ATIM-21. INTRAVENOUS DELIVERY OF TOCA 511 IN PATIENTS WITH HIGH GRADE GLIOMA RESULTS IN QUANTIFIABLE EXPRESSION OF CYTOSINE DEAMINASE IN TUMOR TISSUE
Bibliographic record
Abstract
Toca 511 (vocimagene amiretroprepvec) is an investigational, conditionally lytic, retroviral replicating vector that encodes an optimized yeast cytosine deaminase (CD) gene. The CD gene converts the prodrug, Toca FC (investigational, extended-release 5-fluorocytosine), into the chemotherapeutic, 5-FU in infected tumors. In a Phase 1 study (NCT01985256), Toca 511 was injected intravenously for 1, 3, or 5 days to patients with recurrent high grade glioma. Tumors were subsequently resected, and Toca 511 was injected into the resection cavity walls. At the time of resection, tissue from various regions of the tumor was collected and processed for quantitative PCR analysis of CD RNA and DNA. Tissue from corresponding locations was fixed for assessment of CD protein expression by immunohistochemistry (IHC). Expression of CD protein was quantified based on immunofluorescence signal and was shown to co-localize in cells with detectable levels of gag, a viral structural protein. CD protein expression by IHC was assessed in tissue from locations that corresponded with samples positive for CD by PCR and ranged from 1.16% to 10.4% area of the field. These data show that intravenous delivery of Toca 511 results in appreciable deposition of vector in the tumor. Further, we have observed an inverse correlation between T cell infiltrate in the tumor microenvironment and clinical benefit in a complementary Phase I study in which Toca 511 was solely delivered into the resection cavity. Therefore, the nature of the study design described herein, which uses IV delivery of Toca 511, provides a unique opportunity to assess the spatial relationship between CD protein expression and histological features of the tumor. Immunohistochemical assessment to determine spatial correlates between CD protein and T cells, T regulatory cells, and immunosuppressive myeloid cells will be presented. Updated clinical response data will also be presented.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".