Months Of Imatinib Research Articles

A novel primary KIT exon 9 single nucleotide substitution c.1427G>T (p.Ser476Ile) in a gastrointestinal stromal tumor

Dear Sir: Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that originate from the interstitial cells of Cajal. These neoplasms are characterized by the expression of the receptor tyrosine kinase KIT (CD117, c-Kit), and mutations in the ckit proto-oncogene resulting in constitutive activation of the receptor are associated with the tumorigenesis of most GISTs [1]. For unresectable and metastatic tumors, the multitargeted tyrosine kinase inhibitor imatinib mesylate is considered the first choice of treatment. We report the case of a 44-year-old male who initially presented with a GIST of the stomach measuring 16.0 cm in August 2007 at his local hospital. The tumor was incompletely resected by partial gastrectomy, and adjuvant imatinib at 400 mg/d was started in September 2007. Following 15 months of imatinib, the patient developed hepatic and peritoneal metastases (January 2009). He then asked for a recommendation for further treatment at our sarcoma center. We recommended a dose escalation of imatinib to 800 mg/d. Computed tomography showed disease stabilization at first follow-up in March 2009 but a progression of the disease 3 months later. The patient’s treatment regimen was changed to 37.5 mg/d of sunitinib in a continuous daily schedule, which resulted in disease stabilization for 6 months and, subsequently, progressive hepatic disease. The histopathological analysis revealed a mixed type GIST (Fig. 1a, b) with a mitotic index of ten mitoses/50 high-power fields (1HPF=0.23 mm). Immunohistochemical staining of the GIST showed a positive reaction with antibodies against c-KIT, CD34, and DOG1. The assessment of tumor behavior, which was performed following the NIH consensus guidelines [2] or the classification proposed by Miettinen and Lasota [3], revealed a “high-risk” for malignancy. We performed a sequence analysis of KIT exons 9, 11, 13, and 17 as well as PDGFRα exons 12 and 18 in the primary tumor (central tumor section) and adjacent nonneoplastic formalin-fixed and paraffin-embedded tissue. The analysis was carried out by PCR amplification (Primus 25 Thermocycler, MWG, Ebersberg, Germany) followed by direct sequencing of both the forward and reverse strands with an ABI 3130 Genetic Analyzer (Applied Biosystems, Foster City, CA, USA). We used two independent PCR reactions for sequence analysis, which was additionally confirmed by a second test in a different institution (GenOPath GbR Bonn, Germany). As a result of the genetic analysis of the tumor tissue, we identified a novel primary KIT exon 9 single nucleotide substitution c.1427G>T (p.Ser476Ile) that was not detectable in the adjacent normal tissue (Fig. 2). The electropherogram of the tumor tissue showed almost no wild-type component, so that a homozygous mutation status is very likely. It was shown that the loss of the wild-type allele may be present at F. Grabellus (*) : S.-Y. Sheu :K. W. Schmid :K. Worm Institute of Pathology and Neuropathology, University Hospital Essen, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany e-mail: florian.grabellus@uk-essen.de

Impact of Imatinib Dose Escalation in Chronic Myeloid Leukemia Patients in Chronic Phase with Sub-Optimal Response or Failure with Imatinib 400 Mg.

Abstract 3289Poster Board III-1Imatinib dose escalation has been used in sub-optimal response and therapeutic failure to imatinib in conventional doses. The aim of this study was to evaluate the efficacy of imatinib dose increase in CML patients in CP who did not achieve the best response to imatinib 400 mg QID. Patients and methods:All CML patients in CP treated in our institution with imatinib 400mg between March 2002 and December 2008 were evaluated. Imatinib was escalated to 600–800mg in cases with sub-optimal response or failure, according to Leukemia Net or IRIS Trial criteria. All survival curves were calculated from date of dose increase: overall survival (OS) until death or last follow-up, event free survival (EFS) until loss of complete hematological response (CHR) or major cytogenetic response (MCyR), progression to accelerated phase (AP) or blast crisis (BC) or death from any cause. Transformation free survival (TFS) was calculated from dose increase until progression to AP, BC or death. Results:137 patients in CP were treated with imatinib 400 mg. Dose was escalated in 55 (40%) patients due to loss or failure to achieve CRH (13 = 24%); progression to BC (2 = 3.5%); no CCR (11 = 20%); loss of RCC (5 = 9%); CCR without major molecular response (MMR) after 18 months of imatinib (24 = 43.5%). Males: 37, females 18 cases. Median age: 44 (16–74) years. Twenty-eight patients (49%) were treated with imatinib as first line therapy and 51% had used IFN previously. Median time between diagnosis and imatinib start was 4.5 (0–94) months. Responses: 94% achieved CHR; 58% CCR and 34% MMR. After dose increase, 31 (56%) responded: 58% of the patients with previous sub-optimal molecular response achieved MMR. Among those who benefited from dose increase, only 3 cases lost the response: one with hematological resistance and two with cytogenetic resistance (2 lost CCR and one CHR). Seven out of 16 patients who increased dose due to cytogenetic failure (loss of response, failure and sub-optimal response) achieved response: one had partial cytogenetic response (PCyR) and 6 CCR. Five patients with hematological failure presented response: CHR (2), CCR (1), PCyR (1) and MMR (1). Patients with BC (2 cases) did not respond to dose escalation. TFS was 89% and 67% in 2 and 5 years, respectively. EFS was 71% and 64% in 2 and 5 years respectively. When stratified by the type of failure, EFS was 100%, 49% and 34% in the group with molecular sub-optimal response with median time of 22 (4–41) months, cytogenetic 17 (1.2–42) and hematological failure 7.7 (0.2–57), respectively (P<0.03). Conclusions:imatinib dose escalation was successful in molecular sub-optimal response. However, the patients who do not achieve MMR might be candidates to second line treatment. Patients who did not achieve cytogenetic or hematological response did worse with imatinib dose escalation. Disclosures:No relevant conflicts of interest to declare.

