[Allogeneic hematopoietic stem cell transplantation for treatment of Philadelphia chromosome positive acute lymphoblastic leukemia].

OBJECTIVE

To explore the optimal time of allogeneic hematopoietic stem cell transplantation (allo-HSCT) applied in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), and the optimum order of donor selection.

METHODS

From Mar 2000 to Jul 2004, 32 patients with Ph+ ALL were treated by Allo-HSCT, and the follow up ended at Dec 30.2004 with medium of 13 months. Of whom, 24 were male, and 8 were female. Twenty-three patients have been transplanted in CR1, 9 patients beyond CR1 (1 in CR2, 8 in refractory or relapse status). Twelve cases received HSCT from identical sibling donor, 4 unrelated Cord Blood Transplantation (CBT), 3 HSCT from matched unrelated donor (MUD), and 13 HSCT from mismatched related donor (MMRD), of which, 6 cases were M(BCR/ABL) subtype, and 20 m(BCR/ABL) subtype. The Kaplan-Meier method was used to estimate the probabilities of leukemia-free survival (LFS), overall survival (OS) and relapse incidence (RI), and the factors were compared by means of the Log-rank test. Simultaneous effect of multiple covariates were estimated with Cox model.

RESULTS

Of all the 32 cases engrafted, 4-year OS was 57.19%, LFS 37.09%, and RI 56.36%. In univariate prognostic analysis model, the OS was higher in CR1 group pre-HSCT than that in non-CR1 group (74.50% vs 22.22%, P=0.0046), LFS was higher (49.06% vs 11.11%, P=0.0057), RI was lower (44.80% vs 84.76%, P=0.0157); the OS was higher in M(BCR/ABL) group than that in m(BCR/ABL) group (100% vs 40.91%, P=0.0318), LFS was higher (75% vs 17.72%, P=0.0057), RI was lower (25% vs 77.88, P=0.0116); OS was similar in HLA MM RD group to that in HLA identical group (52.65% vs 55.56%, P=0.6247), LFS was similar (45.12% vs 30.00%, P=0.8315), and RI was also similar (50.77% vs 60.62%, P=0.8217). In multiple covariate analysis model, the BCR/ABL type was the risk factor of LFS [P=0.005, Exp(B)=9.971] and RI (P=0.006, Exp(B)=9.488), the status of disease pre-HSCT and BCR/ABL subtype was the risk factor of OS [P was 0.010 and 0.038, Exp(B) was 4.532 and 37.537 respectively].

CONCLUSION

We had better do HSCT in CR1 to treat Ph+ ALL, if patient is refractory to chemotherapy, we can try STI571, and HSCT should be done as soon as possible if the patients get CR. Mismatched related donor is considered as regular donor for Ph+ ALL patients without identical donors. We should pay more attention to monitoring and prophylaxis of relapse in m(BCR/ABL) patients after HSCT.