A Study Evaluating Safety, Tolerability, and Clinical Activity of Forimtamig-Based Treatment Combinations in Participants With Relapsed or Refractory Multiple Myeloma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study Evaluating Safety, Tolerability, and Clinical Activity of Forimtamig-Based Treatment Combinations in Participants With Relapsed or Refractory Multiple Myeloma (NCT06055075), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Adverse Effects (AEs).

2. Clinical Question

3. Trial Design

This was an open-label, randomized Phase IB/II study evaluating the safety, tolerability, and clinical activity of forimtamig-based treatment combinations in participants with relapsed or refractory multiple myeloma. The study was listed as having a sequential model and two phases: dose exploration and dose expansion. Its stated purpose included evaluating forimtamig alone and in combinations with carfilzomib, daratumumab, or other combination partners. The registry record lists an enrollment of 21 and the status as terminated.

The posted primary outcome data concern three Cohort 1 arms: forimtamig 0.3 mg plus carfilzomib, forimtamig 0.75 mg plus carfilzomib, and forimtamig 1.5 mg plus carfilzomib. Their listed participant counts are 7, 6, and 6. The primary endpoint is a participant count for adverse effects, measured from initiation of study treatment up to approximately 15.7 months. The arm descriptions say forimtamig was given by subcutaneous injection and carfilzomib by intravenous infusion, continuing until disease progression in dose exploration.

The study description also includes dose-exploration arms pairing forimtamig with daratumumab, and dose-expansion arms for forimtamig alone and for combinations with carfilzomib or daratumumab. In dose expansion, the forimtamig dose was to be a fixed dose determined during dose exploration; the described treatment duration varies by arm. However, the posted primary outcome counts concern the three carfilzomib dose arms, not all of those planned treatment groups.

The registry record gives a start date of 2023-12-08 and a primary completion date of 2025-07-08. It does not report why the study was terminated, the timing or basis of the termination decision, or whether all planned phases and arms were completed. Although the study is described as randomized, details of sequence generation, allocation concealment, or assignment across the dose arms are not reported in the registry record. Masking is listed as none, so the study was open-label.

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: In dose exploration phase of the study, 3 forimtamig dose levels were to be tested in combination with carfilzomib or daratumumab \& selected forimtamig dose(s) were to continue in the expansion phase with the respective combination partner. However, since the Sponsor terminated the study prematurely, the dose exploration forimtamig + daratumumab \& the dose expansion phase arms were never opened for enrollment. All participants were enrolled in dose exploration forimtamig + carfilzomib arms only.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety population included all participants enrolled in the study who received any amount of any study treatment.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Data for all participants randomized in the study have been presented.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Adverse Effects (AEs), measured over From initiation of study treatment up to approximately 15.7 months.

The primary endpoint is the number of participants with adverse effects. It counts participants who experienced an adverse event rather than counting the total number of separate event episodes. The registry definition is broad: an adverse event is an untoward medical occurrence in a participant given a pharmaceutical product, regardless of whether it was attributed to that product. It may include an unfavorable sign, symptom, disease, or abnormal laboratory finding temporally associated with use of a medicinal product.

The endpoint is assessed from initiation of study treatment up to approximately 15.7 months in the stated safety population: participants enrolled in the study who received any amount of any study treatment. Posted counts are 7 participants in the forimtamig 0.3 mg plus carfilzomib arm, 6 in the 0.75 mg arm, and 6 in the 1.5 mg arm.

As a general statistical point, a participant count is a straightforward way to describe how many people experienced at least one event. It does not by itself convey the number of events per participant, their severity, duration, timing, or causal relationship to treatment. Nor does a count alone quantify uncertainty around a difference between treatment groups. Those distinctions matter in a small early-phase study, where descriptive safety monitoring is central and where the endpoint should not be interpreted as proof of treatment causation.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a binary participant-level outcome: whether a participant had an adverse effect during the stated assessment period. The registry reports counts of participants with events, rather than a model-based estimate. General statistical explanation: for a binary outcome, a group count tells how many participants met the endpoint, while a comparative analysis would need to define a contrast between groups and quantify uncertainty around that contrast. The posted record does not provide such an analysis for these arms.

What do the counts represent?

