Ru 41.740 triggers human mononuclear blood cells to release tumor growth inhibitory factors in vitro.

Ru 41.740 (Biostim) is an immunostimulating drug of microbial origin which may stimulate human mononuclear blood cells (mainly monocytes) to release soluble factors which inhibit replication of several tumor cell lines in vitro. Since this effect may be of clinical importance in the treatment of cancer a number of tests have been conducted in order to find methods to augment this secretion. In vitro tests suggested that this non-specific antitumor activity of Biostim may not be enhanced by concomitant treatment of patients with inhibitors of cyclo-oxygenase and lipoxygenases or by interferons alpha, beta, gamma or the hemopoietic growth factors GM-CSF and G-CSF.