Response In Chronic Myeloid Leukemia Research Articles

CML patients with deep molecular responses to TKI have restored immune effectors and decreased PD-1 and immune suppressors

AbstractImmunological control may contribute to achievement of deep molecular response in chronic myeloid leukemia (CML) patients on tyrosine kinase inhibitor (TKI) therapy and may promote treatment-free remission (TFR). We investigated effector and suppressor immune responses in CML patients at diagnosis (n = 21), on TKI (imatinib, nilotinib, dasatinib) before achieving major molecular response (pre-MMR, BCR-ABL1 >0.1%, n = 8), MMR (BCR-ABL1 ≤0.1%, n = 20), molecular response4.5 (MR4.5, BCR-ABL1 ≤0.0032%, n = 16), and sustained TFR (BCR-ABL1 undetectable following cessation of TKI therapy, n = 13). Aberrant immune-inhibitory responses (myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and programmed death-1 (PD-1) inhibitory molecule expression on CD4+/CD8+ T cells were increased in CML patients at diagnosis. Consequent quantitative and functional defects of innate effector natural killer (NK) cells and cytotoxic T-lymphocyte responses to leukemia-associated antigens WT1, BMI-1, PR3, and PRAME were observed at diagnosis. Treg and PD-1+CD4+/CD8+ T cells persisted in pre-MMR CML patients on TKI. Patients in MMR and MR4.5 had a more mature, cytolytic CD57+CD62L− NK cell phenotype, consistent with restoration of NK cell activating and inhibitory receptor repertoire to normal healthy donor levels. Immune responses were retained in TFR patients off-therapy, suggesting the restored immune control observed in MMR and MR4.5 is not an entirely TKI-mediated effect. Maximal restoration of immune responses occurred only in MR4.5, as demonstrated by increased NK cell and effector T-cell cytolytic function, reduced T-cell PD-1 expression and reduced numbers of monocytic MDSCs.

Early BCR-ABL1 Transcript Decline after 1 Month of Tyrosine Kinase Inhibitor Therapy as an Indicator for Treatment Response in Chronic Myeloid Leukemia.

In chronic myeloid leukemia (CML), early treatment prediction is important to identify patients with inferior overall outcomes. We examined the feasibility of using reductions in BCR-ABL1 transcript levels after 1 month of tyrosine kinase inhibitor (TKI) treatment to predict therapy response. Fifty-two first-line TKI-treated CML patients were included (imatinib n = 26, dasatinib n = 21, nilotinib n = 5), and BCR-ABL1 transcript levels were measured at diagnosis (dg) and 1, 3, 6, 12, 18, 24, and 36 months. The fold change of the BCR-ABL1 transcripts at 1 month compared to initial BCR-ABL1 transcript levels was used to indicate early therapy response. In our cohort, 21% of patients had no decrease in BCR-ABL1 transcript levels after 1 month and were classified as poor responders. Surprisingly, these patients had lower BCR-ABL1 transcript levels at dg compared to responders (31% vs. 48%, p = 0.0083). Poor responders also significantly more often had enlarged spleen (55% vs. 15%; p<0.01) and a higher percentage of Ph+ CD34+CD38- cells in the bone marrow (91% vs. 75%, p<0.05). The major molecular response rates were inferior in the poor responders (at 12m 18% vs. 64%, p<0.01; 18m 27% vs. 75%, p<0.01; 24m 55% vs. 87%, p<0.01). In conclusion, early treatment response analysis defines a biologically distinct patient subgroup with inferior long-term outcomes.

Cytogenetic and molecular response of EUTOS risk groups in children with chronic myeloid leukemia chronic phase on imatinib treatment

Introduction Recently (2011), the European Treatment and Outcome Study (EUTOS) scoring system was formulated to risk-stratify chronic myeloid leukemia (CML) chronic phase patients on imatinib treatment. CML during childhood is rare, making prognostication and management difficult. This study was conducted to investigate the cytogenetic and molecular response rates among EUTOS risk groups in pediatric CML patients on treatment with imatinib. Patients and methods Hospital records of pediatric CML chronic phase patients (age18 years) from 2009 to 2012 were analyzed retrospectively for demographic data, imatinib dose, date of initiation of treatment, EUTOS risk score, follow-up details, and cytogenetic and molecular response. Results A total of 57 children were included in this study, with a median age of 14.5 years (range: 5–18 years) and male preponderance (M:F, 1.19:1). The majority (67%) of them were in the low-risk group as per the EUTOS score and the remaining were in the high-risk group. Complete hematological response at 3 months was 100% in the low-risk and 94% in the high-risk group. Complete cytogenetic response at 12 months was 76 and 73% in the low-risk and high-risk groups, respectively. Major molecular response at 18 months was 85 and 79% in the low-risk and high-risk groups, respectively. Two-year event-free survival was 89 and 80% in the low-risk and high-risk groups, respectively. Conclusion The EUTOS low-risk cohort responded better than the high-risk cohort, but the difference was not statistically significant. Both groups had similar outcome at the end of 2 years. The EUTOS score did not predict the response and outcome in pediatric CML.

Trough concentration and ABCG2 polymorphism are better to predict imatinib response in chronic myeloid leukemia: a meta-analysis.

