Efficacy of SCRI-CAR19x22 T cell product in B-ALL and persistence of anti-CD22 activity.
Bibliographic record
Abstract
3035 Background: Loss of CD19 expression is a major cause of limited durable B-ALL remission following CD19 CAR T cells, which might be overcome by utilization of dual CD19xCD22 CAR T cell targeting. Methods: A Phase I trial (NCT03330691) of SCRI-CAR19x22 was developed using dual transduction of lentiviral vectors encoding for either a CD19- or CD22-specific CAR T cell construct, both with 4-1BB co-stimulation. Manufacturing was performed in a closed G-Rex system with IL-7, IL-15 and IL-21. After lymphodepletion, CAR T cells were infused at 1 or 3 X 106 CAR T cells/kg dose levels. Leukemic response and CAR T cell persistence were evaluated by flow cytometry. Results: Products were successfully manufactured in all 28 enrolled subjects with 7.92 average days in culture (range of 7-11 days) and consisted of an average CD8:CD4 ratio of 3.09 (range 0.19 to 8.9). The cellular product CAR composition was 29% CD19, 31% CD22 and 39% CD19 and CD22 targeting. 13 subjects had prior exposure to CD19 or CD22 targeting therapies with diverse expression of CD19 and CD22 on the leukemic blasts. No dose limiting toxicities occurred in the 27 infused subjects. The recommended phase 2 dose is 3 x 106 CAR+ cells/kg. CRS was present in 80% of subjects, with 85% of CRS being grade 2 or less, and a peak grade of 3 (n = 3). Mild neurotoxicity occurred in 38%, with a single grade 3 event. 84.6% obtained a CR, of which 95% were MRD negative. Of the 4 subjects who did not achieved a CR, 2 had a pre-existing CD19 negative population and one had previously received CAR T cells and rejected SCRI-CAR19x22. There have been 4 relapses with varying CD19 and CD22 expression as follows: 1 CD19-CD22-, 1 CD19+CD22+, and 2 CD19-CD22+. The in vivo engraftment of CAR T cells peaked most frequently between day +7 and +14 and was predominated by the CD19 CAR+ T cells. Conclusions: We demonstrate manufacturing feasibility and safety of SCRI-CAR19x22. While initial efficacy is demonstrated, CD22 activity is poor due to limited expansion of the CD22 CAR-containing components and subjects with pre-existing CD19 negative leukemia fared poorly. Development of a revised CD22 CAR that exhibits a reduction tonic signaling is underway, with plans to explore the new construct in the context of a dual-targeting CD19xCD22 CAR T cell product. Clinical trial information: NCT03330691 .
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Not applicable | medium |
| gpt | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Other design | medium |
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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, unvalidatedLabeled directly by 2 models reading the full record.
The models disagree on parts of this classification; every voice is preserved in the section at the end of the page.
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".