Long-term follow-up of allogeneic hematopoietic stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: impact of tyrosine kinase inhibitors on treatment outcomes

UKALLXII/ECOG2993: addition of imatinib to a standard treatment regimen enhances long-term outcomes in Philadelphia positive acute lymphoblastic leukemia

The Philadelphia chromosome positive arm of the UKALLXII/ECOG2993 study for adult acute lymphoblastic leukemia (ALL) enrolled 266 patients between 1993 and 2003 (pre-imatinib cohort). In 2003 imatinib was introduced as a single-agent course following induction (N = 86, late imatinib). In 2005 imatinib was added to the second phase of induction (N = 89, early imatinib). The complete remission (CR) rate was 92% in the imatinib cohort vs 82% in the preimatinib cohort (P = .004). At 4 years, the overall survival (OS) of all patients in the imatinib cohort was 38% vs 22% in the preimatinib cohort (P = .003). The magnitude of the difference between the preimatinib and imatinib cohorts in event-free survival (EFS), OS, and relapse-free survival (RFS) seen in univariate analysis was even greater in the multivariate analysis. In the preimatinib cohort, 31% of those starting treatment achieved hematopoietic stem cell transplant (alloHSCT) compared with 46% in the imatinib cohort. A Cox multivariate analysis taking alloHSCT into account showed a modest additional benefit to imatinib (hazard ratio for EFS = 0.64, 95% confidence interval 0.44-0.93, P = .02), but no significant benefit for OS and RFS. Adding imatinib to standard therapy improves CR rate and long-term OS for adults with ALL. A proportion of the OS benefit derives from the fact that imatinib facilitates alloHSCT. This trial was registered at clinicaltrials.gov as NCT00002514.

Improving results of autologous stem cell transplantation for Philadelphia-positive acute lymphoblastic leukaemia in the era of tyrosine kinase inhibitors: a report from the Acute Leukaemia Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND

Outcome of Philadelphia-positive acute lymphoblastic leukaemia (Ph+ ALL) improved significantly with the introduction of tyrosine kinase inhibitors (TKIs). Autologous stem cell transplantation (ASCT) has never been considered a standard of care in this setting. The aim of our study was to analyse if results of ASCT improved in the era of TKIs.

PATIENTS AND METHODS

One-hundred and seventy-seven adults with Ph+ ALL treated with ASCT in first complete remission were analysed for the impact of year of transplantation on outcome. Additional analysis was performed including 32 patients for whom detailed data on the use of TKIs and the status of minimal residual disease were collected.

RESULTS

The probability of the overall survival (OS) at 3 years increased from 16% for transplants performed between 1996 and 2001 to 48% between 2002 and 2006 and 57% between 2007 and 2010 (P<.0001). Leukaemia-free survival (LFS) was 11%, 39% and 52%, respectively (P<.0001). Relapse incidence decreased from 70% to 45% and 45% (P=.01), respectively, while non-relapse mortality was 19%, 15% and 3% (P=.08). In a multivariate analysis, year of ASCT was the only independent factor influencing the risk of treatment failure (hazard ratio (HR)=0.37; P<.001). In a subgroup of 22 patients actually treated with TKIs and being in complete molecular remission at the time of ASCT, the LFS rate at 3 years was 65%.

CONCLUSIONS

Results of ASCT for Ph+ ALL improved significantly over time. Prospective, innovative studies are needed to verify the role of ASCT in this patient setting.

Clinical outcome of hematopoietic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL): experience from a single institution

