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 A Trial to Compare the Safety of Once Weekly Dosing of Somapacitan With Daily Norditropin® FlexPro® for 26 Weeks in Previously Human Growth Hormone Treated Adults With Growth Hormone Deficiency (NCT02382939), a randomized phase 3 study. The primary outcome is Incidence of Adverse Events.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02382939 |
| Phase | Phase 3 |
| Condition | Adult Growth Hormone Deficiency, Growth Hormone Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 92 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Novo Nordisk A/S |
| Results posted | Yes |
2. Clinical Question
Population
Adults with growth hormone deficiency who had previously been treated with human growth hormone were eligible for the trial. The registry record describes the safety analysis set as all randomized participants who received at least one dose of randomized treatment. Enrollment was 92, with 31 participants in the Norditropin arm and 61 in the somapacitan arm. The trial was conducted in Europe and Asia.
Intervention
The intervention was once-weekly somapacitan, administered with an investigational pen. The registry record describes the study as a safety comparison over 26 weeks. The reported primary outcome is the rate of adverse events per 100 patient years of exposure.
Comparator
The active comparator was daily Norditropin® FlexPro®, a prefilled pen containing somatropin. The trial compared the two treatment regimens in parallel groups. It was open-label, so participants and investigators were not masked to treatment assignment.
Primary question
The primary question was how the adverse-event rate during Weeks 0 - 26 compared between once-weekly somapacitan and daily Norditropin in this previously treated adult population. The registry reports rates of 514.2 and 530.8 events per 100 patient years, respectively, and a rate ratio of 0.969 for somapacitan relative to Norditropin. The reported interval for that rate ratio is 0.802 to 1.17. This is a comparison of event rates, not a direct comparison of the proportion of participants who experienced at least one adverse event.
3. Trial Design
This was a Phase 3, randomized, open-label, parallel-group, active-controlled trial. Its official description identifies it as multicentre and multinational. It compared once-weekly somapacitan with daily Norditropin® FlexPro® for 26 weeks in adults with growth hormone deficiency who had previously received human growth hormone. The registry says the trial was conducted in Europe and Asia.
The registry records enrollment of 92. The safety analysis set comprised randomized participants who received at least one dose of assigned treatment. The reported arm sizes for the primary outcome are 31 for Norditropin and 61 for somapacitan. The record gives no further explanation of the difference in arm sizes or details about the randomization procedure, allocation concealment, or treatment assignment ratio; those details are not reported in the registry record.
The study began on 2015-02-12, had primary completion on 2016-01-04, and is recorded as completed. Its primary outcome was titled “Incidence of Adverse Events” and was expressed as events per 100 patient years over Weeks 0 - 26. This rate-based endpoint counts events in relation to exposure time. It is therefore distinct from a simple percentage of participants with one or more events.
The trial’s stated aim was to compare safety. The registry also names two secondary outcomes: occurrence of Anti-NNC0195-0092 Antibodies and change in Treatment Satisfaction Questionnaire for Medication scores, including effectiveness, convenience, and global satisfaction. Results for those secondary outcomes are not reported in the registry record. Further information about the original design assumptions, including any sample-size justification or planned statistical analysis, 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: Participants, who were diagnosed with adults with growth hormone deficiency ≥ 6 months (defined as 180 days) prior to screening and receiving treatment with human growth hormone at least 6 months (defined as 180 days) at screening, were enrolled.
