Discontinuation of Imatinib in Japanese Patients with Chronic Myeloid Leukemia,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3759-3759
Author(s):  
Naoto Takahashi ◽  
Taiichi Kyo ◽  
Yasuhiro Maeda ◽  
Takashi Sugihara ◽  
Kensuke Usuki ◽  
...  
Keyword(s):  
Stem Cells ◽  
Chronic Myeloid Leukemia ◽  
Prospective Study ◽  
Myeloid Leukemia ◽  
Dose Intensity ◽  
Imatinib Therapy ◽  
Molecular Response ◽  
Immunological Mechanism ◽  
Significant Difference ◽  
Complete Molecular Response

Abstract Abstract 3759 Imatinib treatment dramatically improves survival in chronic myeloid leukemia (CML) patients, but whether its effects of imatinib can be considered a cure remains controversial. This is because primitive, quiescent, Philadelphia-positive stem cells from patients with CML are insensitive to imatinib in vitro. Nonetheless, it was recently recognized that some patients with a complete molecular response (CMR) could sustain that response after discontinuation of imatinib. In a non-randomized prospective study, Mahon et al. reported that among patients with CMR lasting at least 2 years, CMR was sustained in 41% after discontinuation of imatinib. To characterize the clinical outcomes and profiles of chronic phase CML patients who discontinued imatinib, we conducted a nationwide survey in Japan. Among 3,242 imatinib-treated CML patients, 50 (1.5%) were identified who discontinued imatinib therapy for at least 6 months; of those, 43 were analyzed further. Molecular recurrence was detected in 19 patients, and the complete molecular response (CMR) rate was estimated to be 47% following imatinib discontinuation. Notably, the durations of imatinib therapy and CMR before cessation of therapy were significantly longer, and imatinib dose intensity and the frequency of prior IFN-a administration were significantly higher, in patients sustaining CMR for 12 months after cessation than in those with molecular recurrence. No significant correlations were detected between molecular recurrence and age, sex, Sokal risk, imatinib daily dose, combination with IFN-a, or time to achieve CMR. Moreover, we found a significant difference in estimated CMR rate following discontinuation between patients who had sustained CMR for greater than 24 months prior to imatinib discontinuation and those with less than 24 months (78% vs. 15%, p =0.0002 by Log-rank test, Figure). Based on multivariate regression analysis, only imatinib dose intensity and prior IFN-a administration were independently predictive of molecular recurrence within 12 months (p =0.0035, p =0.0060). The identified prediction formula was: Y= −0.0061 x dose intensity of imatinib(g)-3.17171 x prior IFN-a(Yes=1/No=0) +4.0124. If 1/(1+exp(-1 × Y)) > 0.5, molecular recurrence was predicted; the total accuracy rate of the formula was 82.5%. Although the depth of the molecular response should be a factor influencing long-term sustained CMR after discontinuation of imatinib, other factors, for example an immunological mechanism modified by IFN-a, might control quiescent CML stem cells. To increase the “cure” rate among CML patients, it will be necessary to establish a treatment strategy on the basis of large prospective study of imatinib discontinuation. This should entail the use of a highly sensitive and strict method for monitoring minimal residual disease over the course of a long follow-up period. Disclosures: No relevant conflicts of interest to declare.

scholarly journals BCL2L11 (BIM) Deletion Polymorphism Is Associated with Molecular Relapse after ABL Tyrosine Kinase Inhibitor Discontinuation in Patients with Chronic Myeloid Leukemia with Complete Molecular Response

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1797-1797 ◽  
Author(s):  
Seiichiro Katagiri ◽  
Tetsuzo Tauchi ◽  
Yuu Saito ◽  
Tamiko Sugro ◽  
Michiyo Asano ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Molecular Response ◽  
Deletion Polymorphism ◽  
Significant Difference ◽  
Treatment Free Remission ◽  
Tki Discontinuation ◽  
Complete Molecular Response

