Imatinib Mesylate Discontinuation Research Articles

Clinical Spectrum, Long-Term Outcomes and Predictors of Relapse after Imatinib Discontinuation in FIP1L1-Pdgfra-Associated Chronic Eosinophilic Leukemia: Data from 150 Patients

Introduction. Cases series of patients with FIP1L1-PDGFRA (F/P)-associated chronic eosinophilic leukemia (F/P+ CEL) are scarce and of small sample-size. Low-dose imatinib mesylate (IM) is highly effective in this setting. Although successful treatment discontinuation has been reported, approximately 40% of the patients subsequently relapse. To date, no predictor of relapse after IM discontinuation has yet been evidenced. Methods. We conducted a French multicentric retrospective of patients diagnosed with F/P+ CEL between 2003-2019. Weight loss was defined as a 10% weight loss over the course of the disease's history. Complete (CHR) and partial (PHR) hematological responses were defined as a normalization of the absolute eosinophil count (AEC) and as a reduction in peripheral blood eosinophilia by at least 50% from baseline, respectively. Relapses were defined as the recurrence of eosinophilia, with or without evidence of F/P-gene transcript, but without any other explanation. Complete molecular response (CMR) was defined as a negative RT-PCR and/or RQ-PCR assay for F/P rearrangement. A backward stepwise logistic regression model was used to identify factors associated with relapse after IM discontinuation. Results. One hundred and fifty F/P+ CEL patients (145 males; mean (SD) age at diagnosis: 49 (+/-12 years) were included, among which 26 (17%) did not report any symptom. The main involved organs were the spleen (n=65, 43%), skin (n=47, 31%), heart (n=27, 18%), lungs (n=36, 24%), central nervous system (n=14, 9%), and bones/joints (n=8, 5%). Four (2,6%) patients showed features of vasculitis, involving the skin (n=2) and the CNS (n=2). The mean peak AEC was 10.3 G/L (+/-6 G/l). Besides eosinophilia, the most frequent associated complete blood count (CBC) abnormalities were thrombocytopenia (n=43, 28%), anemia (n=37, 24%), hyperleukocytosis (n=33, 22%) and monocytosis (n=25, 16%). Forty-seven (31%) patients had normal CBC besides eosinophilia. Bone marrow karyotype was normal in 91% (when tested, n=94). Serum vitamin B12 and tryptase (mean: 2386 (+/-1435) pmol/L and 34 (+/-20) µg/L) levels were elevated in 74 (94%) and 44 (79%) of patients respectively, whereas CRP and IgE levels were elevated in 31 (26%) and 12 (14%) each. None of the 37 (25%) patients that received first-line glucocorticoid therapy achieved CHR. All but 3 patients received IM (daily starting dose: 100 (n= 102; 72%), 200 (n=13; 9%) or 400 mg (n=20; 14%)), of whom 100% and 99% achieved CHR and CMR (when tested: n=84), respectively. The mean follow-up (FU) was 80 (+/- 56) months, with overall survival at 1, 5 and 10 years of 99%, 95% and 84% (reaching 100%, 98% and 89% in the 147 IMB-treated patients) respectively. Overall, 8 (5%) patients died during FU, including untreated patients with acute myeloblastic leukemia transformation (n=2) and a single patient with massive cerebral infarction. Eight patients relapsed during IM tapering, all of which were successfully treated when higher doses of IM were resumed. After a median [IQR] of 44 [27-72] months of IM treatment, 46 (32%) patients eventually discontinued IM, amongst whom 19 (41%) relapsed after a median of 10[4-23] months (42% of relapses defined by PCR). In multivariate analysis, weight loss (HR: 5,02 95%CI[1,9 - 28,04]; p =0,004), the time between onset of eosinophilia and IM initiation (HR 1,02 [1,00 - 1,03]; 0,01) and duration of IM treatment prior to discontinuation (HR: 0,97 [0,95-0,99]; p=0,01) were independent factors of relapse (Table 1). Conclusion. This large cohort further confirms that F/P+ CEL almost exclusively affects male patients, with spleen, skin, heart and lung involvements being the most frequent. While glucocorticoids never lead to the normalization of CBC parameters, IM is highly effective and treated patients carry an excellent prognosis. After IM discontinuation, although 60% of patients maintain CHR overtime, 40% subsequently relapse, with weight loss, time between onset of eosinophilia and IM initiation and duration of IM treatment prior to discontinuation being significant but moderate independent factors of relapse. Disclosures Nicolini: Incyte Biosciences: Honoraria, Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Sun Pharma Ltd: Consultancy. Tavitian:Novartis: Membership on an entity's Board of Directors or advisory committees. Huguet:Novartis: Honoraria; BMS: Honoraria; Pfizer: Honoraria; Incyte Biosciences: Honoraria; Amgen: Honoraria; Servier: Honoraria; Jazz Pharmaceuticals: Honoraria. Jardin:Servier: Honoraria; janssen: Honoraria; celgene: Honoraria; roche: Honoraria; amgen: Honoraria.

A new highly sensitive real-time quantitative-PCR method for detection of BCR-ABL1 to monitor minimal residual disease in chronic myeloid leukemia after discontinuation of imatinib.

