Background: An oncolytic herpes simplex virus type 1 mutant (HF10) has been isolated and evaluated for antitumor efficacy in a syngeneic immunocompetent mouse model, where it was effective against cancer and conferred resistance to rechallenge with tumor cells in all surviving mice. Several studies have shown that HF10 is effective and safe for use against localized or peritoneally disseminated nonneuronal malignant tumors in animals.
Methods: A pilot study using HF10 was initiated in six patients with cutaneous or subcutaneous metastases from breast cancer. For each patient, .5 mL of HF10 suspension containing various viral doses was injected into one nodule; .5 mL of sterile saline was injected into another. All patients were monitored for local and systemic adverse effects. Nodules were excised 14 days after injection for histopathologic studies.
Results: All patients tolerated the intratumoral injection of HF10. No adverse effects occurred, and histopathological evaluation revealed 30% to 100% cancer cell death.
Conclusions: This pilot study found HF10 to be safe and effective against metastatic breast cancer.