Absence of Progression As Assessed by Response Evaluation Criteria in Solid Tumors Predicts Survival in Advanced GI Stromal Tumors Treated With Imatinib Mesylate: The Intergroup EORTC-ISG-AGITG Phase III Trial

From February 2001 to February 2002, 946 patients with advanced GI stromal tumors (GISTs) treated with imatinib were included in a controlled EORTC/ISG/AGITG (European Organisation for Research and Treatment of Cancer/Italian Sarcoma Group/Australasian Gastro-Intestinal Trials Group) trial. This analysis investigates whether the response classification assessed by RECIST (Response Evaluation Criteria in Solid Tumors), predicts for time to progression (TTP) and overall survival (OS). Per protocol, the first three disease assessments were done at 2, 4, and 6 months. For the purpose of the analysis (landmark method), disease response was subclassified in six categories: partial response (PR; > 30% size reduction), minor response (MR; 10% to 30% reduction), no change (NC) as either NC- (0% to 10% reduction) or NC+ (0% to 20% size increase), progressive disease (PD; > 20% increase/new lesions), and subjective PD (clinical progression). A total of 906 patients had measurable disease at entry. At all measurement time points, complete response (CR), PR, and MR resulted in similar TTP and OS; this was also true for NC- and NC+, and for PD and subjective PD. Patients were subsequently classified as responders (CR/PR/MR), NC (NC+/NC-), or PD. This three-class response categorization was found to be highly predictive of further progression or survival for the first two measurement points. After 6 months of imatinib, responders (CR/PR/MR) had the same survival prognosis as patients classified as NC. RECIST perfectly enables early discrimination between patients who benefited long term from imatinib and those who did not. After 6 months of imatinib, if the patient is not experiencing PD, the pattern of radiologic response by tumor size criteria has no prognostic value for further outcome. Imatinib needs to be continued as long as there is no progression according to RECIST.

Advanced Philadelphia chromosome positive acute lymphoblastic leukemia patients relapsed after treatment with tyrosine-kinase inhibitors: successful response to clofarabine and cyclophosphamide

Advanced Philadelphia chromosome positive acute lymphoblastic leukemia patients relapsed after treatment with tyrosine-kinase inhibitors: successful response to clofarabine and cyclophosphamide

Delayed achievement of cytogenetic and molecular response is associated with increased risk of progression among patients with chronic myeloid leukemia in early chronic phase receiving high-dose or standard-dose imatinib therapy

AbstractPatients not in complete cytogenetic response (CCyR) continuously face the competing possibilities of eventually achieving a cytogenetic response versus progressing. We analyzed the probability of achieving a CCyR, major molecular response, and progression in 258 patients with chronic myeloid leukemia in early chronic phase at 3, 6, and 12 months from imatinib start. The initial imatinib dose was 800 mg/day in 208 (81%) and 400 mg/day in 50 (19%) patients. For patients not in CCyR, the probability of achieving CCyR (P = .002) or major molecular response (P = .004) significantly decreased, whereas the risk of progression increased (P = .16) at each time point. Patients with a BCR-ABL1/ABL1 ratio greater than 1% to 10% after 3 months of imatinib had a 92% probability of achieving CCyR with continued therapy, similar to the 98% for those with 1% or less, but their risk of progression (11%) was almost 3-fold that of patients with a BCR-ABL1/ABL1 transcript ratio of 1% or less (4%) and similar to that of patients with transcript levels more than 10% (13%). These results suggest that patients not in CCyR after 12 months on imatinib have a higher risk of progression. This risk is discernible as early as 3 months into imatinib therapy by molecular analysis and may provide the rationale to institute therapies that render higher rates of early response.