Overall Study
| Stage | Norditropin | Somapacitan |
|---|---|---|
| STARTED | 31 | 61 |
| Exposed | 31 | 61 |
| COMPLETED | 28 | 58 |
| NOT COMPLETED | 3 | 3 |
Reasons for not completing this period:
| Reason | Norditropin | Somapacitan |
|---|---|---|
| Adverse Event | 1 | 1 |
| Withdrawal by Subject | 2 | 2 |
Analysis population for the primary outcome, as defined in the registry: Safety analysis set: all randomised participants that received at least one dose of randomised 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): all randomised participants that received at least one dose of randomised treatment.
| Characteristic | Unit | Norditropin | Somapacitan | Total |
|---|---|---|---|---|
| Participants analysed | 31 | 61 | 92 | |
| Age, Continuous | years | 51.7 (SD 17.1) | 48.1 (SD 16.2) | 49.3 (SD 16.5) |
| Age, Customized: 18-64 years | Participants | 23 | 50 | 73 |
| Age, Customized: ≥65 years | Participants | 8 | 11 | 19 |
| Sex: Female, Male: Female | Participants | 14 | 28 | 42 |
| Sex: Female, Male: Male | Participants | 17 | 33 | 50 |
6. Primary Endpoint
The registry lists the primary outcome as Incidence of Adverse Events, measured over Weeks 0 - 26.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Events per 100 patient years |
| Endpoint classification | Event-Rate Endpoint |
The primary endpoint is titled “Incidence of Adverse Events.” An adverse event is defined in the registry as an unfavourable and unintended sign, symptom, or disease, including an abnormal laboratory finding, that is temporally associated with product use, whether or not considered related to the product. The reported measure is an event rate per 100 patient years of exposure during Weeks 0 - 26.
A rate uses both the number of events and the time participants contribute to observation. That makes it useful when exposure time differs or when a participant can experience more than one event: repeated events can contribute to the event count rather than being reduced to a yes-or-no indicator for each participant. Rates therefore answer a different question from the percentage of participants who experienced at least one event.
As a general statistical point, expressing a rate per a common exposure-time unit can make rates easier to compare across groups with different amounts of observation. It does not, by itself, describe the severity, duration, or cause of events, nor does it show how events were distributed among participants. Those distinctions matter when interpreting a safety endpoint. The registry’s primary result is an aggregate rate comparison; separate serious adverse-event figures provide additional descriptive information but are not the primary endpoint.
7. Results Posted in the Registry
- Somapacitan: 514.20 versus 530.80 (Events per 100 patient years) on control; rate ratio 0.97 (95% CI 0.80–1.17, approximate, Poisson model); p ≈ 0.741.
Rate ratio: Somapacitan
95% CI: 0.80 to 1.17
Recalculated from the posted summary statistics
8. Statistical Interpretation
The posted primary outcome gives an adverse-event rate of 530.8 events per 100 patient years for Norditropin and 514.2 events per 100 patient years for somapacitan. The comparison is expressed as a rate ratio of 0.969, with somapacitan as the numerator and Norditropin as the reference. An estimate below 1 indicates that the recorded rate in the somapacitan arm was lower in this comparison. The reported interval, 0.802 to 1.17, includes values on both sides of 1, so it is compatible with a range of relative rate differences rather than pinning down a single precise contrast.
The unadjusted p-value is 0.741. A p-value describes how compatible the observed data are with a specified null model under the analysis assumptions; it is not the probability that the null hypothesis is true, and it is not a measure of clinical importance. The registry record does not report a prespecified decision threshold for this primary comparison, so the p-value should not be used to assert a trial-defined conclusion. The estimate and its interval are more informative about the direction and precision of the contrast than the p-value alone.
The result concerns events per unit of exposure time, not the chance that a particular participant experiences an event. The arm-level rates cannot identify whether events were spread broadly across participants or concentrated in a smaller number of participants with repeated events. They also do not identify which events were judged related to treatment: the endpoint definition includes events whether or not they were considered related.
Serious adverse events were recorded in 2 of 31 participants in the Norditropin group and 4 of 61 in the somapacitan group. Other adverse events were recorded in 18 of 31 and 30 of 61, respectively. These counts are descriptive and are not the same measure as the primary exposure-adjusted event rate. The record lists serious-event terms with percentages, but does not provide enough detail in the registry record to infer the clinical course, event attribution, or comparative risk for each term. Deaths are not reported in the registry record.
