Identification of multivariable microRNA and clinical biomarker panels to predict imatinib response in chronic myeloid leukemia at diagnosis.

Imatinib Mesylate (imatinib) was once hailed as the magic bullet for chronic myeloid leukemia (CML) and remains a front-line therapy for CML to this day alongside other tyrosine kinase inhibitors (TKIs). However, TKI treatments are rarely curative and patients are often required to receive life-long treatment or otherwise risk relapse. Thus, there is a growing interest in identifying biomarkers in patients which can predict TKI response upon diagnosis. In this study, we analyze clinical data and differentially expressed miRNAs in CD34+ CML cells from 80 patients at diagnosis who were later classified as imatinib-responders or imatinib-nonresponders. A Cox Proportional Hazard (CoxPH) analysis identified 16 miRNAs that were associated with imatinib nonresponse and differentially expressed in these patients. We also trained a machine learning model with different combinations of the 16 miRNAs with and without clinical parameters and identified a panel with high predictive performance based on area-under-curve values of receiver-operating-characteristic and precision-recall curves. Interestingly, the multivariable panel consisting of both miRNAs and clinical features performed better than either miRNA or clinical panels alone. Thus, our findings may inform future studies on predictive biomarkers and serve as a tool to develop more optimized treatment plans for CML patients in the clinic.

Identification of key microRNAs as predictive biomarkers of Nilotinib response in chronic myeloid leukemia: a sub-analysis of the ENESTxtnd clinical trial.

Despite the effectiveness of tyrosine kinase inhibitors (TKIs) against chronic myeloid leukemia (CML), they are not usually curative as some patients develop drug-resistance or are at risk of disease relapse when treatment is discontinued. Studies have demonstrated that primitive CML cells display unique miRNA profiles in response to TKI treatment. However, the utility of miRNAs in predicting treatment response is not yet conclusive. Here, we analyzed differentially expressed miRNAs in CD34+ CML cells pre- and post-nilotinib (NL) therapy from 58 patients enrolled in the Canadian sub-analysis of the ENESTxtnd phase IIIb clinical trial which correlated with sensitivity of CD34+ cells to NL treatment in in vitro colony-forming cell (CFC) assays. We performed Cox Proportional Hazard (CoxPH) analysis and applied machine learning algorithms to generate multivariate miRNA panels which can predict NL response at treatment-naïve or post-treatment time points. We demonstrated that a combination of miR-145 and miR-708 are effective predictors of NL response in treatment-naïve patients whereas miR-150 and miR-185 were significant classifiers at 1-month and 3-month post-NL therapy. Interestingly, incorporation of NL-CFC output in these panels enhanced predictive performance. Thus, this novel predictive model may be developed into a prognostic tool for use in the clinic.

Incidence and socioeconomic factors in older adults with acute myeloid leukaemia: Real-world outcomes from a population-based cohort.

OBJECTIVES: Acute myeloid leukaemia (AML) is a disease of older adults, who are vulnerable to socio-economic factors. We determined AML incidence in older adults and the impact of socio-economic factors on outcomes. METHODS: We included 3024 AML patients (1996-2016) identified from a population-based registry. RESULTS: AML incidence in patients ≥60 years increased from 11.01 (2001-2005) to 12.76 (2011-2016) per 100 000 population. Among 879 patients ≥60 years in recent eras (2010-2016), rural residents (<100 000 population) were less likely to be assessed by a leukaemia specialist (39% rural, 47% urban, p = .032); no difference was seen for lower (43%, quintile 1-3) vs. higher (47%, quintile 4-5) incomes (p = .235). Similar numbers received induction chemotherapy between residence (16% rural, 18% urban, p = .578) and incomes (17% lower, 17% high, p = 1.0). Differences between incomes were seen for hypomethylating agent treatment (14% low, 20% high, p = .041); this was not seen for residence (13% rural, 18% urban, p = .092). Among non-adverse karyotype patients ≥70 years, 2-year overall survival was worse for rural (5% rural, 12% urban, p = .006) and lower income (6% low, 15% high, p = .017) patients. CONCLUSIONS: AML incidence in older adults is increasing, and outcomes are worse for older rural and low-income residents; these patients face treatment barriers.