Response of imatinib-resistant extra-abdominal aggressive fibromatosis to sunitinib: case report and review of the literature on response to tyrosine kinase inhibitors

Aggressive fibromatosis (AF) is usually a slowly growing locally invasive tumor, but may exhibit a much more aggressive phenotype. The role of chemotherapy in AF is not well defined, but can be useful in some cases. We examined the response of a case to both imatinib and sunitinib. We report a case of an aggressive multicentric extra-abdominal AF that was responsive to sunitinib, but resistant to imatinib. A 23-year-old woman developed painful multifocal AF of both legs and gluteal muscles that progressed after surgery and treatment with methotrexate/vinblastine and pegylated-liposomal doxorubicin. She received six cycles of ifosfamide/etoposide (IMV), and obtained a good response with elimination of pain. After 5 months, she developed progression and again received six cycles of IMV, with cessation of symptoms. After 13 months, tumors recurred. Although the AF was symptomatic and progressing, she was hesitant to receive chemotherapy and began treatment with sunitinib 50 mg/day for 28 days of a 42-day cycle. At 4 months, she could walk on her heels without pain. After 13 months of sunitinib, therapy was changed to imatinib 400 mg/day; after 7 days she noticed increasing pain in the AF lesions and decreased knee flexibility. Imatinib was continued, but after 2 months of imatinib, she could only walk a few steps due to pain. Sunitinib was reinstituted at 37.5 mg/day and symptoms improved within 1.5 weeks, with a marked reduction of symptoms at 1 month. She was doing well with a normal activity level, 32 months after initially beginning sunitinib. We conclude that sunitinib may be useful in some cases of AF.

Late Responders to Imatinib: Is Timing of Achievement of Complete Cytogenetic and Molecular Responses the Same in Previously Treated as Compared to the Newly Diagnosed CML Patients?

Appropriate monitoring of the effect of tyrosine kinase (TK) therapy is a relevant issue for CML therapeutic strategy. Although cytogenetics is the gold-standard method for response evaluation, serial quantification of BCR-ABL levels by real time PCR (RQ-PCR) has shown accuracy in predicting therapeutic response. Optimal cytogenetic (CCyR) and molecular (MMR) responses for newly diagnosed chronic phase (CP) CML patients were defined within 12 and 18 months of Imatinib (IM) therapy. However, patients not achieving optimal responses (OpRes) within these times are classified as “late responders”. We evaluated a group of 142 patients (4 year follow up) treated with IM as 2nd line. Patients were classified in 3 groups according to previous treatment: IFN (n=90), SCT (n=11) and HU/IFN ≤3 months (n=41, considered as without treatment). BCR–ABL levels were measured every 3 months, at least 5 times/patient during follow-up. A laboratory-specific conversion factor of 1.33 was generated to convert the BCR-ABL/ABL% values to an International Scale (IS). At the moment, 90 patients are being followed (69 CP, 11 AP). Cytogenetics results were available in 80/90 cases, and 63/80 (79%) (55 CP, 8 AP) achieved CCyR. After 12 months of IM treatment, 30/63 cases (48%) obtained CCyR (early responders), and 33/63 (52%) were late responders. When 18 months were considered as a cut-off time to achieved OpRes, 46 (73%) were considered early and 17 (27%) late responders. Molecular data were available for 74 patients; 45/74 (61%) (40 CP, 5 AP) achieved MMR, and 20 (27%) also showed Complete MR. 10/45 cases (22%) were early responders, and 35/45 (78%) late at 18 months of IM. When evaluating at 24 months, 17 (38%) were early and 28 (62%) were late responders. When only CP patients that achieved CCyR (n=55) and MMR (n=40) were considered, these proportions were maintained. Attainment of CCyR/MMR was similar between patients with and without previous treatment (p=0,26;p=0,09). However, we found a delay in the timing of OpRes achievement in comparison with previous related work analyzing patients in 1st line IM. Thus, to achieve similar frequencies of CCyR/MMR obtained from the use of 1st line IM, previously treated patients needed an extension time of 6 months. Thus we suggest for the patients treated with IM as 2nd line a threshold of 18 months for CCyR and 24 for MMR for the establishment of the OpRes. This swap concept might be important in countries such as Brazil that postponed the introduction of IM as 1st line therapy for CML.

Actualisation des indications chirurgicales des tumeurs stromales gastrointestinales

S. Bonvalot Complete resection without tumor rupture remains the mainstay of the treatment in patients with localized, resectable GIST. Operative indications should take account of size and location of the tumor which impact the risk of recurrence. More micro-GIST are discovered with the development of investigations, rising the question of wait and see policy for some of them. In locally advanced inoperable patients and metastatic patients, Imatinib is the standard treatment. Secondary excision of residual disease has been shown to be related to a good prognosis in responding patients to imatinib, but it is still not demonstrated whether this is due to surgery itself or to a selection bias. A phase 3 EORTC study will start and will randomise this secondary surgery after 6 to 12 months of imatinib in responding patients.

