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Updated: Jul 16, 2026
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Published on: September 20, 2021
Clinical experiment of mutant herpes simplex virus HF10 therapy for cancer
A Nakao1, S Takeda, S Shimoyama
1Department of Surgery II, Nagoya University, Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan. nakaoaki@med.nagoya-u.ac.jp
Abstract:
We reviewed our clinical trial using mutant herpes simplex virus "HF10". We have evaluated the safety and effect of HF10 against recurrent breast cancer since 2003 and also applied HF10 to non-resectable pancreatic cancer since 2005. An oncolytic herpes simplex virus type 1, mutant HF10, has been isolated and evaluated for anti-tumor efficacy in syngeneic immunocompetent mouse models. From long time before clinical trial, we have found that the mutant virus can have remarkable potential to effectively treat cancer in experimental studies using animals, and that all of the surviving mice acquire resistance to rechallenge of the tumor cells. A number of studies have shown that HF10 is effective and safe for use in localized or peritoneally disseminated malignant tumors of non-neuronal origin in animals. Pilot studies using HF10 have been initiated in patients with metastatic breast cancer. For each patient, 0.5 ml HF10 diluents at various doses were injected into test nodule, and 0.5 ml sterile saline was injected into a second nodule. All patients were monitored for local and systemic adverse effects, and the nodules were excised 14 days after viral injection for histopathological studies. All patients tolerated the clinical trial well. While no adverse effects occurred, there was cancer cell death and 30-100% regression histopathologically in recurrent breast cancer. As mentioned above, intratumoral injection of mutant herpes simplex virus HF10 for recurrent metastatic breast cancer was safe and effective. Also a trial for non-resectable pancreatic cancer being carried out on the basis of the above result has proved to be innocuous and has been in progress to assess the clinical benefit and enhance the potentiality of HF10 against cancer.
Insights
Mutant herpes simplex virus HF10 shows promise as an oncolytic virus therapy. Clinical trials indicate HF10 is safe and effective for treating recurrent breast cancer, with ongoing studies for pancreatic cancer.
Area of Science:
- Oncolytic virotherapy
- Cancer research
- Virology
Background:
- Mutant herpes simplex virus type 1 (HF10) has demonstrated anti-tumor efficacy in preclinical animal models.
- HF10 has shown potential for treating various localized and disseminated malignant tumors of non-neuronal origin in animal studies.
- Preclinical findings suggest surviving animals develop resistance to tumor rechallenge.
Purpose of the Study:
- To evaluate the safety and efficacy of intratumoral injection of mutant herpes simplex virus HF10 in patients with recurrent metastatic breast cancer.
- To assess the safety and potential clinical benefit of HF10 in patients with non-resectable pancreatic cancer.
Main Methods:
- Pilot studies involved intratumoral injection of HF10 into tumor nodules in patients with metastatic breast cancer, with saline injections as controls.
- Patients were monitored for local and systemic adverse effects.
- Tumor nodules were excised 14 days post-injection for histopathological analysis to assess cancer cell death and tumor regression.
Main Results:
- Intratumoral HF10 injections were well-tolerated by all patients, with no reported adverse effects.
- Histopathological studies revealed cancer cell death and significant tumor regression (30-100%) in recurrent breast cancer nodules.
- Initial trials for non-resectable pancreatic cancer indicate the treatment is innocuous and ongoing studies aim to assess clinical benefit.
Conclusions:
- Intratumoral administration of mutant herpes simplex virus HF10 is a safe and effective treatment for recurrent metastatic breast cancer.
- HF10 demonstrates significant potential as an oncolytic virotherapy agent for various cancer types, including pancreatic cancer.
- Further clinical evaluation is warranted to fully establish the therapeutic potential and optimize the application of HF10 in cancer treatment.
