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 Study of BOS161721 in Systemic Lupus Erythematosus (SLE) Patients on a Background of Limited Standard of Care (NCT03371251), a randomized phase 1, phase 2 study. The primary outcome is Phase 1b: Number of Participants With Adverse Events (AEs).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03371251 |
| Phase | Phase 1, Phase 2 |
| Condition | Systemic Lupus Erythematosus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 143 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boston Pharmaceuticals |
| Results posted | Yes |
2. Clinical Question
Population
Adults with moderately to severely active systemic lupus erythematosus (SLE) who were receiving limited background standard of care. The primary safety endpoint specifies a Safety Analysis Set consisting of participants who received at least one dose, partial or complete, of study treatment and had at least one evaluable post-baseline safety evaluation.
Intervention
BOS161721, given by subcutaneous injection. In Phase 1b, the planned doses were 20 mg, 60 mg, and 120 mg. In Phase 2, the study used the 120 mg dose selected from Phase 1b.
Comparator
Matching placebo, given subcutaneously. The study was randomized, double-blind, and parallel-group. The registry describes placebo groups in both Phase 1b and Phase 2.
Primary question
What was the safety experience, measured by the number of participants with adverse events, during repeat dosing and follow-up through Day 270? The study description also states that the chosen dose would be compared with placebo for SLE Responder Index 4 response with sustained reduction of oral corticosteroids. A result for that response comparison is not reported in the registry record.
3. Trial Design
NCT03371251 was a randomized, quadruple-masked, parallel-group Phase 1b/2 study sponsored by Boston Pharmaceuticals. The registry reports enrollment of 143 and a completed study status. The study started on 2018-01-10, with primary completion on 2020-11-26. Participants had systemic lupus erythematosus and were described as having moderately to severely active disease while receiving limited background standard of care.
Phase 1b evaluated BOS161721 at 20 mg, 60 mg, and 120 mg, alongside placebo groups corresponding to those dose cohorts. Phase 2 compared BOS161721 120 mg with placebo; the registry says that dose was determined from Phase 1b. Treatment was administered subcutaneously. The arm descriptions state that participants may receive seven monthly doses on Days 0, 30, 60, 90, 120, 150, and 180, followed by safety follow-up visits on Days 210, 240, and 270. The wording describes the planned schedule and does not establish that every participant received every dose or attended every visit.
The registry lists the number of participants with adverse events as the primary outcome, assessed up to Day 270. The study description also identifies safety, tolerability, and immunogenicity as Phase 1b aims and describes a planned Phase 2 comparison using SLE Responder Index 4 response with sustained reduction of oral corticosteroids. The record does not report the statistical analysis plan, allocation ratios, or detailed procedures for dose selection.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Phase 1b: Placebo | Phase 1b: Cohort 1: BOS161721 20 mg | Phase 1b: Cohort 2: BOS161721 60 mg | Phase 1b: Cohort 3: BOS161721 120 mg | Phase 2: Placebo | Phase 2: BOS161721 120 mg |
|---|---|---|---|---|---|---|
| STARTED | 7 | 5 | 9 | 9 | 37 | 76 |
| COMPLETED | 5 | 5 | 8 | 9 | 30 | 71 |
| NOT COMPLETED | 2 | 0 | 1 | 0 | 7 | 5 |
Reasons for not completing this period:
| Reason | Phase 1b: Placebo | Phase 1b: Cohort 1: BOS161721 20 mg | Phase 1b: Cohort 2: BOS161721 60 mg | Phase 1b: Cohort 3: BOS161721 120 mg | Phase 2: Placebo | Phase 2: BOS161721 120 mg |
|---|---|---|---|---|---|---|
| Withdrawal by Subject | 1 | 0 | 1 | 0 | 2 | 2 |
| Phase 1b: Pregnancy, Phase 2: fear of COVID-19 or local restrictions | 1 | 0 | 0 | 0 | 2 | 3 |
| Adverse Event | 0 | 0 | 0 | 0 | 1 | 0 |
| Decision by Sponsor | 0 | 0 | 0 | 0 | 2 | 0 |
Analysis population for the primary outcome, as defined in the registry: Safety Analysis Set (SS): Defined as all participants who received at least 1 dose (partial or complete) of study treatment and had at least one evaluable post-baseline safety evaluation.