To identify factors affecting transplant outcome, data from 65 Philadelphia Chromosome-positive acute lymphoblastic leukemia (Ph + ALL) patients who had undergone allogeneic hematopoietic transplantation (allo-HSCT) in our institution were analyzed. The probability of OS (overall survival) and DFS (disease free-survival) at 3 years after allo-HSCT was 40.1% and 38%, respectively. Multivariate analysis showed that gender and disease status (p = 0.0059, p = 0.0039, respectively) were significant factors for OS. Among 51 patients with CR (complete remission), multivariate analysis showed that the factors associated with OS included gender (p = 0.014), number of white blood cell at diagnosis (p = 0.025), and the source of stem cells (bone marrow <BM > versus cord blood; BM stem cell source was associated with favorable OS, p = 0.042). Twenty-one patients relapsed after allo-HSCT with a median of 207 days (range, 19-1,324 days). The estimated cumulative incidence of relapse at 3 years was 39.4%. Patients with CR showed a lower relapse rate at 3 years (34.2%) when compared with patients with non-CR (62.7%). Among 21 patients, eight patients received imatinib-based chemotherapy and 13 received chemotherapy without imatinib before HSCT. In terms of treatment after relapse, seven patients received chemotherapy with imatinib and 13 received chemotherapy without imatinib. Five patients underwent a second HSCT. One patient survived, and 20 patients died. In this study, disease status at time of allo-HSCT had a significant impact on OS, DFS, and relapse. Imatinib administration given before allo-HSCT was not associated with favorable outcome. Second-generation tyrosine kinase inhibitors may be more suitable candidates for Ph + ALL before and after allo-HSCT.

Feasibility of allografting in patients with advanced acute lymphoblastic leukemia after salvage therapy with inotuzumab ozogamicin

BACKGROUND

No highly effective salvage therapy exists for patients with relapsed acute lymphoblastic leukemia (ALL). Inotuzumab ozogamicin (IO) is a CD22 monoclonal antibody attached to calicheamycin that targets B lymphocytes in early stages of development, successfully inducing remission in patients with multiply relapsed ALL.

METHODS

We describe our findings in 26 patients who received allogeneic hematopoietic stem cell transplantation (SCT) after treatment with IO between September 2010 and October 2011.

RESULTS

Patients with a median age of 33 years (range, 5-70 years) received an allogeneic matched sibling donor (n = 9), matched- or 1-antigen mismatched unrelated donor (n = 16), or cord blood donor SCT (n = 1) while in complete remission (n = 23) or with active disease (n = 3). At the time of SCT, 15 patients were in complete remission without evidence of minimal residual disease (MRD) measured by multiparameter flow cytometry. Patients were heavily pretreated, including 5 patients who had received previous allogeneic SCT. Patients received a median of 3 courses of IO (range, 1-5 courses) before SCT. Seven patients are alive at a median follow-up of 13 months (range, 5-16 months), with 1-year event-free and overall survival (OS) of 22% and 20%, respectively. Patients without MRD at time of SCT had a markedly better 1-year OS of 42%. The cumulative incidence of nonrelapse mortality (NRM) at 6 months and 1 year were 40% and 60%, respectively, with 5 deaths attributed to venoocclusive disease (VOD).

CONCLUSIONS

Treatment with IO allows more patients to undergo transplantation while in remission, with favorable overall survival in patients without MRD who undergo transplantation. Reduction in hepatic toxicity is needed to improve overall results.

Intravenous BU plus Mel: an effective, chemotherapy-only transplant conditioning regimen in patients with ALL

We investigated the administration of i.v. BU combined with melphalan (Mel) in patients with ALL undergoing allogeneic hematopoietic SCT. Forty-seven patients with a median age of 33 years (range 20-61) received a matched sibling (n=27) or matched unrelated donor transplant (n=20) for ALL in first CR (n=26), second CR (n=13), or with more advanced disease (n=8). BU was infused daily for 4 days, either at a fixed dose of 130 mg/m² (5 patients) or using pharmacokinetic (PK) dose adjustment (42 patients), to target an average daily area-under-the-curve (AUC) of 5000 μmol/min, determined by a test dose of i.v. BU at 32 mg/m². This was followed by a rest day, then two daily doses of Mel at 70 mg/m². Stem cells were infused on the following day. The 2-year OS, PFS and non-relapse mortality (NRM) rates were 35% (95% confidence interval (CI), 23-51%), 31% (95% CI, 21-48%) and 37% (95% CI, 23-50%), respectively. Acute NRM at 100 days was favorable at 12% (95% CI, 5-24%); however, the 2-year NRM was significantly higher for patients older than 40 years, 58% vs 20%, mainly due to GVHD.