Integrin-Linked Kinase Mediates Therapeutic Resistance of Quiescent CML Stem Cells to Tyrosine Kinase Inhibitors.

Patients with chronic myeloid leukemia (CML) often require lifelong therapy with ABL1 tyrosine kinase inhibitors (TKIs) due to a persisting TKI-resistant population of leukemic stem cells (LSCs). From transcriptome profiling, we show integrin-linked kinase (ILK), a key constituent of focal adhesions, is highly expressed in TKI-nonresponsive patient cells and their LSCs. Genetic and pharmacological inhibition of ILK impaired the survival of nonresponder patient cells, sensitizing them to TKIs, even in the presence of protective niche cells. Furthermore, ILK inhibition eliminated TKI-refractory LSCs from patients, but not normal HSCs, in vitro and in vivo. RNA-sequencing and functional validation studies implicated an important role of ILK in maintaining a requisite level of mitochondrial oxidative metabolism in highly purified, quiescent LSCs. Thus, these findings point to ILK as a critical survival mediator to TKIs and quiescent stem cells, offering an attractive therapeutic target and model for curative combination therapies in stem-cell-driven cancers.

The miR-185/PAK6 axis predicts therapy response and regulates survival of drug-resistant leukemic stem cells in CML.

Overcoming drug resistance and targeting cancer stem cells remain challenges for curative cancer treatment. To investigate the role of microRNAs (miRNAs) in regulating drug resistance and leukemic stem cell (LSC) fate, we performed global transcriptome profiling in treatment-naive chronic myeloid leukemia (CML) stem/progenitor cells and identified that miR-185 levels anticipate their response to ABL tyrosine kinase inhibitors (TKIs). miR-185 functions as a tumor suppressor: its restored expression impaired survival of drug-resistant cells, sensitized them to TKIs in vitro, and markedly eliminated long-term repopulating LSCs and infiltrating blast cells, conferring a survival advantage in preclinical xenotransplantation models. Integrative analysis with mRNA profiles uncovered PAK6 as a crucial target of miR-185, and pharmacological inhibition of PAK6 perturbed the RAS/MAPK pathway and mitochondrial activity, sensitizing therapy-resistant cells to TKIs. Thus, miR-185 presents as a potential predictive biomarker, and dual targeting of miR-185-mediated PAK6 activity and BCR-ABL1 may provide a valuable strategy for overcoming drug resistance in patients.

Response to Comment on "PP2A inhibition sensitizes cancer stem cells to ABL tyrosine kinase inhibitors in BCR-ABL+ human leukemia".

LB100 sensitizes resistant chronic phase CML stem and progenitor cells to TKIs and spares healthy bone marrow cells.

Canadian chronic myeloid leukemia outcomes post-transplant in the tyrosine kinase inhibitor era.

The majority of patients with TKI failure respond to HCT. However, the relapse risk remains high. This study has evaluated transplant outcomes in 223 CML patients with TKI failure due to resistance (n = 132) or intolerance (n = 29), as well as those that were TKI naïve/responding with advanced disease (n = 35) or with chronic phase (CP, n = 27). We studied outcomes according to post-transplant BCR-ABL transcript level within 3 months. With respect to transplant outcomes according to the post-transplant BCR/ABLtranscript level within 3 months, the group failing to achieve a 1.3 log reduction (n = 14, 12.4%) showed the highest relapse rate of 78.6% at 5 years, compared to 26.2% and 24.1% in the groups achieving 1.3-4.0 log reduction (n = 45, 39.8%), and ≥4.1 log reduction (n = 54, 47.8%) respectively (p < 0.001). Multivariate analysis confirmed that the group failing to achieve a 1.3 log reduction had a 2.3-fold higher risk of death and 6.6 times higher risk of relapse. Poor overall survival after HCT was associated with advanced disease at diagnosis, but not disease status prior to HCT. Of 61 patients who relapsed after HCT, 47 were treated with post-transplant TKI therapy; those receiving TKI after loss of MR2 or MMR showed higher rates of response and survival compared to those receiving TKI after hematologic relapse (p < 0.001). QPCR log reduction level within 3 months post transplantation is prognostic in this population.

