values should be read in the context of the analyses as identified in the record.

General: a p-value describes how compatible the observed data, or more extreme data, are with a null hypothesis under the assumptions of the test. A larger p-value does not prove no difference, and a smaller p-value does not by itself establish clinical importance. Confidence intervals add information about the range and direction of estimates that a p-value alone cannot convey.

Why does variability matter?

The primary outcome standard deviations are 9.48 in the placebo group and 7.35 in the VX-210 9 mg group. These values describe variation in participant-level changes. When outcomes vary considerably among participants, a group average may be estimated less precisely unless there are enough observations to offset that variation.

General: over-dispersion refers to variation greater than a statistical model assumes. When present, it can make standard errors too small if not handled appropriately, leading to overly narrow intervals or misleading tests. The registry does not report an over-dispersion assessment for this continuous endpoint, so no such issue can be concluded from the posted summaries.

The posted result is a group-level comparison. It does not show whether changes were similar across participants, identify individual trajectories, or explain the sources of variability. Those questions would require participant-level data or further registry reporting.

11. Confidence Intervals and Precision

The recalculated 95% confidence interval for the primary unadjusted mean difference is -4.498 to 4.078 units. This interval is wide enough to include differences favoring either group as well as no difference. The point estimate, -0.21 units, is therefore not a precise estimate of the underlying group contrast. The interval should be read together with the observed group means and the sizeable spread in the outcome.

The sponsor-reported model estimate is -0.69, with a 95% confidence interval from -5.08 to 3.69. It likewise spans no difference and values on both sides. The interval is attached to the model-based least-squares mean difference, not the simple unadjusted recalculation. Because the registry does not give the model specification, the exact role of modeling choices in its precision cannot be assessed from the record.

General: confidence interval width reflects statistical precision, not clinical importance. To judge whether a range is clinically consequential, a relevant threshold or interpretation of meaningful change is needed. The registry does not report a clinically important difference for UEMS. It also does not give a formal precision target for the study.

The intervals do not establish equivalence. Equivalence requires a prespecified margin and an analysis designed to assess whether the plausible difference is contained within that margin; the registry record does not report such a margin or analysis. Nor should a confidence interval be read as a prediction range for individual participants. It concerns uncertainty in a group-level estimate.

The study enrolled 70 participants, while the primary summary includes 29 in placebo and 32 in the VX-210 9 mg group. Those group counts, together with the observed variation, are relevant to the uncertainty in the comparison. The registry does not report enough information to quantify how precision would have changed under another design or analysis.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The displayed planning figures are illustrations based on the observed effect, not the trial’s original design calculation. For these continuous outcomes, the figures are participants per arm, not total event counts. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect set at the stated fraction of the observed effect. The registry record does not report the trial’s own original sample-size assumptions or justification.

The 80% power column describes the estimated number of participants per arm under which a study would have an 80% chance of detecting the specified effect under the planning assumptions, if that effect were the true one. The 90% column uses a higher chance of detection, so it generally calls for more participants per arm. These figures are planning quantities, not observed outcomes.

The displayed scenarios use 100%, 75% and 50% of the observed effect. A smaller effect is harder to distinguish from random variation, so the planning illustration requires more participants per arm as the target effect becomes smaller. The primary outcome’s 100% observed-effect scenario lists 25,286 participants per arm for 80% power and 33,851 for 90% power; the smaller-effect scenarios list larger requirements.

These calculations are not observed power. They do not tell whether the completed study had a particular probability of success, and they should not be read as a post hoc explanation of the trial’s enrollment. Because they use the observed effect as their starting point, they are illustrations of how sample-size requirements respond to the chosen effect size under the stated assumptions.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.210; pooled standard deviation σ = 8.428.
2. n = 2 × (1.96 + 0.842)² × 8.428² / -0.210² = 25,285.5, rounded up to 25,286 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.210000000000001                      # observed difference in means
sigma <- 8.42823010553606                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2669849)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 25,286 (80% power), 33,851 (90% power)
 75% of observed effect: n per arm = 44,953 (80% power), 60,179 (90% power)
 50% of observed effect: n per arm = 101,143 (80% power), 135,401 (90% power)
power.t.test: 25286.5 
Simulated power at n = 25,286 per arm: 0.798 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary analysis as a mixed-effects model for repeated measure. It estimates a least-squares mean difference of -0.69 units for VX-210 9 mg versus placebo, with a 95% confidence interval from -5.08 to 3.69 and a reported p-value of 0.752. This is the trial’s stated model-based result.

