Background. The outcome in older patients with acute lymphoblastic leukemia (ALL) remains unsatisfactory due to high relapse and nonrelapse mortality (NRM) rates. Allogeneic stem cell... Show moreBackground. The outcome in older patients with acute lymphoblastic leukemia (ALL) remains unsatisfactory due to high relapse and nonrelapse mortality (NRM) rates. Allogeneic stem cell transplantation (alloHSCT) as postremission therapy has an important role in reducing relapse rate, albeit its application is limited in older adult patients due to alloHSCT-related morbidity and mortality. Reduced-intensity conditioning (RIC) alloHSCT has been developed as a less toxic conditioning regimen, but comparative studies with myeloablative conditioning (MAC) are limited in patients with ALL.Methods. In this retrospective study, RIC-alloHSCT (n = 111) was compared with MAC-alloHSCT (n = 77) in patients aged 41 to 65 y with ALL in first complete remission. MAC was predominantly applied by combining high-dose total body irradiation and cyclophosphamide, whereas RIC mainly consisted of fludarabine and 2 Gy total body irradiation.Results. Unadjusted overall survival was 54% (95% confidence interval [CI], 42%-65%) at 5 y in MAC recipients compared with 39% (95% CI, 29%-49%) in RIC recipients. Overall survival and relapse-free survival were not significantly associated with type of conditioning after adjusted for the covariates age, leukemia risk status at diagnosis, donor type, and donor and recipient gender combination. NRM was significantly lower after RIC (subdistribution hazard ratio: 0.41, 95% CI, 0.22-0.78; P = 0.006), whereas relapse was significantly higher (subdistribution hazard ratio: 3.04, 95% CI, 1.71-5.40; P < 0.001).Conclusions. Collectively, RIC-alloHSCT has resulted in less NRM, but it was also found to be associated with a significantly higher relapse rate. These results suggest that MAC-alloHSCT may provide a more effective type of consolidation therapy for the reduction of relapse and that RIC-alloHSCT may be restricted to patients at higher risk for NRM. Show less
Rijneveld, A.W.; Holt, B. van der; Weerdt, O. de; Biemond, B.J.; Loosdrecht, A.A. van de; Wagen, L.E. van der; ... ; Dutch-Belgian HOVON Cooperative Gr 2022
Clofarabine (CLO) is a nucleoside analog with efficacy in relapsed/refractory acute lymphoblastic leukemia (ALL). This randomized phase 3 study aimed to evaluate whether CLO added to induction and... Show moreClofarabine (CLO) is a nucleoside analog with efficacy in relapsed/refractory acute lymphoblastic leukemia (ALL). This randomized phase 3 study aimed to evaluate whether CLO added to induction and whether consolidation would improve outcome in adults with newly diagnosed ALL. Treatment of younger (18-40 years) patients consisted of a pediatric-inspired protocol, and for older patients (41-70 years), a semi-intensive protocol was used. Three hundred and forty patients were randomized. After a median follow-up of 70 months, 5-year event-free survival (EFS) was 50% and 53% for arm A and B (CLO arm). For patients <= 40 years, EFS was 58% vs 65% in arm A vs B, whereas in patients >40 years, EFS was 43% in both arms. Complete remission (CR) rate was 89% in both arms and similar in younger and older patients. Minimal residual disease (MRD) was assessed in 200 patients (60%). Fifty-four of 76 evaluable patients (71%) were MRD- after consolidation 1 in arm A vs 75/81 (93%) in arm B (P = .001). Seventy (42%) patients proceeded to allogeneic hematopoietic stem cell transplantation in both arms. Five-year overall survival (OS) was similar in both arms: 60% vs 61%. Among patients achieving CR, relapse rates were 28% and 24%, and nonrelapse mortality was 16% vs 17% after CR. CLO-treated patients experienced more serious adverse events, more infections, and more often went off protocol. This was most pronounced in older patients. We conclude that, despite a higher rate of MRD negativity, addition of CLO does not improve outcome in adults with ALL, which might be due to increased toxicity. This trial was registered at www.trialregister.nl as #NTR2004. Show less
