ADDITIONAL MYELOABLATION WITH FE-52 BEFORE BONE-MARROW TRANSPLANTATION

For many hematological malignancies, high-dose chemoradiotherapy follo wed by bone marrow transplantation offers the best and sometimes the o nly chance for cure, However, the main causes of failure of this thera py are relapse and toxicity, In order to selectively deliver higher do ses of radiotherapy to the bone marrow and to spare normal organs, we explored Fe-52 therapy before a conventional BMT conditioning regimen, Twenty-four patients at high risk for relapse after BMT were included in a phase II study, The median follow-up was 42 months, The median F e-52 dose was 59 mCi, This resulted in a median radiation-absorbed dos e (RAD) to the BM of 626 rad, The median RAD to the liver was 338 rad, No untoward effects were noted after the injections of Fe-52, The pat ients recovered hematopoiesis without toxicity in excess of that expec ted with conventional conditioning alone, The 3-year DFS probability w as 49% (95% CI: 20-78%), Eight patients have relapsed, three of them i n extramedullary sites, Fe-52 should provide a way to boost the radiat ion dose to marrow-based diseases before bone marrow transplantation w ithout excessive toxicity.