The present study aimed to conduct a series of meta-analyses to investigate the influence of imatinib trough concentration (C0), as well as ABCB1 and ABCG2 polymorphisms, on the clinical response in patients with chronic myeloid leukemia (CML). A literature search was conducted using the PubMed and Cochrane electronic databases to locate relevant papers from 2003 onward. Then, an initial meta-analysis of 14 studies involving 2184 patients was conducted to understand the effect of imatinib mesylate (IM) C0 on clinical outcome in CML patients. Subsequently, a series of meta-analyses were performed, including up to 23 studies with 2577 patients, on the effect of genetic polymorphisms of ABCB1 and ABCG2 on the clinical response to IM. Meta-analysis revealed that patients who achieved a major molecular response (MMR) have a significantly higher IM C0 than those who failed to achieve an MMR. We also found that the patients who achieved a complete cytogenic response (CCyR) have a significantly higher IM C0 than those who did not achieve a CCyR. However, no significant difference in IM C0 was found between the complete molecular response and non-complete molecular response groups. Additional analysis showed that ABCG2 421 variant A allele was significantly associated with a higher rate of MMR and overall response, especially in Asian patients. Meta-analysis did not reveal a correlation between ABCB1 C3435T and C1236T polymorphisms with any clinical response to IM. However, the G2677T/A polymorphism could play a role in IM response in the recessive model. This meta-analysis demonstrates that there was a significant correlation between the IM trough concentration and clinical responses, especially MMR and CCyR, in CML patients. Furthermore, we found that the probability of successful treatment was correlated with the ABCG2 C421A polymorphism, at least within the Asian population. We failed to determine an association between ABCB1 polymorphisms and IM response, although the G2677T/A polymorphism might be involved. However, further large-scale investigations using more sensitive genotyping methods would be required to confirm this.

"M3-M6" Molecular Response Evolution As Early Predictor of Outcome Considering Generic Vs Branded TKIs for Chronic Myeloid Leukemia (CML): An Argentine Multicentric Study

Introduction: Early reduction of BCR-ABL transcript level has been associated with improved outcomes in CML treatment. Inability to achieve early molecular response(MR) at 3 months (M3>10%) is considered a predictor factor for unfavourable outcome. However, the kinetics of BCR-ABL transcript level reduction measured at early time points have shown to be an independent predictor of response.The aim of this analysis was to determine whether the "M3-M6" status is critical to categorize CML patients (pts) focusing in high-risk group.Method: Molecular monitoring was performed in all pts prior treatment (M0), at months 3 (M3), 6 (M6), 12 (M12) and every 6 months thereafter, applying Q-PCR method according international recommendations. Results of BCR-ABL1 transcript level were reported on the international scale as IS-BCR-ABL %. Optimal responses: M3≤10%, M6≤1%, M12≤0,1%. Deep responses (MR4.0): ≤0,01% or undetectable/10.000 ABL copies.Results: A total of 70 CML pts were included, median age 49 (19-82), female 39%. First line treatment: sustained branded 81% and generic 19% TKIs. Imatinib 59%, Dasatinib and Nilotinib 41%. Sokal risk score: low (L) 51%, intermediate (In) and high (H) 49%. Optimal responses at molecular milestones: 75% at M3, 72% at M6, 61% at M12 and 53% pts achieved MR4.0. Event-free survival (EFS) was evaluated according to time point M3: M3≤10% group had significantly better EFS compared with the M3>10% (96% vs 70%; P=0.028). M3-M6 status defined 4 groups of pts: M3≤10%-M6≤1%, M3≤10%-M6>1%, M3>10%-M6≤1%, M3>10%-M6>1%. Molecular response evolution by M3-M6 status is described in Table 1. EFS stratified by groups according to combined M3-M6 responses showed significant differences: 92% for group 1, 87% for group 2, 68% for group 3, 54% for group 4. (P=0.002). M6 time point was shown to be critical in 32 high-risk pts (H+In): 17 pts with M6 ≤1% showed significant differences in MR4.0 achievement compared to 15 pts with M6 >1% (82% vs 27% P=0.02). Better EFS was observed in this high-risk group under branded vs generic TKIs treatment (97% vs 54% P=0.04). Statistical differences in deep responses and MMR at M12 were observed between branded and generic TKIs independently of Sokal risk (P=0.06, P=0.02).Conclusions: M3≤10% pts showed a favourable evolution with better EFS than M3>10% group. However not all patients with M3<10% had a similar behavior, showing lower rates of MMR at M12 and deep responses in those pts with M6>1%. In pts with M3 >10% and optimal response at M6 also showed higher MR4.0 rate. Our study supports that M6 is a crucial endpoint to predict MMR at M12 and deep responses in CML pts.Pts with M3≤10% without optimal response at M6 (>1%) had a worse evolution than those slow responders who showed M3>10% and M6≤1%.High-risk pts are still a challenge, observing better outcomes in those under branded TKIs treatment. The M3-M6 status would be a prognostic marker of responses and EFS in chronic phase CML pts treated with TKIs. Our data support the critical role of M6 response in non-optimal M3>10% pts and intermediate and high risk Sokal score. Treatment adherence is mandatory for achieving and sustaining optimal responses. This multicentric Argentine study, reinforces the importance of clinical follow-up and molecular monitoring under IS standardization at early time points. Education on early molecular monitoring with adequate resources must continue to be an objective in our region. [Display omitted] DisclosuresPavlovsky:Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Speakers Bureau. Moiraghi:Novartis: Speakers Bureau; Bristol: Speakers Bureau. Varela:Novartis: Speakers Bureau; Bristol: Speakers Bureau. Enrico:Novartis: Honoraria, Patents & Royalties; Bristol Myers squib: Speakers Bureau. Brodsky:International PNH Registry: Other: -; Alexion Pharma Argentina: Speakers Bureau. Pavlovsky:Novartis: Speakers Bureau; Janssen: Speakers Bureau; Bristol Myers Squib: Speakers Bureau.