Outcomes of Intermediate Risk Karyotype Acute Myeloid Leukemia in First Remission Undergoing Autologous Stem Cell Transplantation Compared With Allogeneic Stem Cell Transplantation and Chemotherapy Consolidation: A Retrospective, Propensity-score Adjusted Analysis.

INTRODUCTION: Optimal post-remission therapy (PRT) for intermediate risk acute myeloid leukemia remains an area of ongoing research. We aimed to retrospectively compare outcomes following autologous stem cell transplantation (autoSCT) with allogeneic SCT (alloSCT) and consolidation chemotherapy (CMT) in patients with intermediate-risk karyotype AML in first complete remission. PATIENTS AND METHODS: We compared overall survival (OS) and leukemia-free survival (LFS) using propensity score (PS)-adjusted analysis of patients receiving PRT with autoSCT, matched sibling (MSD) alloSCT, unrelated/mismatch (UD/MM) alloSCT, and CMT. We included patients diagnosed between 1984 and 2003 (period of autoSCT at our center) in CR1 following induction CMT and received at least 2 consolidative cycles. RESULTS: We identified 190 patients (62 MSD-alloSCT, 18 UD/MM-alloSCT, 30 autoSCT, and 80 CMT). Baseline characteristics were used for PS calculation and were well-balanced after weight adjustment. The median follow-up for patients surviving beyond 1 year was 8.7 years. We excluded 55 patients based on PS calculation. Adjusted multivariate hazard ratio (HR), 95% confidence interval (CI) and P-value for OS, considering CMT as reference, were: MSD-alloSCT (HR, 0.4; 95% CI, 0.2-0.8; P = .009), UD/MM-alloSCT (HR, 1.5; 95% CI, 0.6-3.9; P = .363), and autoSCT (HR, 1.2; 95% CI, 0.5-3.1; P = .666), respectively. Adjusted multivariate HR, 95% CI and P-value for LFS were MSD-alloSCT (HR, 0.3; 95% CI, 0.2-0.6; P < .001), UD/MM-alloSCT (HR, 1.1; 95% CI, 0.4-2.7; P = .854), and autoSCT (HR, 0.8; 95% CI, 0.3-2.2; P = .697), respectively. CONCLUSION: Patients with intermediate risk-karyotype acute myeloid leukemia who underwent MSD-alloSCT in first complete remission had the best outcomes. There were no survival differences between autoSCT, UD/MM-alloSCT, and CMT. Further study incorporating molecular changes and minimal residual disease status is warranted to select appropriate patients for autoSCT.

Excellent real-world outcomes of adults with Burkitt lymphoma treated with CODOX-M/IVAC plus or minus rituximab.

Treatment of Burkitt lymphoma (BL) with intensive, multi-agent chemotherapy with aggressive central nervous system (CNS) prophylaxis results in high cure rates, although no regimen is standard of care. We examined population-based survival outcomes of adults with BL treated with a modified combination of cyclophosphamide, vincristine, doxorubicin, prednisone and systemic high-dose methotrexate (MTX) (CODOX-M) with IVAC (ifosfamide, mesna, etoposide, cytarabine and intrathecal MTX) (CODOX-M/IVAC) ± rituximab over a 15-year period in British Columbia. For the 81 patients identified (including 8 with CNS involvement and 18 with human immunodeficiency virus-associated BL), 5-year progression-free survival (PFS) and overall survival (OS) were 75% [95% confidence interval (CI): 63-83%] and 77% (95% CI: 66-85%), respectively, with no treatment-related deaths. Those who completed the regimen per protocol (n = 38) had significantly improved 5-year PFS 86% (P = 0·04) and OS 92% (P = 0·008), as did those under 60 years with 5-year PFS 82% (P = 0·005) and OS 86% (P = 0·002), which remained significant in multivariate analysis [PFS: hazard ratio (HR) 3·36, P = 0·018; OS HR 4·03, P = 0·012]. Incorporation of high-dose systemic methotrexate also significantly affected multivariate survival outcomes (OS HR 0·28, P = 0·025). Stem cell transplant in first remission had no effect on OS or PFS. This large, real-world analysis of BL patients treated with CODOX-M/IVAC ± rituximab demonstrates excellent survival outcomes comparable to clinical trials. These results help to serve as a benchmark when comparing curative therapies for BL patients as novel regimens are incorporated into clinical practice.