Overall, the posted results describe similar-looking arm-level event rates, but the interval leaves uncertainty around the relative rate. The figures do not establish equivalence, prove the absence of a difference, or establish a causal explanation for any observed events. Interpretation is also bounded by the trial’s open-label design, the 26-week observation period, and the analysis details that are not reported in the registry record.
9. Statistical Methods Explained
What does an event rate represent?
General statistical explanation: an event rate divides an event count by accumulated exposure time. In this trial the measure is reported per 100 patient years, so the rate is standardized to that exposure-time unit. The reported values are 530.8 for Norditropin and 514.2 for somapacitan. Unlike a risk or proportion, a rate can count repeated events in the same participant. It is therefore possible for the rate to reflect multiple events experienced by some participants, rather than only the number of participants with any event.
The endpoint description says the population is the safety analysis set: randomized participants who received at least one dose. Rates are useful for comparisons when follow-up exposure is relevant, but interpretation depends on how exposure time and event counts are defined and collected. The registry reports the outcome period as Weeks 0 - 26. Further detail about event adjudication, censoring, or exposure-time calculation is not reported in the registry record.
How should the rate ratio be read?
The rate ratio compares the somapacitan event rate with the Norditropin event rate. A value of 1 would indicate equal rates under the ratio definition; values below 1 indicate a lower estimated rate in the numerator group, and values above 1 indicate a higher estimated rate. The posted estimate is 0.969. This is a relative comparison of rates, not a difference in the number of events, and it should be read alongside the interval from 0.802 to 1.17.
General statistical explanation: a rate ratio compresses two rate estimates into one relative measure. It does not convey the absolute number of events, the number of people affected, or how frequently events recurred in particular participants. Those quantities require separate descriptive information. The registry reports arm-level participant counts and separate serious and other adverse-event counts, but those summaries do not reveal the event-level distribution behind the primary rate.
What role does the Poisson label play?
The posted comparison is marked as Poisson-based. General statistical explanation: Poisson methods are commonly used for count outcomes, including event counts modeled in relation to exposure time. Such methods rely on assumptions about the count process; the particular assumptions and diagnostics used for this trial are not reported in the registry record.
One possible concern in count data is over-dispersion: the observed variation in counts can exceed what a basic Poisson model assumes. General statistical explanation: when over-dispersion is present and not appropriately handled, uncertainty estimates may be too narrow. The registry lists no dispersion value and does not report a diagnostic or correction, so the available record does not establish whether over-dispersion was assessed or how it was handled. The Poisson label should not be taken as evidence that every model assumption was checked or satisfied.
What do the interval and p-value add?
The interval quantifies uncertainty around the estimated rate ratio under the analysis method. Its endpoints, 0.802 and 1.17, span values below and above 1. This means that the posted estimate is not precise enough to isolate one direction of relative rate difference from the interval alone. The registry does not state the confidence level or provide the detailed interval calculation in the record, so those details should not be inferred.
The unadjusted p-value is 0.741. General statistical explanation: a p-value measures how unusual data at least as inconsistent with a null model would be if that model and the analysis assumptions held. It does not measure the probability that a treatment effect exists, nor does it quantify the size or importance of an effect. The term “unadjusted” indicates that the posted p-value is not described as adjusted for multiplicity. Whether a multiplicity adjustment was planned or applied is not reported in the registry record.
What is known about the analysis plan?
The registry gives the primary endpoint, its timeframe, and the safety population definition, and it posts a rate comparison. It does not report a detailed statistical analysis plan, an analysis model specification beyond the Poisson marking, covariate adjustments, missing-data methods, interim analyses, or a sample-size justification. The record also does not report a formal analysis entry for the outcome. These omissions limit the ability to assess whether the posted comparison matches a prespecified plan or to reproduce the analysis fully.
The trial was randomized, which is relevant to the intended comparison, but randomization alone does not settle questions about implementation, missing observations, model fit, or analysis choices. The trial was open-label, and the registry does not describe blinded event assessment. This does not establish that assessment was biased; it means the record does not let readers evaluate the assessment procedures in detail.