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.
Only the first 6 of 7 groups are shown.
| Characteristic | Unit | Phase 1b: Placebo | Phase 1b: Cohort 1: BOS161721 20 mg | Phase 1b: Cohort 2: BOS161721 60 mg | Phase 1b: Cohort 3: BOS161721 120 mg | Phase 2: Placebo | Phase 2: BOS161721 120 mg |
|---|---|---|---|---|---|---|---|
| Participants analysed | 7 | 5 | 9 | 9 | 37 | 76 | |
| Age, Continuous: Placebo | years | 48.1 (SD 17.67) | — | — | — | 45.7 (SD 12.52) | — |
| Age, Continuous: BOS161721 | years | — | 50.0 (SD 8.51) | 49.3 (SD 11.31) | 47.3 (SD 10.43) | — | 44.5 (SD 12.52) |
| Sex: Female, Male: Female | Participants | 7 | 5 | 8 | 8 | 36 | 69 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 1 | 1 | 1 | 7 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 | 1 | 2 | 0 | 17 | 32 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 6 | 4 | 7 | 9 | 20 | 44 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 | 0 | 0 | 3 | 6 | 7 |
| Race (NIH/OMB): White | Participants | 5 | 5 | 9 | 6 | 20 | 45 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 | 11 | 24 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Phase 1b: Number of Participants With Adverse Events (AEs), measured over Up to Day 270.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with adverse events through Day 270. It is a safety measure: it describes how many participants in the defined Safety Analysis Set experienced an adverse event during the stated observation period. It is not a measure of disease response, and a participant count does not by itself describe the timing, duration, severity, or clinical importance of every event.
The registry defines the Safety Analysis Set as participants who received at least one dose of study treatment, whether partial or complete, and had at least one evaluable post-baseline safety evaluation. That definition matters when interpreting counts: the relevant population is not necessarily identical to everyone enrolled or randomized. The number included in each endpoint analysis is not reported in the registry record beyond the group-specific at-risk counts shown for the adverse-event summaries.
Safety endpoints are used in dose-escalation and early-phase studies to characterize adverse events during treatment and follow-up. General statistical interpretation: event counts are most informative when read with their corresponding denominators, endpoint definitions, and observation periods. They do not alone establish that treatment caused an event or that one group’s overall safety experience differs from another’s. The posted primary endpoint is distinct from the SLE Responder Index 4 response comparison described in the study summary; a result for that comparison is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted safety summaries report serious adverse events and other adverse events separately for the Phase 1b and Phase 2 groups. In Phase 1b, the placebo group had 1 participant with a serious adverse event among 7 at risk, and 4 with other adverse events among 7 at risk. The 20 mg BOS161721 group had 0 with a serious adverse event among 5 at risk, and 2 with other adverse events among 5 at risk. The 60 mg group had 2 with serious adverse events among 9 at risk, and 7 with other adverse events among 9 at risk. The 120 mg group had 0 with serious adverse events among 9 at risk, and 8 with other adverse events among 9 at risk.
In Phase 2, the placebo group had 3 participants with serious adverse events among 37 at risk, and 22 with other adverse events among 37 at risk. The 120 mg BOS161721 group had 2 with serious adverse events among 76 at risk, and 44 with other adverse events among 76 at risk. The registry records 0 deaths for each listed group. These are descriptive counts. They do not establish whether differences between groups are due to treatment, chance, differences in exposure, or other factors.
General statistical interpretation: counts should be read alongside the number at risk, the follow-up period, and the way events were defined and collected. Small groups can produce unstable estimates: a change in a single participant’s status may materially alter the pattern of observed counts, without providing a precise estimate of the underlying event risk. The Phase 1b cohorts and Phase 2 groups also have different sizes, so their counts should not be compared as if they came from equally sized groups. No confidence intervals or inferential comparisons for these safety counts are reported in the registry record.
