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 Ketamine Tolerated Dose for Postpartum Depression and Pain After Cesarean Delivery (PREPARE 1) (NCT05907213), a non-randomized phase 1 study. The primary outcome is Maximum Tolerated Dose of Ketamine.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05907213 |
| Phase | Phase 1 |
| Condition | Pain, Postoperative, Depression, Postpartum |
| Allocation | Non-Randomized |
| Design model | Sequential |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Grace Lim, MD, MS |
| Results posted | Yes |
2. Clinical Question
Population
Postpartum women following cesarean delivery. The registry record lists postoperative pain and postpartum depression as the conditions of interest and describes assessment between 0 to 24 hours postpartum. It does not report further eligibility details or a more specific description of the enrolled population.
Intervention
Ketamine (Ketalar) infusion, evaluated across four dose levels. The loading dose varied by level, from 0.05 mg/kg/hr to 0.18 mg/kg/hr for one hour; the listed maintenance dose was 0.05 mg/kg/hr for 12 hours.
Comparator
There was no randomized control group. Participants were assigned to dose levels within a non-randomized, sequential dose-finding design. These groups are not like-for-like controls, so the posted figures should not be read as a randomized comparison of ketamine against another treatment or no treatment.
Primary question
Which ketamine dose level met the registry’s definition of maximum tolerated dose, based on dose-limiting toxicity defined by intolerability? The record reports the maximum tolerated dose as a loading dose of 0.18 mg/kg/hr for one hour, followed by 0.05 mg/kg/hr for 11 hours.
PREPARE 1 is a dose-tolerability study, rather than a trial designed to estimate a comparative effect on postpartum depression or pain. Its primary focus is whether participants experience a specified severe, unresolved hemodynamic effect during the postpartum assessment period. The registry also lists patient-reported acceptability of any reported side effects as a secondary outcome, but does not report its results in the record.
The clinical question is therefore narrower than whether ketamine improves symptoms or recovery. The posted record identifies a dose under a stated tolerability rule; it does not establish a comparative benefit on pain or depression, nor does it provide a control-group estimate for those outcomes. More detailed eligibility criteria, symptom measures, and the procedures used to assess patient acceptability are not reported in the registry record.
3. Trial Design
PREPARE 1 is listed as a phase 1, completed study with enrollment of 12. The registry start date is 2023-09-25 and the primary completion date is 2024-06-26. Its stated purpose is to identify a tolerable postpartum ketamine dose using a maximum tolerated dose 3+3 design. The record describes the loading dose over one hour as the dose variable under evaluation, while the maintenance dose is listed as 0.05 mg/kg/hr.
The study is non-randomized, unmasked, and sequential. These design features matter when interpreting the dose-level groups: they were not formed as randomized treatment and control arms, and the registry explicitly cautions against treating them as a like-for-like control comparison. Sequential allocation means the dose-finding process is ordered, but the specific escalation, de-escalation, or stopping rules are not reported in the registry record. The record also does not explain how the sequence was implemented or whether any dose levels were skipped.
The four listed regimens differ in loading dose: 0.05 mg/kg/hr, 0.08 mg/kg/hr, 0.12 mg/kg/hr, and 0.18 mg/kg/hr, each for one hour. Each listed regimen has a maintenance dose of 0.05 mg/kg/hr for 12 hours. The primary outcome description names the maximum tolerated dose as 0.18 mg/kg/hr for one hour, followed by 0.05 mg/kg/hr for 11 hours. That maintenance duration differs from the 12 hours stated in the dose-level descriptions; the registry record does not explain the discrepancy.
The registry lists two outcome measures, including the primary maximum tolerated dose and a secondary patient-reported acceptability measure. It reports no outcome analyses. Details such as the planned sample-size rationale, formal analysis plan, assessment schedule beyond the primary timeframe, and handling of participants who did not complete infusion are not reported in the registry record. The posted data are best understood as a small dose-finding record, not as a randomized efficacy comparison.