PP2A inhibition sensitizes cancer stem cells to ABL tyrosine kinase inhibitors in BCR-ABL+ human leukemia.

Overcoming drug resistance and targeting leukemic stem cells (LSCs) remain major challenges in curing BCR-ABL+ human leukemia. Using an advanced drug/proliferation screen, we have uncovered a prosurvival role for protein phosphatase 2A (PP2A) in tyrosine kinase inhibitor (TKI)-insensitive leukemic cells, regulated by an Abelson helper integration site-1-mediated PP2A-ß-catenin-BCR-ABL-JAK2 protein complex. Genetic and pharmacological inhibition of PP2A impairs survival of TKI nonresponder cells and sensitizes them to TKIs in vitro, inducing a dramatic loss of several key proteins, including ß-catenin. We also demonstrate that the clinically validated PP2A inhibitors LB100 and LB102, in combination with TKIs, selectively eliminate treatment-naïve TKI-insensitive stem and progenitor cells, while sparing healthy counterparts. In addition, PP2A inhibitors and TKIs act synergistically to inhibit the growth of TKI-insensitive cells, as assessed by combination index analysis. The combination eliminates infiltrated BCR-ABL+ blast cells and drug-insensitive LSCs and confers a survival advantage in preclinical xenotransplant models. Thus, dual PP2A and BCR-ABL inhibition may be a valuable therapeutic strategy to synergistically target drug-insensitive LSCs that maintain minimal residual disease in patients.

Allogeneic Hematopoietic Stem Cell Transplantation Is an Effective Salvage Therapy for Patients with Chronic Myeloid Leukemia Presenting with Advanced Disease or Failing Treatment with Tyrosine Kinase Inhibitors.

Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only known curative therapy for chronic myeloid leukemia (CML); however, it is rarely utilized given the excellent long-term results with tyrosine kinase inhibitor (TKI) treatment. The purpose of this study is to examine HSCT outcomes for patients with CML who failed TKI therapy or presented in advanced phase and to identify predictors of survival, relapse, and nonrelapse mortality (NRM). Fifty-one patients with CML underwent HSCT for advanced disease at diagnosis (n = 15), TKI resistance as defined by the European LeukemiaNet guidelines (n = 30), TKI intolerance (n = 2), or physician preference (n = 4). At a median follow-up of 71.9 months, the 8-year overall survival (OS), event-free survival (EFS), relapse, and NRM were 68%, 46%, 41%, and 23%, respectively. In univariate analysis, predictors of OS included first chronic phase (CP1) disease status at HSCT (P = .0005), European Society for Blood and Marrow Transplantation score 1 to 4 (P = .04), and complete molecular response (CMR) to HSCT (P < .0001). Donor (female) to patient (male) gender combination (P = .02) and CMR to HSCT (P < .0001) predicted lower relapse. In multivariate analysis, CMR to HSCT remained an independent predictor of OS (odds ratio [OR], 43), EFS (OR, 56) and relapse (OR, 29). This report indicates that the outlook is excellent for those patients who remain in CP1 at the time of HSCT and achieve a CMR after HSCT. However, only approximately 50% of those in advanced phase at HSCT are long-term survivors. This highlights the ongoing need to try to identify patients earlier, before disease progression, who are destined to fail this treatment to optimize transplantation outcomes.

Outcome of Patients With Non-Hodgkin Lymphomas With Concurrent MYC and BCL2 Rearrangements Treated With CODOX-M/IVAC With Rituximab Followed by Hematopoietic Stem Cell Transplantation.

