This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Long-term Treatment Study of Certolizumab Pegol (CDP870) as Add-on Medication to Methotrexate in Japanese Rheumatoid Arthritis (RA) Patients (NCT00851318), a randomized phase 3 study. The primary outcome is Number of Participants With Adverse Events.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00851318 |
| Phase | Phase 3 |
| Condition | Rheumatoid Arthritis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 285 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Astellas Pharma Inc |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned Japanese patients with active rheumatoid arthritis who transferred from Study 275-08-001. The safety analysis population included participants who received at least one administration of study drug. The registry record does not report further eligibility details in the information summarized for this study.
Intervention
Certolizumab pegol was given as add-on medication to methotrexate. One regimen used 200 mg by subcutaneous injection once every 2 weeks. The other used 400 mg by subcutaneous injection once every 4 weeks. Treatment was planned for up to 52 weeks or until certolizumab pegol was approved for rheumatoid arthritis in Japan; the reported maximum duration on study drug was 204 weeks.
Comparator
The registry lists two dosing regimens and reports random allocation, but it does not describe a methotrexate-only control group. The reported groups also distinguish participants by responder status and study completion. The precise allocation procedure and how it related to those categories are not reported in the registry record.
Primary question
The stated primary outcome was the number of participants with adverse events. The study objectives also included long-term safety and efficacy, and the effects of different dosing regimens among ACR20 responders who completed the earlier study. The registry record lists ACR20, ACR50 and ACR70 response, and changes in DAS 28 and mTSS as secondary outcomes. It does not provide a single primary efficacy comparison or a reported statistical comparison between regimens.
3. Trial Design
This was a Phase 3, randomized, parallel-group, open-label study sponsored by Astellas Pharma Inc. It enrolled 285 participants and is listed as completed. The study began in 2009-03, with primary completion in 2013-06. Its official title describes a multicenter, long-term safety study of CDP870, also called certolizumab pegol, in combination with methotrexate among patients transferred from Study 275-08-001.
The registry describes two active dosing regimens. Participants in the 200 mg group received subcutaneous injections once every 2 weeks, while participants in the 400 mg group received injections once every 4 weeks. Both regimens were combined with methotrexate. The planned treatment period was up to 52 weeks or until approval of certolizumab pegol for rheumatoid arthritis in Japan. The primary-outcome timeframe notes that dosing could continue until that launch and that the maximum duration on study drug was 204 weeks.
Although allocation is listed as randomized, masking is listed as none. Thus, the registry describes an open-label comparison of regimens rather than a blinded study. It does not report the randomization method, allocation concealment, stratification factors, or details of how participants were assigned to the reported responder and completion categories. A separate methotrexate-only group is not listed in the arm descriptions.
The study included participants transferred from an earlier efficacy confirmatory study. Its objectives included long-term safety and efficacy, and assessment of dosing regimens in ACR20 responders who completed that earlier study. The adverse-event results also distinguish discontinued non-responders, completed non-responders and completed responders. These categories are important to the interpretation: the registry results are not simply a comparison of all participants allocated to two dosing schedules. Further details of the transition and analysis design are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Participants were assigned to treatment groups based on whether they discontinued study 275-08-001 at Week 16 or completed Week 24 and based on American College of Rheumatology 20% (ACR20) response at Week 24.
Overall Study
| Stage | Discontinued Non-responders 200 mg | Completed Non-responders 200 mg | Completed Responders 200 mg | Completed Responders 400 mg |
|---|---|---|---|---|
| STARTED | 81 | 19 | 93 | 92 |
| Completed Week 24 | 69 | 17 | 90 | 87 |
| Completed Week 52 | 64 | 16 | 87 | 85 |
| COMPLETED | 51 | 14 | 72 | 73 |
| NOT COMPLETED | 30 | 5 | 21 | 19 |
Reasons for not completing this period:
| Reason | Discontinued Non-responders 200 mg | Completed Non-responders 200 mg | Completed Responders 200 mg | Completed Responders 400 mg |
|---|---|---|---|---|
| Withdrawal by Subject | 7 | 1 | 5 | 3 |
| Adverse Event | 13 | 2 | 9 | 12 |
| Pregnancy | 0 | 0 | 1 | 1 |
| Lack of Efficacy | 8 | 2 | 4 | 2 |
| Non-compliance with Study Procedures | 2 | 0 | 1 | 0 |
| Physician Decision | 0 | 0 | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: All participants who received at least one study drug administration were included in the safety analysis population (SAF).