The study summary describes a planned Phase 2 comparison of SLE Responder Index 4 response with sustained reduction of oral corticosteroids. The registry record does not report results for that comparison. The reported adverse-event information therefore addresses safety descriptions, not whether the study met a disease-response objective. The record also does not report a conclusion about an optimal dose.
9. Statistical Methods Explained
What does randomization contribute?
Randomization assigns participants to study groups by chance. General statistical explanation: when implemented as planned, it helps make groups comparable on average with respect to factors that could affect outcomes, including factors that are not measured. It does not guarantee that small groups will be balanced, and it does not remove uncertainty from observed differences. The registry identifies the study as randomized, but the randomization sequence, allocation concealment procedures, and allocation ratios are not reported in the registry record.
What does masking mean?
The registry describes the study as quadruple-masked and double-blind in its title. Masking is intended to reduce the influence of knowledge about assigned treatment on participant experience, study conduct, event assessment, or analysis. General statistical explanation: masking is particularly relevant for outcomes that depend partly on observation or reporting, but its presence does not show that masking was maintained successfully. The identities of the four masked parties and any assessment of masking are not reported in the registry record.
How should binary safety counts be read?
The adverse-event summaries give counts of participants with events and counts at risk. These are binary participant-level summaries: each participant is classified according to whether the specified event occurred during the assessment period. A count does not capture how many times an event occurred in one participant, when it began, how long it lasted, or whether multiple event types occurred in the same participant. The record presents serious adverse events separately from other adverse events; those categories should be interpreted according to their registry definitions, which are not further detailed in the record.
General statistical explanation: a count has limited interpretability without its denominator. The at-risk counts make it possible to see the group sizes used in the posted summaries, but they do not supply every detail needed to reproduce an analysis. For example, the registry does not report the statistical comparison method, confidence intervals, or handling of participants with incomplete observation. Because the groups differ in size, raw counts alone are not a suitable basis for judging comparative event frequency.
What does a confidence interval communicate?
General statistical explanation: a confidence interval describes uncertainty around an estimate under a specified statistical procedure. Wider intervals indicate less precision; narrower intervals indicate greater precision. An interval can help readers distinguish an estimate that is imprecise from one that is estimated more precisely, but it does not by itself establish clinical importance or causation. No confidence intervals for the posted adverse-event counts are reported in the registry record, so the precision of comparative safety estimates cannot be assessed from those counts alone.
What is the role of the study phases?
The Phase 1b portion assessed safety, tolerability, and immunogenicity across the listed BOS161721 doses, with the aim of estimating an optimal dose. Phase 2 used 120 mg, described as determined from Phase 1b, and included a placebo comparison. This structure makes dose selection part of the study’s stated purpose. The dose-selection procedure and its statistical criteria are not reported in the registry record, so the basis for selecting 120 mg cannot be independently evaluated from the stated information.
What do the planning illustrations represent?
General statistical explanation: sample-size planning uses assumptions about the effect to detect, the significance level, allocation, and the analysis method. The stated planning assumptions describe illustrations based on the observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. For non-time-to-event outcomes, the stated convention is participants per arm for each planning target; time-to-event calculations use a total event count. These are planning illustrations, not observed power and not evidence that the trial was designed with those assumptions. The registry record does not report the trial’s own sample-size justification, and it does not provide the calculated planning values in the registry record for interpretation.
10. Multiplicity, Missing Data and Analysis Populations
The study includes multiple phases, dose groups, safety outcomes, and additional measures. The registry lists 33 outcome measures and 23 analyses. When many outcomes or comparisons are examined, the chance of finding an apparently notable result by chance can increase. General statistical explanation: multiplicity procedures can control or describe that issue, but their use and the prespecified hierarchy of outcomes need to be documented to interpret results. A multiplicity strategy is not reported in the registry record.
