Studies by researchers at Introgen Therapeutics, Inc. and their collaborators at The University of Texas M. D. Anderson Cancer Center show that the combination of Introgen's INGN 241 and Tarceva (erlotinib HCl) significantly inhibits tumour cell growth compared with either agent alone.
The preclinical data suggest that the two agents work in concert to inhibit activity of the epidermal growth factor receptor (EGFR), a potent driver for cell growth in many types of cancer. The results were presented at the American Society of Gene Therapy 2006 Annual Meeting (ASGT), held May 31-June 4.
INGN 241 is a targeted molecular therapy currently being evaluated in a Phase 2 trial in patients with metastatic melanoma and a phase 3 trial for solid tumours in combination with radiation. Tarceva, marketed by Genentech, is a small molecule drug approved for the treatment of non-small cell lung cancer and pancreatic cancer.
"Although several EGFR inhibitors have been approved for use in a variety of cancers, their use as monotherapy has limited impact on clinical response and patient outcome," said Sunil Chada, Ph.D., Introgen's associate vice president, Clinical Research and Development. "This study demonstrates that the combination of an EGFR inhibitor with INGN 241 resulted in greater inhibition of EGFR activity and significantly increased inhibition of tumour cell growth. These results suggest that this combination could improve the efficacy of EGFR inhibitors, and provides additional evidence of the very broad utility of INGN 241 in a variety of settings and in combination with a growing number of anti-cancer agents."
The preclinical studies evaluated the effects of INGN 241 or Tarceva alone and both agents together on human lung and prostate tumour cells. The results show that the combination of INGN 241 and Tarceva produced greater growth inhibition of both cell types compared with Tarceva. Molecular analysis revealed that inhibition of EGFR activation was greatest in cells treated with INGN 241 in combination with Tarceva, and identified the molecular pathways that regulate this inhibition. The data support additional evaluation of INGN 241 in combination with Tarceva and, potentially, other EGFR inhibitors.
Additional INGN 241 data to be presented at the meeting describes the results of preclinical studies designed to elucidate the mechanism by which INGN 241 kills breast cancer cells. Results show that MDA-7/interleukin 24 (IL-24) protein (the active component of INGN 241) induces tumour cell death by binding to a receptor complex comprising type 1 and type 2 IL-20 receptors. The researchers identified a novel receptor-mediated death pathway in breast cancer cells specifically targeted by MDA-7. Additionally, the cell-killing activity is selective for cancer cells and can be inhibited by IL-10. These findings enhance the understanding and application of INGN 241 in the treatment of cancer.
In a Phase 1 trial of INGN 241 clinical activity was observed in patients with advanced melanoma. Based on the encouraging findings of INGN 241 treatment in the Phase 1 clinical trial, later stage trials have been initiated. A Phase 2 trial in patients with metastatic melanoma and a phase 3 trial for solid tumours in combination with radiation therapy are ongoing. The mda-7 gene was discovered by the laboratory of Dr. Paul B. Fisher, professor of clinical pathology at Columbia University. Introgen holds an exclusive worldwide license for all gene therapy applications from the Corixa Corporation.