Abstract Background: The inhibition of BCR-ABL1 kinase with tyrosine kinase inhibitors (TKIs) has markedly improved the prognosis of chronic myeloid leukemia (CML). Recently, it has been recognized that some CML patients with a complete molecular response (CMR) are able to maintain treatment-free remission (TFR) after discontinuation of TKIs. However, no predictive prognostic factors for successful discontinuation of the treatment have yet been identified. We set out to further clarify the role of predictive biomarkers in molecular relapse and non-relapse after ABL TKI discontinuation. Materials and methods: Patients in sustained CMR (MR 4.5) undergoing TKI therapy were eligible for inclusion in the study. Molecular relapse was defined as loss of major molecular response (MMR) of at least one point. Genomic DNA was obtained from whole blood using a DNA Extractor WB Kit (Wako, Osaka, Japan), and was subjected to polymerase chain reaction (PCR) amplification using primers designed to detect a deletion site (2903 bp) in intron two of the BCL2L11 gene (forward: 5′-AATACCACAGAGGCCCACAG-3′; reverse: 5′-GCCTGAAGGTGCTGAGAAAG-3′) and JumpStart RedAccuTaq LA DNA polymerase (Sigma Aldrich, St. Louis, MO, USA). Results: 32 CML patients (17 men, 15 women, median age 58.4 years) were included in this study (Sokal category; low 24, intermediate 7, high 1). Six patients were treated with IFNα before TKI treatment, and 3 were treated with IFNα after stopping TKI. Median duration from TKI initiation to discontinuation was 79.3 months (range; 22 to 138 months); median duration of CMR before TKI discontinuation was 47.3 months (range; 5 to 97 months). Seven patients showed loss of MMR; 6 relapsed within 6 months and one showed late relapse at 25 months after discontinuation. The cumulative incidence of MMR loss was estimated as 18.8% at 12 months and at 24 months. Fluctuation of BCR-ABL transcript levels below the MMR threshold (> two consecutive positive values) was observed in 6.25% of patients at 24 months after ABL TKI discontinuation. Treatment-free remission was estimated as 81.2% at 12 months and at 24 months. The median period of restoration of second CMR was 6.0 months in re-treated patients. No patient died during the follow-up period. TKI-free remission was estimated as 78.1% at 30 months. There was only a significant difference in BCL2L11 (BIM) deletion polymorphism between the patients who maintained and those who lost MMR (p = 0.0253). No significant difference was observed in prior IFNα therapy, time to complete cytogenetic response (CCyR), time to MMR, and time to CMR between relapsing and non-relapsing patients. Conclusion: Our study shows a specific association between BCL2L11 (BIM) deletion polymorphism and clinical outcome after ABL TKI discontinuation in patients with long-lasting molecular undetectable residual disease. BCL2L11 (BIM) deletion polymorphism may predict relapse after ABL TKI discontinuation, which may have an impact on future ABL TKI discontinuation trials. These results further illustrate the importance of single nucleotide polymorphisms in successful long-term treatment of CML. Disclosures Ohyashiki: Bristol-Myers Squibb KK : Research Funding, Speakers Bureau; Novartis KK: Research Funding, Speakers Bureau.

scholarly journals European Treatment and Outcome Study (Eutos) Score Predicts Early Molecular Response to Imatinib Therapy in Chronic Phase Chronic Myeloid Leukemia Patients (Cp-Cml)

2014 ◽  
Vol 25 ◽  
pp. iv337
Author(s):  
K. Sudheer Reddy ◽  
M. Manickavasagam ◽  
V. Venkata Sampath ◽  
D. Barghavi ◽  
A. Vindhyavasini ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Chronic Phase ◽  
Imatinib Therapy ◽  
Molecular Response ◽  
Outcome Study ◽  
Eutos Score