Tyrosine kinase inhibitors (TKIs) targeting the BCR-ABL1 fusion protein, encoded by the Philadelphia chromosome, have drastically improved the outcomes for patients with chronic myeloid leukemia (CML). Although several real-time quantitative polymerase chain reaction (RQ-PCR) kits for the detection of BCR-ABL1 transcripts are commercially available, their accuracy and efficiency in laboratory practice require reevaluation. We have developed a new in-house RQ-PCR method to detect minimal residual disease (MRD) in CML cases. MRD was analyzed in 102 patients with CML from the DOMEST study, a clinical trial to study the rationale for imatinib mesylate discontinuation in Japan. The BCR-ABL1/ABL1 ratio was evaluated using the international standard (IS) ratio, where IS < 0.1% was defined as a major molecular response. At enrollment, BCR-ABL1 transcripts were undetectable in all samples using a widely-applied RQ-PCR method performed in the commercial laboratory, BML (BML Inc., Tokyo, Japan); however, the in-house method detected the BCR-ABL1 transcripts in five samples (5%) (mean IS ratio: 0.0062 ± 0.0010%). After discontinuation of imatinib, BCR-ABL1 transcripts were detected using the in-house RQ-PCR in 21 patients (21%) that were not positive using the BML method. Nineteen samples were also tested using a commercially available RQ-PCR assay kit with a detection limit of IS ratio, 0.0032 (ODK-1201, Otsuka Pharmaceutical Co., Tokyo, Japan). This method detected low levels of BCR-ABL1 transcripts in 14 samples (74%), but scored negative for five samples (26%) that were positive using the in-house method. From the perspective of the in-house RQ-PCR method, number of patients confirmed loss of MMR was 4. These data suggest that our new in-house RQ-PCR method is effective for monitoring MRD in CML.

Imatinib-induced hepatitis treated by corticosteroids in a patient with metastatic gastrointestinal stromal tumor

Imatinib mesylate is currently used as the first-line treatment for metastatic gastrointestinal stromal tumors (GISTs). Imatinib-induced hepatotoxicity in patients with GIST is very rare. Its features vary from subclinical elevation of serum aminotransferase to clinically apparent acute hepatitis, which is associated with immunologic reactions. Imatinib-induced hepatotoxicity with autoimmune-like features can be treated by the discontinuation of imatinib mesylate and the administration of oral steroids. Here, we report a case of late-onset imatinib-induced hepatitis with autoimmune-like features in a patient with metastatic GIST, which was improved by oral corticosteroids.

Discontinuation of Imatinib Mesylate could Improve Renal Impairment in Chronic Myeloid Leukemia.

We aim to report a CML case that had fluid retention and serum creatinine increase under long-term imatinib mesylate (IM) treatment. A 68-year-old woman was diagnosed with chronic myeloid leukemia, and IM was started in 2002 with a dose of 400 mg/day. She had achieved complete hematological, molecular and cytogenetic remission under IM treatment. In September 2015, her creatinine level was 1.7 mg/dl. In May 2016, she was admitted to our hospital with dyspnea. Hypervolemia secondary to fluid retention was detected in our patient. Her laboratory tests results showed hemoglobin 9.7 gr/dl, white blood cell 7.6x103/μl, platelet 157x103/μl, creatinine 3.2 mg/dl, blood urea nitrogen (BUN) 88 mg/dl. In her X-ray chest film, bilateral pleural effusion was detected. The effusion was detected as transuda. The other reasons of pleural effusion were excluded and the development of pleural effusion was considered secondary to IM. IM was also considered responsible for the acute rise of serum creatinine levels of our patient. Therefore for these two reasons IM was stopped. After the discontinuation of IM, her creatinine levels decreased to 1.6 mg/dl and her pleural effusions disappeared. IM treatment was considered as the reason of serum creatinine elevation since serum creatinine levels decreased after the discontinuation of IM. All of the side-effects disappeared after discontinuation of IM.

Revisiting Early Stages of Chronic Myeloid Leukemia (CML): Evidence That Leukemic Progenitors Appear First in Peripheral Blood during Molecular Recurrence