Clofarabine combined with busulfan provides excellent disease control in adult patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation

We investigated the safety and early disease control data for i.v. busulfan (Bu) in combination with clofarabine (Clo) in patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation (SCT). Fifty-one patients (median age, 36 years; range, 20-64 years) received a matched sibling (n = 24), syngeneic (n = 2), or matched unrelated donor transplant (n = 25) for acute lymphoblastic leukemia in first complete remission (n = 30), second complete remission (n = 13), or active disease (n = 8). More than one-half of the patients had a high-risk cytogenetic profile, as defined by the presence of t(9;22) (n = 17), t(4;11) (n = 3), or complex cytogenetics (n = 7). Clo 40 mg/m(2) was given once daily, with each dose followed by pharmacokinetically dosed Bu infused over 3 hours daily for 4 days, followed by hematopoietic SCT 2 days later. The Bu dose was based on drug clearance, as determined by the patient's response to a 32-mg/m(2) Bu test dose given 48 hours before the high-dose regimen. The target daily area under the receiver-operating characteristic curve was 5500 μM/min for patients age <60 years and 4000 μM/min for those age ≥60 years. The regimen was well tolerated, with a 100-day nonrelapse mortality rate of 6%. With a median follow-up of 14 months among surviving patients (range, 6-28 months), the 1-year overall survival, disease-free survival, and nonrelapse mortality rates were 67% (95% confidence interval [CI], 55%-83%), 54% (95% CI, 41%-71%), and 32% (95% CI, 16%-45%), respectively. For patients undergoing SCT in first remission, these respective rates were 74%, 64%, and 25%. Our data indicate that the combination of Clo and Bu provides effective disease control while maintaining a favorable safety profile.

Persistent complete molecular remission after nilotinib and graft-versus-leukemia effect in an acute lymphoblastic leukemia patient with cytogenetic relapse after allogeneic stem cell transplantation

We report the successful treatment and sustained molecular remission using single agent nilotinib in a relapsed Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia patient after allogeneic hematopoietic stem cell transplantation. Compared to previously published studies, this is the first report where a patient did not receive additional chemotherapy after relapse, nor did she receive donor lymphocyte infusions. With nilotinib, the patient reverted back to normal blood counts and 100% donor reconstitution by single tandem repeat (STR) chimerism analysis in the bone marrow and in peripheral blood, granulocytes, T and B-lymphocytes. This report also highlights the use of nilotinib in combination with extracorporeal photopheresis (ECP) for concomitant graft-versus-host disease. Our data suggests that ECP, together with nilotinib, did not adversely affect the overall Graft-versus-leukemia (GVL) effect.

Treatment of young patients with Philadelphia chromosome-positive acute lymphoblastic leukaemia using increased dose of imatinib and deintensified chemotherapy before allogeneic stem cell transplantation

The main outcomes of the Programa Español para Tratamiento de Hemopatías (PETHEMA)-acute lymphoblastic leukaemia (ALL)-Ph-08 trial were described and compared with those of the historical PETHEMA-CSTIBES02 trial. The trials differed in imatinib dose (600 vs. 400 mg/d) and amount of chemotherapy (one vs. two consolidation cycles) before stem cell transplantation (SCT). All patients (n = 29) enrolled in the ALL-Ph-08 trial achieved complete remission (CR) (vs. 90% in CSTIBES02), and SCT was performed in CR in 90% (vs. 78%). The reduction in early death, relapse before SCT and transplant-related mortality observed in the ALL-Ph-08 trial resulted in an improved 2-year event-free survival (63% vs. 37%, P = 0·009).

The role of allogeneic hematopoietic stem cell transplantation in the therapy of patients with acute lymphoblastic leukemia

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is an effective post-remission therapy in patients with acute lymphoblastic leukemia (ALL), but is associated with significant toxicity, so the optimal timing and use of this modality remains an issue of debate. Increased advances in reduced-intensity transplant preparative regimens and alternative donors has increased the accessibility of allogeneic transplantation. A risk adapted paradigm, using minimal residual disease analysis, may help in the selection of patients at highest risk for relapse, who may benefit most from alloHSCT. In this review, we summarize the indications for allogeneic transplantation within the risk-oriented paradigm, and also explore the latest literature on reduced intensity transplant regimens, as well as alternative donor transplantation for patients with ALL.