The primary outcome is a count of participants with adverse events, while the study summary also describes a planned Phase 2 SLE Responder Index 4 response comparison with sustained reduction of oral corticosteroids. The statistical relationship between these aims, including whether one was formally primary for a particular phase, is not detailed beyond the listed primary endpoint and summary description. The analysis plan, decision rules, and any interim analyses are not reported in the registry record.
Missing-data handling is also not reported in the registry record. The Safety Analysis Set definition requires at least one evaluable post-baseline safety evaluation, but the record does not describe how missing visits, incomplete follow-up, withdrawal, or unavailable outcome assessments were handled in analysis. Nor does it report the number of participants excluded from any particular analysis or the reasons for exclusion.
The record defines an analysis population for safety, but it does not report a separate intention-to-treat population definition or the analysis population for the planned disease-response comparison. These omissions limit assessment of how closely the posted summaries reflect randomized assignment and how robust any comparison would be to incomplete outcome data.
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 |
|---|---|---|---|
| Phase 1b: Placebo | 1 | 7 | 14.3% |
| Phase 1b: Cohort 1: BOS161721 20 mg | 0 | 5 | 0.0% |
| Phase 1b: Cohort 2: BOS161721 60 mg | 2 | 9 | 22.2% |
| Phase 1b: Cohort 3: BOS161721 120 mg | 0 | 9 | 0.0% |
| Phase 2: Placebo | 3 | 37 | 8.1% |
| Phase 2: BOS161721 120 mg | 2 | 76 | 2.6% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Phase 1b: Placebo | 0 of 7 |
| Phase 1b: Cohort 1: BOS161721 20 mg | 0 of 5 |
| Phase 1b: Cohort 2: BOS161721 60 mg | 0 of 9 |
| Phase 1b: Cohort 3: BOS161721 120 mg | 0 of 9 |
| Phase 2: Placebo | 0 of 37 |
| Phase 2: BOS161721 120 mg | 0 of 76 |
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 |
|---|---|
| Phase 1b: Placebo | 4 of 7 |
| Phase 1b: Cohort 1: BOS161721 20 mg | 2 of 5 |
| Phase 1b: Cohort 2: BOS161721 60 mg | 7 of 9 |
| Phase 1b: Cohort 3: BOS161721 120 mg | 8 of 9 |
| Phase 2: Placebo | 22 of 37 |
| Phase 2: BOS161721 120 mg | 44 of 76 |
Most frequent serious adverse event terms
| Event term | Organ system | Phase 1b: Placebo | Phase 1b: Cohort 1: BOS161721 20 mg | Phase 1b: Cohort 2: BOS161721 60 mg | Phase 1b: Cohort 3: BOS161721 120 mg | Phase 2: Placebo | Phase 2: BOS161721 120 mg |
|---|---|---|---|---|---|---|---|
| Acute Respiratory Failure | Respiratory, thoracic and mediastinal disorders | 0 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 1 of 37 | 0 of 76 |
| Asthma | Respiratory, thoracic and mediastinal disorders | 0 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 1 of 37 | 0 of 76 |
| Chronic Obstructive Pulmonary Disease | Respiratory, thoracic and mediastinal disorders | 0 of 7 | 0 of 5 | 1 of 9 | 0 of 9 | 0 of 37 | 0 of 76 |
| Lupus Pneumonitis | Respiratory, thoracic and mediastinal disorders | 0 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 1 of 37 | 0 of 76 |
| Basal Cell Carcinoma | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 7 | 0 of 5 | 1 of 9 | 0 of 9 | 0 of 37 | 0 of 76 |
| Intraductal Proliferative Breast Lesion | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 0 of 37 | 1 of 76 |
| Squamous Cell Carcinoma of Skin | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 7 | 0 of 5 | 1 of 9 | 0 of 9 | 0 of 37 | 0 of 76 |
| Anaemia | Blood and lymphatic system disorders | 0 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 1 of 37 | 0 of 76 |
| Exomphalos | Congenital, familial and genetic disorders | 1 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 0 of 37 | 0 of 76 |
