Benefits and risks of clofarabine in adult acute lymphoblastic leukemia investigated in depth by multi-state modeling

Background: We recently reported results of the prospective, open-label HOVON-100 trial in 334 adult patients with acute lymphoblastic leukemia (ALL) randomized to first-line treatment with or without clofarabine (CLO). No improvement of event-free survival (EFS) was observed, while a higher proportion of patients receiving CLO obtained minimal residual disease (MRD) negativity. Aim: In order to investigate the effects of CLO in more depth, two multi-state models were developed to identify why CLO did not show a long-term survival benefit despite more MRD-negativity. Methods: The first model evaluated the effect of CLO on going off-protocol (not due to refractory disease/relapse, completion or death) as a proxy of severe treatment-related toxicity, while the second model evaluated the effect of CLO on obtaining MRD negativity. The subsequent impact of these intermediate events on death or relapsed/refractory disease was assessed in both models. Results: Overall, patients receiving CLO went off-protocol more frequently than control patients (35/168 [21%] vs. 18/166 [11%], p = 0.019; HR 2.00 [1.13–3.52], p = 0.02), especially during maintenance (13/44 [30%] vs. 6/56 [11%]; HR 2.85 [95%CI 1.08–7.50], p = 0.035). Going off-protocol was, however, not associated with more relapse or death. Patients in the CLO arm showed a trend towards an increased rate of MRD-negativity compared with control patients (HR MRD-negativity: 1.35 [0.95–1.91], p = 0.10), which did not translate into a significant survival benefit. Conclusion: We conclude that the intermediate states, i.e., going off-protocol and MRD-negativity, were affected by adding CLO, but these transitions were not associated with subsequent survival estimates, suggesting relatively modest antileukemic activity in ALL.</p

Joint models quantify associations between immune cell kinetics and allo-immunological events after allogeneic stem cell transplantation and subsequent donor lymphocyte infusion

Alloreactive donor-derived T-cells play a pivotal role in alloimmune responses after allogeneic hematopoietic stem cell transplantation (alloSCT); both in the relapse-preventing Graft-versus-Leukemia (GvL) effect and the potentially lethal complication Graft-versus-Host-Disease (GvHD). The balance between GvL and GvHD can be shifted by removing T-cells via T-cell depletion (TCD) to reduce the risk of GvHD, and by introducing additional donor T-cells (donor lymphocyte infusions [DLI]) to boost the GvL effect. However, the association between T-cell kinetics and the occurrence of allo-immunological events has not been clearly demonstrated yet. Therefore, we investigated the complex associations between the T-cell kinetics and alloimmune responses in a cohort of 166 acute leukemia patients receiving alemtuzumab-based TCD alloSCT. Of these patients, 62 with an anticipated high risk of relapse were scheduled to receive a prophylactic DLI at 3 months after transplant. In this setting, we applied joint modelling which allowed us to better capture the complex interplay between DLI, T-cell kinetics, GvHD and relapse than traditional statistical methods. We demonstrate that DLI can induce detectable T-cell expansion, leading to an increase in total, CD4+ and CD8+ T-cell counts starting at 3 months after alloSCT. CD4+ T-cells showed the strongest association with the development of alloimmune responses: higher CD4 counts increased the risk of GvHD (hazard ratio 2.44, 95% confidence interval 1.45-4.12) and decreased the risk of relapse (hazard ratio 0.65, 95% confidence interval 0.45-0.92). Similar models showed that natural killer cells recovered rapidly after alloSCT and were associated with a lower risk of relapse (HR 0.62, 95%-CI 0.41-0.93). The results of this study advocate the use of joint models to further study immune cell kinetics in different settings

Benefits and risks of clofarabine in adult acute lymphoblastic leukemia investigated in depth by multi-state modeling

