A preliminary study published as a research letter in this week's issue of THE LANCET suggests that the herpes virus could contribute to the treatment of malignant melanoma, the most serious form of skin cancer.

Previous laboratory research has shown that a mutant herpes simplex virus (HSV1716) has improved the survival times of animals with tumours. In humans, the virus replicates preferentially in melanoma cell tissue, causing cell death. To assess the therapeutic potential of HSV1716 in human disease, Professor Rona MacKie and colleagues from the University of Glasgow, UK, did a study of toxicity and possible efficacy in five patients with metastatic melanoma (skin cancer that had spread to other parts of the body).

All five patients had advanced metastatic melanoma, and had soft-tissue nodules that were accessible to direct intratumoral injection. For each patient, a test nodule was injected with HSV1716, and a second nodule was injected with 1 mL sterile saline as a control. The first two patients had the injected nodules removed 14 days after injection for examination; patients 3, 4, and 5, had a second injection of HSV1716 on day 14 and the nodule removed on day 21; the fifth patient had a second set of two injections of HSV 2 weeks apart injected into a different nodule 8 weeks after the first series of injections (four injections in total).

Examination of the removed nodules showed dead melanoma cells in three of the virus-injected removed nodules from the three patients who had two injections on days 1 and 14 and removal on day 21. The nodule from patient 5 showed the most striking tumour cell death.

Professor MacKie comments: "This pilot study shows that HSV1716 replicates in melanoma cells, causes tumour-cell death if in direct contact with the melanoma cells, and is not toxic. The results are sufficiently encouraging to continue with higher doses of HSV1716 in patients with metastatic melanoma".

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Contact: Professor Rona MacKie, Department of Dermatology, University of Glasgow, G12 8QQ, UK; T) +44 (0)141 330 4018; F) +44 (0)141 330 4008; E) R.M.MacKie@clinmed.gla.ac.uk

First published: 16 February 2001