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
3524 - Cabazitaxel For Octogenarian Patients With Metastatic Castration-Resistant Prostate Cancer (MCRPC).
Presenter: Paolo Tralongo
Session: Poster Display session 3
Resources:
Abstract
5637 - External Validation of a Prognostic Score in First-Line Metastastic Castration-Resistant Prostate Cancer (mCRPC)
Presenter: David Lorente
Session: Poster Display session 3
Resources:
Abstract
3228 - Treatment outcomes of 3rd treatment in a real-world metastatic castration resistant prostate cancer (mCRPC) population: results from the Dutch CAPRI-registry
Presenter: Jessica Notohardjo
Session: Poster Display session 3
Resources:
Abstract
4695 - Pelvic lymph node dissection and its extent on survival benefit in prostate cancer patients with a risk of lymph node invasion>5%: a propensity score matching analysis from SEER database
Presenter: Junru Chen
Session: Poster Display session 3
Resources:
Abstract
4438 - Multi-institutional evaluation of therapeutic management for oligometastatic cancer prostate recurrence with choline-PET/CT
Presenter: Morgane Guibert-broudic
Session: Poster Display session 3
Resources:
Abstract
4574 - Safety of new androgen receptor inhibitors (ARi) in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC): a network meta-analysis of randomized controlled trials (RCT)
Presenter: Amelia Altavilla
Session: Poster Display session 3
Resources:
Abstract
3816 - Real-world use of radium-223 for treatment of metastatic castration resistant-prostate cancer (mCRPC): results from the Dutch CAPRI registry
Presenter: Malou Kuppen
Session: Poster Display session 3
Resources:
Abstract
5180 - A phase 2a study of radium-223 dichloride (Ra-223) alone or in combination with abiraterone acetate or enzalutamide in metastatic castration-resistant prostate cancer (mCRPC)
Presenter: Daniel Petrylak
Session: Poster Display session 3
Resources:
Abstract
1067 - Adding ADT to PSMA-PET/CT-guided SBRT for oligometastatic prostate cancer improves distant progression-free survival
Presenter: Carole Mercier
Session: Poster Display session 3
Resources:
Abstract
5529 - Safety and efficacy of Ac-225-PSMA-617 in metastatic castration resistant prostate cancer (mCRPC) after failure of Lu-177-PSMA
Presenter: Robert Tauber
Session: Poster Display session 3
Resources:
Abstract