Long-Term Survival In Patients With Acute Steroid Refractory Graft-Versus-Host-Disease (SR-GVHD) Treated With Infliximab Combined With Daclizumab
Authors: Soltani Sanaz Nicky , Srinivasan Ramaprasad , Jerussi Theresa , Barrett A. John , Hughes Thomas E , Ramos Catalina , Cook Lisa , Cho Elena , Childs Richard W. 
Published: October 2019

Acute SR-GVHD occurs in approximately 15% of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT), and is associated with a 70-90% long-term mortality rate. We previously reported that concomitant blockade of TNF-α and IL-2 pathways with infliximab combined with daclizumab have a synergistic therapeutic effect, with a high probability of complete resolution of SR-GVHD. Although various treatment modalities are effective in the treatment of SR-GVHD, minimal long-term follow up data exists for complete responders to second line treatments. Here we report long-term outcomes in a cohort of 23 subjects developing SR-GVHD treated with infliximab/daclizumab. A consecutive series of 141 patients with a variety of hematological and non-hematological malignancies as well as nonmalignant hematological disorders including severe aplastic anemia (SAA), paroxysmal nocturnal hemoglobinuria and pure red cells aplasia, underwent a reduced intensity allogeneic HSCT from an HLA identical or single antigen mismatched relative at a single institution between 2/2001 and 12/2008. Transplant conditioning consisted of cyclophosphamide (60 mg/kg days -7, -6) and fludarabine (25 mg/m2days -5 to -1) with or without equine ATG or 6-12 Gy of total body irradiation. GVHD prophylaxis was with cyclosporine with or without additional MMF or MTX. Twenty three patients (median age 35 years, range 13-65 years) developed SR-GVHD at a median of 28 days post transplant. SR-GVHD was defined as absence of response to at least 6 days of high dose methylprednisolone therapy. Following a diagnosis of SR-GVHD, patients received a combination of daclizumab (1mg/kg given on days 1, 4, 8, 15, 22), infliximab (10mg/kg given on days 1, 8, 15, 22), broad spectrum bacterial and anti-fungal prophylaxis, and had their methylprednisolone tapered to 1mg/kg/day. Combined cytokine blockade was highly active against SR-GVHD, with 21/23 (87.5%) patients achieving a complete response (CR), defined as total resolution of GVHD in all involved organ systems. All complete responders survived to hospital discharge. With a median follow-up of 9 years (range 5-10 years), 9/23 (39%) survive, including 6 patients without chronic GVHD whose immunosuppressive therapy (IST) has been discontinued and 3 patients with chronic GVHD (2 limited and 1 extensive) who continue to be tapered off IST. Fourteen of 21 patients with resolution of SR-GVHD died a median 173 days post transplant (range 67-1039 days), including 1 from complications related to recurrent SR-GVHD, 6 from progression of malignancy (all solid tumors), 2 from bleeding related to peptic ulcer disease and 5 from infectious complications including invasive fungal infection and CMV disease. A subgroup analysis showed 5/6 patients with SAA developing SR-GVHD had a complete response to combined infliximab/daclizimab. Remarkably, at a median 6 years follow up, 67% (4/6) of these SAA patients were long-term survivors. All these survivors have maintained normal blood counts and remained transfusion independent with 100% donor chimerism in myeloid and T-cell lineages.

Conclusion
Patients with SR-GVHD treated with infliximab combined with daclizumab had a high probability of achieving a complete response with nearly 40% of patients having long-term survival. This is the first report to show that long-term survival can be achieved in a substantial proportion of patients receiving combined IL-2 and TNF blockade for SR-GVHD.

Disclosures:
Off Label Use: Infliximab is FDA approved for the treatment of psoriasis, Crohn's disease, ankylosing spondylitis, psoriatic arthritis, rheumatoid arthritis and ulcerative colitis. Daclizumab gained FDA approval for use in transplant rejection.