Prognostic Impact of p190 and p210 Co-Expression in Early Molecular Response in Chronic Myeloid Leukemia (CML) Patients Treated with Tyrosin Kinase Inibitors

Background: Expression of p190 BCR-ABL mRNA is generally considered to be confined to patients with acute lymphoid or more rarely myeloid leukemias, whereas p210 BCR-ABL mRNA is the hallmark of CML. In reality it is not uncommon the presence of p190 m-RNA in p210 CML in chronic phase, due to alternative or missplicing. Its presence seems to have no impact on prognosis in the pre-TKI era, although it may be expression of genomic instability.Aim: Primary object of this study was to investigate if the co-expression might influence the rate of early outcome surrogate endpoints such as such as optimal molecular response (EMR; BCR-ABL < 10% (IS) at 3 month and BCR-ABL < 1% or 6 month). in patients treated with TKI.Methods: Were evaluated patients with CML in chronic phase treated with TKI at our institution. We excluded cases with less than one year of treatment or treated with conventional chemotherapy. The fusion transcripts BCR-ABL were evaluated at diagnosis in peripheral blood by NESTED-PCR and the molecular response were evaluated in peripheral blood with Real-Time PCR. The patients were divided into two groups, "double transcripts" (DT) and "single transcript" (ST).Results: A total of 34 patients were analyzed. The median age was 61 years (range 22-80) and 26 (68%) were male. Ten patients (29%) were DT and twenty-fouru(71%) ST. The distribution according to Sokal score was: 2 (10%), 5 (50%) 3(30%) patients for low, intermediate and high risk in the DT, whereas 13 (54%), 10 (41%) 1 (5%) low, intermediate and high risk in ST, respectively. The optimal response at 3 month was achieved in 3 patients with DT and 20 patients with ST ( 10% vs 83), at 6-month optimal response was achieved in 3 patients with DT and 20 patients with ST (10% vs 83). No patients with BCR-ABL > 10 % at 3 months, achieved molecular response at 6 months.Summary/Conclusion: In our study the co-expression of p190 and p210 BCR-ABL transcripts influences the early molecular response to TKI and suggesting the need for a larger validation study DisclosuresNo relevant conflicts of interest to declare.

Assessment of Value Using the American Society of Clinical Oncology (ASCO) and European Society of Medical Oncology (ESMO) Frameworks for Novel Therapies for the Hematologic Malignancies

IntroductionThe cost of cancer care is rising to unsustainable levels, predominantly driven by an increase in expenditures for novel therapies. In the era of biologic therapies, these excessive costs are disproportionately borne by patients with hematologic malignancies. Although the American Society of Clinical Oncology (ASCO) and European Society of Medical Oncology (ESMO) have both developed frameworks to determine the relative value associated with new solid tumor therapies (and specifically with ESMO, to the exclusion of therapies in hematology), it is unclear if they can be applied in the assessment of value of treatments for blood cancers.MethodsWe evaluated the value of new therapies for hematologic malignancies using the ASCO (version 1 from August 10, 2015 and version 2 from May 31, 2016) and ESMO (version 1 or v1) frameworks. All US Food and Drug Administration, European Medicinal Agency, or Health Canada approved parenteral therapies for hematologic malignancies from 2006-2015 were identified. A systematic review of randomized controlled trials (RCTs) for these therapies was conducted. Two reviewers independently scored the trials using the ASCO value framework v1 (range of scores -20 to 130), v2 (lower range undefined to 180) and ESMO Magnitude of Clinical Benefit Scale (range 1-5). Disagreements were descriptively presented and resolved by consensus. The concurrent validity between the ASCO and ESMO scores was measured by the Spearman correlation coefficient.ResultsTwenty-three RCTs in malignant hematology were identified and scored. Seven of 23 studies reported primary outcomes unique to hematologic malignancies (for example, time-to-progression in myeloma, cytogenetic response in chronic myeloid leukemia, and symptomatic response in multicentric Castleman's), other than the main outcomes used to derive ASCO/ESMO scores (overall and progression-free survival). The median ASCO v1 score for the trials was 24 (IQR 22-40, min 6 and max 53). The median ASCO v2 score was 26.7 (IQR 17.4-37.6, min -33.3 and max 116.3). The median ESMO score was 2 (IQR 2-3, min 1 and max 4). Using the ASCO v1 framework, 10 studies resulted in disagreements in scoring, predominantly due to variable interpretations of the scoring system. Two studies could not be scored. One study did not report toxicity grades and another study of maintenance rituximab in lymphoma did not report on conventional oncology outcomes that could fit into the ASCO model. Using the ASCO v2 framework, 14 studies resulted in disagreements, predominantly due to differences in scoring toxicities. With the ESMO Scale, 12 studies resulted in disagreements, most occurring due to variable interpretations in scoring survival or progression-free survival outcomes when median values were not provided in the study publication. Two studies could not be scored with the ESMO Scale. One study did not report hazard ratios and another study's reported outcomes did not fit the ESMO scoring options. The correlation coefficient between ASCO v1 and ESMO scores was 0.10 (95% CI: -0.37 to 0.53), suggesting that the correlation was not significantly different from chance only. The coefficient between ASCO v2 and ESMO was -0.21 (95% CI: -0.59 to 0.24) and between ASCO v1 and ASCO v2 was 0.30 (95% CI: -0.15 to 0.65).ConclusionsCurrent value frameworks are challenging to apply to therapies for hematologic malignancies. When studies could be scored, the correlations between ASCO (v1 and v2) and ESMO results were poor, suggesting that these frameworks may not reliably identify the value of therapies in hematology. Consideration for the unique outcomes and toxicities in this population is warranted. The ASCO and ESMO frameworks continue to evolve, and a partnership with societies representing hematologists and their patients would be fruitful. DisclosuresNo relevant conflicts of interest to declare.

Timely Molecular Monitoring and Achievement of Major Molecular Response in Chronic Myeloid Leukemia

