Drug-HPMA-HuIg conjugates effective against human solid cancer.

N-(2-hydroxypropyl)methacrylamide copolymer (PHPMA)-bound doxorubicin conjugated with human Ig as a targeting moiety was used for the first time in the setting of metastatic breast cancer (patients E. G., J. K., K. R. and K.H.) and angiosarcoma (patient D. H) resistant to conventional cytotoxic chemotherapy. It was confirmed that Dox-PHPMA-Hulg conjugate is stable and doxorubicin remains in the peripheral blood mostly in its polymer-bound form. In patients E. G., J. K., K.R. and K.H. more than 116 biochemical and immunological parameters were tested in blood samples taken from the patients 24 h, 48 h, 72 h, 7 d, 14 d and 21, 28 and eight weeks after the treatment. In the patient E. G., 15 parameters had pathological values before the treatment. During the treatment, seven parameters dropped permanently or temporarily to a normal level and seven moved markedly towards the physiological value. While the number of peripheral blood reticulocytes was significantly decreased after the treatment with free doxorubicin, their number was stable or elevated after the treatment with Dox-PHPMA-Hulg conjugate. Increased absolute number of CD16+56+ and CD4+ cells in the peripheral blood and activation of NK and LAX cells in a human patients support the data previously obtained in experimental animals pointing to a dual role, i.e. the cytotoxic and immunomobilizing character of doxorubicin-PHPMA conjugates containing a targeting immunoglobulin moiety.