The use of tyrosine kinase inhibitors (TKI) has dramatically changed the natural history and the prognosis of CML with a major improvement of survival in patients responding to therapy. However, tyrosine kinase inhibitor (TKI) discontinuation trials in patients with deep molecular responses (DMR), show that 50-60% of patients will have a molecular recurrence requiring to resume the TKI therapy. The great majority of these relapses occur during the first 6 months of TKI discontinuation. Although the sustained persistence of leukemic stem cells (LSC) is clearly the cause of the recurrent disease, cellular dynamics of these early relapses and the pattern of cells giving rise to them are not determined. We had the opportunity to study this pattern in 4 patients (pts) who presented molecular recurrence after Imatinib mesylate (IM) discontinuation (n= 3) or on TKI therapy with Dasatinib (n= 1) after obtaining a deep molecular response de grade MR 4.5. The total duration of TKI therapy before TKI discontinuation was 14 years (UPN1), 15 years (UPN2) and 30 months (UPN3). All three pts (Aged 47, 66, 87 respectively) had CML-CP treated with IM 400 mg as a first line therapy with induction of DMR in all three. The duration of DMR (MR4.5- was for 6, 5 and 2 years for UPN1, 2 and 3 respectively. The reasons for TKI discontinuation were the TKI-discontinuation protocol in French observatory (UPN1, UPN2) and suspicion of interstitial pneumonia (UPN3). The patient UPN4 was on Dasatinib as a second line therapy and in DMR for 3 years. At the time of detection of molecular recurrence, all 4 pts had normal clinical examination with normal complete blood counts (CBC) with no evidence of circulating immature blood cells. After IM-discontinuation, molecular relapses occurred at 2 months (BCR-ABL IS 27%) 3 months (BCR-ABL IS transcript level at 13.1%) and at 9 months (BCR-ABL IS transcript level at 2.7%.) in patients UPN1, 2 and 3 respectively. In UPN 4, the molecular recurrence (BCR-ABL IS transcript 10%) was documented at + 4 months. In all 4 patients, colony forming cell (CFC) assays were performed from the same blood samples in which the molecular recurrence was documented. At day + 14, clonogenic cells (CFU-GM, BFU-E, CFU-Mixed) were plucked and BCR-ABL expression in each individual or pooled (2-4) CFC was determined. For 5.104PBMC plated in methycellulose assays in culture, the mean numbers of CFC obtained varied between 12 and 29 CFC / dish. Despite the normal CBC, the presence of BCR-ABL-expressing CFC in blood was demonstrated in all 4 pts. In UPN1, all CFC (20/20) obtained from peripheral blood were positive for BCR-ABL with a heterogeneous expression amongst CFC (BCR-ABL /ABL ratio range 2- 25%, mean 33%). Interestingly in this patient, CFC and LTC-IC assays performed in a bone marrow aspirate prior to IM discontinuation showed no evidence of BCR-ABL-expressing progenitors, suggesting a rapid and massive expansion of a dormant LSC clone migrating to blood at the time of molecular relapse. In pt UPN2, 9 individual CFC were found to express BCR-ABL with a significant heterogeneity (BCR-ABL/ABL ratio 0.2% - 56% , mean = 15 %). In Pt UPN3, with the lowest levels of BCR-ABL during molecular relapse, 4/73 CFC expressed BCR-ABL. All three pts had a favorable response after resuming Imatinib (UPN1, 2, 3) or after switching therapy to Bosutinib (UPN4). On UPN4, 2 pools of 4 CFC/20 expressed BCR-ABL. In two pts with 100% clonogenic relapse (UPN 1 and UPN2) the estimated circulating leukemic CFC numbers were 607 / ml and 468 / ml of blood respectively, in the presence of normal appearing CBC. In UPN 3 and 4, with approximately 10% of CFC being BCR-ABL +, these numbers were estimated to be 507 and 45 per ml of blood, respectively. Thus, the study of these four patients demonstrates that circulating leukemic CFC are the first detectable abnormal cellular components during molecular recurrence and that the clonogenic relapse in peripheral blood precedes myeloid expansion. These results show also for the first time to our knowledge, that leukemic CFC egress from bone marrow to peripheral blood is an early event during early stages of CML and the CFC expansion takes place not only in bone marrow but also in peripheral blood. Besides shedding light into the pathophysiology of CML, these findings could be of major interest to predict relapse parameters and could lead to the design of novel biological follow-up protocols after TKI discontinuation. DisclosuresNo relevant conflicts of interest to declare.

Intermittent Imatinib Mesylate in Children with Chronic Myeloid Leukemia: Results and Outcome

Intermittent Imatinib Mesylate in Children with Chronic Myeloid Leukemia: Results and Outcome

Adhesion to stromal cells mediates imatinib resistance in chronic myeloid leukemia

Chronic Myeloid Leukemia (CML) is a myeloproliferative disorder initiated by BCR-ABL fusion in which the leukemic stem cells give rise to abnormally high number of myeloid cells. Tyrosine kinase inhibitor, Imatinib mesylate (IM) is the mainline drug used for the treatment of CML. CML responds to IM treatment efficiently. However, in several patients, CML relapses even after few years of remission, upon discontinuation of IM. Persistent leukemic cells in the BM during IM treatment play a major role in causing relapse in CML patients. In the present work, MAPK pathways (ERK, P38), NFkB, STAT pathways (STAT3/5), BMP signaling pathway through SMAD, CXCL12-CXCR-4 signaling axis, actin cytoskeleton and RhoAGTPase were examined for their role in CML-stromal interactions and CML chemoprotection. We found that actin cytoskeleton, RhoA GTPase and BMP-SMAD signaling play an important role in establishing direct cell-cell interaction between CML and stromal cells. This effect could be abrogated by use of small molecule inhibitors for ERK-MAPK and BMP-SMAD signaling as well as actin cytoskeleton disruptions in combination with IM. Moreover, it was observed that as a result of stroma mediated chemoprotection, CML cell line K562 cells could persist long-term in the presence of IM when attached to stromal cells. These persistent K562 cells acquired stroma-independent chemoresistance and could be maintained in stroma-independent suspension culture in the presence of IM, which resembles a relapse status in the patient. The resulting chemoresistant cells showed activation of BCR-ABL independent signaling pathways such as ERK and BMP/SMAD pathways and the cells could be induced to undergo apoptosis by use of small molecule inhibitors against these pathways. In conclusion, the present study showed that a reciprocal interaction exists between the CML cells and the stromal cells in their microenvironment. The stromal cells, modified by the leukemic cells, chemoprotected CML cells from IM induced cell death, which further developed into stroma independent chemoresistance which can be effectively targeted by inhibiting oncogene-independent signaling pathways.

Phase III Randomized Study of Imatinib Therapy in Chronic Phase Chronic Myeloid Leukemia Comparing Standard Dose-Escalation with Progressive Dose-Escalation (JALSG CML207 study)

Phase III Randomized Study of Imatinib Therapy in Chronic Phase Chronic Myeloid Leukemia Comparing Standard Dose-Escalation with Progressive Dose-Escalation (JALSG CML207 study)

Adherence and/or discontinuation of imatinib mesylate in patients with chronic myeloid leukemia

Adherence to mesylate improves clinical outcomes and promotes a reduction in health expenditure. However, treatment duration and lack of efficacy decrease adherence to pharmacotherapy, resulting in increased mortality associated with Chronic Myeloid Leukemia. This study aimed to evaluate and compare adherence and/or discontinuation of mesylate in different studies from the literature. An integrative review of original articles published between the years of 2004 and 2014 was performed using the databases PubMed/MEDLINE, Scopus and SciELO. The descriptor imatinib was used in two combinations employing the connector AND between terms: medication adherence'' AND ''imatinib AND leukemia'' and ''patient compliance'' AND imatinib AND leukemia. We identified 476 studies, being 14 included in the study. The rates of adherence and discontinuation were diverse, ranging from 19.0 to 97.0% and from 1.8 and 41.0%, respectively, and a high number of longitudinal studies was observed (71.4%). Most studies used questionnaires as an indirect method to assess adherence and factors related to poor adherence were adverse drug reactions, dose changes and unavailability of the medication. Patient education associated with follow up by pharmacists and other health professionals can improve patient adherence and minimize the pharmacotherapy discontinuation.