Background: Timely molecular monitoring is the cornerstone of chronic myeloid leukemia (CML) treatment guidelines. These guidelines are based on the design of clinical trials, but none have been validated prospectively. We hypothesized that timely molecular monitoring in routine patient care increases the likelihood of achieving major molecular response (MMR) in CML.Methods: We conducted a prospective cohort study using the Québec CML Registry, which comprises 713 patients from 16 hospitals. Patients with newly-diagnosed CML (2009-2014) and measurable disease by quantitative PCR were followed from tyrosine kinase inhibitor (TKI) initiation. Timely PCR (tPCR) was defined as a PCR performed at 2-4, 11-13, and 17-19 months. (Figure). Study outcome was the achievement of MMR at 25 months, defined as international scale ratio (IS) <0.1% or a 3-log reduction in BCR-ABL1 copy number. Achievement of MMR was determined using any PCR during follow-up. Generalized estimating equations (GEE) using an exchangeable correlation structure, to account for patient clustering by center, were used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of achieving MMR comparing adherence and nonadherence to tPCR. The models were adjusted for age, sex, first-line TKI, year of study entry, and Charlson comorbidity index.Results: A total of 246 patients with 25 months of follow-up were included in the analysis (Table 1). Patients were excluded due to diagnoses before 2009 (350), insufficient follow-up (76), and other (41). The mean (standard deviation) age was 56.1 (15.5), 43.9% were female; 67.5% were started on imatinib, and 47.6% were treated in higher-volume (>50 CML patients) centers. Timely PCRs were performed in 76.3%, 69.5%, and 61.0% of patients at 2-4, 11-13, and 17-19 months, respectively. When compared with not performing tPCRs, performing one and two tPCRs were associated with achieving an MMR by 25 months (OR: 17.05, 95% CI: 5.18-56.09 and OR: 14.96, 95% CI 3.63-61.73, respectively, Table 2). The highest OR of achieving MMR was observed among those who underwent three tPCRs (OR: 24.02, 95% CI: 7.07-81.55).Conclusions: To our knowledge, this is the first study to assess clinical outcomes associated with timely molecular monitoring in early CML. While performing one and two tPCRs was associated with achieving MMR at 25 months, the point estimate for performing three tPCRs was the highest. These findings indicate that timely monitoring may allow for faster switching of TKI, which ultimately permits patients with early failure to "catch up." Alternatively, more regular testing may increase patient adherence to therapy. If replicated, these findings support routine and punctual monitoring of patients on TKI therapy. [Display omitted] [Display omitted] [Display omitted] DisclosuresAssouline:Pfizer: Speakers Bureau; BMS: Speakers Bureau.

Optimized Treatment Schedules for Chronic Myeloid Leukemia.

Over the past decade, several targeted therapies (e.g. imatinib, dasatinib, nilotinib) have been developed to treat Chronic Myeloid Leukemia (CML). Despite an initial response to therapy, drug resistance remains a problem for some CML patients. Recent studies have shown that resistance mutations that preexist treatment can be detected in a substantial number of patients, and that this may be associated with eventual treatment failure. One proposed method to extend treatment efficacy is to use a combination of multiple targeted therapies. However, the design of such combination therapies (timing, sequence, etc.) remains an open challenge. In this work we mathematically model the dynamics of CML response to combination therapy and analyze the impact of combination treatment schedules on treatment efficacy in patients with preexisting resistance. We then propose an optimization problem to find the best schedule of multiple therapies based on the evolution of CML according to our ordinary differential equation model. This resulting optimization problem is nontrivial due to the presence of ordinary different equation constraints and integer variables. Our model also incorporates drug toxicity constraints by tracking the dynamics of patient neutrophil counts in response to therapy. We determine optimal combination strategies that maximize time until treatment failure on hypothetical patients, using parameters estimated from clinical data in the literature.

Plasma proteomics in CML patients before and after initiation of tyrosine kinase inhibitor therapy reveals induced Th1 immunity and loss of angiogenic stimuli

Background and aimsThe simultaneous measurement of many proteins is now possible using multiplex assays. In this pilot study we investigated a total of 124 proteins in plasma from chronic myeloid leukemia (CML) patients with the purpose of identifying proteins that are differently expressed at diagnosis and after tyrosine kinase inhibitor (TKI) treatment initiation. MethodsSamples were taken from 14 CML patients at diagnosis and after three months of TKI treatment (imatinib or dasatinib). Samples were analyzed by Mesoscale Discovery, Myriad RBM MAP technology and Olink Proseek. ResultsMultiple plasma proteins were differentially expressed before and after initiation of TKI therapy. Protein patterns demonstrated a possible shift towards Th1-immunity and reduced angiogenic stimuli. Further, some plasma proteins were identified that can be of potential interest to study further for biologic, prognostic or therapeutic significance such as E-selectin, uPAR, growth hormone and carbonic anhydrase IX. ConclusionsPlasma proteomics seems feasible and useful in CML patients, both for studying patterns of protein expression and for identifying single proteins differentially expressed before and after treatment. Plasma proteomics may be useful to map disease activity and biological processes. Hence, plasma proteomics can be used to understand drug mechanisms and treatment responses in CML.

Medication Adherence to Tyrosine Kinase Inhibitors: 2-Year Analysis of Medication Adherence to Imatinib Treatment for Chronic Myeloid Leukemia and Correlation with the Depth of Molecular Response

Objective: Adherence to tyrosine kinase inhibitor treatment is a significant factor in the achievement of a good clinical response in chronic myeloid leukemia (CML). The aim of this retrospective study is to investigate 1- and 2-year medication adherence to imatinib treatment, linking adherence rates with the clinical outcome, in accordance with European LeukemiaNet Recommendations for the management of CML. We have tried to find a cutoff value for adherence in order to achieve a good clinical outcome. Methods: The method used to calculate medication adherence was the ratio between the received and the prescribed daily dose. Results: We observed the levels of mean adherence for each of the following response groups (in years 1 and 2, respectively): complete response (0.96, 0.95), MR4.5 (1.00, -), MR4 (0.93, 0.91), major molecular responses (0.96, 0.97), warning (0.91, 0.89) and failure (0.79, 0.84). Conclusion: Results show that the higher the adherence, the lower the level of BCR-ABL1. Furthermore, using cutoffs ≥0.9, outcomes were significantly improved compared to those with cutoffs <0.90. This value of adherence is in line with previous publications.

The Cancer Stem Cell Fraction in Hierarchically Organized Tumors Can Be Estimated Using Mathematical Modeling and Patient-Specific Treatment Trajectories.

