Abstract 5791
Background
There is a great demand for improved oncolytic viruses that selectively replicate inside cancer cells while sparing normal tissues. Here we describe a novel oncolytic adenovirus, Ixovex, that obtains a cancer selective replication phenotype by modulating the level of expression of the different alternatively spliced E1B mRNA isoforms.
Methods
In our work to probe the function of the E1B proteins we generated a virus mutant, the Ixovex virus, in which the SA1 3’ splice acceptor site sequence CAG:GA was mutated to CgG:GA. This single nucleotide point mutation (genomic location 3216) changed aa 399 in the E1B-496R protein from an arginine (AGG) to a glycine (gGG). IxoVex was validated for its viral replication (TCID-50 assay) and cytotoxicity (MTS assay) in a panel of normal and cancer cell lines. Animal studies for anti-tumour efficacy studies were performed in nude mice.
Results
Ixovex is a recombinant adenovirus that carries a single point mutation in the E1B-93R 3’ splice acceptor site that results in an overexpression of the E1B-156R splice isoform. Further, the mutation resulted in a loss of E1B-496R (E1B-55K) protein expression and as a consequence a failure of Ixovex to efficiently degrade the p53 tumour suppressor protein. Ixovex significantly inhibited tumour growth and prolonged survival of mice in an immune-deficient lung carcinoma tumour model. In complementation experiments overexpression of E1B-156R was shown to increase the oncolytic index of both Ad5wt and ONYX-015. In contrast to prior art viruses of similar type, Ixovex includes a functional E3B region for better in vivo efficacy. Ixovex virus, throughout this study has been proven to be by far the superior virus in potency compared to ONYX-015.
Conclusions
The decrease in toxicity and the inhibition of replication in normal cells indicate an astounding safety profile of Ixovex. The observation that the ONYX-015 virus replicated better in normal cells compared to Ixovex is intriguing considering that the ONYX-015 virus carries a large deletion that removes the coding sequences and splice signals needed to express the E1B-496R, E1B-93R and E1B-156R proteins. Ixovex significantly inhibit tumour growth in a human lung carcinoma animal model and that ONYX-015 does not.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
IxoGen.
Disclosure
M. Anwar: Shareholder / Stockholder / Stock options: IxoGen. G. Alusi: Shareholder / Stockholder / Stock options: IxoGen. D. Oberg: Shareholder / Stockholder / Stock options: IxoGen.
Resources from the same session
5650 - Tissue-based activation of mucosal-associated invariant T (MAIT) cells in combination ipilimumab and nivolumab checkpoint inhibitor (CI) colitis.
Presenter: Sarah Sasson
Session: Poster Display session 3
Resources:
Abstract
5944 - Significance of severe immune-related adverse effects (irAE) on patients with advanced tumors treated with immune checkpoint inhibitors being admitted for secondary toxicity: Clinical relevance and next steps
Presenter: Leyre Zubiri
Session: Poster Display session 3
Resources:
Abstract
5989 - Implementation of a dedicated immuno-oncology toxicity service reduces the acute impact of immune-related adverse events
Presenter: Anna Olsson-Brown
Session: Poster Display session 3
Resources:
Abstract
3267 - Cardiotoxic and pro-inflammatory effects induced by the association of immune checkpoint inhibitor Pembrolizumab and Trastuzumab in preclinical models
Presenter: Nicola Maurea
Session: Poster Display session 3
Resources:
Abstract
3417 - Interstitial lung disease associated with immune-checkpoint inhibitors in malignant diseases
Presenter: Akira Yamagata
Session: Poster Display session 3
Resources:
Abstract
2071 - A Phase 1 Study of Intraperitoneal MCY-M11 Anti-Mesothelin CAR for Women with Platinum Resistant High Grade Serous Adenocarcinoma of the Ovary, Primary Peritoneum, or Fallopian Tube, or Subjects with Peritoneal Mesothelioma with Recurrence after Prior Chemotherapy
Presenter: Christina Annunziata
Session: Poster Display session 3
Resources:
Abstract
4935 - Trial in progress: First-in-human study of a novel anti-NY-ESO-1–anti-CD3, TCR-based bispecific (IMCnyeso) as monotherapy in NY-ESO-1/LAGE-1A-positive advanced solid tumors (IMCnyeso-101)
Presenter: Juanita Lopez
Session: Poster Display session 3
Resources:
Abstract
5613 - Nimotuzumab-Cisplatin-Radiation versus Cisplatin-Radiation in HPV negative oropharyngeal cancer
Presenter: Kumar Prabhash
Session: Poster Display session 3
Resources:
Abstract
2576 - Interim analysis of a single arm phase 2 study of adjuvant nivolumab after salvage resection in head and neck squamous cell carcinoma patients previously treated with definitive therapy.
Presenter: Trisha Wise-draper
Session: Poster Display session 3
Resources:
Abstract
4758 - A Phase I Study of the CDK4/6 Inhibitor, Palbociclib in combination with Cetuximab and Intensity Modulated Radiation Therapy (IMRT) for Locally Advanced Squamous Cell Carcinoma of the Head and Neck (SCCHN); A Result of Dose Escalation Cohort
Presenter: Nuttapong Ngamphaiboon
Session: Poster Display session 3
Resources:
Abstract