The posted comparison is not marked as a discrepancy. This means there is no discrepancy flag in the registry record; it does not replace a full review of the statistical plan or analysis. The reported values should be understood as the registry’s posted outcome comparison, with the limitations of the available methodological detail.
10. Confidence Intervals and Precision
The rate-ratio estimate is 0.969, and its reported interval extends from 0.802 to 1.17. The point estimate lies near 1, while the interval includes values below and above 1. Thus, the estimate alone suggests a small relative difference in the observed rates, but the interval indicates uncertainty about both the size and direction of the underlying relative difference. It does not support a precise claim of equal rates.
General statistical explanation: an interval is a range of values compatible with the data and the assumptions of the method at a stated confidence level. The confidence level is not reported in the registry record, so it should not be assigned to this interval based only on the available information. The interval also does not capture every possible source of uncertainty, such as limitations in outcome collection or unreported analysis decisions.
The unadjusted p-value is 0.741. It complements the interval but does not replace it: the p-value does not show how large a difference could be consistent with the data, while the interval communicates a range of plausible rate ratios under the model. Neither figure establishes equivalence or rules out meaningful differences. The registry record does not report a prespecified equivalence margin or a non-inferiority margin.
The arm-level rates are reported without intervals in the registry record. The comparison interval applies to the rate ratio, not to each arm rate separately. The relatively different arm sizes, 31 for Norditropin and 61 for somapacitan, are also relevant context for interpreting the information available, but the record does not provide enough detail to quantify their effect on precision independently.
11. 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.
| Effect to detect | Participants per arm, 80% power | Participants per arm, 90% power |
|---|---|---|
| 100% of the observed effect | 2,977 | 3,986 |
| 75% of the observed effect | 5,271 | 7,057 |
| 50% of the observed effect | 11,812 | 15,813 |
The sample-size table and curve are planning illustrations based on fractions of the observed effect, not a reconstruction of the original trial design. The listed figures are participants per arm, not total events. The planning assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is the stated fraction of the observed effect. The original trial’s own sample-size assumptions are not reported in the registry record.
The 80% power column gives the illustrative number of participants per arm for a design with an 80% chance of detecting the specified effect under those assumptions, if that effect and the model assumptions were correct. The 90% power column gives the corresponding planning number for a 90% chance. These are design targets, not guarantees about what a future study would find. This is not observed power.
The rows express planning for 100%, 75%, and 50% of the observed effect. For the 100% row, the figures are 2,977 participants per arm for 80% power and 3,986 for 90% power. For 75%, they are 5,271 and 7,057; for 50%, they are 11,812 and 15,813. The pattern illustrates a general planning principle: smaller effects require more participants to detect, and targeting higher power also requires a larger planned sample. The calculations depend on the stated assumptions and do not account for unreported design features or changes in the outcome definition.
12. 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 z1−α/2 = 1.960) and the desired power (z1−β = 0.842 for 80% and 1.282 for 90%).
Formula
n is the number of participants in each arm, λ0 and λ1 are event rates per patient-year, and T is follow-up per participant in years. This assumes Poisson counts and equal follow-up.
Worked calculation for this trial
- Control rate λ0 = 5.3080; treatment rate λ1 = 5.1420 events per patient-year; follow-up T = 1.00 years.
- n = (1.96 + 0.842)2 × (1/5.3080 + 1/5.1420) / (1.00 × [ln(0.969)]2) = 2,976.8, rounded up to 2,977 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
lambda0 <- 5.308 # control rate, events per patient-year
lambda1 <- 5.142 # treatment rate
tt <- 1 # follow-up per participant, years
n_per_arm <- function(power, frac = 1) {
l1 <- lambda0 * (lambda1 / lambda0)^frac # smaller effect = fraction of the observed log rate ratio
ceiling(round((z_a + qnorm(power))^2 * (1 / lambda0 + 1 / l1) / (tt * log(l1 / lambda0)^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 = ",")))
# Simulation 1: Poisson counts. Simulation 2: over-dispersed counts (variance = 1.5 x mean), analysed with the matching variance.