Many tumors are hierarchically organized and driven by a subpopulation of tumor-initiating cells (TIC), or cancer stem cells. TICs are uniquely capable of recapitulating the tumor and are thought to be highly resistant to radio- and chemotherapy. Macroscopic patterns of tumor expansion before treatment and tumor regression during treatment are tied to the dynamics of TICs. Until now, the quantitative information about the fraction of TICs from macroscopic tumor burden trajectories could not be inferred. In this study, we generated a quantitative method based on a mathematical model that describes hierarchically organized tumor dynamics and patient-derived tumor burden information. The method identifies two characteristic equilibrium TIC regimes during expansion and regression. We show that tumor expansion and regression curves can be leveraged to infer estimates of the TIC fraction in individual patients at detection and after continued therapy. Furthermore, our method is parameter-free; it solely requires the knowledge of a patient's tumor burden over multiple time points to reveal microscopic properties of the malignancy. We demonstrate proof of concept in the case of chronic myeloid leukemia (CML), wherein our model recapitulated the clinical history of the disease in two independent patient cohorts. On the basis of patient-specific treatment responses in CML, we predict that after one year of targeted treatment, the fraction of TICs increases 100-fold and continues to increase up to 1,000-fold after 5 years of treatment. Our novel framework may significantly influence the implementation of personalized treatment strategies and has the potential for rapid translation into the clinic. Cancer Res; 76(7); 1705-13. ©2016 AACR.

Assessment of bone marrow lymphocytic status during tyrosine kinase inhibitor therapy and its relation to therapy response in chronic myeloid leukaemia.

Tyrosine kinase inhibitors (TKIs) used in the treatment of chronic myeloid leukaemia have been reported to induce immunomodulatory effects. We aimed to assess peripheral blood (PB) and bone marrow (BM) lymphocyte status at the diagnosis and during different TKI therapies and correlate it with treatment responses. BM and PB samples were acquired from 105 first-line TKI-treated patients. Relative number of BM lymphocytes was evaluated from MGG-stained BM aspirates, and immunophenotypic analyses were performed with multicolour flow cytometry. Early 3-month expansion of BM lymphocytes was found during all different TKIs (imatinib n = 71, 20 %; dasatinib n = 25, 21 %; nilotinib n = 9, 22 %; healthy controls n = 14, 12 %, p < 0.0001). Increased PB lymphocyte count was only observed during dasatinib therapy. The BM lymphocyte expansion was associated with early molecular response; patients with 3-month BCR-ABL1 <10 % showed higher lymphocyte counts than patients with BCR-ABL1 >10 % (23 vs. 17 %, p < 0.05). Detailed phenotypic analysis showed that BM lymphocyte expansion consisted of various lymphocyte subclasses, but especially the proportion of CD19+ B cells and CD3negCD16/56+ NK cells increased from diagnostic values. During dasatinib treatment, the lymphocyte balance in both BM and PB was shifted more to cytotoxic direction (increased CD8+CD57+ and CD8+HLA-DR+ cells, and low T regulatory cells), whereas no major immunophenotypic differences were observed between imatinib and nilotinib patients. Early BM lymphocytosis occurs with all current first-line TKIs and is associated with better treatment responses. PB and BM immunoprofile during dasatinib treatment markedly differs from both imatinib- and nilotinib-treated patients.

B-Cell Chronic Lymphocytic Leukemia with 11q22.3 Rearrangement in Patient with Chronic Myeloid Leukemia Treated with Imatinib

The coexistence of two diseases chronic myeloid leukemia (CML) and B-cell chronic lymphocytic leukemia (B-CLL) is a rare phenomenon. Both neoplastic disorders have several common epidemiological denominators (they occur more often in men over 50 years of age) but different origin and long term prognosis. In this paper we described the clinical and pathological findings in patient with CML in major molecular response who developed B-CLL with 11q22.3 rearrangement and Coombs positive hemolytic anemia during the imatinib treatment. Due to the presence of the symptoms of autoimmune hemolytic anemia and optimal CML response to the imatinib treatment, the decision about combined therapy with prednisone and imatinib was made. During the follow-up, the normalization of complete blood count and resolution of peripheral lymphadenopathy were noted. The hematologic response of B-CLL was diagnosed. The repeated FISH analysis of cultured peripheral blood lymphocytes showed 2% of cells carrying 11q22.3 rearrangement. At the same time, molecular monitoring confirmed the deep molecular response of CML. The effectiveness of such combination in the described case raises the question about the best therapeutic option in such situation, especially in patients with good imatinib tolerance and optimal response.

Molecular monitoring in CML and the prospects for treatment-free remissions

Monitoring treatment responses in chronic myeloid leukemia (CML) is based on complete blood counts (CBCs) to determine hematologic response, karyotyping of bone marrow metaphase cells to delineate cytogenetic response and quantitative reverse transcription polymerase chain reaction (qPCR) to quantify expression of BCR-ABL1 mRNA (molecular response; MR) in peripheral blood. Fluorescence in situ hybridization (FISH) to identify BCR-ABL1 in interphase nuclei and mutational analysis of the BCR-ABL1 kinase domain (KD) are used in certain clinical circumstances. As most patients treated with tyrosine kinase inhibitors (TKIs) achieve complete cytogenetic responses (CCyRs), qPCR with its increased sensitivity and dynamic range has become the main tool used to monitor CML patients. Landmark analyses of large TKI trials have established MR milestones that identify patients with high risk of failure, are the basis of consensus management guidelines, and have led to a strong push toward qPCR test standardization. Today many laboratories report BCR-ABL1 qPCR results on the international scale (IS), a system based on the conversion of laboratory-specific numerical values to conform to a universal scale. The fact that qPCR is technically demanding and liable to assay variations poses considerable challenges for its routine clinical use. This is important as the prevalence of patients on chronic TKI therapy increases and critical clinical decisions are made based on qPCR results, for example if discontinuation of TKI therapy should be considered. Here we will review the current state of molecular monitoring in CML, focusing on qPCR, the definition of TKI failure and the results of TKI discontinuation studies.