An Intron-Derived Insertion/Truncation Mutation in the BCR-ABL Kinase Domain in Chronic Myeloid Leukemia Patients Undergoing Kinase Inhibitor Therapy

Although targeted inhibition of BCR-ABL with imatinib is an effective therapy for patients with chronic myeloid leukemia (CML), a minority of patients acquire mutations in the BCR-ABL kinase domain, resulting in imatinib resistance. The spectrum of kinase domain mutations discovered to date is quite heterogeneous, consisting almost exclusively of single nucleotide substitutions affecting key amino acids that regulate drug binding or BCR-ABL function. Here, we describe an alternative kinase domain insertion/truncation mutation in three CML patients undergoing kinase inhibitor therapy. In each of these patients, direct DNA sequencing of BCR-ABL RT-PCR products revealed that the same 35 nucleotides from ABL intron 8 had been inserted at the normal exon 8 to 9 splice junction. This 35-bp intronic sequence was flanked by excellent consensus splice donor and acceptor sequences, suggesting alternative splicing as the likely mutational mechanism. The insertion created a premature translational stop codon after 10 intron-encoded amino acids (amino acid 484). This resulted in truncation of 653 C-terminal amino acids, which included part of the kinase domain and the entire "last exon" region. These findings demonstrate that kinase domain insertions are an alternative (and not entirely uncommon) mutational mechanism in CML patients undergoing kinase inhibitor therapy.

Imatinib Versus Interferon-alpha (IFN) for Patients with Newly Diagnosed Chronic-Phase (CP) Chronic Myeloid Leukemia (CML) from the Chinese Public Healthcare System Perspective: 12 Months Cost and Cost Per Responder Analyses.

Background: Imatinib, a break-through oral molecular targeted therapy, has demonstrated impressive and durable responses as well as survival advantage over IFN based therapy in CML (1, 2). Reed et al. estimated the survival for a newly diagnosed CP CML patient treated with imatinib was 19.07 years vs. 9.09 years with IFN plus low dose cytarabine (LDAC) (3). However, imatinib has not been registered on the Chinese National Reimbursement Drug List (RDL) whereas IFN has. Although studies have shown IFN plus Ara-C is more effective than IFN alone, IFN is normally used alone in China in CP CML. Therefore, this study compared imatinib with IFN alone. Complete cytogenetic response (CCyR) at 12 months has been established as an effective measure for treatment efficacy in CML (4). The 12 months cost and cost per responder in CCyR analyses were conducted to compare imatinib with IFN alone from the Chinese public healthcare systems perspective.Methods: The cost per responder at 12 months for a newly diagnosed CP CML patient was calculated as dividing the total 1-year cost of treatment by the CCyR rate at 12 months. The 1-year cost of treatment consists of the following occurred during one year: drug cost, office visits, and blood tests. The cost of managing adverse events was excluded as local China data were unavailable at the time of the analyses. The CCyR at 12 months for imatinib was obtained from the International Randomized Infereron vs. STI571 Study (IRIS) (1). The CCyR at 12 months for IFN was from the Baccarani et al. study (6). Price information on drugs was obtained from the listed retail price in China. The price for imported IFN was used as the cytogenetic response data were unavailable for domestic made IFN. Unit cost on office visit and blood test was estimated based on the average fees charged by tier 3 hospitals. Dosages for imatinib and IFN were based on the approved product labels in China.Results: The 12-month CCyR rate for imatinib was 69% vs. 3% for IFN. The 1-year cost of treatment associated with imatinib was RMB77,700, lower than that with IFN (RMB79,200). The cost to achieve 1 CCyR at 12 month was RMB112,609 with imatinib vs. RMB2,640,000 with IFN.Conclusion: In newly diagnosed CP CML, patients treated with imatinib achieved a significantly higher CCyR at a lower cost than those treated with IFN at 12 months. Based on the 1 year analysis, imatinib is a dominant treatment option in comparison to IFN in newly diagnosed CP CML treatment from the Chinese public healthcare system's perspective.

The Philadelphia-Chromosome Is Unmasked as the Secondary Genetic Change in Acute Myeloid Leukemia on Imatinib Treatment.

The Philadelphia chromosome (Ph) is present in less than 3% of the acute myeloid leukemia (AML) and associated with poor prognosis. There are only few reports on the use of imatinib in Ph+ AML. We describe an adult female patient presenting with AML (Hb 3.6 g/dl, Wbc 137×109/L, Plt 295,000/uL and marrow blast 74%, with no basophilia or splenomegaly). Cytogenetic studies showed 45,XX,inv(3)(q21q26),-7,t(9;22)(q34;q11.2) [12] and RT-PCR showed p190BCR-ABL transcripts. The leukemia failed to respond to 2 cycles of daunorubicin and ara-C and imatinib 600mg daily was then started. Fluorescence in-situ hybridization (FISH) analysis of 300 marrow cells using dual fusion BCR-ABL translocation probes (D-FISH, Vysis, Downers Grove, IL, USA) showed that before imatinib, 78% of the cells were positive for BCR-ABL (at diagnosis, it was 83%), which after 6 weeks of imatinib treatment, became BCR-ABL negative (sensitivity 0.3%). However, marrow biopsy still showed 15% blasts. Repeated cytogenetics showed poor growth, but one metaphase showed 45,XX,inv(3)(q21q26),-7. With FISH, 39% of the marrow cells, including neutrophils, were positive for monosomy 7. At 4 months of imatinib, when the marrow blasts count increased to 40%, BCR-ABL remained negative by FISH, whereas monosomy 7 positive cells had risen to 82%. However, by nested RT-PCR with sets of BIOMED primers (sensitivity of 10−5), the p190BCR-ABL transcript was still present, suggesting persistence of a small and quiescent population of BCR-ABL positive leukemic stem cells. In summary, our case study demonstrates the need for careful cytogenetic and molecular analysis in cases of acute leukaemia with Ph chromosome to exclude the possibility of Ph chromosome being a secondary event, in which case durable leukemia remission will be unlikely if treatment is by BCR-ABL inhibition alone.

