Successful Re-Engraftment after Second Allogeneic Transplantation for Graft Failure in Patients with Refractory Hematologic Malignancies.

Graft failure (GF), either primary or after transient engraftment, following matched, related allogeneic hematopoetic stem cell transplantation (HSCT) without T-cell depletion is usually less than 3% for hematological diseases. Graft failure using non-T-cell depleted unrelated donors in chronic myelogenous leukemia (CML) as reported by the national marrow registry is approximately 9.7%. For aplastic anemia, the incidence of graft failure is estimated to be 10%. In this report, we present 3 patients (Pts) with GF following unrelated ablative allogeneic HSCT (two with peripheral blood stem cells and one with bone marrow). Pt. 1 had transient engraftment and Pts 2 & 3 had primary GF. Their relevant demographics are as follows:

TABLE 1

All patients were initially conditioned with alemtuzumab (A) 30mg/day on days −8 to −6, fludarabine (F) 30mg/m2/day on days −7 to −3, and busulfan .8mg/kg x 16 doses (two patients) or x 8 doses (one patient) on days −5 to −2. Conditioning for HSCT #2 included cyclophosphamide 50mg/kg/day, Mesna 50mg/kg/day, and thymoglobulin 2.5mg/kg/day on days −5 to −2. Graft versus host disease (GVHD) prophylaxis included tacrolimus for both HSCT transplants, and low dose methotrexate (3 doses) combined with prednisone (2mg/kg) on days 0–18 followed by a two week taper for HSCT #2. The stem cell product and engraftment kinetics are shown below.

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Significant toxicities after HSCT#2 have included successful resolution of PTLD in patient #1 (who also experienced infection with pulmonary respiratory syncitial virus, BK viruria, and fatty infiltration of the liver). BK viruria was noted in patient #2, as well as hypertension and a modest pericardial effusion with global hypokinesis (but with a normal ejection fraction). Hepatomegaly was documented, but no vaso-occlusive disease was established. Patient #3 developed a cardiac arrhythmia, hypertension, and BK viruria and remains Plt transfusion dependent. Patient #1 had grade II GVHD of the skin and gut, but patients 2 and 3 had none. GVHD has been <grade II. GF occurred in 3/17 Pts with MUD transplants that included alemtuzamab in the conditioning regimen. While GF is unacceptably high, it is encouraging that all 3 Pts. successfully completed 2^nd MUD transplant with transfusion and cytokine independence using same donor preceded in Pts. 1 & 2 by depletion of anti-ABO incompatible antibodies in the recipient.[table2]