Treatment with pembrolizumab in combination with the oncolytic virus pelareorep promotes anti-tumor immunity in patients with advanced pancreatic adenocarcinoma.
Bibliographic record
Abstract
4144 Background: Pelareorep is an intravenously delivered oncolytic reovirus that can induce a T-cell-inflamed phenotype in pancreatic ductal adenocarcinoma (PDAC). In prior studies, tumor tissue analysis from patients treated with pelareorep shows pelareorep replication, increased T cell infiltration, and upregulation of PD-L1. We hypothesized that pelareorep in combination with pembrolizumab in patients with PDAC would lead to improved responses and anti-tumor immunological changes within peripheral blood and tumor biopsies in responding patients. Methods: PDAC patients who progressed after first-line treatment received pelareorep at a dose of 4.5x1010 TCID50 IV on Days 1, 2, 3 & 8 of Cycle (C) 1, and Days 1 & 8 with C2 onwards. Pembrolizumab was administered on Day 1 of each 21-day cycle at 200 mg IV. The primary objective was overall response rate by RECIST v 1.1 criteria. Secondary objectives included evaluating immunological changes within tumor tissue and peripheral blood, performed by multi-plex immunohistochemistry and spectral flow cytometry (Cytek), respectively. Results: Thirteen patients were enrolled. Disease control was achieved in 33% of the 12 efficacy-evaluable patients. One patient achieved a partial response (PR). Three additional patients achieved stable disease (SD). On-treatment tumor biopsies, collected during C1, showed pelareorep replication, increased infiltration of CD8+ T cells and PD-L1+ cells, and decreased expression of VDAC1, a mitochondrial gatekeeper for tumor promotion, relative to archival tissue. Reduced infiltration of Foxp3+ regulatory T cells (Treg) was observed in patients showing tumor response. Peripheral blood was collected at day 1 of each cycle and on C1 day 8. Relative to pretreatment samples, the number of CD8+ effector memory T cells and B cells tend to increase while the number of Treg cells declined in C2 onwards in patients with tumor response. Furthermore, these patients had increased expression of the mitochondrial protein TOMM20 in CD8+ T cells and decreased expression of PD-1 and the H3K27me3 epigenetic mark in Treg. Treatment was well tolerated with most treatment-related adverse events, including flu-like symptoms, being grade 1 or 2. Conclusions: The combination of pelareorep and pembrolizumab showed a manageable safety profile and modest efficacy in an unselected PDAC population. Additional correlation analyses between treatment efficacy and immunological changes will be presented. The anti-tumor activity of pelareorep and checkpoint blockade therapy is being evaluated further in additional ongoing studies. Clinical trial information: NCT03723915.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".