SUCCESSFUL TREATMENT OF STEROID-RESISTANT SEVERE ACUTE GVHD WITH 24-HCONTINUOUS-INFUSION OF FK506

We report our findings in two cases of steroid-resistant severe acute GVHD after allogeneic BMT successfully treated with FK506 (tacrolimus) . An 18-year-old female (patient 1) who underwent BMT from an HLA-iden tical sibling for ALL in first CR, developed generalized erythema and profuse watery diarrhea, which progressed to acute GVHD of grade III s everity, resistant to steroid control. After continuous 24-h administr ation of FK506, the diarrhea improved within 10 days, Patient 2, a 9-y ear-old girl,vith AML who underwent unrelated BMT, had skin, gut and l iver lesions of acute GVHD grade IV, which did not respond to high-dos e steroid therapy, They were controlled, however, by continuous intrav enous infusion of FK506, Both patients are still surviving after more than 1 year without any acute GVHD sequelae or signs of chronic illnes s, The adverse effects of FK506 were mild and tolerable in both cases, Comparison of our findings with those in the literature suggests that it is important to give FK506 at plasma concentrations as high as 25- 35 ng/ml by continuous intravenous infusion for extended periods to co ntrol steroid-resistant severe acute GVHD.