Abstract PR04: Locoregionally administered B7H3-targeting CAR T cells mediate potent antitumor effects in atypical teratoid/rhabdoid tumor
Bibliographic record
Abstract
Abstract Atypical teratoid/rhabdoid tumors (ATRT) are highly malignant embryonal brain tumors, arising in very young children, and are associated with inactivation of SMARCB1. The prognosis is extremely poor. Hence new treatments are urgently needed. We show that 100% of ATRT express B7-H3 and residual SMARCA4 SWI/SNF activity drives B7-H3 expression. Further, we demonstrate that prenatal brain expresses high levels of B7-H3, but expression is absent on pediatric brain, suggesting that the cell of origin may conserve high B7-H3 expression. We recently created a 4-1BB second-generation CAR targeting B7-H3. To date, there are little data on the most efficacious route of administration of CAR T cells in malignant brain tumors. The goal of this study was to test the antitumor activity of the B7-H3 CAR in highly aggressive ATRT xenograft models and compare intracavitary (IT), intraventricular (ICV), and intravenous (IV) administration in terms of efficacy, toxicity, and persistence of CAR T cells. Locoregionally (IT and ICV) administered B7H3.BB.z-CAR T cells mediate potent antitumor effects against cerebral ATRT xenografts, with more rapid kinetics, greater potency, and diminished systemic levels of inflammatory cytokines compared to CAR T cells administered intravenously. ICV-administered CAR T cells also demonstrate robust trafficking from the CNS into the periphery, and following clearance of ATRT xenografts, ICV or IV administered B7H3.BB.z-CAR T cells mediate antigen specific protection from tumor rechallenge in the CNS or in the flank. In summary, B7H3 is a promising immune target for this largely incurable pediatric tumor. We demonstrate that CNS delivered CAR T cells cure ATRT xenografts and efficiently traffic from the CNS into the periphery and can mediate long-term immune protection from disease recurrence in the CNS or in peripheral tissues. This abstract is also being presented as Poster A12. Citation Format: Johanna Theruvath, Elena Sotillo, Claus Moritz Graef, Sabine Heitzeneder, Louai Labanieh, Robbie Majzner, Crystal Mackall. Locoregionally administered B7H3-targeting CAR T cells mediate potent antitumor effects in atypical teratoid/rhabdoid tumor [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr PR04.
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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 | 0.000 | 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".