Clinical Results With Zeneca's ICI 182780

Zeneca Pharmaceuticals' ICI 182780 appears to be a promising new agent for the treatment of advanced and early breast cancer and is effective in tumors which are resistant to treatment with the company's Nolvadex (tamoxifen) product, according to the results of a 19-patient clinical trial published in The Lancet (January 7).

ICI 182780 is a steroidal specific anti-estrogen compound which has certain properties which may make it an attractive alternative to tamoxifen. "Although an antagonist with respect to the cancer, tamoxifen is an estrogenic agonist with respect to the bone, liver and endometrium," note the authors of the study. "One cause of resistance may be the cancer reacting to tamoxifen as an agonist or that tamoxifen is, in some way, rendered unavailable to estrogen receptors so that endogenous estradiol is able to restimulate cancer growth," they add. ICI 182780 has not been shown to have any agonist activity in animal studies.

A total of 19 patients were enrolled into the study, all of whom had advanced breast cancer which was resistant to tamoxifen treatment. After treatment with monthly intramuscular injections of ICI 182780 (100mg-250mg depot) for a mean duration of 18 months, 13 (69%) of the patients showed a response (7 partial responses and 6 non-progressors). No serious drug-related adverse events occurred, although minor events were reported in two patients; transient blood-stained vaginal discharge in one and an alteration in body odor, possibly associated with increased hair greasiness, in another.