Seven immunocompetent, revaccinated patients with surgically incurable cutaneous
melanoma underwent treatment of dermal and/or subcutaneous
metastases with twice-weekly intratumoral
injections of escalating doses (10(4)-2 x 10(7) plaque-forming units (PFU)/lesion; 10(4)-8 x 10(7) PFU/session) of a
vaccinia/
GM-CSF recombinant virus for 6 weeks. Patients with stable or responding disease were maintained on treatment until
tumor resolution or progression. Systemic toxicity was infrequent, dose-related, and limited to mild flu-like symptoms that resolved within 24 hours. Local
inflammation, at times with pustule formation, was consistently seen with doses of > or =10(7) PFU/lesion. Chronically treated lesions showed a dense infiltration, with CD4+ and CD8+ lymphocytes, histiocytes, and eosinophils. All seven patients developed an antivaccinia humoral immune response 14-21 days following revaccination. Despite the presence of these antivaccinia
antibodies, the reporter gene was expressed, as judged by the development of anti-
beta-galactosidase antibodies in all patients. Passenger
cytokine gene function was evidenced by the presence of virally encoded
GM-CSF mRNA at injection sites both early (weeks 1 and 5) and late (week 31) in the course of treatment.
Eosinophilia at treatment sites indicated that physiologically significant levels of functional
cytokine were generated. However, there were no changes in the total number of peripheral white blood cells or in the numbers or percentages of polymorphonuclear leukocytes, monocytes, or eosinophils.
GM-CSF was not detected in the sera. The two patients with the largest
tumor burdens failed to respond even at treatment sites. Three patients had mixed responses, with regression of treated and untreated dermal
metastases and progression of disease elsewhere. One patient had a partial response, with regression of injected and uninjected regional dermal
metastases. Residual
melanoma was excised, rendering the patient disease free. One patient with only dermal
metastases confined to the scalp achieved a complete remission. Sequential administration of escalating doses of a
GM-CSF recombinant vaccinia virus is safe, effective at maintaining passenger gene function, and can induce
tumor regression.