Droplet Digital PCR Reliably Detects a Single Copy of BCR-ABL1

Data show 40% of chronic myeloid leukemia (CML) patients maintain complete molecular remission (CMR), i.e. failure to detect BCR-ABL1, consenting to termination of Imatinib mesylate (IM) therapy, following undetectable disease for ≥2 years by quantitative PCR (Q-PCR). These findings suggest majority of the patients experience molecular relapse. Furthermore, majority relapse in the first 6 months, implying Q-PCR assay sensitivity is suboptimum, to confidently identify patients for discontinuation of IM. Droplet digital PCR (ddPCR) is suggested to have sensitivity that is one log greater than the Taqman (Q-PCR) assay. If verified, ddPCR would enhance safe withdrawal of IM therapy from CML patients. Here we present data comparing ddPCR with Q-PCR.In total we assayed 161 samples, of these 6 were serial dilutions of the International reference (IR) BCR-ABL1 plasmid, the remainder were cDNA samples. The 161 samples comprised of 4 sample groups; I: CML chronic phase samples (n=118); II: CML samples post stem cell transplant (SCT) (n=22); III: normal control (NC) samples (n=16); IV: Serially diluted BCR-ABL1 1.04x10e2 copies/µl, IR ERM-AD623e (n=6). Group I comprised of 121 samples from 21 CML patients in chronic phase treated with IM. Group II comprised of 21 samples from 19 CML patients (2 samples each for 2 of these 19 patients) who had undergone SCT. Group II comprised of samples from normal adult blood donor volunteers. Finally, Group IV included 6 serially diluted samples, ranging 100 to 0.001 copies of the IR (1.04x10e2 copies/µl) plasmid (Sigma, Munich, Germany). All the Group I, III and IV samples were subjected to Q-PCR Taqman assay and ddPCR (Biorad, California, USA). The Group III samples were in addition subjected to nested PCR. Only those samples with cycle threshold (Ct) <37 in 2 or more replicates by Q-PCR were recorded positive. For ddPCR those samples with sum of ≥3 positive droplets with a minimum 5500 droplets per well were reported positive. All the PCR reactions were performed in triplicate in final volume of 20µl, which included 5µl of cDNA or reference plasmid.Among Group I, Q-PCR detected BCR-ABL1 in 57 of the 118 patient samples assayed, with a median of 16.72 transcripts (range 1.38-47450). In only 2 (2.25 and 4.96 transcripts) of these 57 samples, ddPCR failed to detect BCR-ABL1 transcripts. Q-PCR and ddPCR failed to detect BCR-ABL1 in 45 (38.1%) samples. For 14 (11.8%) of the samples ddPCR was positive, median 3.4 copies (range 3-15) but negative by Q-PCR. Among Group II, one of the 21 samples was excluded from the analysis because <5500 droplets were generated. Of the 21 samples 7 were negative by ddPCR. Nested PCR was negative for all 7 samples. Three samples were positive by all 3 technologies, nested PCR, Q-PCR and ddPCR. Remarkably, 5 of the 21 samples were negative by nested, but positive by ddPCR; median 18.0 copies (6.2-22.0). These 5 samples were not subjected to Q-PCR. In Group III all 16 NC samples were negative by Q-PCR and ddPCR. In Group IV, ddPCR did detect BCR-ABL1 in the serially diluted IR sample calculated to have 1 copy (26 positive droplets of the 106095 total droplets), but Q-PCR failed. However, the lower dilutions, calculated to contain 0.1, 0.01 and 0.001 copies were negative by ddPCR and Q-PCR.We assayed 161 samples by ddPCR and Q-PCR, of these 139 were from CML patients. In addition 21 of the samples were also subjected to nested PCR. Our data support the notion ddPCR is at least one log more sensitive than Q-PCR. Of the 140 patient samples assayed, 19 (13.5%) were positive by ddPCR but negative by Q-PCR. Only 2 of the 118 samples in Group I were negative by ddPCR but positive by Q-PCR. There was in insufficient sample to repeat these 2 assays. The increased sensitivity of ddPCR as implied by the clinical samples was supported by assays performed using the IR. The serial dilution equivalent to 1.0 BCR-ABL1 copy was reliably detected by ddPCR, but was negative by Q-PCR. In summary, these data suggest ddPCR is more sensitive. However, the clinical significance of this must be assessed in context of long-term clinical outcome of patients with detectable BCR-ABL1 by ddPCR and negative by Q-PCR. But, clearly increased sensitivity is likely to enhance safe withdrawal of IM therapy for CML patients in CMR. Furthermore, regular monitoring of these patients by ddPCR would enable early detection of molecular relapse and thereby minimize the risk of disease progression. DisclosuresLe Coutre:Novartis: Honoraria.