set.seed(2382939)
n <- n_per_arm(0.80)
reps <- 20000
m0 <- lambda0 * n * tt; m1 <- lambda1 * n * tt
x0 <- rpois(reps, m0); x1 <- rpois(reps, m1)
z <- log(x1 / x0) / sqrt(1 / x0 + 1 / x1)
cat(sprintf("Simulated power, Poisson counts, n = %s per arm: %.3f\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE)))
phi <- 1.5
y0 <- rnbinom(reps, mu = m0, size = m0 / (phi - 1)); y1 <- rnbinom(reps, mu = m1, size = m1 / (phi - 1))
z2 <- log(y1 / y0) / sqrt(phi * (1 / y0 + 1 / y1))
cat(sprintf("Simulated power, over-dispersed counts (phi = 1.5), same n: %.3f\n", mean(abs(z2) > z_a, na.rm = TRUE)))
Output from running the code
100% of observed effect: n per arm = 2,977 (80% power), 3,986 (90% power)
75% of observed effect: n per arm = 5,271 (80% power), 7,057 (90% power)
50% of observed effect: n per arm = 11,812 (80% power), 15,813 (90% power)
Simulated power, Poisson counts, n = 2,977 per arm: 0.803
Simulated power, over-dispersed counts (phi = 1.5), same n: 0.630The first simulation draws Poisson counts and should land close to the target power. The second allows extra variability (variance 1.5 times the mean, a purely illustrative value), which lowers the power at the same sample size, so rate trials usually need more participants than the Poisson formula suggests.
13. Multiplicity, Missing Data and Analysis Populations
The registry names two secondary outcomes: occurrence of Anti-NNC0195-0092 Antibodies and change in Treatment Satisfaction Questionnaire for Medication scores for effectiveness, convenience, and global satisfaction. Results for these outcomes are not reported in the registry record. The record lists the primary adverse-event outcome and an unadjusted p-value for its comparison, but does not describe whether other hypothesis tests were planned or performed.
Multiplicity arises when several outcomes, comparisons, time points, or subgroup analyses are tested. General statistical explanation: as the number of tests increases, the chance of at least one apparently unusual result can increase if each is judged without adjustment. Methods such as adjusting significance thresholds or controlling an error rate may be used, but the registry does not report whether any such method was planned or applied. It is therefore not possible to determine from the record how multiplicity was addressed.
The registry defines the primary safety population as randomized participants who received at least one dose. That definition clarifies who is included in the stated analysis set, but the record does not detail the handling of participants with incomplete follow-up, missing outcome information, or deviations from assigned treatment. A missing-data method, if any, is not reported in the registry record. The record does not report interim analyses or stopping rules.
These gaps do not prove that a particular procedure was absent from the study; they mean that it cannot be evaluated from the registry record. The posted primary comparison should therefore be interpreted with its stated population and outcome definition, while avoiding assumptions about unreported multiplicity control, missing-data handling, or interim monitoring.