BACKGROUND: Double-hit lymphoma is characterized by the presence of concurrent MYC (myelocytomatosis oncogene) and BCL2 (B-cell lymphoma 2) gene rearrangements. Prognosis is poor with standard chemoimmunotherapy. Since 2003, the British Columbia Cancer Agency has used CODOX-M/IVAC+R (cyclophosphamide, vincristine, doxorubicin, methotrexate, cytarabine, ifosfamide, and etoposide, combined with rituximab) followed by consolidative hematopoietic cell transplantation as definitive treatment for double-hit lymphoma. PATIENTS AND METHODS: A retrospective review of the survival outcomes of patients with double-hit lymphoma treated at our institution was conducted. Thirty-two patients diagnosed with non-Hodgkin lymphoma with concurrent MYC and BCL2 translocations from 2003 to 2013 were identified. Cases with MYC or BCL2 amplification and those with overexpression in immunohistochemistry analysis were excluded. RESULTS: Median age at diagnosis was 53.0 years (range, 35.5-70.9 years), 23 (72%) were male, and 30 (94%) had stage III to IV disease. CODOX-M/IVAC+R was administered in 25 (78%) patients and 20 (80%) achieved a partial remission or better, of which 9 (36%) had a complete remission. Nineteen of the 32 (59%) patients underwent upfront hematopoietic cell transplantation. At a median follow-up of living patients of 26.4 months, 14 (44%) were alive in remission, 15 (47%) died, and 3 (9%) were alive in relapse. The 2-year progression-free survival (PFS) and overall survival (OS) of all patients were 41% and 53%, respectively. The sixteen patients treated with CODOX-M/IVAC+R followed by hematopoietic cell transplantation had a 2-year PFS of 60% and 2-year OS of 82%. CONCLUSION: Patients with double-hit lymphoma treated with CODOX-M/IVAC+R followed by hematopoietic cell transplantation can achieve durable remissions, although disease progression before transplantation remains a significant problem.

The core autophagy protein ATG4B is a potential biomarker and therapeutic target in CML stem/progenitor cells.

Previous studies demonstrated that imatinib mesylate (IM) induces autophagy in chronic myeloid leukemia (CML) and that this process is critical to cell survival upon therapy. However, it is not known if the autophagic process differs at basal levels between CML patients and healthy individuals and if pretreatment CML cells harbor unique autophagy characteristics that could predict patients' clinical outcomes. We now demonstrate that several key autophagy genes are differentially expressed in CD34(+) hematopoietic stem/progenitor cells, with the highest transcript levels detected for ATG4B, and that the transcript and protein expression levels of ATG4 family members, ATG5 and BECLIN-1 are significantly increased in CD34(+) cells from chronic-phase CML patients (P < .05). Importantly, ATG4B is differentially expressed in pretreatment CML stem/progenitor cells from subsequent IM responders vs IM nonresponders (P < .05). Knockdown of ATG4B suppresses autophagy, impairs the survival of CML stem/progenitor cells and sensitizes them to IM treatment. Moreover, deregulated expression of ATG4B in CD34(+) CML cells inversely correlates with transcript levels of miR-34a, and ATG4B is shown to be a direct target of miR-34a. This study identifies ATG4B as a potential biomarker for predicting therapeutic response in treatment-naïve CML stem/progenitor cells and uncovers ATG4B as a possible drug target in these cells.

Targeting primitive chronic myeloid leukemia cells by effective inhibition of a new AHI-1-BCR-ABL-JAK2 complex.