Imatinib Mesylate Therapy in Late Ph+ Chronic Myeloid Leukemia Patients in Stable Complete Cytogenetic Response after Interferon-Alpha Results in a Very High Complete Molecular Response Rate.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2158-2158
Author(s):  
Giuliana Alimena ◽  
Massimo Breccia ◽  
Luigia Luciano ◽  
Fabrizio Quarantelli ◽  
Daniela Diverio ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Imatinib Mesylate ◽  
Copy Number ◽  
Myeloid Leukemia ◽  
Residual Disease ◽  
Cytogenetic Response ◽  
Molecular Response ◽  
Complete Cytogenetic Response ◽  
Complete Molecular Response

Abstract Imatinib mesylate was given to 26 Philadelphia positive (Ph+) chronic myeloid leukemia (CML) patients who were in late chronic phase (CP) and in stable complete cytogenetic response (CCR) after interferon-alfa (IFN-α), but showed persistent positive residual disease at PCR analysis under this treatment. At diagnosis median age was 40 years (range 21–64) and according to Sokal’s score, 18 patients were low risk and 8 were intermediate risk. Median IFN treatment was 88 mo.s (range 15–202) and median CCR duration was 73 mo.s (range 10–148). Imatinib was administered at the standard dose of 400 mg/die, after stopping IFN for 1 week. Residual disease was measured on bone marrow (BM) cells at baseline, before starting Imatinib, at 3, 6, 12, 18 mo.s and at the last follow-up (median 32 mo.s, range 21–49), by assaying BCR-ABL transcripts using quantitative PCR (RQ-PCR). The copy number (CN) of BCR/ABL and ABL transcript were derived by the interpolation of CT values to the appropriate standard curve, and the result, for each sample, was expressed as ratio of BCR/ABL mRNA copies to ABL mRNA x 100 (normalized copy number - NCN). Imatinib treatment resulted in a progressive and consistent decline of residual disease in all but one patient, from a median of 0.89 at baseline to 0.01 at the end of follow-up. Major molecular response (BCR/ABL levels <0.1) was reached in 20 patients (77%) and BCR/ABL transcripts were undetectable in 13 (50%). Achievement of molecular response was significantly correlated with post-IFN baseline transcript level (mean 1.194 for patients achieving complete molecular response vs 18,97 for those who did not; p<0.001), but not with other clinical/biological patient characteristics. In all patients, imatinib was well tolerated with no side effects requiring drug dose reduction or dose discontinuation. Albeit obtained from an unusual subset of selected patients with favourable prognosis, and likely particularly sensitive to imatinib, present results confirm the efficacy of combining Imatinib and IFN-α and further support investigating treatment approaches employing these two drugs.

Outcome of Patients with Chronic Myeloid Leukemia Who Recieved an Intermittent Imatinib Therapy.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1034-1034
Author(s):  
Hyun-Gyung Goh ◽  
Soo-Hyun Kim ◽  
Jeong Lee ◽  
Sae-Eun Jang ◽  
Wan-Seok Kim ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Oral Dose ◽  
Median Duration ◽  
Myeloid Leukemia ◽  
Cytogenetic Response ◽  
Imatinib Therapy ◽  
Intermittent Therapy ◽  
Molecular Response ◽  
Imatinib Treatment ◽  
600Mg Daily