14. 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 |
|---|---|---|---|
| Norditropin | 2 | 31 | 6.5% |
| Somapacitan | 4 | 61 | 6.6% |
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 |
|---|---|
| Norditropin | 18 of 31 |
| Somapacitan | 30 of 61 |
Most frequent serious adverse event terms
| Event term | Organ system | Norditropin | Somapacitan |
|---|---|---|---|
| Cholelithiasis | Hepatobiliary disorders | 0 of 31 | 1 of 61 |
| Intestinal ischaemia | Gastrointestinal disorders | 1 of 31 | 0 of 61 |
| Mammoplasty | Surgical and medical procedures | 0 of 31 | 1 of 61 |
| Nephrolithiasis | Renal and urinary disorders | 1 of 31 | 0 of 61 |
| Patella fracture | Injury, poisoning and procedural complications | 0 of 31 | 1 of 61 |
| Procedural complication | Injury, poisoning and procedural complications | 0 of 31 | 1 of 61 |
| Short-bowel syndrome | Gastrointestinal disorders | 1 of 31 | 0 of 61 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Norditropin | Somapacitan |
|---|---|---|---|
| Nasopharyngitis | Infections and infestations | 8 of 31 | 12 of 61 |
| Headache | Nervous system disorders | 6 of 31 | 7 of 61 |
| Fatigue | General disorders | 5 of 31 | 6 of 61 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 2 of 31 | 5 of 61 |
| Asthenia | General disorders | 1 of 31 | 4 of 61 |
| Abdominal pain | Gastrointestinal disorders | 0 of 31 | 4 of 61 |
| Dizziness | Nervous system disorders | 3 of 31 | 1 of 61 |
| Sciatica | Nervous system disorders | 0 of 31 | 4 of 61 |
| Hypothyroidism | Endocrine disorders | 2 of 31 | 1 of 61 |
| Depression | Psychiatric disorders | 2 of 31 | 0 of 61 |
Serious events with the highest arm-level rate: intestinal ischaemia (3.2%), nephrolithiasis (3.2%), short-bowel syndrome (3.2%), cholelithiasis (1.6%), mammoplasty (1.6%).
The registry records serious adverse events for 2 of 31 participants in the Norditropin group and 4 of 61 participants in the somapacitan group. It records other adverse events for 18 of 31 and 30 of 61 participants, respectively. These are participant counts, not the primary endpoint’s event rates per 100 patient years. A participant-level count does not indicate how many events each affected participant experienced.
The record lists serious adverse-event terms and percentages: Intestinal ischaemia, 3.2%; Nephrolithiasis, 3.2%; Short-bowel syndrome, 3.2%; Cholelithiasis, 1.6%; Mammoplasty, 1.6%; and Patella fracture, 1.6%. These entries should be read as reported terms and percentages, not as evidence that treatment caused the events. The registry does not provide further event-level context in the information recorded.
Deaths are not reported in the registry record. The serious-event counts are descriptive and should not be substituted for the primary rate comparison or interpreted as a complete account of event severity, duration, or attribution.
15. What the Result Does, and Does Not, Mean
The posted result describes adverse-event rates of 530.8 events per 100 patient years with Norditropin and 514.2 events per 100 patient years with somapacitan over Weeks 0 - 26. The rate ratio is 0.969, and the reported interval is 0.802 to 1.17. These values summarize the observed comparison in the trial’s safety analysis set; they do not establish that the regimens have identical safety profiles.
The interval includes values on both sides of 1, and the unadjusted p-value is 0.741. Together, these figures indicate that the posted comparison does not precisely isolate a relative rate difference. They do not prove that there is no difference, and they do not establish equivalence. No equivalence margin or non-inferiority margin is reported in the registry record.
The endpoint counts events relative to exposure time and includes events whether or not considered related to the product. It does not directly report the proportion of participants with at least one event as its primary measure, nor does it indicate how recurrent events were distributed across participants. Separate serious adverse-event counts provide one additional description, but cannot explain the primary rate on their own.
The trial was randomized and active-controlled, but open-label. Its observation period was 26 weeks, and its population was previously human growth hormone treated adults with growth hormone deficiency. The result therefore describes that trial setting and population, rather than establishing what would occur in other populations or over other observation periods. The registry record does not report enough methodological detail to assess all analysis choices or outcome-assessment procedures.
Statistically, the most defensible reading is a descriptive comparison with substantial uncertainty around the relative rate. The values alone do not demonstrate a causal mechanism, rule out uncommon or longer-term events, or support a treatment recommendation. They should be interpreted alongside the trial’s population, exposure period, endpoint definition, and unreported analysis details.
16. Why This Trial Matters Statistically
This trial illustrates why safety outcomes may need more than one statistical summary. Its primary outcome is an event rate per 100 patient years, whereas the serious and other adverse-event summaries count participants affected. Rates can account for exposure time and allow repeated events to contribute; participant counts answer whether individuals experienced events. Those measures are related but not interchangeable.