Increasing Frequency and Marked Stability of Complete Molecular Response Is Observed in Imatinib-Treated CML Patients with Long-Term Follow Up.

The degree of reduction of BCR-ABL in imatinib-treated patients with chronic phase CML is an important indicator of prognosis. The IRIS trial established that with first-line therapy patients with a major molecular response (MMR, 3 log reduction from a standardized baseline value for untreated patients) have a significantly more favorable progression free survival. Although 40% achieved a MMR by 12 months, very few had undetectable BCR-ABL according to strict PCR sensitivity criteria. We measured peripheral blood BCR-ABL levels by quantitative PCR at 3 to 6 month intervals in 155 patients with chronic phase CML enrolled in clinical trials of imatinib for up to 6 years. We aimed to (i) determine if BCR-ABL levels continued to decline over time, and (ii) evaluate the stability and significance of undetectable BCR-ABL. The patients included the Australasian subset of IRIS trial patients treated with 400mg of imatinib; 29 first-line patients evaluated for a median of 69 months (25th to 75th percentile range (pr) 58–72) and 24 second-line patients for a median of 54 months of imatinib (pr 38–60). 102 de-novo patients enrolled in the TIDEL trial of 600mg imatinib were evaluated for a median of 39 months (pr 30–42). Complete molecular response (CMR) was defined as undetectable BCR-ABL at a PCR sensitivity of at least 4.5 logs below the standardized baseline value confirmed on subsequent analysis after at least 3 months. The BCR control transcript level determined sensitivity and was dependent on RNA quality and reverse transcription efficiency. Of note CMR may not indicate eradication of leukemic cells, rather a reduction of BCR-ABL below the detection limit. CMR occurred in 34 patients who had 178 analyses after achieving CMR (median 4 tests per patient) and a median follow up of 15 months (pr 9–24). Very low level BCR-ABL was detected in 3 patients, the remaining 31 had undetectable BCR-ABL on every subsequent assay. Of the IRIS trial patients treated with first-line imatinib, 41% achieved a CMR by 69 months, a frequency significantly higher than occurred in these patients at 24 months (7%, p=0.006). The rate of CMR appeared to increase substantially beyond the 3 year time point (7%, 24% and 34% at 3, 4 and 5 years). 75 patients achieved MMR but not CMR and were followed for a median of 24 months after achieving MMR (pr 17–33). Six of 75 patients (8%) lost MMR as defined by >2-fold rise in BCR-ABL and loss of MMR on 2 consecutive analyses. The median fold rise was 18-fold (4 to 1900-fold), of whom 1 went on to blast crisis. Four of the 6 patients had BCR-ABL mutations detected at the time of the rise and 1 of the remaining patients had duplicate Ph. MMR was lost in these 6 patients within 18 months of its achievement. The overall rate of CMR and MMR (including patients with CMR) did not differ significantly between the 3 treatment groups at the 3 year time point (CMR 7%, 8% and 18%; MMR 66%, 71% and 70% for first-line 400mg, second-line 400mg and first-line 600mg respectively). In conclusion at a median follow-up of 5.75 years of 400mg first-line imatinib, CMR was achieved in 41% of patients. Importantly, of all patients who achieved a CMR in this study using strict criteria to define the sensitivity of analysis, none have lost MMR and 91% have maintained CMR. The slow acquistion and marked stability of CMR favour the notion that the leukemic stem cell pool is steadily declining with prolonged exposure to imatinib.

Significant Reduction of BCR-ABL Transcripts after Switching to Imatinib Therapy in Patients with CML and Complete or Near-Complete Cytogenetic Responses to Interferon-Alpha (IFN).

