Brostallicin (PNU-166196), a new minor groove DNA binder: preclinical and clinical activity

Brostallicin (PNU-166196), a-bromo-acrylamido tetra-pyrrole derivative, showed high cytotoxic potency and myelotoxicity dramatically reduced compared with other minor groove DNA-binding agents. In the presence of high intracellular glutathione concentrations, which are associated with resistance to chemotherapy, brostallicin performs a DNA minor groove attack leading to alkylation of DNA nucleophilic functions. In preclinical models, the antitumor activity of brostallicin has been tested in ovarian cancer xenografts, L1210 murine leukemia models, renal, colon and prostatic cancer cells and glutathione-S-transferase (GST) transfected human breast carcinoma cells. In clinical setting, the antitumor activity of brostallicin has been tested in ovarian cancer and in soft tissue sarcoma patients. A clear therapeutic advantage is also observed in preclinical models when brostallicin is combined with anticancer agents such as cisplatin (CDDP), doxorubicin, irinotecan and docetaxel. Brostallicin was also tested in combination with gefitinib, imatinib and bevacizumab in in vitro and in vivo studies, documenting a synergistic effect and with cetuximab showing an additive effect. Preliminary results of activity and toxicities of brostallicin in Phase I and II studies will be provided.