[Response in patients with melanoma to immunization using melanoma oncolysates of vaccine virus]

Thirty-two patients with high risk melanoma (either primary melanoma of the limbs or trunk, or recurrent melanoma) and clinically disease-free following appropriate surgical treatment were immunized with a vaccinia virus oncolysate made from a pool of 4 human melanoma cell lines. Injections were given id weekly for 3 months, and then bi-monthly for a further 21 months or until relapse. Treated patients have been under study for 11-72 months, and 15 of them for more than 36 months. Twelve patients received a full 24-month treatment: 3 relapsed and 10 are alive (9 of them disease-free) with a survival of 34-72 months. One patient is still under treatment. Nineteen patients relapsed during treatment: among the 13 patients that relapsed early during the course of treatment, 9 patients died after a survival of 5-30 months and 4 are alive with a survival of 30-59 months; among the 6 patients that later relapsed, 2 patients died after a survival of 21 and 29 months and 4 are alive with a survival of 16-69 months. An analysis of the patients' disease-free survival and overall survival was made using the actuarial method, and limited to 5 years: the disease-free survival curve shows a 35% plateau reached after 40 months, and the survival curve shows a 60% plateau reached after 30 months. The patients' responses to the immunization antigens expressed by the oncolysate were studied. Lymphocytes from immunized patients do respond in vitro to the stimulation by oncolysate in the presence of low amounts of IL-2, and this response is greater than that of normal individuals. IgG antibody production to gangliosides with N-glycolyl neuraminic acid is of prognostic significance, the increase in IgG anti-ganglioside antibody in patients after 3 and 6 months of treatment being linked to the absence of relapse in these patients. Finally, preliminary results show, in several patients under treatment, the appearance of antibodies directed against a 31 kD protein of the oncolysate not detectable in the vaccinia virus or in melanoma cell lysates. Such results are in accordance with previously reported ones from similar studies conducted by other investigators and tend to indicate the efficacy of vaccinia virus oncolysate immunization in the treatment of high risk melanoma.