A Comparison of Dexamethasone Plus Vincristine versus Standard Regimen in Induction Therapy of Adult Acute Lymphoblastic Leukemia Patients Undergoing Hematopoietic Stem Cell Transplantation.

Background: Current treatment options of acute lymphoblastic leukemia(ALL) include chemotherapy alone or hematopoietic stem cell transplantation (HSCT) following induction chemotherapy both along with CNS prophylaxis. The usual and standard induction regimens currently administered could have severe complications and mortality. Materials and Methods: To lessen induction regimen complications in ALL patients who undergo HSCT, we used a cytoreduction induction regimen including dexamethasone (8 mg, IV, three times a day, for 28 days) and vincristine(1.4 mg/m2, IV, on days 1,8,15 and 22) for 49 newly diagnosed adult ALL patients followed by an early sibling donor HSCT within two months. The results were matched with outcomes of HSCT in 172 ALL patients inducted by standard induction regimen. Results: Median follow-up time was 5.41 years in the standard group and 5.27 years in the other. All patients of the case group (100%) achieved complete remission. Landmark analyses were performed to scrutinize the effect of treatments on different time intervals: first two years and 2nd to end years. Type of treatment had no significant effect on the hazard of death in the first landmark (HR=0.87, P=0.64). Cytoreduction regimen amplified the hazard of death 3.43 times more than the standard regimen in the second landmark (HR=3.43 P=0.035). Multivariate analysis showed that the cytoreduction regimen reduced the hazard of relapse about 22%, but not statistically significant (HR=0.78, P-value=0.24). Conclusion: Overall, it seems despite achieving complete remission in induction therapy, depth of response is a critical predictor for long-term outcomes of HSCT in ALL patients, and the use of multiple agents may be necessary to decrease tumor cell burden and minimal residual disease(MRD).