The primary measure is titled “Number of Participants With Adverse Effects (AEs)” and has participants as its unit. The reported values are 7, 6, and 6. They are not counts of every adverse event occurrence: one participant may experience more than one event, but the participant contributes once to a participant-level count. General statistical explanation: this kind of endpoint is useful for a broad summary of how many participants experienced an event, but it does not describe event frequency per person or distinguish mild from severe events unless those details are separately reported.

The registry definition includes medical occurrences regardless of causal attribution. This matters because an adverse event is not automatically an adverse reaction caused by a study drug. A temporal association with medicinal product use is sufficient for the broad event definition described in the record. The record also gives serious adverse-event counts and selected serious-event terms, which are related safety descriptions but are not interchangeable with the primary endpoint.

Why is there no comparative estimate?

The record indicates that values are missing or not estimable for a two-arm comparison of this binary endpoint. It lists zero analyses. As a result, no inferential estimate, confidence interval, or p-value is available for a comparison among the dose arms. General statistical explanation: a confidence interval expresses the uncertainty compatible with an estimate under a specified statistical method and assumptions. Without a posted estimate and interval, the reader cannot judge the precision of a dose-group difference from inferential statistics.

The study is labeled randomized, but the registry record does not explain the allocation procedure for these three arms or give a specific pairwise analysis plan. The listed groups differ by forimtamig dose while sharing carfilzomib as a combination partner. That makes descriptive dose-arm summaries possible, but does not, on its own, establish a valid randomized contrast. In a small early-phase study, observed differences can be sensitive to individual outcomes and to the composition of each group. A descriptive difference should not be recast as a treatment effect.

What can a sample-size illustration tell us?

The planning illustrations are described as using the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They are planning illustrations, not the study's own design justification and not observed power. The record does not report a sample-size justification or the assumptions used by investigators to plan enrollment. The actual numeric planning results are not stated in the registry entries, so no particular required sample size can be interpreted.

General statistical explanation: a sample-size calculation asks how much information a proposed study would need to detect an effect under stated assumptions. If an effect is taken from a small observed dataset, the resulting planning figure can be unstable and should be treated as illustrative. It does not show that the completed study had a particular probability of detecting a real effect. The record does not provide enough information to assess whether the trial's enrollment target was chosen using these calculations.

How should event-type percentages be read?

The serious-event terms are accompanied by percentages: cytokine release syndrome, 50.0%; pyrexia, 33.3%; pneumonia, sepsis, bone pain, and cauda equina syndrome, 16.7% each. The denominator for those percentages is not reported in the registry record. Without a defined denominator, the percentages cannot be translated into a number of participants or compared reliably across arms. General statistical explanation: percentages describing event terms may overlap when participants can have more than one event, so they should not be added unless the record explicitly defines mutually exclusive categories.

General statistical explanation: over-dispersion is relevant when count data vary more than a simple model expects. It can make standard errors and confidence intervals too narrow if the analysis assumes less variability than the data contain. The primary endpoint is a count of participants with a binary event status, not a recurrent-event total; the record does not report an over-dispersion analysis or a model for event counts. It would therefore be inappropriate to claim that over-dispersion was assessed or that a particular adjustment was used.

Overall, the registry record supports descriptive reading of participant counts and selected serious-event terms. Statistical methods for handling censoring, repeated events, covariate adjustment, missing observations, or multiplicity are not reported in the registry record. The absence of those details does not establish that no such methods were used outside the registry; it means they cannot be evaluated from the record.

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("Cohort 1: Arm B1: Forimtamig 0.3 mg + Carfilzomib", "Cohort 1: Arm B2: Forimtamig 0.75 mg + Carfilzomib", "Cohort 1: Arm B3: Forimtamig 1.5 mg + Carfilzomib")
n      <- c(7, 6, 6)
events <- c(7, 6, 6)
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  Cohort 1: Arm B1: Forimtamig 0.3 mg + Carfilzomib  7  7  100.0  59.0  100.0  64.6  100.0  63.1  99.7
ARM  Cohort 1: Arm B2: Forimtamig 0.75 mg + Carfilzomib  6  6  100.0  54.1  100.0  61.0  100.0  59.0  99.6
ARM  Cohort 1: Arm B3: Forimtamig 1.5 mg + Carfilzomib  6  6  100.0  54.1  100.0  61.0  100.0  59.0  99.6

11. Multiplicity, Missing Data and Analysis Populations

The study lists multiple outcomes, including progression-free survival, duration of response, time to response, time to best response, overall survival, anti-drug antibodies, serum concentrations, and area under the concentration-time curve. The record lists 15 outcome measures and 9 posted secondary outcomes. The primary safety endpoint is one part of a broader assessment spanning safety and clinical activity.