Long-Term Outcomes after Imatinib Mesylate Discontinuation in Chronic Myeloid Leukemia Patients with Undetectable Minimal Residual Disease

Background: Imatinib mesylate (IM) discontinuation is under active investigation in chronic myeloid leukemia-chronic phase (CML-CP) patients with undetectable minimal residual disease (UMRD). However, limited data exist on the long-term outcomes following IM discontinuation in patients treated with frontline IM therapy. Methods: We consecutively enrolled patients with CML-CP who discontinued IM after achieving UMRD for ≥12 months between June 2009 and January 2013. Results: Nineteen patients (8 male, 11 female) were included. After IM discontinuation, 14 patients (74%) lost UMRD after a median of 4.0 months. Of the 14 patients with molecular relapses, 12 (86%) relapsed within the first 9 months after IM discontinuation and 2 (14%) relapsed at 20.5 and 22.8 months, respectively. No molecular relapse was observed after 2 years of IM discontinuation. With a median follow-up of 58.1 months (range 23.0-66.5), the estimated UMRD persistence rate at 5 years was 23.7%. IM was readministered in all patients with molecular relapse, and 12 patients (86%) reachieved UMRD at a median of 5.3 months. A high-risk Sokal score, delayed UMRD achievement and short-term IM therapy were significantly associated with molecular relapse. Conclusion: These findings suggest that IM discontinuation in patients who achieved UMRD after frontline IM therapy resulted in favorable long-term outcomes in terms of safety and feasibility.

Therapy-Free Remission after Interferon Alfa Maintenance with Imatinib Discontinuation in Patients with Chronic Myeloid Leukemia

Introduction: Imatinib mesylate (IM) induces sustained molecular remissions in patients with chronic myeloid leukemia (CML) but a life-long therapy is required for most of these patients. We previously reported that CD8+ memory T cells showed significant predominance over naive T cells in the patients with sustained therapy-free major molecular response (MMR), all of that had previously received IFN [1]. We have been performing a phase 2 study of treatment discontinuation after the drug change from IM to IFN (Japanese Imatinib Stop And Interferon Study; JISAS). This trial is comprised of 2 parts; the first part is to change therapy drug from imatinib to IFN and the second part is to stop IFN for therapy-free. We present here a final result of this trial.Patients: Patients with a confirmed diagnosis of CML in 1st chronic phase (CP1) as well as in CMR (undetectable BCR-ABL transcript) following over 2 years of MMR on IM were enrolled in this pilot study after obtaining the written informed consent. All the eligible patients were recruited from September 2009 to December 2011 whether or not any therapeutic drug had been given before IM.Evaluation and response criteria:Since a conversion factor for International scale was not available in Japan until recently, for entry to the study, BCR-ABL transcripts at a level equal to or below 100 copy/mg RNA in a real-time quantitative-polymerase chain reaction (RQ-PCR) assay or equal to or below 50 copy/assay in a highly sensitive transcription-mediated amplification (TMA) method were defined as MMR. CMR was defined as detection of no BCR-ABL transcript in RQ-PCR assay, nested reverse transcriptase-polymerase chain reaction (RT-PCR) assay, or TMA.During the study, molecular response was assessed at the baseline and every month thereafter, by determining the BCR-ABL to ABL mRNA transcript ratio isolated from the peripheral blood using RQ-PCR and RT-PCR. The BCR-ABL to ABL transcript ratio at a level below 0.001 was defined as MMR and no detectable BCR-ABL transcript in RT-PCR was defined as CMR. Molecular relapse defined as a loss of MMR was taken into account if confirmed in 2 successive assessments.Study design and treatment: Administration of IFN is started at a dose of 3 million units 2-5 times per week within 4 weeks after IM discontinuation. IFN administration was stopped after 2 years of IFN maintenance. In case of molecular relapse, IM was resumed at 400 mg daily.Statistical analysis: Non-parametric values or numbers were compared between the two groups using the Mann-Whitney test. Relapse-free survival was estimated using the Kaplan-Meier method.Results: Fifteen patients were enrolled from September 2009 to December 2011. Median age was 50 years (range, 28-67 years) and male to female ratio was 1.5. Sokal score at the diagnosis was low in 13 patients and high in 2 patients. Four patients had been treated before IM. Previous therapies comprised IFN in all these patients, including 1 patient who relapsed after allogeneic stem cell transplantation (SCT). The clinical stage of this patient was amended to be accelerated phase at the time of diagnosis. Two other patients withdrew the consent. Excluding these 3 patients, the remaining 12 patients with low Sokal score were analyzed.The average follow-up period is 1220 days (range: 797-1519 days). Four patients lost MMR (1, 3, and 6 months in IFN maintenance phase and 10 months after IFN discontinuation, respectively) and other 8 maintained CMR. Estimated molecular relapse-free survival at 1 year after discontinuation of IFN is 60%. The patients in therapy-free remission revealed significantly longer CMR period on IM (median 31 months, range 26-79 months) compared with relapsed patients (0, 9, and 14 months, respectively; p=0.0142). Molecular relapse free survival was significantly better in patients with over 2 years of CMR on IM than otherwise (80% vs 25%; log-rank test, p=0.0013). All the relapsed patients achieved MMR after 2, 2, 4, and 5 months of IM resumption, respectively.Conclusion: IFN maintenance can provide high probability of therapy-free remission in patients with sustained molecular response of IM treatment for CML, especially with over 2 years of sustained CMR of IM treatment.

Treatment patterns, prescribing decision drivers, and predictors of complete response following disease recurrence in gastrointestinal stromal tumor patients-a chart extract-based approach.

