PARTIALLY MISMATCHED RELATED DONOR TRANSPLANTS AS SALVAGE THERAPY FORPATIENTS WITH REFRACTORY LEUKEMIA WHO RELAPSE POST-BMT

Patients who relapse post-ABMT are usually resistant to conventional t herapy, and a potentially curative therapy with allogeneic BMT is limi ted due to availability of a matched donor. To assess whether such pat ients can be salvaged using partially mismatched related donors (PMRD) , eight patients age 6-50 years old underwent PMRD-BMT. All patients A LL (n = 3) and AML (n = 5) were in relapse 7-31 months after first BMT . Donors (1-3 Ag mismatch) were selected from family members. Conditio ning included TBI, etoposide, Ara-C and cytoxan (n=3), or busulfan, th iotepa, and etoposide (n = 5). GVHD prophylaxis consisted of partial T cell depletion followed by systemic immunosuppression. All evaluable patients established sustained engraftment by day 18. Severe regimen-r elated toxicity was evident in the gastrointestinal and hepatic system s (6/8 and 4/8, respectively), the latter associated with poor outcome (P < 0.014). Acute but not chronic GVHD, grade greater than or equal to II occurred in 3/7 patients. Four of eight patients are disease-fre e, maintaining longer remission than following their first BMT (14 vs 9 months). In conclusion, our data shows that PMRD-BMT is a feasible o ption for patients who relapse post-PMT and use of such alloreactive g rafts may be appropiate earlier in the disease course of high risk pat ients.