Myeloprotective effect of high dose medroxyprogesterone acetate (MPA).

Results of clinical studies in advanced and, recently, also in early breast cancer have shown a clear protective effect of high dose medroxyprogesterone acetate (MPA) on the bone marrow toxicity induced by chemotherapy. The underlying mechanism of this phenomenon is unsettled and in vitro studies have yielded contradictory results. The results of these clinical and in vitro studies are summarized. The myeloprotective effect may have important therapeutical implications.