The unadjusted recalculation from the posted group summaries estimates a mean difference of -0.21 units, with a 95% confidence interval from -4.498 to 4.078 and p = 0.924. It is a simple comparison of posted summaries and does not reproduce the sponsor’s repeated-measures model. The recalculation is useful as a descriptive cross-check, but it should not replace the sponsor’s reported analysis.

The registry record does not give the model specification, its covariates, the treatment of missing measurements, or enough detail to explain why the model-based and unadjusted estimates differ. The record does not flag a discrepancy between the posted sponsor analysis and the summary data. Both analyses nonetheless show broad intervals spanning no difference, and neither provides a precise estimate of the group contrast.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and nine secondary outcomes. The primary outcome is change in UEMS, while the secondary outcomes cover self-care, upper-extremity capability, prehension, responder measures and pharmacokinetic measures. Numeric results are posted for three secondary measures. The record does not report a multiplicity adjustment, a hierarchy among secondary outcomes, or a plan for controlling the chance of false-positive findings across multiple tests.

General: testing many outcomes creates multiple opportunities for a result to appear notable by chance, even when no underlying difference exists. Prespecified testing order, adjustment procedures, or clear exploratory labeling can help readers understand how to interpret a collection of results. Without those details, individual secondary p-values are best treated as descriptive rather than as independent confirmation.

The registry identifies the primary analysis method as a mixed-effects model for repeated measure, but does not report detailed model terms or the missing-data strategy. It does not state whether all planned follow-up measurements were available, how incomplete outcome records were handled, or whether sensitivity analyses were conducted. These omissions limit assessment of the assumptions underlying the model-based estimate.

The primary population description says the overall number analyzed included randomized subjects who received study drug. It also states that the 3 mg arm was no longer planned for primary or secondary outcome assessment after a protocol amendment. The registry does not report further detail on the amendment, the original analysis population, or how exclusions and missing observations were handled. The record therefore permits a description of the stated analysis population, but not a full reconstruction of the trial’s analysis plan.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pneumonia (50.0%), acute respiratory failure (33.3%), pulmonary embolism (33.3%), respiratory failure (33.3%), bradycardia (16.7%).

The safety results list serious adverse events for 18 of 29 participants in the placebo group, 6 of 6 in the VX-210 3 mg group, and 16 of 32 in the VX-210 9 mg group. The registry lists other adverse events for 28 of 29, 6 of 6 and 32 of 32 participants in those respective groups. Deaths are listed as 1, 1 and 2, respectively.

These are participant counts within the registry’s safety groups; they are not estimates of the probability that an individual will experience an event. The 3 mg group has 6 participants at risk, so its count should be read in light of that group size. The record lists pneumonia at 50.0%, acute respiratory failure at 33.3%, pulmonary embolism at 33.3%, respiratory failure at 33.3%, bradycardia at 16.7%, and sinus bradycardia at 16.7% among the top serious adverse event terms.

The registry summary does not establish whether an event was caused by study drug, and these counts alone do not support a causal comparison. Detailed event definitions, timing and attribution are not reported in the registry record.

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

The posted primary result is a comparison of average change in UEMS between the VX-210 9 mg and placebo groups at 6 months post-treatment. The group means are 8.69 and 8.9 units, respectively. The simple unadjusted estimate is -0.21 units, while the sponsor’s repeated-measures analysis estimates a least-squares mean difference of -0.69 units. Both confidence intervals span no difference and include values in either direction.

These results do not provide a precise estimate of the group contrast. They also do not prove that the groups are equivalent, because the registry does not report an equivalence margin or an equivalence analysis. A lack of a clear statistical separation is not the same as evidence that all meaningful differences have been ruled out.

The outcome measures hand and arm motor function, but the registry does not report a threshold for clinically important change. Statistical estimates therefore cannot, by themselves, establish whether a difference would matter to participants. The summaries also describe group averages and do not reveal the range of individual responses or explain why participants’ scores varied.