BACKGROUND: Imatinib mesylate (IM) induces clinical remission of chronic myeloid leukemia (CML). The Abelson helper integration site 1 (AHI-1) oncoprotein interacts with BCR-ABL and Janus kinase 2 (JAK2) to mediate IM response of primitive CML cells, but the effect of the interaction complex on the response to ABL and JAK2 inhibitors is unknown. METHODS: The AHI-1-BCR-ABL-JAK2 interaction complex was analyzed by mutational analysis and coimmunoprecipitation. Roles of the complex in regulation of response or resistance to ABL and JAK2 inhibitors were investigated in BCR-ABL (+) cells and primary CML stem/progenitor cells and in immunodeficient NSG mice. All statistical tests were two-sided. RESULTS: The WD40-repeat domain of AHI-1 interacts with BCR-ABL, whereas the N-terminal region interacts with JAK2; loss of these interactions statistically significantly increased the IM sensitivity of CML cells. Disrupting this complex with a combination of IM and an orally bioavailable selective JAK2 inhibitor (TG101209 [TG]) statistically significantly induced death of AHI-1-overexpressing and IM-resistant cells in vitro and enhanced survival of leukemic mice, compared with single agents (combination vs TG alone: 63 vs 53 days, ratio = 0.84, 95% confidence interval [CI] = 0.6 to 1.1, P = .004; vs IM: 57 days, ratio = 0.9, 95% CI = 0.61 to 1.2, P = .003). Combination treatment also statistically significantly enhanced apoptosis of CD34(+) leukemic stem/progenitor cells and eliminated their long-term leukemia-initiating activity in NSG mice. Importantly, this approach was effective against treatment-naive CML stem cells from patients who subsequently proved to be resistant to IM therapy. CONCLUSIONS: Simultaneously targeting BCR-ABL and JAK2 activities in CML stem/progenitor cells may improve outcomes in patients destined to develop IM resistance.

Normal karyotype CALLA-positive adult pre-B ALL: dismal outcome with chemotherapy for patients with loss/gain of ABL1 and/or BCR FISH signals.

BACKGROUND: Diagnostic karyotype and molecular studies represent the most powerful prognostic indicators in acute myeloid leukemia and provide the framework for risk stratification. Risk stratification in ALL has also a vital role in predicting outcome and identifying patients at higher risk of relapse with multiagent chemotherapy, but the role of diagnostic karyotype and molecular markers in adult ALL is limited to few well recognized cytogenetic abnormalities. PATIENTS AND METHODS: We report a case series of 6 adult ALL patients with a characteristic molecular abnormality that have done poorly with chemotherapy. Between April 2004 and November 2009, 72 adult ALL patients (Pre-B-cell 61; T-cell 11) were referred to and treated at the Leukemia/BMT Program of BC in Vancouver, Canada. FISH for BCR-ABL fusion was positive in 12 of 61 Pre-B cell ALL patients. An additional 6 patients were negative for this typical fusion but had FISH abnormalities related to BCR and/or ABL1. RESULTS: In this report, we describe the clinical and hematopathologic characteristics of these 6 patients and their poor outcome. We review the literature where only 2 similar cases with normal karyotype Pre-B ALL and associated FISH BCR/ABL1 numerical abnormalities were found. CONCLUSION: We recommend screening all adult pre-B ALL patients with normal karyotype for this clonal abnormality and suggest classifying these ALL patients into the high-risk category.

Allogeneic haematopoietic stem cell transplantation for chronic lymphocytic leukaemia: outcome in a 20-year cohort.

The curative potential of allogeneic haematopoietic stem cell transplant (allo HSCT) in chronic lymphocytic leukaemia CLL is established, with a demonstrated role for graft-versus-leukaemia and less certainty for other factors in determining outcome. The first two decades of CLL patients proceeding to allo HSCT at the Leukaemia/Bone Marrow Transplant Program of British Columbia (n = 49 consecutive, 1991-2009) were studied to clarify factors predicting outcome. The donor was related in 29 (59%) and unrelated in 20 (41%). Conditioning was reduced-intensity in 27 (55%) and myeloablative in 22 (45%). Thirty-one of 49 patients survive with median follow-up of 5 years (0·2-15). Cumulative incidence of non-relapse mortality; complete remission (CR); clearance of fluorescence in situ hybridization (FISH) abnormality and progression at 10 years was 36%; 69%; 55% and 22%. Overall survival (OS) was 63% at 2 years; 55% at 5 years and beyond. Factors predicting OS (P value by log rank <0·05) were: comorbidity index <3, FISH rank (Dohner) and 17p deletion, alemtuzumab pre-HSCT, achievement of CR post-HSCT, donor chimerism >90%, clearance of FISH abnormality post-HSCT and absence of high-grade (3-4) graft-versus-host disease. Results from this province-wide, two-decade cohort demonstrated that a substantial proportion of patients with high-risk CLL become long term disease-free survivors.

