Phase 1b Study of SL-172154 Administered With Combination Agent(s) in Subjects With Ovarian Cancers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Phase 1b Study of SL-172154 Administered With Combination Agent(s) in Subjects With Ovarian Cancers (NCT05483933), a non-randomized phase 1 study. The primary outcome is Evaluate Safety and Tolerability of SL-172154 When Administered With PLD or Mirvetixumab.

2. Clinical Question

This is a phase 1b study, not a randomized comparison of the combinations. Its central question is whether adverse events were recorded among participants receiving these regimens, rather than whether one regimen outperformed a control. The registry also lists secondary objectives involving preliminary evidence of antitumor activity, immunogenicity, and serum pharmacokinetic measures. Results for those objectives are not reported in the registry record.

3. Trial Design

The registry identifies this as a phase 1b, open-label, nonrandomized, parallel study. It lists two intervention groups: pegylated liposomal doxorubicin plus SL-172154, and mirvetuximab plus SL-172154. The arm descriptions specify intravenous administration for the drugs. The study is described as multicenter in its brief summary. Masking is listed as none, so the record does not describe blinded treatment assignment or outcome assessment.

The registry lists enrollment as 86. The brief summary says approximately 102 patients will be enrolled, so the record contains different enrollment figures in those fields. It does not explain the difference. The study start is listed as 2022-08-18, primary completion as 2025-02-07, and status as completed. These details describe the registry record; they do not establish how many participants completed follow-up or contributed data to each outcome.

The primary objective was safety and tolerability. The primary endpoint is a participant count for treatment-emergent adverse events in dose-escalation and expansion cohorts. The primary population is described as participants who received at least one dose of SL-172154, PLD or Mirvetixumab. The time frame extends from Day 1 to 30 days after the last dose, averaging approximately 6 months.

Because allocation was nonrandomized, the arms should not be treated as exchangeable comparison groups. The registry record does not report how treatment assignment was determined, whether the groups differed at baseline, or whether any adjustment was planned to account for such differences. It also does not report a statistical analysis plan or a sample-size justification. Thus, this design can describe experience within each combination group, but the information recorded does not support a causal comparison between the regimens.

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: Dose escalation was limited to a single dose level for SL-172154 within each arm (in combination with the standard dose of PLD or MIRV). No participants were enrolled in other dose levels in either arm.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Subjects who received at least one dose of SL-172154, PLD or Mirvetixumab

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.

6. Primary Endpoint

The registry lists the primary outcome as Evaluate Safety and Tolerability of SL-172154 When Administered With PLD or Mirvetixumab, measured over From Day 1 to 30 days after last dose of SL-172154, PLD or Mirvetixumab, an average of approximately 6 months.

The primary endpoint is defined as the number of participants with treatment-emergent adverse events from the dose-escalation and expansion cohorts. The named unit is participants, and the population is described as people who received at least one dose of SL-172154, PLD or Mirvetixumab. The observation period begins on Day 1 and continues until 30 days after the last dose of SL-172154, PLD or Mirvetixumab; the registry gives an average duration of approximately 6 months.

A participant count is a way to describe how many people experienced an event, rather than how many separate event episodes occurred. It is useful in a safety-focused early-phase study because it can indicate how broadly adverse events were experienced among treated participants. The endpoint is also aligned with the stated objective of evaluating safety and tolerability. General statistical context: counts are most interpretable when their population, observation period, and event definitions are clear, since differences in these features can change what is being counted.

The registry record does not report the primary endpoint’s complete results or the detailed definition and grading rules for treatment-emergent adverse events. The serious and other adverse-event counts recorded separately should not automatically be treated as the complete primary endpoint result: the record does not establish that those categories include every event included in the primary outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a count outcome: participants with an event. A count of affected participants answers how many people in a defined group experienced an event during the stated observation period. It is different from a count of event episodes, since one participant may experience more than one episode. General statistical context: participant-level counts are often used in safety summaries because they focus on how many people were affected, but they do not convey the number, duration, or severity of all episodes unless those details are reported separately.

What does nonrandomized allocation imply?

In a randomized study, assignment by chance is intended to make groups comparable on average with respect to factors known and unknown at the time of assignment. This study is listed as nonrandomized, and the registry explicitly cautions that the arms are not a like-for-like control comparison. Treatment groups may differ for reasons connected with treatment selection, participant characteristics, or the course of care. The registry record does not report the assignment process or baseline comparability, so it is not possible to judge or adjust for those differences using the information recorded.

As a result, a numerical contrast between the groups would remain descriptive. Even if one group had a larger count, that observation alone would not establish that its combination caused more adverse events. The group sizes recorded are also unequal, so raw counts are not directly comparable as measures of frequency. No recalculated rates or adjusted contrasts are reported in the registry record.

Why do event definitions and follow-up matter?

