Preliminary evaluation of platinum transferrin (MPTC-63) as a potential nontoxic treatment for breast cancer.

Transferrin receptors on proliferating and malignant cells are well documented. Faulk et al. demonstrated transferrin receptors in breast carcinoma by immunofluorescence. Malignant cells requiring more iron modulate a transferrin receptor and the iron transporting protein transferrin delivers iron to the cell. We have developed a physiologically active platinum transferrin complex that has been tested on several cell lines in culture, a tumor model in the Fischer rat, and five human patients with advanced breast carcinoma. The complex slowed the rate of growth of feline lymphoma cells to one-half that of controls and killed human HeLa cell cultures in 7 days. Growth of the rat tumor was slightly impaired, but treated rats never got systemic disease and controls died. Two patients had dramatic responses to treatment. One had systemic disease and the other advanced locoregional disease. Both patients were on Tamoxifen, as receptors were positive for estrogen. Disease was progressing in the former with little improvement in the latter. After treatment both had a marked response. We postulate that MPTC-63 may work synergistically with Tamoxifen and be an effective nontoxic antitumor agent. More studies are indicated.