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 | Ketamine (Ketalar) Dose Level 1 | Ketamine (Ketalar) Dose Level 2 | Ketamine (Ketalar) Dose Level 3 | Ketamine (Ketalar) Dose Level 4 |
|---|---|---|---|---|
| STARTED | 3 | 3 | 3 | 3 |
| COMPLETED | 3 | 3 | 3 | 3 |
| NOT COMPLETED | 0 | 0 | 0 | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Ketamine (Ketalar) Dose Level 1 | Ketamine (Ketalar) Dose Level 2 | Ketamine (Ketalar) Dose Level 3 | Ketamine (Ketalar) Dose Level 4 | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 3 | 3 | 3 | 3 | 12 | |
| Age, Continuous | years | 36.7 (SD 3.2) | 35.3 (SD 6.0) | 32.0 (SD 3.6) | 33.0 (SD 1.7) | 34.3 (SD 3.9) |
| Sex: Female, Male: Female | Participants | 3 | 3 | 3 | 3 | 12 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 | 3 | 3 | 3 | 12 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 | 0 | 1 | 1 | 3 |
| Race (NIH/OMB): White | Participants | 2 | 3 | 2 | 2 | 9 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 3 | 3 | 3 | 3 | 12 |
| Estimated Gestational Age at Delivery: 37-weeks | Participants | 0 | 0 | 1 | 1 | 2 |
| Estimated Gestational Age at Delivery: 38-weeks | Participants | 0 | 1 | 0 | 0 | 1 |
| Estimated Gestational Age at Delivery: 39-weeks | Participants | 3 | 1 | 2 | 2 | 8 |
| Estimated Gestational Age at Delivery: 40-weeks | Participants | 0 | 1 | 0 | 0 | 1 |
| History of Anxiety | Participants | 1 | 0 | 2 | 1 | 4 |
| History of Depression | Participants | 2 | 3 | 1 | 2 | 8 |
6. Primary Endpoint
The registry lists the primary outcome as Maximum Tolerated Dose of Ketamine, measured over Between 0 to 24 hours postpartum.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the maximum tolerated dose of ketamine, reported in the registry as a dose and measured by the number of participants. The endpoint definition links dose tolerance to dose-limiting toxicity: the selected dose should have fewer than 33% of patients experiencing a dose-limiting toxicity, which is defined by intolerability.
For this study, tolerability is described as lack of adverse events, with an adverse event defined as a severe unresolved hemodynamic effect. The listed thresholds are systolic blood pressure <80 or >160, or heart rate <40 or >120. The registry says tolerability and intolerability are to be reported as n (%). It does not report separate outcome counts by this endpoint definition in the record.
The endpoint is used because the study’s stated objective is dose finding: identifying a dose level that satisfies its tolerability rule. It is not a symptom-improvement endpoint, and it does not directly measure pain relief, depressive symptoms, or comparative effectiveness. The registry reports the maximum tolerated dose as 0.18 mg/kg/hr for one hour, followed by 0.05 mg/kg/hr for 11 hours. The dose-level descriptions instead specify a 12-hour maintenance period, and the record does not reconcile these durations.
As a general statistical point, a dose-finding endpoint summarizes safety and tolerability under the study’s operational definition. Its interpretation depends on how events are defined, observed, and attributed to dose. The registry describes the hemodynamic thresholds, but further assessment and attribution procedures are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main result stated in the registry is that the maximum tolerated dose was 0.18 mg/kg/hr for one hour, followed by 0.05 mg/kg/hr for 11 hours. This is the study’s reported dose-finding conclusion under its stated definition of dose-limiting toxicity. The registry does not provide the per-level counts for tolerability or intolerability as n (%), so readers cannot verify the selection from those endpoint counts in the posted record.
The safety figures list zero serious adverse events among the three participants at risk in each of the four dose levels. They also list three participants with other adverse events among the three at risk in each level. These are descriptive safety counts. The other-event figures do not, by themselves, establish whether an event met the primary endpoint’s narrower definition of a severe unresolved hemodynamic effect. The record does not list the specific other events or their severity, duration, or attribution.