| Biliary Colic | Hepatobiliary disorders | 0 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 1 of 37 | 0 of 76 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Phase 1b: Placebo | Phase 1b: Cohort 1: BOS161721 20 mg | Phase 1b: Cohort 2: BOS161721 60 mg | Phase 1b: Cohort 3: BOS161721 120 mg | Phase 2: Placebo | Phase 2: BOS161721 120 mg |
|---|---|---|---|---|---|---|---|
| Nasopharyngitis | Infections and infestations | 1 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 3 of 37 | 7 of 76 |
| Nausea | Gastrointestinal disorders | 1 of 7 | 0 of 5 | 1 of 9 | 2 of 9 | 1 of 37 | 4 of 76 |
| Urinary Tract Infection | Infections and infestations | 0 of 7 | 1 of 5 | 0 of 9 | 0 of 9 | 4 of 37 | 4 of 76 |
| Pharyngitis | Infections and infestations | 0 of 7 | 1 of 5 | 0 of 9 | 0 of 9 | 2 of 37 | 4 of 76 |
| Headache | Nervous system disorders | 0 of 7 | 1 of 5 | 0 of 9 | 0 of 9 | 2 of 37 | 4 of 76 |
| Diarrhoea | Gastrointestinal disorders | 1 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 3 of 37 | 1 of 76 |
| Back Pain | Musculoskeletal and connective tissue disorders | 0 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 3 of 37 | 2 of 76 |
| Hypertension | Vascular disorders | 0 of 7 | 1 of 5 | 1 of 9 | 0 of 9 | 1 of 37 | 2 of 76 |
| Constipation | Gastrointestinal disorders | 1 of 7 | 0 of 5 | 0 of 9 | 0 of 9 | 1 of 37 | 2 of 76 |
| Upper Respiratory Tract Infection | Infections and infestations | 1 of 7 | 0 of 5 | 0 of 9 | 2 of 9 | 1 of 37 | 0 of 76 |
Serious events with the highest arm-level rate: exomphalos (14.3%), chronic obstructive pulmonary disease (11.1%), basal cell carcinoma (11.1%), squamous cell carcinoma of skin (11.1%), acute respiratory failure (2.7%).
The registry separates serious adverse events from other adverse events and reports a count of affected participants alongside the number at risk in each group. For example, the Phase 2 placebo group records 3 participants with serious adverse events among 37 at risk, while the Phase 2 BOS161721 120 mg group records 2 among 76 at risk. The other-adverse-event counts are 22 among 37 at risk for Phase 2 placebo and 44 among 76 at risk for Phase 2 BOS161721 120 mg. The Phase 1b group counts are described in the statistical interpretation.
The registry records 0 deaths for each listed group. It also lists serious adverse-event terms with percentages: Exomphalos, 14.3%; Chronic Obstructive Pulmonary Disease, 11.1%; Basal Cell Carcinoma, 11.1%; Squamous Cell Carcinoma of Skin, 11.1%; Acute Respiratory Failure, 2.7%; and Asthma, 2.7%. The denominator and method used for these term percentages are not reported in the registry record, so they should not be treated as group-level risks.
General statistical explanation: serious events and other events are different summaries, and the same participant may contribute to more than one event category. Participant counts do not indicate event frequency per person or prove that treatment caused an event. No comparative statistical analysis of these safety figures is reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record describes a randomized, masked trial with a Phase 1b dose-escalation component and a Phase 2 placebo comparison. Its posted primary endpoint concerns the number of participants with adverse events through Day 270. The adverse-event summaries provide group-specific counts of participants with serious and other events, with corresponding at-risk counts, and record 0 deaths for each listed group. These are descriptive safety data from the registry, not a complete account of each participant’s clinical course.
The figures do not by themselves establish that BOS161721 caused an event, prevented an event, or changed the overall safety profile relative to placebo. They also do not quantify uncertainty through confidence intervals or formal between-group tests. General statistical explanation: interpretation of comparative safety requires attention to event definitions, time under observation, completeness of follow-up, and the method used to compare groups. Those analysis details are not reported in the registry record.