The Allosteric Inhibitor ABL001 Is Susceptible to Resistance in Vitro Mediated By Overexpression of the Drug Efflux Transporters ABCB1 and ABCG2

Tyrosine Kinase Inhibitors (TKIs) result in excellent responses in Chronic Myeloid Leukaemia (CML) patients. However, secondary resistance is observed in ~35% of patients, mostly due to Bcr-Abl kinase domain (KD) mutations. Overexpression of the efflux transporter ABCB1 is a known mediator of primary resistance to imatinib (IM) and nilotinib (NIL). ABL001, a potent allosteric inhibitor, binds to the myristate pocket of the Bcr-Abl KD. In this study, we modelled ABL001 resistance in vitro with particular focus on ABCB1 and ABCG2.ABL001 sensitivity was evaluated in BCR -ABL1 + cell lines K562, K562-Dox (ABCB1 overexpressing) and K562-ABCG2 (transfected with ABCG2 overexpression vector). Also, K562, K562-Dox and KU812 cells were made resistant to ABL001 by culturing long term in increasing concentrations of ABL001 (increased once >80% survival in culture for >10 days). Parental ABL001 naive cells were maintained in parallel culture. Initial onset of resistance was characterised by significantly increased IC50ABL001 based on AnnexinV/7-AAD cytotoxicity assays performed at each ABL001 dose escalation. Resistance mechanisms were interrogated during escalation and once 10 μM was reached (based on clinically achievable doses). Protein expression levels of efflux transporters ABCB1/ABCG2 were examined by flow cytometry; KD mutation sequencing and Bcr-Abl protein quantitation were performed.K562-Dox and K562-ABCG2 cells demonstrated significantly increased IC50ABL001 compared with parental K562 control cells: 256 and 299 nM respectively vs 23 nM, p<0.001 suggesting both ABCB1 and ABCG2 are important in ABL001 transport. Furthermore, resistance was reversible through use of specific inhibitors cyclosporin (ABCB1) and Ko143 (ABCG2). IC50ABL001 +inhibitors was comparable to that of control K562 cells: K562-Dox +cyclosporin=11 nM; K562-ABCG2 +Ko143=15 nM.A prior study identified ABCB1 overexpression as an initiator of resistance to IM and NIL (expression increased up to 7- and 5-fold in IM and NIL resistant cells compared with respective control cells p<0.002). In this study, expression levels of ABCB1 and ABCG2 were interrogated in 3 ABL001 resistant cell lines; results indicated overexpression of both transporters was integral in development of resistance. Up to 17- and 60-fold greater levels of ABCB1 and ABCG2 respectively was observed in resistant vs control cells (Table 1). No KD mutations were detected in early resistance intermediates; however, a myristate pocket mutation was detected in later stage KU812 ABL001 resistant cells (percentage mutation correlated with IC50ABL001).Table 1ABL001 resistance characteristics in selected resistant intermediatesIC50ABL001 (nM)Fold change (MFI)Bcr-Abl over expressionKD mutationABCB1ABCG2K562 Control23NNK562 500 nM ABL001>2500 p <0.001-1.4 p =0.00348.3 p =0.007YNK562 10 μM ABL00127, 800p <0.001-2.3 p =0.53560.3 p <0.001YNK562 10 μM ABL001 +Ko14389 p <0.001K562-Dox Control256NNK562-Dox 500 nM ABL0012393 p <0.0012.3 p <0.001-2.9 p <0.001NNK562-Dox 500 nM ABL001 +cyclosporin17 p <0.001K562-Dox 10 μM ABL001>50, 000 p <0.001-1.6 p <0.001-0.1 p <0.001NNKU812 Control2.7NNKU812 5 nM ABL0016.4 p <0.0012.2 p =0.0084.0 p =0.002YNKU812 10 μM ABL00133, 300 p <0.0018.1 p =0.00311.0 p =0.010YY (90%)p-value: resistant vs respective control; n>3; N=No; Y=YesWhile further in vitro and in vivo studies will determine the clinical relevance of efflux-mediated resistance to ABL001 mono- and combination therapy, our preclinical data provide evidence that kinase domain mutations may not be the predominant cause of ABL001 resistance; drug transporters likely play an important role as well. Susceptibility to ABCB1 overexpression is well recognised for IM and NIL resistance and we now show it is also relevant for ABL001. ABCG2-mediated resistance has not been observed with NIL or IM but is clearly important for ABL001. ABL001 treatment induced ABCG2 overexpression in two cell lines; both have negligible basal expression. ABCG2 overexpression preceded Bcr-Abl overexpression and mutation emergence. Importantly, ABL001 resistance was completely reversible in the presence of the ABCG2 inhibitor Ko143 (K562 10 μM ABL001 cells). Given the lack of strong evidence for ABCG2-mediated transport of NIL or IM at clinically relevant concentrations, our data provide a strong rationale for the use of ABL001 in combination with either of these TKIs. DisclosuresBranford:Ariad: Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Qiagen: Membership on an entity's Board of Directors or advisory committees. White:Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding. Hughes:ARIAD: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.

Clinical Relevance of Failure to Achieve Early Molecular Response in Chronic Myeloid Leukemia in Chronic Phase

