Pb1728: crescendo improvement of survival for adult patients with acute lymphoblastic leukemia during past two decades: a 1000 cases cohort in a single center

Topic: 2. Acute lymphoblastic leukemia - Clinical Background: The outcome of childhood acute lymphoblastic leukemia have been improved dramatically during past six decades, which far beyond counterpart of adolescent and adult ALL. Given that, several multi-centered studies had reported that AYA had better outcome when treated with pediatric-like regimes, one of its feature is more frequent using of asparaginase. However, as for non-AYA (＞40 years) ALL treatment, there are several unresolved questions. Which kind of regime is optimal? And weather high dose asparaginase is efficacy for them? Here, we present real word data in our center about how outcome of ALL patients of all age groups improved stepwise, through two times of treatment changes, especially initiating our PDT-ALL-2016 regime, a pediatric-inspired regime, during past two decades, from a 1023 cases cohor. Aims: To examine historically stepwise improvement of survival by two modified treatments (especially our PDT-ALL-2016 regime, a pediatric-inspired regime) for patients older than 14 years diagnosis with acute lymphoblastic leukemia (ALL) during 2000 to 2021 in our center. Methods: Our center adopted sequential intensified conditioning between 2011 to 2016 for allogeneic hematopoietic stem cell transplantation (HSCT) to compensating the inadequate efficacy of chemotherapy. And introduced PDT-ALL-2016 regime, our pediatric-inspired regime since 2016. A total of 1023 evaluable patients (median age, 26 years, 14 to 73 tears) were retrospectively analyzed. According to changes in treatment option we divided whole series into three dimensions: pre 2011 (time period 1, TP1, N=276), 2011-2016 (time period 2, TP2, N=336) and post 2016 (time period 3, TP3, N=411). And we use the well accepted 40 years as cutoff value to divided patients as adolescence and adult (AYA) group(N=830) and non-AYA group (N=193). Results: 5-year overall survival (OS5years) were 20.8% (TP1) vs 35.3% (TP2) vs 57.8% (TP3), and event free survival (EFS5years) were 20.8% (TP1) vs 28.3% (TP2) vs 45.2% (TP3) for whole series (Fig 1). After adopting PDT-ALL-2016 regime (TP3) the median OS was not reached and EFS was 37.3 months (95% confidence interval [CI], 20.2-50.3 months) which doubled counterpart of other periods. Multivariate analysis show that for whole series patients who received pegylated asparaginase (PEG-ASP) more than 6 doses (median=9 doses, 6-12 doses) have the most excellent survival HR=0.2 (95% CI, 0.11-0.38). When excluded PEG-ASP doses into multivariate analysis, HR for PDT-ALL-2016 regime(HR=0.43, 95% CI, 0.35-0.54) and HSCT (HR=0.41, 95% CI, 0.35-0.49) were close (Table 1). For non-AYA group OS5years were 15.0% vs 20.4% vs 39.9% and EFS5years were 12.0% vs 13.5% vs 33.9% for TP1, TP2 and TP3 respectively (Fig 2). Meanwhile for non-AYA patients who received PDT-ALL-2016 regime treatment, there were no survival deference between with or without HSCT groups. For non-AYA patients, multivariate analysis showed that PDT-ALL-2016 (HR=0.47, 95% CI, 0.32-0.67) had more protective effective than HSCT (HR=0.38, 95% CI, 0.24-0.60) (Table 2). Summary/Conclusion: Survival of patients diagnosed with ALL in our center stepwise improved during past two decades, especially after adopting PDT-ALL-2016. Moreover, data of this large cohort demonstrate that our pediatric-inspired regime is preferred for all ages.Keywords: ALL, Acute lymphoblastic leukemia