Background: Antitumor effects of antibodies against ganglioside antigens of melanoma have been reported, but neither optimal doses nor mechanisms have been established.
Methods: This Phase IB trial of the murine immunoglobulin IgG(3) monoclonal antibody R(24) against disialoganglioside GD3 was conducted with 37 patients to define better the dose-response relation and mechanism of action of R(24) in patients with metastatic melanoma.
Results: Dose-limiting toxicity consisted of a pulmonary capillary leak syndrome in 3 of 5 patients in the 80 mg/M(2)/day dosage tier. Serial blood and tumor biopsy samples were obtained prior to therapy and on Days 5, 9, and 22 following R(24) infusion. Tumor biopsy-infiltrating lymphocytes were enumerated in peritumoral, endotumoral, and perivascular compartments: endotumoral CD4(+) and CD8(+) T cells and HLA-DR(+) T cells increased over time on R(24) antibody. Endotumoral CD4 lymphoid infiltrate activation (DR expression) and antibody-dependent cytotoxicity were the greatest in the one patient who achieved a complete response.
Conclusions: Clinical response was associated with depression in natural killer (CD56(+) and CD56(+)DR(+)) blood cells (P = 0.03) and was associated with R(24) dosage (P = 0.01). A complete response that lasted 2 years and a partial response that lasted 2 months occurred at a dose of 1 mg/M(2)/day. The limited number of clinical responses observed in this trial hampered the correlation of antitumor and immune parameters but provided a rational foundation for the future evaluation of antiganglioside antibodies.
Copyright 2000 American Cancer Society.