The aim of this study was to investigate tumor characteristics, treatment patterns, and outcomes in recurrent KIT + GIST patients treated in a community practice setting. An online tool was used to retrieve data on 410 patients treated with adjuvant imatinib mesylate (IM) for primary resectable KIT + GIST, who discontinued, had a recurrence, and then restarted IM or initiated sunitinib. Tumor characteristics at recurrence, treatment patterns, and factors associated with post-recurrence complete response (CR) achievement were analyzed. About 72.7% of patients did not have surgery post-recurrence as majority of them had unresectable (45%), metastatic (40%), or multifocal tumors (62.4%). Following recurrence, 76.6% of patients were re-started on IM and 23.4% on sunitinib; patients were 7.37 times more likely to re-start IM if initial treatment duration was ≤18months (p < 0.001). Patients were also more likely to re-start IM if recurrence occurred >12months post-discontinuation, or they had a recurrence inside the GI system, lower or unknown Fletcher risk score at primary diagnosis, or lower mitotic rate, (odds ratio (OR) = 3.54, p < 0.001; OR = 2.64, p = 0.006; OR = 2.55, p = 0.007; and OR = 2.45, p = 0.002, respectively). About 22.4% achieved CR; patients were more likely to achieve CR if they had unifocal tumor at recurrence, inside the GI system, of ≤2cm, or had lower mitotic rate (OR = 2.61, p < 0.001; OR = 2.27, p = 0.036; OR = 2.16, p = 0.023, OR = 1.87, p = 0.017, respectively). IM treatment duration at primary diagnosis, time to develop recurrence after IM discontinuation, tumor location, and mitotic rate at recurrence were the main prescribing decision drivers. Tumor characteristics were the most important factor in achieving CR following c-KIT inhibitor retreatment.

Frontline Treatment With Imatinib Mesylate in Chronic Myeloid Leukemia Patients in Early Chronic Phase: a Very Long-Term Analysis by the GIMEMA CML Working Party

BackgroundThe chronic myeloid leukemia (CML) therapeutic scenario has been enriched by the approval of second generation TKIs as frontline treatment of early chronic phase (ECP) patients, but imatinib mesylate (IM) still represents the standard for many patients. The long term outcome is extremely important to assess the treatment efficacy and to decide on the allocation of resources. The phase 3 trials comparing second generation TKIs versus standard-dose IM have not still demonstrated a clear improvement in terms of progression-free survival and overall survival. In the IRIS trial, at 8 year, 55% of patients were still on IM and the overall survival (OS) was 85%. Other published reports have shorter follow-up. Aims and MethodsTo assess the very long-term outcome of CML patients treated frontline with IM, we analyzed 559 patients enrolled within 3 multicentric prospective studies conducted by the GIMEMA CML Working Party (NCT00514488, NCT00510926, observational trial CML023). Definitions: major molecular response (MMR), BCR-ABLIS ratio <0.1%; deep molecular response (MR4.0), detectable disease ≤ 0.01% BCR-ABLIS or undetectable disease with ≥10,000 ABL transcripts; progression, transformation to accelerated or blastic phase; failure, according to 2013 ELN criteria; event, treatment discontinuation for any reason or lost to follow-up. Information on survival and progression were regularly collected. All deaths, at any time and for any reason, were included. All the analysis have been made according to the intention-to-treat principle. ResultsBaseline demographics characteristics: median age: 52 years (extremes 18-84 years); male sex: 60%; high Sokal, high Euro and high EUTOS scores: 22%, 7% and 7%, respectively; clonal chromosomal abnormalities (CCA) in Ph+ cells: 4% (not evaluable in 32% of patients for insufficient number of metaphases); e13a2 BCR-ABL transcript: 36%. Median follow-up: 76 (7-99) months. The cumulative incidence of complete cytogenetic response (CCyR), MMR and MR4 was 88%, 85% and 61%, respectively. The median time to CCyR, MMR and MR4 was 6, 7 and 42 months, respectively. Patients with high Sokal, high Euro and high EUTOS scores had significantly lower overall estimated probability of CCyR and MMR with respect to low and intermediate risk patients. A high Sokal score also predicted a significantly inferior probability of MR4; patients with high Euro and high EUTOS score had lower overall estimated probability of MR4, but the difference were not statistically significant. The reasons for IM discontinuation were: lack of efficacy (19%), toxicity or death (9%), withdrawal of informed consent (3%); 4% of patients were lost to follow-up. The 8-year event-free survival (EFS), failure-free survival (FFS), progression-free survival (PFS) and OS were 55% (95% CI: 51-60%), 66% (95% CI: 61-70%), 84% (95% CI: 78-89%) and 85% (95% CI: 79-90%), respectively. A high Sokal and a high Euro scores were able to identify patients with significantly lower probability of EFS, FFS, PFS and OS with respect to the other patients. High EUTOS score patients had significantly poorer EFS and FFS, but PFS and OS differences were not significant. Age, performance status and e13a2 transcript resulted independent prognostic factors on PFS and OS. ConclusionsUntil now, the available data on the very long-term outcome of newly diagnosed chronic phase CML patients treated frontline with imatinib are limited to a company sponsored study (IRIS study). The GIMEMA CML Working Party provided an unbiased overview of the long-term imatinib therapeutic effects in a multicentric nationwide experience. These results should be taken into consideration to make treatment decision concerning the choice of the first line TKI, particularly in low risk patients. AcknowledgmentsUniversity of Bologna, BolognaAIL, COFIN, Fondazione Carisbo. [Display omitted] Disclosures:Castagnetti:Novartis Farma: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Gugliotta:Novartis: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria. Abruzzese:BMS, Novartis: Consultancy. Soverini:Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; ARIAD: Consultancy. Cavo:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Imatinib mesylate discontinuation in patients with chronic myeloid leukemia who have received front-line imatinib mesylate therapy and achieved complete molecular response

The aims were to investigate the feasibility of imatinib mesylate (IM) discontinuation in chronic myeloid leukemia patients who were initially treated with IM and achieved complete molecular response (CMR). Fourteen patients were included. Ten were relapsed within 9.5months after discontinuation of IM. All 7 patients with high Sokal risk were relapsed. The probability of CMR persistence at 1-year was 28.6%. All relapsed patients were still responsive to IM. A high Sokal risk and delayed acquisition of CMR were associated with relapse. IM discontinuation in patients achieved CMR after treatment with front-line IM might be feasible. Further studies are warranted.