No inferential outcome analyses are reported. There are no posted effect estimates or confidence intervals for a dose-level comparison, and no reported analysis of the secondary patient-reported acceptability outcome. The record therefore gives a dose-finding conclusion and event counts, but not an estimate of uncertainty around the selected dose or a comparative estimate of symptom outcomes. The absence of a confidence interval is especially relevant in a small study: a point conclusion alone does not show how precisely the underlying tolerability rate has been estimated.
The design also limits cross-dose interpretation. Allocation was non-randomized and sequential, and the registry cautions that the dose groups are not a like-for-like control comparison. Differences between groups, if any, would not automatically be attributable to dose alone. The posted safety counts are not a randomized comparison and should not be described as evidence that one dose is safer or less safe than another.
The registry states enrollment of 12 and shows three participants at risk in each dose-level safety group. The posted adverse-event record does not display any serious events in these groups, but this observation is bounded by the participants and follow-up represented in the record. It does not establish that serious events cannot occur, particularly outside the recorded assessment period. The primary endpoint timeframe is between 0 to 24 hours postpartum; longer-term safety is not described.
Overall, the posted results support a narrow reading: the investigators recorded a maximum tolerated dose under their stated protocol definition and reported safety counts by listed dose level. They do not report comparative efficacy results for postpartum pain or depression, the uncertainty of the MTD estimate, or the secondary acceptability outcome. Those distinctions are important when interpreting the tables and plots on this page.
9. Statistical Methods Explained
What a sequential 3+3 design is intended to do
The registry describes the study as a maximum tolerated dose study using a 3+3 design. In general, a sequential dose-finding design evaluates dose levels in an ordered process, using observed tolerability information to guide subsequent study steps. The purpose is to identify a dose under a prespecified toxicity rule, rather than to estimate a treatment effect against a randomized control group. The record does not report the exact rules used to move between dose levels, the stopping rule, or how decisions were made when an observation was incomplete or difficult to classify. These details should not be inferred from the design label alone.
The loading dose is described as the variable being tested, with a common listed maintenance dose of 0.05 mg/kg/hr. The four listed loading doses are 0.05 mg/kg/hr, 0.08 mg/kg/hr, 0.12 mg/kg/hr, and 0.18 mg/kg/hr, each administered for one hour. Although the design is sequential, the registry does not report the order in which participants received the dose levels or any actual escalation decisions. The posted record lists three participants at risk in each dose-level safety group.
How the primary endpoint defines toxicity
The primary outcome is maximum tolerated dose, reported as a count-based endpoint. The registry defines dose-limiting toxicity by intolerability and says the maximum tolerated dose is the dose at which fewer than 33% of patients experience a dose-limiting toxicity. Tolerability is defined as lack of adverse events, with an adverse event characterized as a severe unresolved hemodynamic effect. The listed criteria are systolic blood pressure <80 or >160, or heart rate <40 or >120.
This is an operational definition: it turns a clinical concept into criteria that can be recorded and applied. As a general statistical point, an operational definition supports consistent classification only when event measurement and adjudication are sufficiently clear. The registry does not report further details about duration required for an event to count as unresolved, how repeated measurements were handled, who determined whether a threshold was met, or whether attribution to ketamine was required.
Why descriptive counts are not comparative estimates
The safety section reports participants at risk and participants affected by serious and other adverse events for each dose level. Such counts describe what was recorded among the listed participants. They are not a substitute for an adjusted or randomized comparison. Here, allocation was non-randomized and sequential, and the registry cautions that the groups are not a like-for-like control comparison. General statistical interpretation therefore calls for restraint: apparent differences in event counts across dose levels cannot be treated as isolated dose effects without a design and analysis that support that interpretation.
The outcome record lists no analyses. It consequently does not provide inferential tests, model-based estimates, confidence intervals, or adjustment for potential differences between groups. A confidence interval, in general, is a way to express the precision of an estimate under a specified statistical procedure. Without such an interval or another uncertainty summary, readers have less information about how much the reported dose conclusion might vary across comparable samples. No interval should be reconstructed from the posted counts as though it were the sponsor’s analysis.
How to read the event categories
The adverse-event figures separate serious events from other events. The registry lists zero serious events in each dose group and three participants with other events in each group. The primary endpoint has a more specific definition centered on severe unresolved hemodynamic effects, whereas the other-event category is not described in enough detail to determine which events it includes. These categories should therefore not be conflated. In particular, the other-event counts are not themselves the dose-limiting toxicity counts required to verify the MTD rule.