▪PurposeThe early molecular response (EMR, ≤ 10% BCR-ABL1 at 3 months) of tyrosine kinase inhibitor (TKI) treatment for patients with chronic myeloid leukemia (CML) in chronic phase (CP) has been reported to have strong correlation with long-term outcome. We aim to investigate the prognostic interaction of the EMR and major molecular response (MMR).MethodsWe retrospectively reviewed data for a total of 165 patients with newly diagnosed CML-CP who received TKIs (imatinib, nilotinib, or dasatinib) as first-line treatment between January 2003 and April 2013. Of the total 128 patients who were regularly monitored by peripheral blood molecular analysis, 85 had a BCR-ABL1 assessment at 3 months and were finally included in the analysis.ResultsThe median age of all patients was 49 years and 87.1% received imatinib as first line treatment. High risk group by Sokal and EUTOS were 29.4% and 14.1%, respectively. Patients with EMR (n = 56, 65.9%) had a tendency to have low risk disease and to be treated with 2nd generation of TKIs. With a median follow-up duration of 53.6 months (range, 5.4-131.3), the 5-year OS, 5-year FFS, and 5-year EFS were 92.5%, 74.8%, and 68.0%, respectively. Median time to achieve MMR was 11.1 months (95%CI, 8.4 - 13.8). The outcomes at 5 year comparing patients whose BCR-ABL1 transcript levels ≤ 10% vs >10% at 3 months were as follows: OS, 92.2% (95% CI 84.9-99.1) vs 92.8% (95% CI 83.7-102.3), p = 0.819; FFS, 84.7% (95% CI, 75.6-94.4) vs 57.4% (95% CI, 39.0-75.0), p < 0.001; and EFS, 73.6% (95% CI 62.5-85.5) vs 57.8% (95% CI 40.0-76.0), p = 0.050. Six (10.7%) of 56 patients with BCR-ABL1 transcript levels ≤ 10% at 3 months failed to achieved an MMR and 18 (62.1%) of 29 patients with > 10% at 3 months achieved an MMR. Based on these heterogeneous clinical outcomes, we further explored subgroup analysis according to the achievement of MMR for refined discrimination of survival outcomes. There was no significant difference of clinical outcomes between ≤ 10% vs > 10% at 3 months among the patients who achieved MMR (OS, p = 0.376; FFS, p = 0.793; and EFS, p = 0.266). In patients who did not achieved MMR, only FFS was significantly difference between ≤ 10% vs > 10% at 3 months (OS, p = 0.489; FFS, p = 0.014; and EFS, p = 0.199).ConclusionPatients who failed to achieve EMR but finally reached MMR have excellent prognosis that whether we have to change TKI for EMR failure is to be addressed by ongoing prospective clinical trials. DisclosuresJang:Alexion Pharmaceuticals: Research Funding.

Switching to Nilotinib Are Associated with Deeper Molecular Responses in Chronic Myeloid Leukemia with Persistent Residual Disease on Long-Term Imatinib Therapy: STAT1 Trial in Japan

Introduction: Nilotinib is a second-generation TKI that exhibits significant efficacy as first- or second-line treatment in patients with CML. Superior rates of deeper molecular responses were achieved with nilotinib vs. imatinib in patients newly diagnosed with CML in chronic phase in the ENESTnd trial. In addition, the 24-month analysis of the ENESTcmr study demonstrated that switching to nilotinib after a minimum of 2 years on imatinib led to increased rates of MR4.5 by 24-month vs. remaining on imatinib (42.9% on nilotinib vs. 20.8% on imatinib). Although our CMR study revealed that ABCG2 421C/A genotype was an independent predictor of CMR in imatinib-treated CML patients (Shinohara et al, Haematologica, 2013), a relationship between ABCG2 421C/Agenotypes and CMR rate has not been observed in CML-CP patients treated with Nilotinib until now. The purpose of this study is to evaluate the efficacy of nilotinib in patients with CML-CP who have achieved a MMR with imatinib. In addition, the correlation of deeper molecular responses with clinical, immunological, and pharmacokinetic parameters in CML-CP patients was evaluated.Methods: Patients with CML-CP who had achieved MMR but still had persistent BCR-ABL positivity by RQ-PCR on imatinib were eligible. Nilotinib will be taken twice daily (600 mg/day) for 2 years. Thirty-five institutions in STAT study group participated. The study was conducted in accordance with the principles of the Declaration of Helsinki. Informed consent was written by all patients according to institutional guidelines. The study was approved by all institutional review boards and registered with ClinicalTrials.gov (number UMIN000005903). The primary objective of this multicenter phase II, single arm, open-label clinical study was to identify the MR4.5 rate at 24 months after the initiation of nilotinib treatment. The molecular response was evaluated according to the International Scale RQ-PCR upon study entry and every 3 months thereafter. Nilotinib trough concentrations were determined using high-performance liquid chromatography.Genotyping of SLC22A1 (156T>C, 480G>C, 1022C>T, and 1222A>G), ABCB1 3435T>C, ABCG2 421C>A, and the *6, *27 and *28 alleles of UGT1A1 were performed using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Flow cytometry-based analysis of peripheral blood T cell subsets was performed using a whole blood lysis technique.Results: Between July 2011 and December 2012, 80 Japanese patients were recruited, and 74 patients were evaluated in the study. The median age was 54.5 years. The ratio of men to women was 52:22. The median duration of imatinib treatment was 62.5 months (range, 13.3-131.1 months). All patients showed MMR at the time of entry into the study and the median time to MMR on imatinib therapy was 20.2 months (range, 4.6-92.1 months). The median duration of treatment was 17.9 months (range, 0.5-25.1 months) for nilotinib 300 mg twice daily. Dose reduction and interruption were seen 17.1% and 18.4% in safety data set (N=76), respectively. The patients achieving deeper molecular responses increased over time (Figure1). The rates of MR4 in the evaluable patients were 69% and 73% at 12 and 24 months, respectively, and the rates of MR4.5 were 28% and 49% at 12 and 24 months, respective. Comparison of the clinical backgrounds, pharmacokinetic, pharmacogenomic, and immunological parameters (NK cells, NK activity, and cytokines) in patients with MR4.5 at 24 months (n=33) and without (n=41) is performed. Age, sex, Sokal risk score, prior IFN therapy, duration of imatinib treatment and time to MMR were not significant predictive factors for achieving MR4.5 at 24 months. The mean nilotinib plasma trough concentration was not significantly different in both groups either (Table1). However, the frequency of patients with ABCG2 421A allele was significantly higher in patients with MR4.5 than without (OR 7.056, 95%CI 2.040-24.406, P =0.002). This finding suggested that the ABCG2 421A allele was associated with a higher intracellular retention and therefore, higher nilotinib exposure than the wild-type genotype.Conclusion: We confirmed that switching to nilotinib led to deeper molecular responses in CML patients with persistent residual disease on long-term imatinib therapy. [Display omitted] [Display omitted] [Display omitted] DisclosuresNakaseko:Otsuka: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau. Takahashi:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Masis: Consultancy; Astellas: Speakers Bureau; Sysmex: Research Funding, Speakers Bureau; Celgene: Speakers Bureau; Otsuka: Membership on an entity's Board of Directors or advisory committees. Nishiwaki:Novartis: Research Funding, Speakers Bureau.