Persistence of BCR-ABL-Expressing LEUKEMIC STEM CELLS IN Chronic MYELOID LEUKEMIA (CML) PATIENTS IN COMPLETE REMISSION with Undetectable MOLECULAR Disease

AbstractAbstract 883Currently Imatinib Mesylate (IM) represent the first line therapy for chronic myeloid leukemia (CML). Recent data suggest that despite unprecedented rates of complete cytogenetic responses (CCR) and major molecular responses (MMR) obtained, leukemic stem cells (LSC) persist in the majority of patients (pts). LSC have been shown to be resistant to in vitro treatments with tyrosine kinase inhibitors (TKI). Consequently, discontinuation of IM in pts with undetectable molecular residual leukemia (UMRL) attested by RQ-PCR, leads to molecular relapses in the majority of the cases. Although the persistence of CD34+ CD38- leukemic stem cells has been demonstrated in pts with complete cytogenetic remission (CCR), the persistence of BCR-ABL+ leukemic stem cells in UMRL pts with has not been studied so far.For this purpose, we have performed an extensive analysis of bone-marrow-derived clonogenic and primitive hematopoietic stem cells in 6 pts with RQ-PCR constantly negative in their blood samples. Concerning the treatments; 5 out of 6 pts were off therapy, 3 pts (UPN1, 2, 3) had been treated with interferon-a only (IFN) for 6–13 years and their therapy was discontinued for 11, 16 and 8 years, respectively and 2 pts (UPN4 and 5) had been treated successively with IFN and IM and their IM therapy was discontinued for 2 years. One patient (UPN6) had been treated with IM followed by dasatinib and was on dasatinib at the time of the study. UPN7 was previously treated with first IFN then IM (which induced a stable UMRL) and then she switched to dasatinib because of side effect with IM. Bone marrow cells were collected and CD34+ cells purified using immunomagnetic columns. After performing a clonogenic assay, CD34+ cells were used in long-term culture initiating cell (LTC-IC) assays with weekly half medium changes. At week+5, clonogenic assays were performed and LTC-IC-derived clonogenic cells activity was calculated. For each patient 20 individual and 20 pools of 10 clonogenic cells and 20 individual and 20 pools of 10 LTC-IC derived CFU-C were plucked in order to obtain information in at least 220 CFU-C. After RNA extraction, BCR-ABL was quantified by RQ-PCR and in each positive CFU-C a nested PCR was performed to confirm the results. In one patient (UPN7) a NOD/SCID mouse assay was performed.All 3 pts treated with IFN alone, had BCR-ABL+ clonogenic cells varying from 0.5% (UPN1, 2) to 45 % (UPN3). All 3 had LTC-IC derived CFU-C positive for BCR-ABL (UPN1: 20%; UPN2 5%; UPN3 3%). In two pts previously treated with IFN and IM, clonogenic CFU-C BCR-ABL positivity was 10% and 5% whereas LTC-IC-derived CFU-C was 5% in UPN4) and undetected on UPN5. In UPN6 treated with IM then dasatinib, 5% of CFU-C was BCR-ABL+ whereas 100% of LTC-IC derived CFU-C was positive. The analysis of SCID-NOD assays performed in CD34+ cells from patient UPN7 is ongoing. Overall, these data show, for the first time to our knowledge, that in pts in IFN and IFN/IM-induced long-term remissions, there is persistent clonogenic BCR-ABL+ output maintained by BCR-ABL-expressing stem cells in the absence of relapse. In the only patient with successively treated with IM and dasatinib, 100 % of primitive hematopoietic stem cells are BCR-ABL+, despite PCR-negativity in peripheral blood, suggesting their possible quiescence in vivo and highlighting a theoretical risk of relapse. It remains to be determined if in pts with TKI-induced remissions, the analysis of stem cell compartments could be of use for clinical decisions to discontinue therapy. Disclosures:No relevant conflicts of interest to declare.

Acne rosacea associated imatinib mesylate in a gastrointestinal stromal tumor patient

Tyrosine kinase inhibitors (TKIs) are targeted treatments for various cancers. Skin toxicities are one of the most common nonhematological side-effects of TKIs. We report an imatinib mesylate (IM) induced hyperpigmented acne rosacea (AR) and sunitinib-induced palmar hyperkeratosis in the case with gastrointestinal stromal tumor. AR was arisen due to the discontinuation of IM. To the best of our knowledge, this kind of cutaneous side-effect with IM has not been documented previously.

Lichenoid Drug Eruption with Palmoplantar Hyperkeratosis due to Imatinib Mesylate: A Case Report and a Review of the Literature

Cutaneous adverse effects of imatinib mesylate (Glivec) are common and various types of skin eruptions have been reported. We report here a 57-year-old man who presented with lichen planus-like lesions on his extremities and palmoplantar hyperkeratosis due to the use of imatinib mesylate for chronic myeloid leukaemia. The skin lesions improved after discontinuation of imatinib mesylate but re-administration of the drug at a lower dose provoked a mild recurrence. He could, however, continue to take the drug at the lower dose and his skin lesions were well-controlled by topical corticosteroid treatment. The literature on lichenoid drug eruption due to imatinib mesylate is reviewed.

Cytokine-Mediated Signaling Is Suppressed in Myeloid Cells and Enhanced in Lymphatic Cells in Patients with Chronic Myeloid Leukemia (CML) — Partial Normalization with Tyrosine Kinase Inhibitors.

