TAT-10: Novel IgG t Melanin Show Promise for Radioimmunotherapy of Metastatic Melanoma

Kanazawa, Japan (UroToday.com) Previous studies of treating metastatic melanoma using a murine antibody to melanin labeled with the beta-emitting isotope Re188  established safety and efficacy. However, that antibody (genotype IgM) presented obstacles to humanization. We recently identified an 8C3 murine antibody (genotype IgG) that is amenable to humanization. The purpose of the present study is evaluate 8C3 radio-labeled with Re188 and also the alpha-emitting isotope Bi213.

Female C57B16 were injected with highly aggressive B16-F10 murine melanoma cells which formed metastatic lesions in the lung. On day 4 after the injection, groups of 5-7 mice were injected with either Re188 – 8C3 (400 microCuries), Bi213-8C3 (400 microCuries), bare 8C3, or left untreated. On day 14 after the initial injection of malignant cells, the mice were sacrificed and lungs removed for lesion counts.

Both the Re188 and Bi213 samples showed significant reduction in tumor count compared to the untreated control sample. As expected, the bare 8C3 sample showed no effect. No undesirable side effects were observed.

We conclude that radioimmunotherapy with both Re188-8C3 and Bi213-8C3 show promise for treatment of human metastatic melanoma.

Presented By: Ekaterina Dadachova from University of Saskatchewan, SK, Canada

Written By: William Carithers, Lawrence Berkeley National Laboratory

at the 10th International Symposium on Targeted Alpha Therapy (TAT-10)  May 31 - June 1, 2017 - Kanazawa, Japan.