Omni Bio Pharmaceutical, Inc. announced the presentation of interim clinical data demonstrating the ability of plasma-derived alpha-1 antitrypsin (AAT) to reduce inflammation and promote healing of damaged tissues in patients with graft-versus-host disease (GvHD), a common and potentially life-threatening complication following bone marrow transplantation. The positive interim results support continued clinical studies of this novel approach to treating GvHD and also highlight the potential value of Omni Bio's novel, recombinant AAT candidate, AAT-Fc, currently in preclinical development. Data from the first seven patients to complete the Phase 1/2 study were presented at the 56th annual meeting of the American Society of Hematology in San Francisco by Omni Bio's academic collaborators from the University of Washington and the Fred Hutchinson Cancer Research Center.

Following allogeneic stem cell transplants to treat leukemic malignancies, the patients in the study all developed severe acute GvHD symptoms (severe diarrhea, loss of mucosal lining in the gut) but did not respond satisfactorily to standard of treatment including high dose steroids. The patients then received intravenous doses of plasma-derived AAT every other day for a total of 8 doses (15 days) in an attempt to alleviate their GvHD symptoms. The investigators concluded that the administration of AAT as a safe salvage therapy for gut GvHD is feasible without clinically relevant toxicity. Stool sampling showed a decrease in intestinal AAT clearance and endoscopic evaluation confirmed healing of the bowel mucosa.

The overall findings suggest that further evaluation of AAT as treatment for steroid refractory GvHD, or as first line therapy, is warranted.