As a general point, safety summaries depend on the event definitions, surveillance period, and completeness of reporting. The registry gives the primary outcome timeframe as between 0 to 24 hours postpartum, but the adverse-event follow-up details are not reported in the registry record. The record also does not state how missing observations or participants who discontinued treatment were handled. The listed counts describe the posted record, not necessarily every possible event outside its scope.
Why the sample-size section is not observed power
Sample-size illustrations on this page are planning calculations based on an observed effect and stated assumptions, not evidence that the trial had a particular probability of detecting an effect. General statistical interpretation distinguishes planning scenarios from the actual design and results: a planning illustration asks what sample size might be required under chosen assumptions, while observed power is not a substitute for the effect estimate and its precision. The registry does not report its own sample-size justification or a power calculation, so such planning material should not be attributed to the investigators’ protocol.
The registry’s enrollment is 12, and the listed dose-level groups each show three participants at risk. With a small dose-finding study, event counts can provide an initial descriptive signal but may yield limited precision. No additional numerical precision estimate should be inferred from the counts alone. The main value of the registry result is its record of the selected dose under the stated rule, while the uncertainty and reproducibility of that selection remain incompletely characterized in the posted results.
Finally, the dose description contains a duration difference: the regimen descriptions specify maintenance for 12 hours, while the MTD result specifies 11 hours. Statistical interpretation depends on knowing which regimen corresponds to the reported conclusion. The registry does not explain this difference, so the result should be quoted as written rather than silently harmonized with the dose-level descriptions.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists two outcome measures: maximum tolerated dose as the primary outcome and patient-reported acceptability of any reported side effects as a secondary outcome. It does not report an analysis plan describing how outcomes were prioritized beyond that primary-secondary labeling, or how multiple comparisons or repeated assessments were handled. The number and timing of any planned analyses are not reported in the registry record.
No outcome analyses are listed. The registry reports the MTD conclusion and adverse-event counts, but does not provide the primary endpoint’s tolerability and intolerability counts as n (%), inferential estimates, or uncertainty intervals. It also does not report results for the patient-reported acceptability outcome. The acceptability question’s instrument, response categories, timing, and analysis are not reported in the registry record.
Missing-data procedures are not reported in the registry record. It does not describe whether participants with incomplete hemodynamic observations, interrupted infusions, or unavailable patient reports were included in the outcome summaries, nor how such observations were handled. The analysis population is also not defined in the posted record: there is no explicit description of whether outcomes were analyzed among all enrolled participants, those who received infusion, or those with complete endpoint observations.
As a general statistical matter, missingness and multiple outcome testing can affect how results should be interpreted. Without a stated analysis population and missing-data approach, readers cannot assess whether the displayed summaries include all enrolled participants or only those with available assessments. These omissions do not prove that data were missing or that analyses were selective; they mean the relevant procedures are not reported in the registry record.
The dose-finding conclusion should therefore be read alongside these reporting gaps. The record supplies a stated MTD and safety counts, but it does not show the full endpoint-level analysis or explain how incomplete records, if any, were managed.
