A cold sore virus has been used to treat head and neck cancer patients.
The phase I/II clinical trial run by The Institute of Cancer Research (ICR) and The Royal Marsden NHS Foundation Trust used the genetically engineered herpes simplex virus, known as Oncovex and owned by Biovex Inc. The virus was modified so it multiplies inside cancer cells, but not healthy cells. It bursts and kills tumour cells and, by expressing a human protein, it also helps stimulate patients’ immune systems.
The trial included 17 patients who had the virus injected into cancer-affected lymph nodes in up to four doses. They were also given radiotherapy and chemotherapy.
Head and neck tumour shrinkage could be seen on scans for 14 patients (82.3%), while 93% of patients had no trace of residual cancer in their lymph nodes during subsequent surgery to remove them. After an average follow-up time of 29 months (19 to 40 months), 82.4% of patients had not succumbed to the disease. Only two of 13 patients given the virus treatment at a high dose relapsed.
‘Around 35 to 55% of patients given the standard chemotherapy and radiotherapy treatment typically relapse within two years, so these results compare very favourably,’ principal investigator Dr Kevin Harrington from the ICR and The Royal Marsden said. ‘This was a small study so the results should be interpreted with caution; however the very high rates of tumour response have led to the decision to take this drug into a large scale phase III trial. This will be the first ever phase III trial combining virus therapy with curative chemoradiation.’
Dr Kevin Harrington, principal investigator from the ICR and The Royal Marsden
Side-effects were generally mild to moderate, and most – except fever and fatigue – were thought to be due to the chemotherapy or radiotherapy. Oncovex has previously shown promising results when administered on its own in early stage trials of patients with other cancer types, including a phase II trial of metastaic melanoma patients.
‘This trial showed for the first time that these oncolytic viruses can be safely used in combination with other cancer treatments given with the intention of curing patients,’ Dr Harrington said.
As around 650,000 people are diagnosed with squamous cell cancer of the head and neck each year worldwide, and around 350,000 die from the disease annually, the results of this trial seem promising.