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 | Discontinued Non-responders 200 mg | Completed Non-responders 200 mg | Completed Responders 200 mg | Completed Responders 400 mg | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 81 | 19 | 93 | 92 | 285 | |
| Age, Continuous | years | 51.8 (SD 10.7) | 51.3 (SD 13.7) | 52.9 (SD 11.0) | 54.1 (SD 11.0) | 52.8 (SD 11.1) |
| Age, Customized: < 65 years | participants | 72 | 16 | 81 | 76 | 245 |
| Age, Customized: ≧ 65 years | participants | 9 | 3 | 12 | 16 | 40 |
| Sex: Female, Male: Female | Participants | 67 | 16 | 76 | 77 | 236 |
| Sex: Female, Male: Male | Participants | 14 | 3 | 17 | 15 | 49 |
| Region of Enrollment: Japan | participants | 81 | 19 | 93 | 92 | 285 |
| Body Weight | kg | 56.30 (SD 12.00) | 54.27 (SD 9.57) | 55.81 (SD 11.34) | 54.92 (SD 9.47) | 55.56 (SD 10.83) |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Adverse Events, measured over From the first dosing of this study up to 12 weeks (84 days) after the last dosing. The dosing was allowed until launch of certolizumab pegol for RA in Japan. The maximum duration on study drug was 204 weeks..
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is the number of participants with adverse events. An adverse event is defined as an untoward medical occurrence in a participant who received study drug; it need not be caused by treatment. This endpoint is used to describe safety experience during exposure and follow-up, rather than to establish that an event was caused by a study drug.
The registry’s timeframe begins with the first dose in this study and extends to 12 weeks (84 days) after the last dose. Dosing could continue until certolizumab pegol launched for rheumatoid arthritis in Japan, and the maximum duration on study drug was 204 weeks. The registry also explains how severity was classified: mild events did not disrupt normal daily activities, moderate events affected those activities, and severe events prevented them. Serious events were defined by consequences such as death, life-threatening illness, inpatient hospitalization, significant incapacity, substantial interference with normal life functions, or congenital anomaly or birth defect.
Counting participants with events is a straightforward descriptive safety measure. It does not, on its own, describe how often events occurred per unit of exposure, whether events were related to treatment, or whether groups differed statistically. The registry record does not report a single primary-outcome comparison or an inferential analysis for this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies adverse events as the primary outcome, but the posted results do not reduce that outcome to one comparison. The results instead separate participants into four categories: discontinued non-responders receiving 200 mg, completed non-responders receiving 200 mg, completed responders receiving 200 mg, and completed responders receiving 400 mg. Each category has counts at risk and counts affected by serious and other adverse events. These group-specific counts describe the recorded safety experience; they do not establish that one regimen has a higher or lower risk than another.
For serious adverse events, the registry reports 21 of 81 participants in the discontinued non-responders 200 mg category, 4 of 19 in the completed non-responders 200 mg category, 20 of 93 in the completed responders 200 mg category, and 23 of 92 in the completed responders 400 mg category. For other adverse events, the corresponding reported counts are 77 of 81, 18 of 19, 91 of 93, and 90 of 92. These are registry counts, not adjusted estimates. No deaths are reported in the registry record.
Interpretation across these categories needs caution. The groups differ not only in assigned dose but also in response status and completion status. Participants who completed treatment and those who discontinued may have had different time at risk or clinical histories. The registry record does not provide enough information to separate those influences or to establish that the categories are otherwise comparable. Random allocation is listed for the study, but the reported result categories are not simply the two dosing regimens, and the randomization details are not reported.