First report of imatinib measurement in hair: Method development and preliminary evaluation of the relation between hair and plasma concentrations with therapeutic response in chronic myeloid leukemia

BackgroundImatinib (IM) is a first choice drug for treatment of chronic myeloid leukemia (CML), with a widely accepted concentration threshold of 1000ng/ml being used as a target for therapeutic drug monitoring. Once adherence to the pharmacotherapeutic regimen is of paramount importance during the long treatment course of CML, the measurement of hair IM concentrations could be a surrogate of the patient's exposure to the drug. MethodsIM was extracted from a 5mg hair sample by a liquid–liquid extraction with ethyl acetate, and IM-d8 was used as internal standard (IS). After evaporation, and reconstitution in acetonitrile, the extract was injected into a LC–MS/MS system. Compounds were eluted on a C8 column in isocratic mode. IM and IS were identified in positive electrospray ionization mode using ion transitions of m/z 494.5>394.5 and 503.0>394.3 respectively. The method was applied to 102 paired hair and samples obtained from CML patients. Treatment response was evaluated according to the European LeukemiaNet recommendations. ResultsThe assay was validated in the concentration range of 0.5–25ng/mg, with intra- and inter-assay imprecisions of <13.1% and <9.3%, respectively. The limits of quantification and detection were 0.5 and 0.15ng/mg, respectively. Median hair IM concentrations are significantly smaller in patients with therapeutic failure when compared with patients with partial or optimal response (4.63 vs. 7.93, p=0.040), the same trend presented by median plasma IM concentrations (629.5 vs. 1084.8, p=0.009). An IM hair concentration below 5.8ng/mg has 83% sensibility and 70% specificity to identify patients with therapeutic failure. ConclusionsA fast, sensitive, and selective LC–MS/MS method allowing quantification of IM in hair samples was developed and validated. CML patients with therapeutic failure had significantly lower hair IM concentrations when compared with patients with optimal response. These preliminary findings may support the use of hair as a matrix for IM monitoring in clinical settings, with significant logistic advantages over the collection of venous blood, particularly in developing countries.

A Cure for Paroxysmal Nocturnal Hemoglobinuria Using Molecular Targeted Therapy Specific to a Driver Mutation

Background: The clonal expansion of PIGA mutant hematopoietic stem cells (HSCs) can be induced by secondary driver mutations in genes such as HMGA2 and JAK2 in some patients with paroxysmal nocturnal hemoglobinuria (PNH). Theoretically, this type of PNH may be cured by molecular targeted therapy if the therapy is specific for the driver mutations and can eliminate PIGA mutant HSCs that acquired a proliferative advantage. However, this theory has not been proven because of the lack of an appropriate targeted therapy for known driver mutations responsible for clonal expansion of PIGA mutant HSCs. We recently treated a case of PNH complicated by chronic myeloid leukemia (CML) with nilotinib and observed a complete molecular response of CML followed by a complete disappearance of glycosylphosphatidylinositol-anchored protein-deficient (GPI-AP-, PNH-type) cells after 19 months of treatment.Case report: The patient, a 27-year-old Japanese woman, developed severe anemia with leukocytosis and thrombocytosis in 2013. The laboratory findings on admission were as follows: white blood cell count of 18.7x109/L with 1.7% stab neutrophils, 5.4% segmented neutrophils, 9.3% basophils, 1.3% promyelocytes, 5.0% myelocytes, 3.0% metamyelocytes, 18.0% lymphocytes and 0.7% blasts; hemoglobin (Hb)=6.0 g/dL, platelets=1,000x109/L, 20.0% reticulocytes, total/direct bilirubin=1.9/0.3 mg/dL, LDH=1963 IU/L and haptoglobin <10 mg/dL. A high-sensitivity flow cytometry analysis of the patient's peripheral blood at diagnosis revealed that 99.2% of granulocytes, 75.7% of erythrocytes and 99.3% of monocytes were GPI-AP-, while no T cells, B cells or NK cells had the PNH-phenotype (Figure 1A). This GPI-AP- cell distribution pattern was in sharp contrast to that of a patient with typical PNH who showed various percentages of GPI-AP- cells in all lineages of leukocytes and erythrocytes (Figure 1B). A fluorescent in situ hybridization analysis showed that 98.0% of the patient's granulocytes were BCR-ABL gene-fusion positive. Deep sequencing of leukocytes obtained at diagnosis showed a G279T (Q93H) mutation in exon 4 of the PIGA gene. The patient was diagnosed with PNH complicated by CML in the chronic phase, and was treated with nilotinib at 400 mg/day. The percentage of GPI-AP- cells rapidly decreased in response to nilotinib, with 0.02% GPI-AP- granulocytes after six months of nilotinib therapy when the patient's BCR-ABL mRNA decreased to 0.007%. BCR-ABL mRNA decreased to less than 0.0035% 15 months after therapy; however, small populations of GPI-AP- granulocytes (0.01%) and erythrocytes (0.005%) were still detected at this time (Figure 1A). GPI-AP- cells became undetectable after 19 months of nilotinib therapy, suggesting that the BCR/ABL fusion occurred in a subclone of a PIGA mutant hematopoietic progenitor cell (HPC). The patient was continuing nilotinib as of August 2015 without any signs of an increase in the BCR-ABL mRNA copy number.Conclusions: This case indicates the BCR-ABL fusion can be a driver mutation capable of inducing the clonal expansion of PIGA mutant clones. More importantly, the origin of PNH in our case proved to be a minor HPC clone with a PIGA mutation, suggesting that PNH can be derived from an HPC with a limited life span only if a potent second hit occurs in the PIGA mutant HPC. The identification of driver mutations in patients with PNH may therefore lead to the development of targeted therapy capable of curing PNH. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.