Optimizing suicide gene therapy for head and neck cancer

Area of Science:

• Oncolytic virotherapy
• Gene therapy
• Cancer research

Background:

• Herpes simplex virus thymidine kinase (HSV-tk) suicide gene therapy sensitizes tumors to ganciclovir.
• Previous studies used high viral titers and ganciclovir doses, limiting clinical applicability.
• Optimization is needed to minimize toxicity and enable human trials.

Purpose of the Study:

• To investigate tumor regression in an oral squamous cell carcinoma model using variable adenoviral titers and physiologic ganciclovir dosing.
• To assess the efficacy of HSV-tk suicide gene therapy with optimized parameters.
• To establish a foundation for effective clinical trials.

Main Methods:

• Oral squamous cell carcinoma animal model treated with adenoviral vectors expressing HSV-tk.
• Variable adenoviral titers (1 x 10(8) to 2 x 10(9) pfu) were administered.
• Reduced ganciclovir dosing (10 mg/kg twice daily) was compared to higher established doses (100-150 mg/kg twice daily).

Main Results:

• No statistical difference in tumor regression was observed across different viral doses.
• All treatment groups showed significant tumor regression compared to controls.
• Reduced ganciclovir dosing maintained significant tumor responses and improved mean survival rates.

Conclusions:

• Optimized HSV-tk suicide gene therapy with lower ganciclovir doses is effective in an oral cancer model.
• This strategy minimizes potential toxicities associated with higher doses.
• The findings support the development of clinical trials for HSV-tk suicide gene therapy in oral cancers.