P962: CHANGE IN SOLUBLE BCMA LEVEL MAY BE A SURROGATE MARKER OF EARLY RESPONSE TO THERAPY IN PATIENTS WITH RELAPSED/REFRACTORY MULTIPLE MYELOMA (RRMM): PRELIMINARY RESULTS FROM A PHASE I STUDY OF CEVOSTAMAB
Bibliographic record
Abstract
Background: Cevostamab is an FcRH5xCD3 bispecific antibody that facilitates T-cell directed killing of myeloma cells, and has shown promising activity and manageable safety in a Phase I study in patients (pts) with RRMM (NCT03275103; Trudel et al. ASH 2021). B-cell maturation antigen (BCMA) is a membrane-bound protein that is expressed preferentially by malignant plasma cells and has become an important therapeutic target in MM. Shedding of membrane-bound BCMA, mediated by γ-secretase, gives rise to the soluble form of BCMA (sBCMA) which is often present at elevated levels in pts with MM. Normalization of sBCMA may be a predictor of response to therapy, which may be independent of treatment and target. Aims: To evaluate sBCMA as a biomarker of early response in pts enrolled in the single step-up dosing cohorts of the cevostamab Phase I study. Methods: Plasma samples were collected at baseline and at Cycle (C) 1 Day (D) 1 (pre-infusion and end of infusion [EOI]), C1D2, C1D4, C1D8 (pre-infusion and EOI), C1D9, C1D11, and C2D1 (pre-infusion and EOI). sBCMA levels were quantified using hybrid immunoaffinity capture with LC-MS/MS. Pts were stratified by refractory status, prior therapy, prior transplant, cytogenetic risk and response (responder [≥PR] or non-responder [
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".