Abstract Diagnosis of chronic myeloid leukemia (CML) is based on detection of the BCR-ABL gene or Philadelphia chromosome, and the BCR-ABL tyrosine kinase inhibitor imatinib has been the standard therapy for CML patients. Although imatinib therapy is effective in CML, it is still unclear whether imatinib can be safely discontinued without relapse. This study was designed to investigate the outcome of 26 CML patients after discontinuation of imatinib and to determine whether intermittent imatinib therapy can be employed in CML patients. Between May 2001 and Jun 2007, 555 patients have been treated with imatinib in St Mary’s Hospital of the Catholic University of Korea, and 26 patients discontinued imatinib when they achieved either complete cytogenetic response (CCyR) or complete molecular response (CMR). These 26 patients were diagnosed as Philadelphia positive (Ph+) CML between November 1995 and May 2002, and 22 patients were in chronic phase (CP) and 4 patients were in accelerated phase (AP) at diagnosis. The median age was 35 years (22–56), and 12 patients (46%) were female and 14 (54%) were male. Among 26 patients, 7 received interferon prior to imatinib therapy and 7 underwent SCT. Five patients received both interferon and SCT before imatinib therapy, and the remaining 7 patients received the imatinib as a front line therapy. Imatinib was started at oral dose of 400mg and 600mg daily for patients in CP and AP, respectively, and when they achieved CCyR or CMR, imatinib was discontinued after informed consent of the patient. In case of cytogenetic or molecular relapse, patients in all phases were retreated with imatinib at 400mg daily. Bone marrow (BM) or peripheral blood (PB) samples were obtained at regular intervals from diagnosis for hematologic response (HR), cytogenetic response (CyR) and molecular response (MR) monitorings. Eleven patients discontinued imatinib when they achieved CCyR, and 15 patients discontinued imatinib after achieving CMR. After the median duration of 7 month (4–48) observation without imatinib therapy, hematologic, cytogenetic and molecular relapses occurred in 4, 7 and 10 patients, respectively, and imatinib at oral dose of 400mg daily was reintroduced to all patients except 2 who continued to remain in CMR after imatinib discontinuation. Except 1 patient who expired and 2 patients who are in persistent molecular remission, all of 23 patients are maintaining the best response achieved after imatinib resumption with a median duration of 38 months (16–58). In conclusion, although imatinib cannot be discontinued completely, intermittent therapy can be considered for the treatment of CML patients. Intermittent imatinib treatment should not be restricted to CP patients who achieve CMR, and AP patients or patients with CCyR also can be considered for intermittent imatinib treatment. We will continue the follow-up of the patients enrolled in this study, and long-term study of intermittent imatinib treatment with expanded pool of patients will enable us to determine the accurate consequences of discontinuation of imatinib and intermittent imatinib treatment.

Long Term Adherence to Imatinib Therapy Is the Critical Factor for Achieving Molecular Responses in Chronic Myeloid Leukemia Patients.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3290-3290 ◽  
Author(s):  
Alex Bazeos ◽  
Jamshid Khorashad ◽  
François-Xavier Mahon ◽  
Lina L Eliasson ◽  
Dragana Milojkovic ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Independent Predictor ◽  
Chronic Phase ◽  
Imatinib Therapy ◽  
Adherence Rate ◽  
Molecular Response ◽  
Molecular Responses ◽  
Adherence To Therapy

Abstract Abstract 3290 Poster Board III-1 There is a great variability in the degree of molecular responses achieved by chronic myeloid leukemia (CML) patients treated with imatinib. These different levels of molecular response could reflect different degrees of adherence to therapy. We measured the adherence to imatinib therapy in 87 consecutive CML chronic phase patients who had received imatinib 400 mg day as first line therapy for a median of 59.7 months before enrolment (range 25–104) and therefore all them were in complete cytogenetic response. Adherence levels were monitored during a 3-month period using microelectronic monitoring devices (MEMS) and were related to levels of molecular response. MEMS consist of an electronic device fitted in the cap of a normal looking medication bottle that automatically records each time the bottle is opened. MEMS are considered as the ‘gold standard' for measuring adherence. We also measured the imatinib plasma level, the presence of TKD mutations and the following prognostic factors measured at diagnosis: hOCT1 transcripts level, polymorphism 1236C&gt;T in ABCB1, Sokal risk group, hemoglobin, leukocytes , BCR-ABL1 transcript type and BCR1-ABL1 ratio and demographic data. The study protocol was approved by the Research Ethics Committee and patients gave written informed consent to participate. The median adherence rate was 97.6% (range 22.6–103.8%). In 23 (26.4%) patients adherence was ≤90% (median 76%) and in 12 (13.8%) ≤80% (median 63%). We found a strong association between adherence rate (≤90% or &gt;90%) and the 6-year probability of major molecular response (MMR) (28.4% vs 94.5%, p&lt;0.0001) and complete molecular response (CMR) (0% vs 43.8%, p=0.002) (Fig 1). Multivariate analysis identified adherence (RR=11.7, p=0.001) and expression of the molecular transporter hOCT1, (RR=1.79, p=0.038) as the only independent predictors for MMR. Adherence was the sole independent predictor for CMR. No molecular responses were observed when the adherence was ≤20% (p=0.0001). In patients whose imatinib dose had been increased (n=32) the adherence was poor (median 86.4%). Adherence was the only independent predictor for failure to achieve a 3-log transcript reduction (RR=17.66, p=0.006) in this subgroup of patients. Patients with CML vary greatly in their response, as demonstrated originally by Sokal et al. in 1984, and the same variation is seen in patients treated with imatinib in the modern era. The basis for this variation is unknown but it has been attributed to the intrinsic biological heterogeneity of the leukemia. In contrast we show here that adherence to therapy is the major factor determining the degree of response that a CML patient treated with imatinib will achieve. Disclosures: Mahon: Novartis: Consultancy, Research Funding. Apperley:Novartis: Consultancy, Honoraria. Rezvani:Novartis: Consultancy, Honoraria, Research Funding. Marin:Novartis: Consultancy, Research Funding.