The primary outcome refers to treatment-emergent adverse events, while the safety entries separately identify serious and other adverse events. These labels describe different aspects of safety reporting; the record does not provide enough detail to reconstruct how each event was classified or how the listed categories relate to the full primary endpoint. The endpoint’s stated time frame runs from Day 1 to 30 days after the last dose, with an average duration of approximately 6 months. The registry does not report individual follow-up times or exposure duration by group.

General statistical context: event counts can be affected by the time participants are observed and by how much time they receive treatment. If observation differs, a group with longer exposure may have more opportunity for events to be recorded. Time-to-event or exposure-adjusted methods can sometimes address aspects of differing observation, but the registry record does not report such an analysis for these safety counts.

What would uncertainty estimates add?

Counts are observed summaries, not precise estimates of an underlying risk in every similar population. General statistical context: a confidence interval gives a range of plausible values for a parameter under the assumptions of the selected statistical method. It communicates uncertainty that a single estimate cannot show. The registry record does not report confidence intervals, hypothesis tests, or adjusted estimates for the primary endpoint or the adverse-event counts, so statistical precision cannot be assessed from those entries.

Likewise, a p-value would address compatibility of data with a specified statistical model and null hypothesis; it would not establish causation or clinical importance. No p-values are reported. In a nonrandomized study, statistical adjustment could be useful only if relevant variables and an appropriate model were specified and available. Such an adjustment is not reported in the registry record.

How should the listed percentages be read?

The serious adverse-event terms include percentages, but their denominator and calculation basis are not reported in the registry record. They should therefore be retained as presented and not translated into counts, risks, or comparative rates. General statistical context: percentages are interpretable only when the numerator, denominator, event definition, and observation period are clear. Percentages based on different denominators or different reporting rules cannot be assumed to be directly comparable.

The registry lists sample-size planning assumptions for an illustration based on an observed effect: two-sided significance level 0.05, equal allocation, normal approximation, and effects expressed as fractions of the observed effect. These are planning assumptions, not evidence that the trial was designed or powered according to them. Any sample sizes generated under such assumptions would be planning illustrations, not observed power. The registry record does not report the trial’s own sample-size justification or statistical plan, and no planning calculation can substitute for those missing design details.

What does the absence of registered analyses mean?

The registry lists no analysis records. That absence means that the registry record does not present analysis specifications or results for the outcomes; it does not prove that no statistical work took place. Without analysis details, readers cannot determine which participants were included in each analysis, how missing observations were handled, whether outcomes were adjusted, or whether multiple testing was addressed. These uncertainties are especially relevant when a study lists several secondary objectives alongside a primary safety objective.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Pegylated Liposomal Doxorubicin + SL-172154", "Mirvetixumab + SL-172154")
n      <- c(21, 65)
events <- c(20, 65)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Pegylated Liposomal Doxorubicin + SL-172154  21  20  95.2  76.2  99.9  77.3  99.2  77.2  98.9
ARM  Mirvetixumab + SL-172154  65  65  100.0  94.5  100.0  94.4  100.0  94.6  100.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists secondary objectives covering preliminary antitumor activity, immunogenicity to SL-172154 and MIRV, and pharmacokinetic measures for SL-172154 and MIRV. It lists 11 outcome measures in total, but no analysis records. The registry record does not report a multiplicity procedure, such as a plan to control the chance of false-positive findings across multiple outcomes. Without an analysis plan, any interpretation of several outcome results as confirmatory would be unsupported.

The primary endpoint population is described as participants who received at least one dose of SL-172154, PLD or Mirvetixumab. The registry record does not report the analysis population used for each posted safety count or secondary outcome. It also does not report how missing observations, incomplete follow-up, withdrawals, or participants with incomplete exposure were handled. These details matter because available-case counts can reflect who remained under observation as well as the underlying event experience.

The record does not specify whether the registry enrollment figure or the brief summary’s approximate enrollment target corresponds to the population used in each analysis. Nor does it provide outcome-specific denominators for the listed serious adverse-event terms. These are reporting gaps, not evidence that data were missing or that a particular handling method was used. Any statistical plan for multiplicity or missing data is not reported in the registry record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: embolism (9.5%), small intestinal obstruction (7.7%), ileus (4.8%), large intestinal obstruction (4.8%), palpitations (4.8%).

The registry lists serious adverse events for the PLD plus SL-172154 group as 4 affected among 21 at risk, and for the mirvetuximab plus SL-172154 group as 17 affected among 65 at risk. For other adverse events, it lists 20 affected among 21 at risk in the PLD group and 65 affected among 65 at risk in the mirvetuximab group. These entries are counts of participants, not counts of every event episode.

Deaths are listed as 12 for the PLD combination group and 30 for the mirvetuximab combination group. The registry record does not establish that these deaths were treatment-related. It does not report the causes, timing, or individual circumstances in the information. They should not be interpreted as attributable to either combination on the basis of the counts alone.

The record also lists serious adverse-event terms with percentages, including Embolism at 9.5% and Small Intestinal Obstruction at 7.7%. The denominator and calculation basis for these percentages are not reported in the registry record. They cannot be reliably translated into participant counts or compared with the group-level counts without that context. Because the trial was nonrandomized and follow-up details are not reported, these safety figures are descriptive rather than a causal comparison.