Abstract 2180Poster Board II-157 Introduction.Aberrant phosphorylation of the BCR-ABL1 tyrosine kinase (TK) is characteristic of chronic myeloid leukemia (CML). This oncoprotein interacts directly with intracellular signaling proteins, alters the responsiveness of cytokine receptors and regulates secretion of autocrine cytokines. Targeted inhibition of BCR-ABL1 with TK inhibitor (TKI) imatinib mesylate (IM) is the current standard treatment of CML. For overcoming IM resistance or intolerance, 2nd generation TKIs (nilotinib, dasatinib) with broader kinase inhibition profile have been approved for clinical use. Although in vitro results suggest that TKIs are immunosuppressive, no increases in opportunistic infections or secondary malignancies have been observed to date. In contrast, in some TKI-treated patients immunoactivation in the form of chronic lymphocytosis linked to excellent therapy responses has recently been shown. Dynamic monitoring of aberrant cytokine signaling pathways would aid in understanding and predicting the development of TKI-resistance or adverse/off-target effects. The aim of this study was to analyze the responsiveness of leukocytes to cytokine stimuli in CML patients at diagnosis and during TKI therapy using single-cell profiling of phosphoprotein networks by multiparameter flow cytometry. Patients and methods. The study consisted of 4 healthy controls, 6 CML patients at diagnosis, 6 IM patients and 5 dasatinib patients. Stimuli included GM-CSF, IL-2+IL-10+IFNα and IL-4+IL-6+IFNγ and they were added immeadately to freshly drawn whole blood ex vivo. The readout phosphoproteins were pERK1/2, pSTAT1, pSTAT3, pSTAT5a and pSTAT6 (with isotype controls), and were analyzed separately from granulocytes, monocytes, CD4+ CD25neg T helper cells (Th), CD4neg lymphocytes and CD4+CD25+ T cells including regulatory T-cells (Treg). Analysis was performed with heatmap function of Cytobank software (http://cytobank.stanford.edu/public/). Results.Unstimulated phosphoprotein levels reflecting the activation state of leukocytes in vivo did not differ between healthy controls and CML patients at diagnosis or during dasatinib therapy. Strikingly, in IM patients, baseline levels of pSTAT3 were relatively high indicating in vivo occurring activation of leukocytes in this patient group. We next studied ex vivo responsiveness of immune effector cells with cytokines and found clear differences between healthy controls and CML patients. At CML diagnosis.GM-CSF/pERK1+pSTAT5a, IFNa/pSTAT1,and IL-4/pSTAT6 (stimulus/readout) as well as pSTAT3 responses with all stimuli were suppressed in monocytes. In granulocytes, GM-CSF/pSTAT1 levels were diminished. In Th and Treg lymphocytes, IL-6/pSTAT3 responses were markedly pronounced, while IL-10/pSTAT3 responses were not affected when compared to healthy controls. Such difference was not observed in CD4neg lymphocytes. During TKI therapy.Most patients (9/11) were in cytogenetic remission at the time of analysis. The unresponsiveness of myeloid cells at diagnosis was restored by IM or dasatinib therapy in most, but not all patients. Similarly, in Th and Treg lymphocytes TKI-therapy normalized the enhanced IL-6/pSTAT3 responses that were evident at diagnosis. However, in Th and Treg cells pSTAT3 responses provoked by IL-10 were particularly prominent. Interestingly, one dasatinib patient with aberrant constant blood NK-lymphocytosis and monocytosis had uniquely strong IFNg/pSTAT1 and IL-4/pSTAT6 responses in monocytes. Furthermore, one patient who have stayed in persistent remission after IM discontinuation had exceptionally high pSTAT3 responses with all of stimuli used. Similar kind of signaling profile was unseen with the other patients and could reflect immunoactivation related to leukemia control. Conclusions.Dynamic single-cell profiling of signaling networks is feasible in CML patients and can be used to study mechanisms of aberrant immune reactivity in TKI-treated patients. The method could be particularly suitable for assessing candidate patients for TKI discontinuation. Although in vitro results suggest immunosuppressive effects of TKIs on lymphocytes, leukocytes ex vivo from patients were able to respond similarly to cytokine stimuli as in healthy controls. Disclosures:Mustjoki:BMS: Honoraria. Porkka:BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.

Rare incidence of congestive heart failure in gastrointestinal stromal tumor and other sarcoma patients receiving imatinib mesylate

The authors sought to determine the incidence and severity of cardiovascular toxicity caused by imatinib mesylate in gastrointestinal stromal tumor (GIST) and other sarcoma patients, and to explore cardiotoxicity caused by imatinib mesylate using cell culture and in vitro models. To determine the incidence and significance of serious cardiac adverse events in GIST and other sarcoma patients receiving imatinib mesylate, the authors performed a retrospective analysis of 219 consecutive patients treated with imatinib mesylate. In vitro studies of imatinib mesylate on cultured cardiomyocytes and biochemical studies of cardiac lysates from mice treated with imatinib mesylate were performed to define the potential cardiotoxic effects of imatinib mesylate. Grade 3 or 4 potentially cardiotoxic adverse events (mostly edema or effusions) occurred in 8.2% of patients, were manageable with medical therapy, and infrequently required dose reduction or discontinuation of imatinib mesylate. Arrhythmias, acute coronary syndromes, or heart failure were uncommon, occurring in <1% of treated patients. However, administration of imatinib in a mouse model system resulted in inhibition of activation of protein kinases that are known to be important in the cardiac stress response. The authors concluded that imatinib is an uncommon cause of cardiotoxicity, and that the cardiovascular adverse events that occur are manageable when recognized and treated. Nevertheless, our preclinical findings suggest that imatinib remains a potential cardiotoxin. Furthermore, the cardiac consequences of long-term imatinib therapy remain unknown. We therefore recommend treatment of risk factors for cardiovascular disease in imatinib-treated patients in accord with the American Heart Association guidelines for the prevention and treatment of heart failure.