Rapid Reduction of Chronic Myeloid Leukemia Stem Cells After Treatment with Second-Generation BCR-ABL Kinase Inhibitors, Dasatinib and Nilotinib

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4457-4457
Author(s):  
Yosuke Minami ◽  
Akihiro Abe ◽  
Yuka Nomura ◽  
Miho Minami ◽  
Yachiyo Kuwatsuka ◽  
...  
Keyword(s):  
Stem Cells ◽  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Second Generation ◽  
Kinase Inhibitors ◽  
Newly Diagnosed ◽  
Rapid Reduction ◽  
Population Total ◽  
Significant Difference

Abstract Abstract 4457 Chronic myeloid leukemia (CML) is effectively treated with imatinib (IM), however, several mathematical models and ex vivo-examinations suggested that IM-therapy does not eradicate BCR-ABL-positive hematopoietic stem cells (HSC). We prospectively (0, 3, 6 and 12 months after IM-therapy) investigated 16 newly diagnosed and 22 long-term followed CML-chronic phase (CP) cases using methods previously reported (Jamieson et al., N Engl J Med, 2004. and Abe et al., Int J Hematol, 2008) (Figure 1) with FACSAria™ and quantitative RT-PCR of BCR-ABL among each sorted population; total mononuclear cells, HSC/Thy-1+, HSC/Thy-1–, common myeloid progenitors (CMP), granulocyte macrophage progenitors (GMP) and megakaryocyte erythroid progenitors (MEP). In optimal responders to IM-therapy, BCR-ABL transcripts in the HSC populations (HSC/Thy-1+ and HSC/Thy-1–) tended to be more retentive than other populations while gradual reduction was observed during the first 12 months in all populations. And discrepancy of minimum residual diseases (MRD) between the HSC populations and other populations was larger in patients after longer IM-therapy. In evaluating properties of CML stem cells and other markers, we observed irrelevant distribution of side population (SP) and expressions of ABC transporters (ABCB1 and ABCG2) in comparison with CD34/38 expression. We also prospectively investigated BCR-ABL transcripts in each population of 23 IM-resistant or -intolerant CML-CP cases and one newly diagnosed CML-accelerated phase (AP) case during treatment with second-generation tyrosine kinase inhibitors (2nd TKIs), dasatinib or nilotinib. Treatment with each inhibitor induced more rapid reduction of BCR-ABL transcripts even in the HSC population (CD34+CD38–) during the first 6 months and there was no significant difference of MRD among each population in optimal responders to 2nd TKIs-therapy. In the stromal co-culturing system using primary cells and leukemic NOD/SCID/IL2rgnull (NOG) mice xenotransplanted with Ph+ leukemia cells, retention of quiescent slow-cycling (Hoechst 33342low/Pyronin Ylow) CD34+ population after IM-treatment were observed and cell death mechanisms after treatment with 2nd TKIs are also under investigation. These results imply that therapy with 2nd TKIs could be a promising approach for quick and efficient reduction of the CML stem cells and cure of disease. Figure 1 Figure 1. Disclosures: Naoe: Kyowa-Kirin: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding.

