Sirolimus Yields High Response Rates in Hematopoietic Allograft Recipients with Steroid-Refractory Acute Graft-Versus-Host Disease.

Abstract 2235

Poster Board II-212

Acute graft-versus-host disease (aGVHD) remains the major cause of morbidity and mortality in allogeneic hematopoietic cell transplant recipients. There is no consensus in regards to the best therapy for patients who fail to respond to, or do not tolerate, systemic glucocorticoids. We evaluate the efficacy of sirolimus in 34 pts, median age of 49 (23-67) years, with steroid-refractory (N=31) or steroid-intolerant (N=3) aGVHD. The diagnosis of aGVHD was established at a median of 34 (7-1042) days after transplantation, and confirmed by biopsy in all cases. Initial treatment of aGVHD consisted of prednisone up to 2 mg/kg. Sirolimus was initiated at a median of 9 (1-255) days after glucocorticoid initiation. A loading dose of sirolimus was administered to 19 (56%) of 34 pts, median 6 (3-8) mg, followed by maintenance therapy of 1-2 mg per day with doses adjusted to target therapeutic trough levels between 4 and 12 ng/ml; therapeutic levels were achieved in all cases. The overall response rate was 76%. Fifteen (44%) of the 34 pts achieved a CR after sirolimus initiation and without requiring additional immune suppressive agents. CR was achieved in 11/31 (42%) steroid-refractory patients, and in 2/3 (67%) steroid-intolerant patients. The median overall survival (OS) after initiation of sirolimus was 5.6 months, and one year OS was 44% (95% C.I. 27%-60%). Maximum decrease in dose of steroids over 12 weeks following sirolimus was a median of 50% (range 0-100%). Fourteen (42%) of 33 pts reached a dose < 20 mg of prednisone at a median of 4 months (95% CI: 3.5-13.5) after initiation of sirolimus. Seven (21%) of 34 pts were free from steroids after a median of 20 months (95% CI: 9.2-20.0) after initiation of sirolimus. Two pts were shown to be successfully liberated from all immunosuppressive agents without recurrent GVHD at 2.7 and 7.1 months after initiation of sirolimus, respectively.

These data indicate the sirolimus is effective in controlling steroid-refractory aGVHD. Further studies are needed to determine the most appropriate timing for sirolimus after transplantation, whether prophylaxis, primary or secondary GVHD therapy.