Background: We recently reported results of the prospective, open-label HOVON-100 trial in 334 adult patients with acute lymphoblastic leukemia (ALL) randomized to first-line treatment with or without clofarabine (CLO). No improvement of event-free survival (EFS) was observed, while a higher proportion of patients receiving CLO obtained minimal residual disease (MRD) negativity. Aim: In order to investigate the effects of CLO in more depth, two multi-state models were developed to identify why CLO did not show a long-term survival benefit despite more MRD-negativity. Methods: The first model evaluated the effect of CLO on going off-protocol (not due to refractory disease/relapse, completion or death) as a proxy of severe treatment-related toxicity, while the second model evaluated the effect of CLO on obtaining MRD negativity. The subsequent impact of these intermediate events on death or relapsed/refractory disease was assessed in both models. Results: Overall, patients receiving CLO went off-protocol more frequently than control patients (35/168 [21%] vs. 18/166 [11%], p = 0.019; HR 2.00 [1.13–3.52], p = 0.02), especially during maintenance (13/44 [30%] vs. 6/56 [11%]; HR 2.85 [95%CI 1.08–7.50], p = 0.035). Going off-protocol was, however, not associated with more relapse or death. Patients in the CLO arm showed a trend towards an increased rate of MRD-negativity compared with control patients (HR MRD-negativity: 1.35 [0.95–1.91], p = 0.10), which did not translate into a significant survival benefit. Conclusion: We conclude that the intermediate states, i.e., going off-protocol and MRD-negativity, were affected by adding CLO, but these transitions were not associated with subsequent survival estimates, suggesting relatively modest antileukemic activity in ALL.</p

Risk factors for graft-versus-host-disease after donor lymphocyte infusion following T-cell depleted allogeneic stem cell transplantation

IntroductionUnmodified donor lymphocyte infusions (DLI) after allogeneic stem cell transplantation (alloSCT) can boost the beneficial Graft-versus-Leukemia (GvL) effect but may also induce severe Graft-versus-Host-Disease (GvHD). To improve the balance between GvL and GvHD, it is crucial to identify factors that influence the alloreactivity of DLI. MethodsWe investigated the effects of the presence of patient-derived antigen-presenting cells at time of DLI as estimated by the bone marrow (BM) chimerism status, lymphopenia as measured by the absolute lymphocyte count (ALC) at time of DLI, and the presence of a viral infection (de novo or reactivation) close to DLI on the risk of GvHD after DLI. The cohort consisted of patients with acute leukemia or myelodysplastic syndrome who prophylactically or pre-emptively received DLI as standard care after alemtuzumab-based alloSCT. In patients at high risk for relapse, DLI was administered at 3 months after alloSCT (n=88) with a dose of 0.3x106 or 0.15x106 T cells/kg in case of a related or unrelated donor, respectively. All other patients (n=76) received 3x106 or 1.5x106 T cells/kg, respectively, at 6 months after alloSCT. ResultsFor both DLIs, patients with reduced-intensity conditioning and an unrelated donor had the highest risk of GvHD. For DLI given at three months, viral infection within 1 week before and 2 weeks after DLI was an additional significant risk factor (hazard ratio (HR) 3.66 compared to no viral infection) for GvHD. At six months after alloSCT, viral infections were rare and not associated with GvHD. In contrast, mixed BM chimerism (HR 3.63 for ≥5% mixed chimerism compared to full donor) was an important risk factor for GvHD after DLI given at six months after alloSCT. ALC of &lt;1000x106/l showed a trend for association with GvHD after this DLI (HR 2.05 compared to ≥1000x106/l, 95% confidence interval 0.94-4.45). Furthermore, the data suggested that the presence of a viral infection close to the DLI at three months or ≥5% mixed chimerism at time of the DLI at six months correlated with the severity of GvHD, thereby increasing their negative impact on the current GvHD-relapse-free survival. ConclusionThese data demonstrate that the risk factors for GvHD after DLI depend on the setting of the DLI

DataSheet_1_Risk factors for graft-versus-host-disease after donor lymphocyte infusion following T-cell depleted allogeneic stem cell transplantation.pdf

IntroductionUnmodified donor lymphocyte infusions (DLI) after allogeneic stem cell transplantation (alloSCT) can boost the beneficial Graft-versus-Leukemia (GvL) effect but may also induce severe Graft-versus-Host-Disease (GvHD). To improve the balance between GvL and GvHD, it is crucial to identify factors that influence the alloreactivity of DLI. MethodsWe investigated the effects of the presence of patient-derived antigen-presenting cells at time of DLI as estimated by the bone marrow (BM) chimerism status, lymphopenia as measured by the absolute lymphocyte count (ALC) at time of DLI, and the presence of a viral infection (de novo or reactivation) close to DLI on the risk of GvHD after DLI. The cohort consisted of patients with acute leukemia or myelodysplastic syndrome who prophylactically or pre-emptively received DLI as standard care after alemtuzumab-based alloSCT. In patients at high risk for relapse, DLI was administered at 3 months after alloSCT (n=88) with a dose of 0.3x106 or 0.15x106 T cells/kg in case of a related or unrelated donor, respectively. All other patients (n=76) received 3x106 or 1.5x106 T cells/kg, respectively, at 6 months after alloSCT. ResultsFor both DLIs, patients with reduced-intensity conditioning and an unrelated donor had the highest risk of GvHD. For DLI given at three months, viral infection within 1 week before and 2 weeks after DLI was an additional significant risk factor (hazard ratio (HR) 3.66 compared to no viral infection) for GvHD. At six months after alloSCT, viral infections were rare and not associated with GvHD. In contrast, mixed BM chimerism (HR 3.63 for ≥5% mixed chimerism compared to full donor) was an important risk factor for GvHD after DLI given at six months after alloSCT. ALC of 6/l showed a trend for association with GvHD after this DLI (HR 2.05 compared to ≥1000x106/l, 95% confidence interval 0.94-4.45). Furthermore, the data suggested that the presence of a viral infection close to the DLI at three months or ≥5% mixed chimerism at time of the DLI at six months correlated with the severity of GvHD, thereby increasing their negative impact on the current GvHD-relapse-free survival. ConclusionThese data demonstrate that the risk factors for GvHD after DLI depend on the setting of the DLI.</p

