A preliminary trial of vaccinia oncolysates in the treatment of recurrent melanoma with serologic responses to the treatment.

A preliminary trial was designed as a toxicity/feasibility study using a fixed dose of vaccinia melanoma oncolysates (VMO) to treat recurrent stage II and stage III (skin, subcutaneous, and nodal metastases only) melanoma. There were no adverse consequences of the therapy, and 4 of the 12 patients treated seemed to have responded to the treatment by the criteria of the study. Sera from the six patients with the longest survival showed immunoreactivity to human melanoma lines in a Staphylococcus protein A assay (SpA) after 3 months of therapy. While the specificity of this immunoreactivity remains to be determined, the discovery of posttreatment serologic activity in a SpA assay permits investigation of the degree of VMO immunostimulation at different dose levels of the biologic. This assay may provide the means to quantitate optimal biologic dose for future melanoma oncolysate trials. The Southeastern Cancer Study Group is now conducting a phase I/II trial with these vaccinia melanoma oncolysates using the SpA assay to monitor this trial.