A Retroviral Replicating Vector Encoding Cytosine Deaminase and 5-FC Induces Immune Memory in Metastatic Colorectal Cancer Models

Kader Yagiz, Maria E. Rodriguez-Aguirre, Fernando Lopez Espinoza, Tiffany T. Montellano, Daniel Mendoza, Leah A. Mitchell, Carlos E. Ibanez, Noriyuki Kasahara, Harry E. Gruber, Douglas J. Jolly, Joan M. Robbins

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Treatment of tumors with Toca 511, a gamma retroviral replicating vector encoding cytosine deaminase, followed by 5-fluorocytosine (5-FC) kills tumors by local production of 5-fluorouracil (5-FU). In brain tumor models, this treatment induces systemic anti-tumor immune responses and long-term immune-mediated survival. Phase 1 Toca 511 and Toca FC (extended-release 5-FC) clinical trials in patients with recurrent high-grade glioma show durable complete responses and promising survival data compared to historic controls. The work described herein served to expand on our earlier findings in two models of metastatic colorectal carcinoma (mCRC). Intravenous (i.v.) delivery of Toca 511 resulted in substantial tumor-selective uptake of vector into metastatic lesions. Subsequent treatment with 5-FC resulted in tumor shrinkage, improved survival, and immune memory against future rechallenge with the same CT26 CRC cell line. Similar results were seen in a brain metastasis model of mCRC. Of note, 5-FC treatment resulted in a significant decrease in myeloid-derived suppressor cells (MDSCs) in mCRC tumors in both the liver and brain. These results support the development of Toca 511 and Toca FC as a novel immunotherapeutic approach for patients with mCRC. A phase 1 study of i.v. Toca 511 and Toca FC in solid tumors, including mCRC, is currently underway (NCT02576665).

Original languageEnglish (US)
Pages (from-to)14-26
Number of pages13
JournalMolecular Therapy - Oncolytics
Volume8
DOIs
StatePublished - Mar 30 2018

    Fingerprint

Keywords

  • 5-FU
  • chemoimmunotherapy
  • durable response
  • immunotherapy
  • mCRC
  • MDSC
  • retroviral vector

ASJC Scopus subject areas

  • Molecular Medicine
  • Oncology
  • Cancer Research
  • Pharmacology (medical)

Cite this

Yagiz, K., Rodriguez-Aguirre, M. E., Lopez Espinoza, F., Montellano, T. T., Mendoza, D., Mitchell, L. A., Ibanez, C. E., Kasahara, N., Gruber, H. E., Jolly, D. J., & Robbins, J. M. (2018). A Retroviral Replicating Vector Encoding Cytosine Deaminase and 5-FC Induces Immune Memory in Metastatic Colorectal Cancer Models. Molecular Therapy - Oncolytics, 8, 14-26. https://doi.org/10.1016/j.omto.2017.12.001