IFN confers a survival advantage for the minority of patients with CML who achieve a complete cytogenetic response. The 10-year survival rate was reported as 72%. In the IRIS trial only 3% of patients remained on IFN after randomization and 65% crossed-over to imatinib. Imatinib offered superior compliance and toxicity profiles and clear quality of life advantages. Furthermore, patients on first line imatinib with a major molecular response (MMR) by 12 months had a 100% progression free survival to advanced phase. An important clinical question of whether IFN-responsive patients can experience further improvements with imatinib has not been answered. We studied 23 chronic phase patients treated with IFN for a median of 4.5 years (r1.6–14.3) who had achieved a complete (n=15) or near-complete (n=8) cytogenetic response. IFN was ceased and 400mg imatinib commenced in a clinical trial with the primary objective of determining if switching to imatinib in IFN-responsive patients improves response when assessed at the molecular level. Molecular assessment was undertaken for the first 12 months of imatinib therapy by measurement of peripheral blood BCR-ABL levels by quantitative PCR at 3 month intervals. A subset of 10 patients had follow-up molecular assessment for 3.8 to 4.5 years after commencing imatinib. Prior to IFN cessation all patients had detectable BCR-ABL and 16 of 23 had not achieved a MMR, which is a 3 log reduction of BCR-ABL from a standardized baseline value for untreated patients. At a median of 3 months of imatinib (r3–12) these 16 patients achieved MMR. A significant reduction of BCR-ABL over the 12 month assessment was considered >50% and this occurred in 15 of these 16 patients (median 98.4% reduction, r94.4–99.8). In the sole patient without a significant reduction, BCR-ABL returned to the pre imatinib level after repeated dose interruptions of 93 days and decrease to 200mg imatinib due to thrombocytopenia. Of the 7 patients with a MMR prior to IFN cessation, all 7 maintained this level of response after switching to imatinib. Therefore, over the 12 month assessment all patients either achieved MMR (n=16) or maintained MMR (n=7). One patient withdrew consent after 83 days. The 10 patients with longer molecular follow-up of up to 4.5 years of imatinib all maintained MMR. The typical molecular response is illustrated in the figure, which plots the log reduction of BCR-ABL from the standardized baseline for 3 patients assessed at regular time-points before and after switching to imatinib. In conclusion, the data suggest that switching to imatinib leads to rapid and significant improvement in IFN-responsive patients in terms of achieving MMR, a response with established prognostic value with imatinib therapy. The study should help patients and their physicians make evidence-based decisions about the potential benefits and risks of switching to imatinib with prior response to IFN. [Display omitted]

Outcomes by Cytogenetic and Molecular Response at 12 and 18 Months of Imatinib in Patients with Newly Diagnosed Chronic Myeloid Leukemia (CML) in Chronic Phase (CP) in the IRIS Trial.

Long term data is now available from the International Randomized Study of Interferon vs. STI571 (IRIS). We performed landmark analyses for pts on imatinib (IM) at 12 and 18 months (mos) (n=509 and n=480 respectively) and stratified for CCyR (Ph+ 0%), PCyR (Ph+ >0–35%) or No MCyR (Ph+ >35%) at both timepoints. Progression-free survival (PFS) included all progressions to accelerated phase or blast crisis during treatment with IM, whereas event-free survival (EFS) also included any loss of MCyR/CHR, increase in WBC and CML-unrelated deaths on treatment as events. Overall survival (OS) considered all deaths including those after discontinuation of IM and irrespective of whether pts went on to transplant.Outcomes in IM pts by cytogenetic response at 12 and 18 mosEstimated long-term outcomes at 60 mos (%)CcyRCcyREFSPFSOSby 30 mos (%)by 60 mos (%)12 mos landmarkCCyRN = 350939795––PCyRN = 867893905764No MCyRN = 73618180213618 mos landmarkCCyRN = 358969997––PCyRN = 668090903850No MCyRN = 566983821127Although the level of cytogenetic response was predictive for long-term outcomes, PFS and OS were not statistically significantly different between 12-mos CCyR and PCyR. Note that 64% of PCyR pts and 36% of pts without MCyR at 12 mos subsequently achieved CCyR. Using the 18-mos landmark, 50% of PCyR pts and 27% of pts without MCyR achieved CCyR at a later time. Long-term outcomes were evaluated based on available BCR-ABL transcript levels in pts with CCyR. A 3-log reduction from standardized baseline value in untreated pts was defined as a major molecular response (MMR). No pts who achieved both CCyR and MMR at 12 or 18 mos progressed to AP/BC by 60 mos. Approximately 5% of pts with CCyR but no MMR at 12 mos (p=0.007) and only 2% of CCyR pts without MMR at 18 mos (p=0.11) subsequently progressed. Of approximately 25% of CCyR pts with available PCR analysis who did not achieve MMR at 18 mos, about half did achieve MMR at a later time and their estimated EFS rate at 60 mths was 91%.At 60 mos, 69% of patients randomized to IM remained on treatment. Achievement of CCyR and MMR by 12 and 18 mos after start of IM in newly diagnosed CML-CP are predictive for favorable long-term outcomes. About 50% of pts in PCyR or CCyR at these time points eventually achieve CCyR and MMR, respectively, on continued IM treatment. The ability to identify patients who may be late responders should be further studied.

Sequential imatinib and chemotherapy yield reverse-transcriptase polymerase chain reaction (RT-PCR)-negative peripheral stem cell collections in Philadelphia (Ph) chromosome positive acute lymphoblastic leukemia (ALL)—Preliminary results of CALGB 10001