Distinct Characteristics of e13a2 versus e14a2 BCR-ABL Chronic Myeloid Leukemia under Upfront Treatment with Imatinib – an Analysis of the German CML Study IV,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3773-3773
Author(s):  
Benjamin Hanfstein ◽  
Philipp Erben ◽  
Susanne Saussele ◽  
Michael Lauseker ◽  
Ulrike Proetel ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Median Time ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Fusion Gene ◽  
Standard Dose ◽  
White Blood Cells ◽  
Molecular Response ◽  
Significant Difference ◽  
Equity Ownership

Abstract Abstract 3773 Introduction: The vast majority of chronic myeloid leukemia (CML) patients express a BCR-ABL fusion gene mRNA encoding a 210 kDa tyrosine kinase which is constitutively activated and hence the mainspring of leukemic transformation. Two typical mRNA variants exist that differ in the presence or absence of the 75 basepair BCR exon 14: the e13a2 (lacking exon 14, also known as “b2a2”) and the e14a2 BCR-ABL transcript (“b3a2”). The significance of the additional 25 amino acid residues of the e14a2 BCR-ABL oncoprotein was extensively studied in the pre-imatinib era. However, the influence of the BCR-ABL transcript variant on the individual disease phenotype and outcome remained controversial and is still undefined in the imatinib era. Patients and methods: A total of 1,104 patients (median age 52 years, range 16–85, 40% female) expressing typical BCR-ABL transcript types (e13a2, n=447; e14a2, n=491; e13a2 and e14a2, n=166) were included in the randomized German CML study IV and treated with an imatinib based therapy consisting of imatinib 400 mg, imatinib 800 mg and combinations of standard dose imatinib with interferon alpha and low-dose cytarabine. The type of BCR-ABL transcript was defined by multiplex PCR. BCR-ABL expression was determined by quantitative RT-PCR and standardized according to the international scale (IS). Cytogenetic response was determined by conventional metaphase analyses. Response landmarks were defined according to European LeukemiaNet criteria, MR4 was defined as BCR-ABL IS ≤ 0.01% Results: No differences regarding age, sex and Euro risk were observed. A significant difference was observed comparing white blood cells (90,400/μl vs. 69,100/μl, p<0.001) and platelets (293,000/μl vs. 424,000/μl, p<0.001) at diagnosis (median, e13a2 vs. e14a2, respectively) indicating a distinct phenotype. No significant difference was observed regarding spleen size, basophils, eosinophils, blasts or adverse events under imatinib. Molecular response as determined by a transcript independent quantitative PCR assay was superior in e14a2 patients as compared to e13a2 patients (median time to major molecular response, MMR 1.5 years vs. 1.2 years, p<0.001; median time to MR4 4.2 years vs. 2.5 years, p<0.001). No difference was observed with regard to the achievement of a complete cytogenetic remission (CCyR). The superior molecular response rate of e14a2 patients did not translate into differences in progression free survival (PFS) or overall survival (OS). Conclusion: Distinct initial blood counts suggest a different phenotype of e13a2 and e14a2 driven CML. MMR and MR4 are achieved earlier by e14a2 patients whereas no difference was observed with regard to PFS and OS. Disclosures: Schnittger: Münchner Leukämie Labor: Equity Ownership. Haferlach:Münchner Leukämie Labor: Equity Ownership. German CML Study Group:Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; BMBF: Research Funding; EU: Research Funding; Roche: Research Funding; Essex: Research Funding.