Therapeutic value of clofarabine in younger and middle-aged (18-65 years) adults with newly diagnosed AML

Clofarabine has demonstrated antileukemic activity in acute myeloid leukemia (AML) but has yet to be critically evaluated in younger adults in the frontline with standard chemotherapy. We compared 2 induction regimens in newly diagnosed patients ages 18 to 65 with acute myeloid leukemia (AML)/high-risk myelodysplastic syndromes, that is, idarubicine-cytarabine (cycle I) and amsacrine-cytarabine (cycle II) without or with clofarabine (10 mg/m2 on days 1-5 of each of both cycles). Consolidation involved chemotherapy with or without hematopoietic stem cell transplantation. Event-free survival (EFS, primary endpoint) and other clinical endpoints and toxicities were assessed. We randomized 402 and 393 evaluable patients to the control or clofarabine induction treatment arms. Complete remission rates (89%) did not differ but were attained faster with clofarabine (66% vs 75% after cycle I). Clofarabine added grades 3 to 4 toxicities and delayed hematological recovery. At a median follow-up of 36 months, the study revealsnodifferences in overall survivalandEFSbetweenthe control (EFS,35%63 [standard error] at 4 years) and clofarabine treatments (38% ± 3) but a markedly reduced relapse rate (44% ± 3 vs 35% ± 3) in favor of clofarabine and an increased death probability in remission (15%±2 vs 22%±3). In the subgroup analyses, clofarabine improved overall survival and EFS for European Leukemia Net (ELN) 2010 intermediate I prognostic riskAML(EFS,26%64 vs40%65 at 4 years;CoxP5.002) and for the intermediate risk genotype NPM1 wild-type/FLT3 without internal-tandem duplications (EFS, 18% 6 5 vs 40% 6 7; Cox P < .001). Clofarabine improves survival in subsets of intermediate-risk AML only. HOVON-102 study is registered at Netherlands Trial Registry #NTR2187

Resurrecting the Neglected Liberty of Self‐Government

Clofarabine has demonstrated antileukemic activity in acute myeloid leukemia (AML) but has yet to be critically evaluated in younger adults in the frontline with standard chemotherapy. We compared 2 induction regimens in newly diagnosed patients ages 18 to 65 with acute myeloid leu

Clofarabine added to intensive treatment in adult patients with newly diagnosed ALL: the HOVON-100 trial.

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 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

Clofarabine added to intensive treatment in adult patients with newly diagnosed ALL: the HOVON-100 trial.

Clofarabine (CLO) is a nucleoside analogue with efficacy in relapsed/refractory acute lymphoblastic leukemia (ALL). This randomized phase III study aimed to evaluate whether CLO added to induction and consolidation would improve outcome in adults with newly diagnosed ALL. Treatment for younger (18-40 years) patients consisted of a pediatric inspired protocol and for older patients (41-70 years) of a semi-intensive protocol was used. 340 patients were randomized. After a median follow up of 70 months, 5-year 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, while in patients >40 years EFS was 43% in both arms. 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 negative after consolidation 1 in arm A vs 75/81 (93%) in arm B (p=0.001). Seventy (42%) patients proceeded to allogeneic hematopoietic stem cell transplantation in both arms. Five years OS was similar in both arms, 60% vs 61%. Among patients achieving CR, relapse rates were 28% and 24%, and non-relapse 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. The trial is registered at www.trialregister.nl as NTR2004