When a study evaluates multiple outcomes or several treatment arms, general statistical explanation is that the chance of obtaining at least one apparently unusual result can increase if many comparisons are tested without accounting for multiplicity. The registry record does not report a multiplicity adjustment, a hierarchy among outcome tests, or a prespecified strategy for interpreting multiple comparisons. It also lists zero analyses, so there are no posted inferential tests for this endpoint to evaluate for multiplicity.

The record defines the safety population as all enrolled participants who received any amount of any study treatment. The three primary outcome arms list 7, 6, and 6 participants. The registry does not report, in the registry record for these results, details of missing endpoint status, exclusions, participant-level follow-up completeness, or how missing safety observations were handled. These matters are not reported in the registry record and should not be inferred from the displayed counts.

The primary endpoint's assessment window is from treatment initiation up to approximately 15.7 months. The record does not provide individual follow-up durations or explain whether all participants had the same opportunity for event observation. For other outcomes, the registry lists time-to-event measures, but their analysis methods and handling of censoring are not described in the posted information. No assumptions about missing data, imputation, interim analyses, or a statistical analysis plan can be established from this 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: cytokine release syndrome (50.0%), pyrexia (33.3%), pneumonia (16.7%), sepsis (16.7%), bone pain (16.7%).

The serious adverse-event counts are 5 in the forimtamig 0.3 mg plus carfilzomib arm, 3 in the 0.75 mg arm, and 4 in the 1.5 mg arm. The corresponding listed arm sizes are 7, 6, and 6. These are participant counts, not event totals. The record also lists deaths as 0, 1, and 1, respectively. It does not report whether the deaths were considered related to study treatment.

The serious-event terms reported include cytokine release syndrome (50.0%), pyrexia (33.3%), pneumonia (16.7%), sepsis (16.7%), bone pain (16.7%), and cauda equina syndrome (16.7%). The denominator for the percentages and whether terms can overlap are not reported in the registry record. They should not be summed or treated as arm-specific rates. The record does not provide the term-by-arm breakdown, individual event descriptions, onset times, duration, severity grades, or causal attribution.

General statistical explanation: serious adverse events and all adverse events are distinct safety summaries; seriousness is not the same as intensity or treatment relatedness. These numbers describe reported safety events in small groups and do not establish comparative risk or causality.

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

The posted results document adverse effects among participants in three forimtamig-plus-carfilzomib dose arms. The primary participant counts are 7, 6, and 6. Serious adverse-event counts are 5, 3, and 4, with deaths listed as 0, 1, and 1. The record also names selected serious adverse-event terms and gives percentages for them. These are descriptive safety observations for the reported groups and assessment period.

They do not show that forimtamig caused every reported event. The primary endpoint explicitly includes events regardless of causal attribution. The record does not report treatment-relatedness for the events or the deaths. Nor do the posted numbers establish a causal effect of forimtamig dose: there is no reported inferential comparison, no confidence interval or p-value, and no analysis for a two-arm binary outcome. The study's randomized designation alone does not fill in the missing details about how these dose groups were allocated or compared.

The results also do not establish whether forimtamig alone, or combinations with daratumumab, had similar or different safety outcomes. Although those treatment groups appear in the broader study description, the posted primary outcome data relate to three carfilzomib combination arms. The trial's stated aim included preliminary clinical activity, but the material does not provide results for the listed efficacy outcomes.

General statistical explanation: a small group can yield imprecise estimates, and a count that differs between groups can reflect random variation as well as a true difference. Without a formal estimate and its uncertainty, the size and direction of any underlying dose difference cannot be assessed. The terminated status is part of the registry record, but the reason and consequences of termination are not reported. It cannot be used by itself to infer either favorable or unfavorable findings.