6549 Background: Ph+ ALL has a short complete remission duration and survival. Allogeneic stem cell transplantation (SCT) is recommended. We hypothesized that imatinib plus sequential chemotherapy will result in greater leukemia cell cytoreduction than previously achieved with chemotherapy alone, allowing collection of large numbers of normal hematopoietic stem cells uncontaminated by residual t(9;22) lymphoblasts and thus reduce the likelihood of relapse after autologous SCT for patients without donors. Methods: Treatment consisted of a 4–5 drug induction regimen followed by imatinib 400 mg BID for 4 weeks, CNS prophylaxis with high-dose methotrexate, another month of imatinib, and ideally allogeneic SCT following fractionated total body irradiation (FTBI) and etoposide. Those without donors received high-dose cytarabine, etoposide, and G-CSF for stem cell mobilization, leukapheresis, and autologous SCT after FTBI, etoposide and cyclophosphamide. Imatinib maintenance continues until RT-PCR negative for 12 months. Patients had to be &lt; 60 years old. Results: 18 patients have enrolled to date; so far 3 underwent allogeneic SCT and 5 completed peripheral stem cell collections of whom 4 have undergone autologous SCT. Median stem cell yield was 55.74×106/kg (range, 34.8–94.4). Peripheral stem cells were assayed from 3 patients for RT-PCR with a sensitivity of 1:105-106. All 3 samples were negative for BCR-ABL. Of the 3 patients who underwent allogeneic SCT, 1 failed to engraft and died, 1 died due to respiratory failure on day 70, and 1 relapsed on day 113. Of the 4 patients who underwent autologous SCT, all achieved neutrophil engraftment (&gt; 0.5×109/L) between days 8–10 and platelet engraftment (&gt; 50×109/L) between days 7–17. Two patients relapsed (simultaneous CNS and marrow) on days 164 and 309, and 2 patients are alive in continuous remission on days +297 and +359 following autologous SCT. Conclusions: Sequential imatinib and chemotherapy can achieve RT-PCR negativity in Ph+ ALL, allowing autologous SCT. Ongoing accrual will evaluate the efficacy of this approach in adults with Ph+ ALL. [Table: see text]

Philadelphia Chromosome (Ph') Negative, MLL-Rearranged AML Arising in a Patient Treated with Imatinib for CML.

Background: Imatinib has become standard front-line therapy for CML. In ~3% of patients treated with imatinib, abnormalities including trisomy 8 and/or monosomy 7 occur in Ph' negative subclones and dysplasia occasionally is present, but transformation to AML is rare. We describe the first known case of AML with an MLL translocation during an imatinib-induced molecular remission of CML.Methods: The Ph' and the t(11;19)(q23;p13.1) were detected and monitored in sequential marrows using cytogenetic and FISH analyses. The BCR-ABL1 fusion transcript was traced by RT-PCR. The MLL translocation was identified and characterized in the AML blasts by Southern blot analysis, panhandle PCR-based methods and conventional PCR.Clinical History and Results: The patient presented with chronic phase CML at age 53 and was treated with hydroxyurea for 6 weeks, IFN-α for 20 months and imatinib for 32 months. Complete cytogenetic response was achieved at 10 months. Molecular remission, as indicated by absence of the BCR-ABL1 transcript, occurred after 15 months of imatinib (37 months from CML diagnosis). Mild dysgranulopoiesis was noted 6 months after imatinib was started and increased on subsequent studies. After 28 months of imatinib (50 months from CML diagnosis), there was marked trilineage dysplasia and the karyotype showed t(11;19)(q23;p13.1) in cells that were Ph' negative and negative for the BCR-ABL1 fusion transcript. FAB M5b AML was diagnosed four months later. The patient succumbed to AML despite aggressive management with chemotherapy and allogeneic stem cell transplantation. Southern blot analysis of the AML revealed two MLL bcr rearrangements. The reciprocal breakpoint junctions on the der (11) and der (19) chromosomes indicated a translocation of intron 8 of MLL and intron 1 of the known MLL partner gene ELL, which encodes a transcription elongation factor. The involved region of MLL was more 5′ than the secondary leukemia translocation breakpoint hotspot. The der (11) fusion transcripts joined MLL exon 7 to ELL exon 2, which is consistent with alternative splicing, and the der (19) fusion transcript joined ELL exon 1 to MLL exon 9.Conclusions: Secondary leukemias with MLL translocations have been associated with topoisomerase II poisons, but not with the agents administered to this patient. The entity that we describe is distinct from blast crisis, in which Ph' positive subclones evolve to acquire additional alterations. This case establishes that persistent clonal abnormalities and/or dysplasia in Ph' negative cells following imatinib therapy may not be benign and may herald AML transformation. With effective and selective molecular eradication of the Ph' positive clone, the emergence of leukemia with independent abnormalities may become more common. This is a highly concerning clinical complication to consider with BCR-ABL targeted agents.

Monitoring of Chronic Myeloid Leukemia (CML) Imatinib Response by Fluorescence-In-Situ-Hybridization (FISH).