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 |
|---|---|---|---|
| Ketamine (Ketalar) Dose Level 1 | 0 | 3 | 0.0% |
| Ketamine (Ketalar) Dose Level 2 | 0 | 3 | 0.0% |
| Ketamine (Ketalar) Dose Level 3 | 0 | 3 | 0.0% |
| Ketamine (Ketalar) Dose Level 4 | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Ketamine (Ketalar) Dose Level 1 | 0 of 3 |
| Ketamine (Ketalar) Dose Level 2 | 0 of 3 |
| Ketamine (Ketalar) Dose Level 3 | 0 of 3 |
| Ketamine (Ketalar) Dose Level 4 | 0 of 3 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Ketamine (Ketalar) Dose Level 1 | 3 of 3 |
| Ketamine (Ketalar) Dose Level 2 | 3 of 3 |
| Ketamine (Ketalar) Dose Level 3 | 3 of 3 |
| Ketamine (Ketalar) Dose Level 4 | 3 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Ketamine (Ketalar) Dose Level 1 | Ketamine (Ketalar) Dose Level 2 | Ketamine (Ketalar) Dose Level 3 | Ketamine (Ketalar) Dose Level 4 |
|---|---|---|---|---|---|
| Side effect: Nausea/vomiting | Gastrointestinal disorders | 2 of 3 | 2 of 3 | 2 of 3 | 1 of 3 |
| Side effect: Itchiness | Social circumstances | 3 of 3 | 1 of 3 | 1 of 3 | 1 of 3 |
| Side effect: Dizziness or lightheadedness | Gastrointestinal disorders | 0 of 3 | 2 of 3 | 0 of 3 | 1 of 3 |
| LSD Dysphoria Scale Score | Psychiatric disorders | 0 of 3 | 0 of 3 | 2 of 3 | 0 of 3 |
| Bad Dreams | Psychiatric disorders | 0 of 3 | 0 of 3 | 0 of 3 | 0 of 3 |
| Hallucinations | Psychiatric disorders | 0 of 3 | 0 of 3 | 0 of 3 | 0 of 3 |
The serious adverse-event figures are listed by dose level. Each group shows three participants at risk, zero participants affected by serious adverse events, and zero deaths. These are counts in the posted registry record; they do not show that serious events are impossible or rule out events beyond the recorded participants and follow-up.
The record also lists three participants with other adverse events in each dose-level group. This category is separate from the serious-event count, and the registry does not provide the specific event terms in the posted summary. It is therefore not possible from these figures alone to determine whether the other events met the primary endpoint’s definition of a dose-limiting toxicity, or how severe, persistent, or treatment-related they were.
The primary endpoint focuses on severe unresolved hemodynamic effects, using the stated blood-pressure and heart-rate thresholds. The safety summary’s other-event counts should not be treated as equivalent to endpoint-specific intolerability counts. The registry does not report the primary endpoint counts by dose as n (%), and it does not describe the broader event follow-up period beyond the primary timeframe of between 0 to 24 hours postpartum.
These figures are descriptive rather than comparative. Because allocation was non-randomized and sequential, the groups should not be treated as randomized safety arms. The displayed data summarize events recorded for the listed groups, not a causal comparison between dose levels.
12. What the Result Does, and Does Not, Mean
The result means that the registry records 0.18 mg/kg/hr for one hour, followed by 0.05 mg/kg/hr for 11 hours, as the maximum tolerated dose under the study’s stated dose-limiting toxicity rule. The study was designed to identify a tolerable dose in postpartum women following cesarean delivery, not to compare ketamine with a control treatment for pain or postpartum depression.
The result does not establish that ketamine improves either condition. The registry does not report comparative symptom outcomes, an efficacy estimate, or results for the secondary patient-reported acceptability measure. It also does not report confidence intervals or other uncertainty summaries for the MTD conclusion. The posted safety counts describe the recorded events among a small set of participants; they cannot establish the frequency of uncommon events with precision.
The MTD conclusion should not be generalized beyond the circumstances documented in the registry. It is tied to the stated dose regimen, event definition, and assessment context. The record gives a primary assessment timeframe of between 0 to 24 hours postpartum, but does not report longer-term safety or follow-up outcomes. It also does not report enough detail to independently verify how the MTD decision was reached from participant-level observations.
There is a duration inconsistency within the record: the dose-level descriptions list maintenance for 12 hours, while the MTD result lists 11 hours. The registry does not explain this difference. Readers should retain that distinction rather than assuming the statements refer to an identical regimen.
More broadly, a dose selected under a dose-finding rule is not automatically a dose with proven clinical benefit, nor is a zero serious-event count a guarantee of safety. These are general distinctions between dose tolerability, efficacy, and certainty. The posted result is informative as a reported phase 1 dose-finding conclusion, while the evidence for comparative benefit and the precision of the safety estimate remain unreported.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates a different question from the one commonly addressed by a randomized efficacy comparison. PREPARE 1 is a sequential, non-randomized phase 1 study focused on identifying a maximum tolerated dose. The target is a dose decision under a toxicity rule, not a between-group estimate of improvement in pain or postpartum depression.