The serious-event terms with the highest listed percentages are bronchitis, herpes zoster, rheumatoid arthritis and organising pneumonia, each at 5.3%. Arthritis is listed at 3.3%, and ankle fracture at 2.2%. These percentages are not accompanied by a stated denominator in the record summarized for these results, so they should be read as reported event-term frequencies rather than as comparisons between regimens. The registry does not report inferential estimates, confidence intervals, or p-values for the safety categories or terms.
The outcome list also includes ACR20, ACR50 and ACR70 response, change in DAS 28, and change in mTSS. No numerical results for these outcomes are included in the registry information summarized for this study. Therefore, the posted record supports a description of the study design, outcome definitions, and reported adverse-event counts, but it does not support a statistical conclusion about comparative efficacy or safety between dosing schedules.
9. Statistical Methods Explained
General: what does a count of participants with an event convey?
A participant count answers how many people in a defined group experienced an event during the stated observation period. It is useful for describing the burden of recorded events, but it is not the same as an event rate. A participant may experience more than one event, and a simple count of affected participants does not preserve that event-level information. Nor does a count account for differences in how long participants were observed or exposed to treatment.
In this study, the registry reports the number at risk and the number affected for serious and other adverse events in each listed category. Those counts allow the reader to see the event experience as recorded for each category. They do not by themselves quantify uncertainty around a difference between categories. A comparative estimate would require a clearly specified contrast and an analysis that accounts for the study design and the data available. No such primary-outcome comparison is reported in the registry record.
General: why distinguish descriptive results from statistical comparisons?
A descriptive result reports what was observed in a defined group. An inferential comparison estimates how much the outcomes differ between groups and how uncertain that estimate is. Confidence intervals are a general way to express the range of values compatible with the data and analysis assumptions. A p-value is a general measure of how compatible the observed data are with a specified null hypothesis under a statistical model. Neither is a substitute for understanding the population, endpoint, and contrast being analyzed.
The registry lists random allocation, but the reported adverse-event categories combine dose with responder and completion status. A comparison among these categories would therefore need a clear statistical question and an analysis plan that accounts for how categories were formed. Without reported estimates, confidence intervals, p-values, or a complete analysis description, the counts should remain descriptive. The record does not report a statistical test for the primary outcome.
General: why does observation time matter?
Participants may contribute different amounts of treatment exposure and follow-up. When follow-up differs, the same participant count can arise under different amounts of time at risk. A rate or time-to-event analysis may be appropriate for some questions, but it requires the relevant event times and a stated analysis method. The registry gives an adverse-event follow-up window after the last dose and a maximum duration on study drug, but it does not report event timing or a time-to-event analysis for the listed safety results.
General: how should open-label allocation be considered?
In an open-label study, participants and investigators are not masked to treatment assignment. This can matter for outcomes that involve judgment, reporting, or decisions about stopping treatment. Adverse events are medical occurrences, but their recognition and reporting still depend on study conduct and clinical assessment. The registry explains investigator assessment of severity and defines serious adverse events. It does not report additional procedures used to reduce differences in event detection or assessment between groups.
General: what is over-dispersion?
Over-dispersion occurs when observed variability in counts is greater than a statistical model assumes. It can arise when outcomes vary substantially between participants or when events cluster. If a count model assumes less variability than the data contain, its uncertainty estimates may be too narrow. This is a general consideration for count outcomes; the registry does not report an over-dispersion assessment or a count-model analysis for this study. The primary outcome is framed as the number of participants with adverse events, not as a total event count.
General: what do sample-size planning illustrations mean?
Planning illustrations based on an observed effect are not observed power and do not establish the design rationale used for a trial. They describe hypothetical group sizes under stated assumptions. The registry’s planning assumptions 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. The registry record does not report a trial-specific sample-size justification or enough detail to identify a single primary comparison for such planning. Any planning illustration should therefore be treated as an illustration, not as evidence that the study was designed around that effect.