Predictive Value Of Early Molecular Responses In Outcomes Of Patients With Chronic Myeloid Leukemia Treated With Imatinib In First-Line Therapy

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4941-4941
Author(s):  
Katia B. Pagnano ◽  
Bruna Vergilio ◽  
Eliana C M Miranda ◽  
Marcia Torresan Delamain ◽  
Maria Helena De Almeida ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Cytogenetic Response ◽  
Molecular Response ◽  
First Line ◽  
Molecular Responses ◽  
Advanced Phase ◽  
Significant Difference ◽  
The Impact

Abstract Several studies demonstrated the prognostic significance of an early molecular response in chronic myeloid leukemia (CML) patients (pts) treated with imatinib in first line or other tyrosine kinase inhibitors. Aims: The aim of this study was to evaluate the impact of early molecular responses, at 3 and 6 months after treatment with imatinib in CML pts and correlate these responses with CCR, MMR, overall survival (OS) and event free survival (EFS). Patients and Methods Between February 2006 and June 2012, 95  adult pts with newly diagnosed CML in chronic phase (CP) received imatinib 400mg/daily. CP was defined using WHO 2008 criteria. All pts received a short course of hydroxiurea until imatinib was available. Cytogenetic analysis was performed at diagnosis, 3, 6, 12 and 18 months after starting therapy and then every 12-24 months thereafter. BCR-ABL transcripts were measured in peripheral blood at 3-month intervals using quantitative RT-PCR (RQ-PCR). Results were expressed as BCR-ABL/ABL ratio, with conversion to the international scale (IS). Major molecular response (MMR) was defined as a transcript level ≤ 0.1% (IS). Statistical analysis: OS was measured from imatinib start until date of death or last visit. An event was defined as death from any cause. EFS was measured from imatinib start until the first event (loss of complete hematological response (CHR); complete cytogenetic response (CCR), progression to advanced phase, death or imatinib discontinuation) or last visit. OS and EFS rates were calculated using Kaplan-Meier method and log-rank test to compare its curves. The MMR probabilities according to molecular responses at 3 and 6 months were calculated by c2 method and cumulative incidence, considering as competitive event death or progression, before the event. Results 95 pts were analyzed, 57 (60%) male, with a median age of 47 years (17-79); Sokal score: high, intermediate and low was 30, 38.6 and 31.4% respectively; EUTOS scores was 81.5% low and 18.5% high. The median time from diagnosis until imatinib therapy was 1 month (0-5) and the follow-up was 39 month (3-89). Responses: 88% achieved CHR; 50% CCR and 53% MMR. One patient progressed to advanced phase during follow-up, while on imatinib treatment. 21 (22%) pts discontinued imatinib due to intolerance (47.6%); resistance (42.9%), death (4.8%) and Allo-HSCT (4.8%). At 3 months from the start of therapy, 30/64 (46.8%) achieved CCR, 15/64 (23.4%) partial cytogenetic response and 20/64 (31.2%) less than partial; by RQ-PCR, 72.3% (68/94) achieved at 3 months BCR-ABL transcripts ≤10% and 27.7% (26/94) > 10%. At 6 months 55.2% (48/87) had BCR-ABL transcripts ≤ 1% and 44.8% (39/87) >1%. The OS was 97% (95%CI: 95-99%) and EFS 63% (95%CI: 52-75%).There was no significant difference in OS and EFS in pts with RQ-PCR > 10% vs ≤ 10% at 3 months (figure 1), but pts with BCR-ABL transcripts > 10 and >1-10% at 6 months had an inferior EFS in comparison with pts with  BCR-ABL transcripts ≤ 1%  (41%,50%,89% respectively - p= 0.005), (figure 2). The CI showed that CCR pts at 3 months reached MMR earlier at 24 month (54% vs 18%, p=0.03), as well as CCR pts at 6 months, albeit no significance statistically (52% vs 37%, p= 0.16). For RQ-PCR at 3 months, pts with BCR-ABL transcripts 0-1% had a probability of 88% to achieve MMR, 1-10% had 52% and >10% 42%, p< 0.0001 (figure 3). In conclusion, our results show that early molecular responses are predictive of achieving MMR and BCR-ABL transcripts <1% at 6 months is predictive of EFS in CP-CML treated with imatinib. Disclosures: No relevant conflicts of interest to declare.

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