The study summary describes a planned comparison of SLE Responder Index 4 response with sustained reduction of oral corticosteroids. The registry record does not report a result for that response comparison, so the posted safety counts cannot answer whether that objective was achieved. The record also does not report a conclusion about the optimal dose, despite describing dose estimation as a study aim.
These findings should therefore be read as a limited record of adverse-event counts within the specified study groups and observation period. They do not establish effectiveness, comparative benefit, a causal safety difference, or the degree of precision of any such difference. Those conclusions would require reported outcome analyses and their methods, which are not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically notable for combining an early dose-escalation stage with a later placebo-controlled stage. The Phase 1b groups covered BOS161721 20 mg, 60 mg, and 120 mg, while Phase 2 compared the 120 mg dose with placebo. This design makes safety monitoring and dose selection central to the study’s stated aims, while the summary also identifies a disease-response comparison for Phase 2.
The design also illustrates why counts need context. The group sizes differ, and adverse-event summaries are presented as affected-participant counts with numbers at risk. Reading counts without their denominators can mislead; even with denominators, small groups may yield imprecise estimates. General statistical explanation: confidence intervals and prespecified comparative analyses help show the uncertainty around group differences, but those are not reported for the safety counts in the registry record.
Another important statistical issue is the distinction between a study objective and a posted result. The record describes the intended SLE Responder Index 4 comparison with sustained corticosteroid reduction, but the outcomes available for interpretation are safety counts. Separating those questions prevents safety observations from being mistaken for evidence about disease response.
The record therefore demonstrates the value of transparent reporting of endpoint definitions, analysis populations, denominators, and statistical methods. It gives a safety population definition and group-specific adverse-event counts, but does not report the analysis plan, missing-data methods, or inferential comparisons. Those gaps constrain how far the results can be interpreted.
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 gives counts for serious and other adverse events, but it does not report confidence intervals, hypothesis tests, or adjusted comparisons for those outcomes. The counts therefore support description, not a precise estimate of differences between groups. The differing group sizes also make unqualified comparisons of raw counts inappropriate.
The Safety Analysis Set is defined, but the record does not report the number randomized, treated, and analyzed for each outcome beyond the at-risk counts in the adverse-event summaries. It does not describe missing safety assessments, withdrawals, exposure duration by participant, or how incomplete follow-up was handled. The arm descriptions say participants may receive the planned doses and follow-up visits; they do not establish actual treatment completion or observation for every participant.
The registry does not report the statistical analysis plan, the method for dose selection, the rationale for sample size, any interim analyses, or a multiplicity strategy. The method and denominator for the listed serious-event-term percentages are also not reported in the registry record. These details would be needed to assess analysis choices and the precision or comparability of event estimates.
Finally, a result for the planned Phase 2 SLE Responder Index 4 comparison with sustained reduction of oral corticosteroids is not reported in the registry record. The posted safety information cannot be used to infer that disease-response result or to establish an optimal dose.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of BOS161721 in Systemic Lupus Erythematosus (SLE) Patients on a Background of Limited Standard of Care — NCT03371251.
- Registry record last updated 2022-03-14; status last verified 2022-02.
- Results first posted 2022-03-14.
- 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
NCT03371251 is a completed randomized, quadruple-masked, parallel-group Phase 1b/2 study of BOS161721 in adults with moderately to severely active systemic lupus erythematosus on limited background standard of care. The registry reports enrollment of 143 and identifies Boston Pharmaceuticals as the sponsor. The study started on 2018-01-10 and had primary completion on 2020-11-26.
Phase 1b assessed BOS161721 20 mg, 60 mg, and 120 mg, with placebo groups; Phase 2 compared BOS161721 120 mg with placebo. The primary endpoint was the number of participants with adverse events up to Day 270, in a defined Safety Analysis Set. The record reports serious and other adverse-event counts by group and 0 deaths for each listed group. It also describes a planned Phase 2 response comparison using SLE Responder Index 4 with sustained reduction of oral corticosteroids, but a result for that comparison is not reported in the registry record.