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

The registry record describes a completed, open-label phase 1b study of SL-172154 used with PLD or mirvetuximab in people with platinum-resistant ovarian cancers. Its primary objective was safety and tolerability, and the primary endpoint was a count of participants with treatment-emergent adverse events. The record provides group-level counts for serious and other adverse events and lists several serious adverse-event terms.

Those figures document events recorded in the study groups. They do not, on their own, show that an event was caused by a study drug. The listed deaths likewise cannot be attributed to treatment from the information reported. The registry does not provide the event-level detail, follow-up information, or analysis results needed to establish causality or quantify comparative risk.

The study was nonrandomized, with no masking, and the registry cautions that the arms are not a like-for-like control comparison. Differences between groups may reflect differences in who received each regimen or how they were observed, in addition to any treatment-related factors. The record does not report a statistical comparison that adjusts for these possibilities. It therefore does not establish that either combination is safer or less safe than the other.

The brief summary describes preliminary antitumor activity as a secondary objective, but no efficacy result is reported in the registry record. The absence of a registered efficacy result should not be read as evidence for or against antitumor activity. It means that the record described does not give an estimate with which to assess that question.

Overall, the posted information supports a descriptive reading of recorded safety counts in the two groups. It does not supply a randomized estimate, a formal uncertainty interval, or a causal treatment effect. The findings should be understood within the population, endpoint definitions, and reporting limitations recorded for this study.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of how early-phase safety objectives differ from confirmatory comparisons. The primary objective is safety and tolerability, and the endpoint counts participants with treatment-emergent adverse events. Such summaries can help characterize what was recorded among people receiving the combinations, while avoiding a claim that the study was designed to establish comparative efficacy.

The design also makes the distinction between description and causal inference especially important. The registry lists a nonrandomized, open-label, parallel study and explicitly says the arms are not a like-for-like control comparison. Thus, group-specific safety counts can be reported, but they should not be interpreted as a clean estimate of the effect of choosing one combination over the other. This distinction applies even when counts appear numerically different.

The record illustrates why denominators, event definitions, follow-up, and analysis populations are essential to interpretation. It provides counts at risk and affected for serious and other adverse events, but does not report all details needed to compare rates or assess uncertainty. The percentages attached to serious adverse-event terms also lack a stated denominator in the registry record.

Finally, the registry lists multiple secondary objectives but no analysis records. This leaves unanswered how multiplicity, missing data, and outcome-specific populations were addressed. Recognizing these gaps is part of sound statistical reading: a result’s meaning depends not only on its numerical value, but also on the design and analysis that produced it. The available information is useful for describing the study record, while its limits constrain the strength of any comparative conclusion.

15. 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 reports different enrollment figures in different fields: enrollment is listed as 86, while the brief summary says approximately 102 patients will be enrolled. The record does not explain this difference. It also does not state how many participants were included in each endpoint analysis or completed the specified follow-up, so the listed enrollment should not be assumed to be the denominator for every result.

Details needed to interpret the safety counts are limited. The registry does not report the full event definitions, grading rules, exposure duration by group, individual follow-up, or causes and timing of deaths. It also does not specify the denominator or calculation basis for the percentages attached to serious adverse-event terms. The relationship between these safety categories and the full treatment-emergent adverse-event endpoint is not reported in the registry record.

Nonrandomized allocation and the absence of masking constrain comparisons between groups. The record does not report how treatment assignment occurred, baseline characteristics, or statistical adjustment for differences between participants. Nor does it report confidence intervals, hypothesis tests, analysis populations, missing-data methods, multiplicity procedures, or a statistical analysis plan. The registry lists no analysis records.

The record’s brief summary describes evaluation of preliminary antitumor activity, but no efficacy results are reported in the information described. The registry also does not report a sample-size justification. These gaps limit interpretation of both the precision of the safety findings and the scope of conclusions that can be drawn from the study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Phase 1b Study of SL-172154 Administered With Combination Agent(s) in Subjects With Ovarian Cancers — NCT05483933.
• Registry record last updated 2025-12-23; status last verified 2025-12.
• Results first posted 2025-12-23.
• 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.

19. Record Summary

The registry describes NCT05483933 as a completed, open-label, nonrandomized, parallel phase 1b study of SL-172154 with either pegylated liposomal doxorubicin or mirvetuximab in subjects with platinum-resistant ovarian cancers. Both combinations are described as intravenous. The listed enrollment is 86; the brief summary separately states that approximately 102 patients will be enrolled. The record does not explain the difference.

The primary objective was to evaluate safety and tolerability. The primary endpoint counts participants with treatment-emergent adverse events, in a population described as participants who received at least one dose. The record lists serious and other adverse-event counts, deaths, and selected serious adverse-event terms. It lists 11 outcome measures and no analysis records. The registry record does not report a formal statistical comparison, a complete primary endpoint analysis, or an efficacy result.