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
3630 - Results of phase 1 clinical trial of high doses of Seleno-L-methionine (SLM) in sequential combination with Axitinib in previously treated and relapsed clear cell renal carcinoma (ccRCC) patients
Presenter: Yousef Zakharia
Session: Poster Display session 3
Resources:
Abstract
2356 - Safety and Efficacy of CDX-014 , an Antibody-Drug Conjugate against T Cell immunoglobulin mucin-1 (TIM-1), in advanced Renal Cell Carcinoma
Presenter: Bradley McGregor
Session: Poster Display session 3
Resources:
Abstract
1028 - SPAZO2 (SOGUG): Outcomes and prognostic significance of IMDC intermediate prognosis subclassification in metastatic renal cell carcinoma (mRCC) in patients treated with 1st-line pazopanib (1stPz).
Presenter: Begona P. Valderrama
Session: Poster Display session 3
Resources:
Abstract
2293 - Effect of Antacid Intake on the Therapeutic Efficacy of Sunitinib (SUN) in Metastatic Renal Cell Carcinoma (mRCC) Patients (pts): a Sub-Analysis of the STAR-TOR Registry
Presenter: Katrin Schlack
Session: Poster Display session 3
Resources:
Abstract
1451 - Randomized phase 3 trial of avelumab + axitinib vs sunitinib as first-line treatment for advanced renal cell carcinoma: JAVELIN Renal 101 Japanese subgroup analysis
Presenter: Motohide Uemura
Session: Poster Display session 3
Resources:
Abstract
4399 - Overall and progression-free survival according to MSKCC scores in 1st line sunitinib treatment of metastatic renal cell carcinoma (mRCC)
Presenter: Jindrich Finek
Session: Poster Display session 3
Resources:
Abstract
1344 - Combination therapy with checkpoint inhibitors for first-line treatment of advanced renal cell carcinoma: A systematic review and meta-analysis of randomized controlled trials
Presenter: Kyaw Thein
Session: Poster Display session 3
Resources:
Abstract
3462 - A phase II trial of TKI induction followed by a randomized comparison between nivolumab or TKI continuation in renal cell carcinoma (NIVOSWITCH)
Presenter: Viktor Grünwald
Session: Poster Display session 3
Resources:
Abstract
5268 - Nivolumab (N) treatment beyond progression in a real-world cohort of patients (pts) with metastatic renal cell carcinoma (mRCC)
Presenter: Sophie Hans
Session: Poster Display session 3
Resources:
Abstract
4235 - First results of safety profile of nivolumab (NIVO) in combination with stereotactic body radiotherapy (SBRT) in II and III line of patients (pts) with metastatic renal cell carcinoma (mRCC) in NIVES Study
Presenter: Cristina Masini
Session: Poster Display session 3
Resources:
Abstract