Long-term follow-up of patients with chronic myeloid leukemia in chronic phase developing sudden blast phase on imatinib therapy.

Sudden blast phase (SBP) is a rare event that occurs in an unpredictable fashion amongst patients with chronic myeloid leukemia (CML) who otherwise appear to be responding satisfactorily to imatinib (IM) treatment. We investigated the incidence, clinical characteristics, treatment outcome and long-term follow-up of 213 patients with chronic phase CML treated with IM according to the European LeukemiaNet guidelines. Nine patients, eight of whom received IM as first-line therapy, developed SBP (4.2% of the total). They tended to have low or intermediate risk Sokal scores at diagnosis, a predominance of the lymphoid phenotype and a short interval from "optimal" response to the development of BP. Five of the nine patients with SBP are alive in complete molecular remission; however, all of them underwent allogeneic hematopoietic stem cell transplant. The cumulative incidence of SBP for the patients who received IM as first-line therapy was 5.9% and the 2-year overall survival of the nine patients who developed SBP was 56%. Despite the improved outcome for patients with SBP receiving tyrosine kinase inhibitors (TKIs) and transplant, many of these patients are not salvaged with these therapies. This illustrates the need to develop predictive models to identify patients early whose response to TKI therapy will not be durable and hopefully prevent the transformation to advanced disease.

Novel agents improve survival of transplant patients with multiple myeloma including those with high-risk disease defined by early relapse (<12 months).

The treatment of multiple myeloma (MM) has changed with the advent of thalidomide, bortezomib, and lenalidomide, the so-called novel agents (NAs). Given the complexity of MM therapy in the NA era we pursued a population based study to assess for improvements in survival as well as to characterize the relevance of early relapse (within 12 months) and the International Staging System in this clinical setting. We reviewed our experience with 460 patients with MM treated with autologous stem cell transplant (ASCT) between 1988 and 2008, of whom 306 had relapsed. The cohort was divided into two groups based upon relapse pre-2004 and relapse during/after 2004 (2004+), which correlated to availability of bortezomib and lenalidomide. Improvements in both overall survival (OS) (median 32.0 months vs. 71.8 months; p < 0.001) and post-relapse survival (PRS) (median 15.2 months vs. 42.8 months; p < 0.001) correlated with the NA era. Exposure to NAs conferred a better PRS (median 35.7 months vs. 9.1 months; p < 0.001). Although all patients had improvements in survival, those who relapsed late continued to do better. Lastly, in the NA era, the ISS remains an important prognostic tool in relapse, but only in the late relapsing cohort.

Response to tyrosine kinase inhibitor therapy in patients with chronic myelogenous leukemia relapsing in chronic and advanced phase following allogeneic hematopoietic stem cell transplantation.

Tyrosine kinase inhibitors (TKI) have been used to treat relapse of chronic myelogenous leukemia (CML) after allogeneic stem cell transplant (HSCT), with responses seen predominantly in chronic phase (CP) patients. This study aimed to analyze the response to TKI therapy and overall survival for patients relapsing predominantly in advanced phase. We retrospectively reviewed 22 patients treated with imatinib (n=20) and/or dasatinib (n=6) for relapsed CML after HSCT; 8 patients were in CP, and 14 patients had advanced disease. Seven patients also received donor lymphocyte infusions. Hematologic, cytogenetic, and molecular responses were analyzed. Nineteen patients (86%) achieved complete hematologic response (CHR), 17 patients (77%) achieved complete cytogenetic response (CCR), and 14 patients (64%) achieved complete molecular response (CMR). In advanced phase patients, 11 (79%) achieved CHR, 10 (71%) CCR, and 8 (57%) achieved CMR. Grade 3 or 4 cytopenias occurred in 10 cases. With median follow-up of 31.5 months from relapse, 14 (64%) patients remain alive, 13 in CMR. In multivariate analysis, the achievement of CMR was significantly correlated with OS with an odds ratio of 20.5 (95% confidence interval 2.3-182) P=.007. TKI therapy is capable of inducing durable molecular responses for CML relapsing after HSCT, both in chronic and advanced phases. The achievement of CMR appears to be crucial in providing long-term disease control for these patients.