The secondary summaries provide additional descriptions of function, but they are unadjusted and the registry does not report how multiple outcomes were handled in the analysis plan. They should not be treated as definitive confirmation of the primary result. Similarly, safety counts describe events recorded in the groups but do not establish that the study drug caused them.

In general, a trial result is interpreted by considering the estimate, its uncertainty, the design and the outcome’s meaning together. The posted record supports a cautious account of what was observed, but not a broad conclusion about efficacy, safety or clinical benefit beyond these reported data.

18. Why This Trial Matters Statistically

This trial illustrates why an estimated group difference should be read alongside its uncertainty. The primary unadjusted point estimate is close to zero, but the confidence interval is broad and spans values favoring either group. A single estimate without its interval could make the result appear more conclusive than the data support.

It also illustrates that different analysis methods can yield different point estimates. The sponsor’s repeated-measures model reports a least-squares mean difference, while the unadjusted recalculation compares posted group summaries. Both are informative in their respective roles, but the model-based result is the trial’s reported analysis, and the summary-based recalculation is not a substitute for it. Missing model details limit independent interpretation of how the sponsor estimate was obtained.

The study’s overall enrollment and the primary analysis group counts also highlight why the analysis population matters. The registry notes that the 3 mg arm was no longer planned for outcome assessment after a protocol amendment, while safety results still include that arm. Readers need to distinguish the population used for an outcome from everyone enrolled or included in safety reporting.

Finally, the secondary outcomes and planning illustrations show two common interpretive challenges. Multiple unadjusted outcomes require caution, and planning figures based on observed effects should not be mistaken for the trial’s original design rationale or observed power. Clear reporting of the analysis plan, missing-data handling, multiplicity strategy and clinically meaningful thresholds would help readers assess the results more fully; these details are not reported in the registry record.

19. 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 does not report the reason the study was terminated, so the status alone cannot explain why the trial ended. It also does not provide the original sample-size justification or the trial’s planned statistical assumptions. The displayed sample-size illustrations use observed effects and stated planning assumptions, rather than documenting the original design basis.

The sponsor’s model is identified as a mixed-effects model for repeated measure, but the registry does not give its detailed specification, covariates, covariance structure, missing-data handling or sensitivity analyses. This limits assessment of the assumptions behind the model-based estimate and prevents a full comparison with the unadjusted recalculation.

The registry states that a protocol amendment removed the 3 mg arm from planned primary and secondary outcome assessment, but does not explain when or why the change occurred. The primary analysis counts are 29 for placebo and 32 for VX-210 9 mg, while the total enrollment is 70. The record’s population description identifies randomized participants who received study drug, but does not give a fuller account of participant flow or missing outcome data.

Although nine secondary outcomes are listed, numeric results are posted for three. The registry does not report a multiplicity strategy or the status of the secondary analyses as confirmatory or exploratory. It also gives no clinically important difference threshold for UEMS or the secondary scales. These gaps constrain interpretation of clinical importance and the strength of claims across outcomes.

The safety summary provides group counts and selected serious-event terms, but the registry record does not provide enough detail to determine causal attribution from those figures. Counts should therefore be read as descriptive records, not as evidence that an intervention caused an event.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Study to Assess the Efficacy and Safety of VX-210 in Subjects With Acute Traumatic Cervical Spinal Cord Injury — NCT02669849.
• Registry record last updated 2020-01-22; status last verified 2020-01.
• Results first posted 2020-01-22.
• 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.

23. Record Summary

NCT02669849 is a randomized, quadruple-masked, parallel, placebo-controlled, multicenter Phase 2b/3 study of VX-210 in acute traumatic cervical spinal cord injury. The registry lists enrollment of 70 and study status as terminated. The primary outcome was change in UEMS from baseline at 6 months post-treatment.

For VX-210 9 mg versus placebo, the unadjusted mean difference was -0.21 units, with a 95% confidence interval from -4.498 to 4.078. The sponsor-reported mixed-effects model estimated a least-squares mean difference of -0.69, with a 95% confidence interval from -5.08 to 3.69. Both intervals span no difference and leave substantial uncertainty about the group contrast.

The registry lists nine secondary outcomes, with numeric results posted for three functional measures. It also reports serious adverse event counts and deaths across placebo and two VX-210 groups. The record does not report the original sample-size justification, detailed model specification, missing-data approach, multiplicity strategy or reason for termination.