General: why does the estimand matter?
An estimand is the precise treatment effect a study aims to describe, including the population, outcome, treatment conditions, and handling of events such as treatment discontinuation. That definition is important in a long-term study where participants may stop treatment, complete treatment, or enter from an earlier trial. The registry identifies several such participant categories and gives an adverse-event follow-up window, but does not report a complete estimand or a statistical analysis strategy addressing discontinuation and other intercurrent events. This limits how far the descriptive counts can answer a comparative treatment question.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists several outcomes: the primary adverse-event measure and secondary outcomes covering ACR20, ACR50 and ACR70 response, change in DAS 28, and change in mTSS. Examining multiple outcomes or time points can increase the chance of finding an apparently notable result by chance if many statistical tests are conducted. Statistical approaches to multiplicity can define which outcome has priority or adjust inference across a family of tests. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or analyses for these outcomes.
The primary outcome is described as a number of participants with adverse events, and the registry indicates that it includes several categories or time points rather than presenting one comparison. It is therefore not reduced to a single inferential contrast. The registry record does not report a statistical analysis plan, a prespecified method for handling multiple comparisons, or a primary-outcome estimate with uncertainty.
Missing-data handling is also not reported in the registry record. The information summarized does not state how missing outcome assessments, withdrawals, or incomplete follow-up were treated in analyses. For a long-term study, such details matter because participants may have different durations of treatment and observation. The record describes categories based on completion and response, but does not explain whether or how those statuses were incorporated into an analysis of treatment effects.
The primary safety population is defined as participants who received at least one study drug administration. The registry does not describe additional analysis populations or explain how the efficacy outcomes were analyzed. Without those details, the reported counts should be interpreted as descriptive records for the listed groups rather than as a complete account of an intention-to-treat or other comparative analysis.
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 |
|---|---|---|---|
| Discontinued Non-responders 200 mg | 21 | 81 | 25.9% |
| Completed Non-responders 200 mg | 4 | 19 | 21.1% |
| Completed Responders 200 mg | 20 | 93 | 21.5% |
| Completed Responders 400 mg | 23 | 92 | 25.0% |
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 |
|---|---|
| Discontinued Non-responders 200 mg | 77 of 81 |
| Completed Non-responders 200 mg | 18 of 19 |
| Completed Responders 200 mg | 91 of 93 |
| Completed Responders 400 mg | 90 of 92 |
Most frequent serious adverse event terms
| Event term | Organ system | Discontinued Non-responders 200 mg | Completed Non-responders 200 mg | Completed Responders 200 mg | Completed Responders 400 mg |
|---|---|---|---|---|---|
| Rheumatoid arthritis | Musculoskeletal and connective tissue disorders | 0 of 81 | 1 of 19 | 1 of 93 | 4 of 92 |
| Pneumonia | Infections and infestations | 1 of 81 | 0 of 19 | 2 of 93 | 0 of 92 |
| Arthritis | Musculoskeletal and connective tissue disorders | 0 of 81 | 0 of 19 | 0 of 93 | 3 of 92 |
| Subarachnoid haemorrhage | Nervous system disorders | 1 of 81 | 0 of 19 | 0 of 93 | 2 of 92 |
| Cataract | Eye disorders | 1 of 81 | 0 of 19 | 0 of 93 | 1 of 92 |
| Hepatic function abnormal | Hepatobiliary disorders | 1 of 81 | 0 of 19 | 0 of 93 | 1 of 92 |
| Bronchitis | Infections and infestations | 1 of 81 | 1 of 19 | 0 of 93 | 0 of 92 |
| Subcutaneous abscess | Infections and infestations | 1 of 81 | 0 of 19 | 0 of 93 | 1 of 92 |