The soundest interpretation is therefore narrow: the record reports observed safety counts and selected serious-event terms in these dose arms. It does not support a conclusion about comparative safety, efficacy, treatment causation, or outcomes in treatment groups whose results are not posted.

14. Why This Trial Matters Statistically

This trial illustrates a common statistical challenge in early-phase studies: the design explores doses and combinations while collecting safety information from relatively small groups. A participant count can be useful for describing what occurred, but it provides limited precision for comparisons between doses. In this record, the primary endpoint counts are 7, 6, and 6, while the serious-event counts are 5, 3, and 4. Those summaries deserve careful descriptive reading rather than a ranking of dose safety.

The trial also shows why endpoint definitions matter. An adverse event is defined broadly and does not require a causal link to treatment. A count of participants with any adverse event answers a different question from a count of serious events, an event rate over time, or a count of repeated episodes. Selected serious-event terms add clinical description, but their percentages lack a reported denominator in the record and cannot be treated as directly comparable arm rates.

Statistically, the distinction between a trial's overall design label and a posted analysis is important. The study is described as randomized, yet the registry does not report an estimable two-arm analysis for the binary primary endpoint. With no posted confidence intervals, p-values, or analysis details, the dose-arm counts do not quantify uncertainty about comparative effects. This is particularly consequential when the groups are small and the record includes several intended treatment combinations and outcomes.

The registry's terminated status and limited posted results also highlight the role of completeness in interpreting trial evidence. Without the termination reason, details of follow-up, or results for the broader planned treatment groups, readers cannot reconstruct the full study course. The value of these data is the transparent description of recorded events, not a claim that one treatment strategy is better or safer.

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.

These results cover three Cohort 1 arms pairing forimtamig with carfilzomib, while the study description includes additional dose-exploration and dose-expansion groups involving forimtamig alone and daratumumab. The posted primary outcome counts do not establish safety findings for those other groups. The registry record does not report why the trial was terminated or whether every planned arm and phase was completed.

The outcome groups are small, with listed arm sizes of 7, 6, and 6. The endpoint is a participant count over a period extending from treatment initiation up to approximately 15.7 months, but individual follow-up time is not reported. The registry record does not describe missing safety assessments, endpoint completeness, participant withdrawals, or how any missing information was handled.

No inferential analysis is posted for the primary binary endpoint, and a two-arm comparison is identified as unavailable or not estimable. The record does not provide confidence intervals, p-values, the detailed randomization procedure, or an analysis plan. Although the study is labeled randomized, these details are needed to assess how the listed dose arms can be compared. The record also does not report a sample-size justification, interim-analysis plan, or multiplicity strategy.

The serious-event percentages have no stated denominator in the posted information, and the event terms may overlap. Details on event severity grading, timing, duration, treatment attribution, and the circumstances of deaths are not reported in the registry record. These limitations prevent estimates of comparative risk and limit interpretation to descriptive counts of the events reported for the listed groups.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study Evaluating Safety, Tolerability, and Clinical Activity of Forimtamig-Based Treatment Combinations in Participants With Relapsed or Refractory Multiple Myeloma — NCT06055075.
• Registry record last updated 2026-09-29; status last verified 2026-09.
• Results first posted 2026-09-29.
• 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

NCT06055075 is an open-label, randomized Phase IB/II study of forimtamig-based treatment combinations in relapsed or refractory multiple myeloma. The study is listed as sequential, with dose-exploration and dose-expansion phases. Its status is terminated; the registry record does not report the reason. Listed enrollment is 21, with a start date of 2023-12-08 and primary completion date of 2025-07-08.

The posted primary endpoint is the number of participants with adverse effects, assessed from treatment initiation up to approximately 15.7 months. The three reported Cohort 1 arms combine forimtamig at 0.3 mg, 0.75 mg, or 1.5 mg with carfilzomib. Primary adverse-effect counts are 7, 6, and 6; serious adverse-event counts are 5, 3, and 4; deaths are 0, 1, and 1.

The registry lists zero analyses and does not report an estimable two-arm comparison for the binary endpoint. These results are descriptive safety counts, not an inferential comparison or evidence of treatment causation.