The distinction is consequential in a safety comparison. A group can have a particular event rate because many participants each experienced an event, because a smaller number experienced repeated events, or through another distribution of events. The posted aggregate rate does not reveal that distribution. The separate participant counts add context but do not provide event histories or explain how much each participant contributed to the primary rate.
The rate ratio is a compact relative measure, but its interval matters. Here the estimate is 0.969 and the interval ranges from 0.802 to 1.17. The interval’s span illustrates why a point estimate close to 1 should not be treated as proof of equivalent rates. The unadjusted p-value of 0.741 likewise should not be mistaken for evidence that no difference exists.
The trial also highlights the importance of registry detail. The record identifies the safety population and endpoint timeframe, but does not report a full statistical plan, missing-data procedures, multiplicity handling, or detailed model diagnostics. Without those details, readers cannot fully assess how the posted analysis was planned or how sensitive it may be to its assumptions. This is particularly relevant for count outcomes, where general model assumptions about event variation can affect uncertainty estimates.
For biostatisticians and clinical researchers, the key lesson is to match interpretation to the estimand and reporting: event rate, participant risk, and serious-event counts each describe different aspects of safety. A clear account of exposure, recurrent events, analysis assumptions, and uncertainty is necessary for a well-calibrated comparison.
17. 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.
- Rate comparisons use a Poisson approximation unless the sponsor posted confidence limits; real event counts are often over-dispersed.
Several limitations are specific to the information recorded for this trial. The study was open-label, and the registry does not describe whether adverse-event assessment or classification was blinded. This leaves the assessment procedures difficult to evaluate from the record; it does not establish that open-label conduct changed the reported results.
The primary observation period was Weeks 0 - 26. The registry result therefore concerns that period and does not characterize events beyond it. The record also does not report detailed exposure-time calculations, event recurrence patterns, or how incomplete observation was handled. Those details would help readers understand the construction of the rate per 100 patient years.
The reported arm sizes are 31 for Norditropin and 61 for somapacitan. The registry does not explain the allocation ratio or provide detailed information about the randomization process. It also does not report baseline characteristics in the information recorded for this analysis, so the comparability of the groups on specific prognostic features cannot be assessed from these registry entries.
The rate-ratio interval is reported without a confidence level in the registry record. A dispersion value, model diagnostics, detailed statistical analysis plan, and missing-data procedures are also not reported. The record names secondary outcomes but does not report their results, and does not describe multiplicity handling or interim analyses. Deaths are not reported in the registry record. These omissions limit precision about what was assessed and how, without demonstrating that unreported procedures were not carried out.
18. Related Tutorials
19. Related Statistical Calculators
20. Sources
- ClinicalTrials.gov: A Trial to Compare the Safety of Once Weekly Dosing of Somapacitan With Daily Norditropin® FlexPro® for 26 Weeks in Previously Human Growth Hormone Treated Adults With Growth Hormone Deficiency — NCT02382939.
- Registry record last updated 2020-07-09; status last verified 2020-06.
- Results first posted 2020-06-16.
- 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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21. Record Summary
NCT02382939 is a completed Phase 3 randomized, open-label, parallel-group, active-controlled trial sponsored by Novo Nordisk A/S. It compared once-weekly somapacitan with daily Norditropin® FlexPro® in previously human growth hormone treated adults with growth hormone deficiency. The trial was conducted in Europe and Asia, began on 2015-02-12, and had primary completion on 2016-01-04.
The primary outcome was adverse-event incidence expressed as events per 100 patient years over Weeks 0 - 26. The posted rates were 530.8 for Norditropin and 514.2 for somapacitan, with a rate ratio of 0.969 and a reported interval of 0.802 to 1.17. The unadjusted p-value was 0.741. The registry also records serious and other adverse-event participant counts and names two secondary outcomes, whose results are not reported in the registry record.