| Ankle fracture | Injury, poisoning and procedural complications | 0 of 81 | 0 of 19 | 0 of 93 | 2 of 92 |
| Tendon rupture | Injury, poisoning and procedural complications | 0 of 81 | 0 of 19 | 1 of 93 | 1 of 92 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Discontinued Non-responders 200 mg | Completed Non-responders 200 mg | Completed Responders 200 mg | Completed Responders 400 mg |
|---|---|---|---|---|---|
| Nasopharyngitis | Infections and infestations | 41 of 81 | 12 of 19 | 53 of 93 | 45 of 92 |
| Upper respiratory tract infection | Infections and infestations | 15 of 81 | 3 of 19 | 20 of 93 | 20 of 92 |
| Pharyngitis | Infections and infestations | 15 of 81 | 1 of 19 | 18 of 93 | 10 of 92 |
| Eczema | Skin and subcutaneous tissue disorders | 9 of 81 | 2 of 19 | 14 of 93 | 12 of 92 |
| Bronchitis | Infections and infestations | 10 of 81 | 4 of 19 | 14 of 93 | 8 of 92 |
| Rheumatoid arthritis | Musculoskeletal and connective tissue disorders | 6 of 81 | 4 of 19 | 10 of 93 | 13 of 92 |
| Contusion | Injury, poisoning and procedural complications | 9 of 81 | 1 of 19 | 12 of 93 | 6 of 92 |
| Hypertension | Vascular disorders | 5 of 81 | 2 of 19 | 9 of 93 | 11 of 92 |
| Conjunctivitis allergic | Eye disorders | 8 of 81 | 0 of 19 | 8 of 93 | 8 of 92 |
| Dental caries | Gastrointestinal disorders | 8 of 81 | 1 of 19 | 9 of 93 | 6 of 92 |
Serious events with the highest arm-level rate: bronchitis (5.3%), herpes zoster (5.3%), rheumatoid arthritis (5.3%), organising pneumonia (5.3%), arthritis (3.3%).
The serious adverse-event results are reported as affected participants out of those at risk within four categories. The discontinued non-responders 200 mg category had 21 of 81 participants with serious adverse events; the completed non-responders 200 mg category had 4 of 19; the completed responders 200 mg category had 20 of 93; and the completed responders 400 mg category had 23 of 92. The corresponding counts for other adverse events were 77 of 81, 18 of 19, 91 of 93, and 90 of 92.
These counts are descriptive. They are not adjusted for follow-up duration, and the registry record does not report a statistical comparison or uncertainty interval for differences between groups. The categories also reflect responder and completion status, as well as dose, so they should not be treated as a simple randomized comparison of the two regimens. Death counts are not reported in the registry record.
The listed serious-event terms include bronchitis, herpes zoster, rheumatoid arthritis and organising pneumonia, each reported at 5.3%, followed by arthritis at 3.3% and ankle fracture at 2.2%. These are event-term percentages as recorded; the record summarized does not give their denominators or a comparison by regimen. A serious adverse event is defined by specified consequences, while an adverse event more broadly need not be serious or caused by treatment.
12. What the Result Does, and Does Not, Mean
The results establish that the registry recorded serious and other adverse events among participants in each of the four listed categories. They also show which serious-event terms were reported with the highest listed percentages. This is useful descriptive information about the safety experience recorded during the study’s defined period of observation.
The results do not establish that certolizumab pegol caused any particular event. The registry’s adverse-event definition explicitly includes medical occurrences that do not necessarily have a causal relationship with treatment. Nor do the counts show that one dosing regimen is safer or less safe than the other. The reported categories differ by responder and completion status, and the registry record does not provide a direct comparative estimate, an uncertainty interval, or a statistical test for the primary safety outcome.
The information also does not establish an efficacy result. Although the study objectives included efficacy and the registry lists ACR20, ACR50, ACR70, DAS 28 and mTSS outcomes, numerical results for those measures are not reported in the information summarized for this study. No conclusion about comparative disease activity or structural change can be drawn from the listed safety counts.