That distinction changes how the displayed groups should be read. The dose levels are part of a sequential dose-finding process, not randomized alternatives. Their event counts provide descriptive information, but do not support a like-for-like treatment comparison. The registry explicitly cautions against interpreting the groups as a control comparison.
The study also demonstrates why definitions and reporting details matter. The primary endpoint specifies hemodynamic thresholds and a rule based on fewer than 33% experiencing dose-limiting toxicity. Yet the registry does not report the endpoint-specific tolerability counts or the detailed decision path behind the stated MTD. Readers can identify the recorded conclusion but have limited information to examine its precision or reproduce the decision.
Safety summaries require similar care. Zero serious adverse events appear in the listed groups, while other adverse events are also recorded. The latter are not necessarily equivalent to the primary endpoint’s narrowly defined toxicity, and the posted record does not list specific event terms. Clear separation of event categories helps prevent a broad adverse-event count from being mistaken for an endpoint result.
Finally, the mismatch between the listed maintenance duration and the duration in the MTD result highlights the value of internally consistent regimen reporting. Such details affect the interpretation of what dose was actually selected. The record’s limitations do not erase its usefulness: it documents the study’s stated dose-finding conclusion and its observed safety summaries, while also showing what remains unavailable for statistical evaluation.
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 is limited by the small enrollment of 12 and the non-randomized, sequential design. These features fit a dose-finding objective, but the groups are not randomized comparators. The posted safety counts should therefore be read descriptively, not as evidence of causal differences between dose levels.
The record reports the MTD conclusion but not the endpoint-level counts of tolerability and intolerability as n (%). It also does not provide inferential analyses, confidence intervals, or an account of how the dose decision followed from observed outcomes. The specific escalation and stopping rules, decision procedures, and sample-size justification are not reported in the registry record.
There is an unresolved regimen-duration difference: the dose-level descriptions specify a 12-hour maintenance infusion, whereas the MTD result specifies 11 hours. The record does not explain which duration corresponds to the reported conclusion. The specific terms and severity of the other adverse events are also not provided in the posted summary, limiting interpretation of those event counts.
Other information needed to assess the results is not reported in the registry record, including detailed eligibility criteria, the analysis population, missing-data procedures, patient-level completion information, and the procedures used to assess or attribute hemodynamic events. The secondary patient-reported acceptability outcome is listed, but its results and measurement details are not reported.
The registry gives the primary timeframe as between 0 to 24 hours postpartum, so longer-term tolerability is not established by these posted results. It also does not report comparative outcomes for pain or postpartum depression. These limitations define the scope of what can be concluded from the posted record: a stated dose-finding result and descriptive safety counts, without a detailed analysis of uncertainty or clinical efficacy.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Ketamine Tolerated Dose for Postpartum Depression and Pain After Cesarean Delivery (PREPARE 1) — NCT05907213.
- Registry record last updated 2025-09-12; status last verified 2025-09.
- Results first posted 2025-09-12.
- 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.
Continue through the Clinical Biostats statistical pathway
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18. Record Summary
PREPARE 1 is a completed phase 1, non-randomized, unmasked, sequential study with enrollment of 12. It evaluated four ketamine loading-dose levels in postpartum women following cesarean delivery, with a stated purpose of identifying a maximum tolerated dose using a 3+3 design.
The registry reports an MTD of 0.18 mg/kg/hr for one hour, followed by 0.05 mg/kg/hr for 11 hours. The dose-level descriptions list maintenance for 12 hours, a difference the record does not explain. The primary outcome is based on a dose-limiting toxicity rule for severe unresolved hemodynamic effects, and the record lists patient-reported acceptability as a secondary outcome.
Safety summaries show zero serious adverse events in each listed group and three participants with other adverse events in each group. No outcome analyses are listed, and the endpoint-specific tolerability counts, secondary outcome results, uncertainty estimates, analysis population, and missing-data procedures are not reported in the registry record. The findings are therefore a descriptive dose-finding record, not a randomized efficacy comparison.