Finally, descriptive event counts do not answer every safety question. They do not show the timing of events, how long each participant was observed, the number of recurrent events, or how missing follow-up was handled. The study’s open-label design and the absence of a reported comparative analysis are additional reasons to avoid treating the group counts as causal or definitive estimates. The appropriate reading is limited to what the registry reports: observed participant counts and event terms in the stated categories and timeframe.
13. Why This Trial Matters Statistically
This study raises statistical questions common in long-term safety research: how to describe events over differing exposure periods, how to compare regimens when participants are grouped by response and completion, and how to distinguish event occurrence from treatment causation. Its registry record makes the distinction between broad adverse events and serious adverse events explicit, and defines the safety population as participants who received at least one study drug administration.
The study also illustrates why a randomized label does not alone make every reported grouping a randomized comparison. The registry lists random allocation and two dosing schedules, but the adverse-event results are organized by dose together with response and completion categories. Statistical interpretation depends on the actual contrast and analysis, not merely on the existence of randomization. The registry record does not describe enough allocation or analysis detail to reconstruct such a contrast.
Multiplicity is another important issue because the registry lists several response and disease-activity outcomes in addition to the safety endpoint. Without a reported hierarchy or multiplicity strategy, results across multiple outcomes would require careful interpretation. In this record, numerical results for the efficacy outcomes and inferential analyses are not reported.
For biostatisticians and clinical researchers, the central lesson is that descriptive counts can be informative while remaining limited. A well-defined endpoint, population, follow-up period, and analysis contrast are needed to move from counts to comparative inference. The record gives important endpoint definitions and group counts, but leaves several analysis details unreported. Those gaps should remain visible in interpretation rather than being filled by assumptions.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The registry record does not report a statistical analysis plan, a trial-specific sample-size justification, interim analyses, or a primary-outcome comparison. It also does not report confidence intervals or p-values for the adverse-event counts. Consequently, the results support descriptive reading but not a formal inference about differences between dosing schedules.
The reported adverse-event categories combine treatment dose with response and completion status. The record does not explain how these categories relate to random assignment or whether participants were analyzed according to assigned regimen. As response and completion status may be related to participant experience and time on treatment, the categories are not a straightforward basis for attributing differences to dose. Details of randomization, allocation concealment, and any stratification are not reported in the registry record.
Follow-up could extend to 12 weeks (84 days) after the last dose, and the maximum duration on study drug was 204 weeks. The record does not give event timing, participant-level exposure duration, or person-time, limiting interpretation of counts when follow-up may vary. It also does not report missing-data procedures, the handling of withdrawals in efficacy analyses, or whether recurrent events were analyzed.
Numerical results for the listed efficacy outcomes are not reported in the information summarized. The serious-event terms are presented with percentages, but their denominators and regimen-specific distributions are not reported. Death counts are not reported in the registry record. These omissions restrict comparisons and prevent a fuller assessment of uncertainty, completeness, and clinical context.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Long-term Treatment Study of Certolizumab Pegol (CDP870) as Add-on Medication to Methotrexate in Japanese Rheumatoid Arthritis (RA) Patients — NCT00851318.
- Registry record last updated 2014-11-03; status last verified 2014-10.
- Results first posted 2014-09-17.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT00851318 is a completed Phase 3 randomized, open-label, parallel-group study sponsored by Astellas Pharma Inc. It enrolled 285 participants with rheumatoid arthritis who transferred from Study 275-08-001. The study evaluated long-term certolizumab pegol with methotrexate using a 200 mg regimen once every 2 weeks and a 400 mg regimen once every 4 weeks.
The primary outcome was the number of participants with adverse events, with follow-up from first dosing through 12 weeks (84 days) after the last dose. The maximum duration on study drug was 204 weeks. The registry reports serious and other adverse-event counts across four response and completion categories, and lists several serious-event terms with percentages. It also lists ACR20, ACR50, ACR70, DAS 28 and mTSS outcomes, but numerical efficacy results and a primary comparative analysis are not reported in the registry record.