Abstract Glivec, a tyosine kinase inhibitor is the drug of choice for newly diagnosed chronic phase CML. Whilst Q-PCR is the most sensitive method to monitor response; cytogenetic analysis as well as FISH is routinely used in many laboratories. FISH has the advantage over marrow cytogenetic by allowing analysis of more cells, and cells in interphase, obviating necessity for an invasive marrow procedure. We performed 126 FISH studies using BCR-ABL dual color dual fusion translocation probe for 69 CML patients on imatinib. For each samples, 300 nucleated cells were counted. Clinical information was available from 57 patients (34 chronic-phase (CP), 7 accelerated phase (AP), 8 blastic phase (BT) and 8 post-BMT relapses). Most CP patients (94%) could achieve sustained complete hematological responses (CHR), including 14 of the 15 patients pre-treated with IFN. IFN pre-treated patients received imatinib generally late in the course of CP compared to those without (median 19M vs 0.8M, p&amp;lt;0.001). At 12–15 months, 61% CP patients were FISH-ve. Fewer IFN-pretreated patients achieved FISH-ve responses (41.7% vs 90%, p=0.03). With a mean follow-up of 25 months (4–55M), none of the FISH-ve patients had disease transformation while AP/BT developed in 2 FISH+ patients (0% vs 22%, p=0.14). In CML-AP, early institution of imatinib (1–10M) achieved more FISH-ve responses than late treatment (30–36M) and degree of FISH response after 6–12 months of imatinib in CML-AP appeared to predict prognosis. For patients treated in BT, 4 received imatinib upfront and 4 after remissions or reversion to CP after chemotherapy. FISH negativity in the first few months of imatinib treatment, however, did not predict better prognosis. Two patients remained FISH-ve and disease-free 52 months without transplant, suggesting imatinib may be useful as maintenance after chemotherapy induction for BT patients not eligible for transplant. The observation that imatinib after chemotherapy induction has better prognosis than imatinib upfront requires confirmation by larger studies. In post-BMT relapses (8 patients: 1 cytogenetic relapse, 4 CP relapses, 1 blastic relapse, 2 AP relapses), hematological response could be achieved in all. Half became FISH-ve at 6–9 months and remained so at latest follow-up (44–56M). Three patients (1 CP, all 2 AP) were FISH+ at 6–9 months (42–90% Ph+ cells) and remained FISH+ thereafter, with one progressed to blastic disease at 24 months. FISH response at 6–9 months, thus, appears to carry prognostic significance in post-transplant CML relapses. In summary, our initial experience suggests monitoring of imatinib response by FISH provides useful prognostic information in different stages of CML.

Observation study on Asian patients taking imatinib mesylate in comparison to published data focusing on dosage and adverse events

6727 Background: Studies done mainly in Western communities have clearly described the dose, response and side effects of imatinib mesylate. There is little published data on Asian/Oriental patients. We have observed differences in our patients. Thus, a retrospective study was done. Methods: Retrospectively data on all patients treated between January 2002 to November 2004 were analysed for treatment response, dosage and side effects. Results: Forty-one patients had chronic myeloid leukaemia. 12 patients were in chronic phase. 19 patients were in accelerated phase. 10 patients were in blast crisis. 3 patients had GIST. Thirty patients are ethnic Chinese, 13 Malays and 1 Indian. 6 of 10 assessable patients in chronic phase achieved a complete haematological response. 3 had a pancytopenic response. Of 4 patients tested for cytogenetic remission, there were 1 complete and 2 partial cytogenetic response. The mean dose was 415 mg daily. Of 19 patients with accelerated phase, 13 had complete and 5 pancytopenic response. Three patients had a complete cytogenetic response, 5 patients a partial response and 4 patients did not have any cytogenetic response out of 12 patients tested. Of note 1 patient who weight 39 kg is still having a severe pancytopenic response 20 months on imatinib 100 mg daily. All 10 patients with blast crisis did not achieve any significant response. Skin depigmentation was seen in 25 of 27 assessable patients. No patient developed vertiligo. Weight gain was seen in 20 patients, averaging 3 kilogram. Fluid retention was noted in 5 patients. Conclusions: The Asian/Oriental patients in chronic phase are able to tolerate over 400 mg of imatinib. Similar haematological and cytogenetic responses have been obtained as compared to published data. We describe generalised skin depigmentation in 24 of 26 patients assessed, in contrast to published series. The skin change is gradual and is generally noted after 2–3 months of imatinib and the fairness stablise about 6 to 12 months and the depigmentation/ fairness does not progress further. No patient has vertiligo. The weight increase only in the first 3–6 months and then stablises. No significant financial relationships to disclose.

High-dose (HD) imatinib in patients (pts) with previously untreated chronic myeloid leukemia (CML) in early chronic phase (CP): preliminary results of a multicenter community based trial

6518 Background: A recent single center study suggests that using HD imatinib (800 mg/day) results in significant molecular responses for many patients. We therefore initiated a multicenter community-based single-arm phase II trial of HD imatinib in pts with early CP CML. Methods: Pts were ≥18 years (yrs), in early CP (≤6 months from diagnosis), without prior therapy except for ≤1 month of imatinib or hydroxyurea, and with normal organ function. Pts received imatinib 400 mg twice daily and dose was adjusted for grade ≥3 toxicity; filgrastim was encouraged for pts with grade ≥2 neutropenia. Results: To date, 36 pts have been enrolled in 20 institutions with a median follow-up of 5 months (mos) (0.5–9 mos). The median age is 51 yrs (28–76 yrs). Nineteen patients (53%) had hemoglobin <12 g/dl and 13 (35%) had platelets >450 x109/L. According to the Sokal classification, 14 (39 %), 18 (50%), and 3(8%) were in the low, intermediate and high-risk groups, respectively. Twenty seven pts have had a molecular analysis at 3 mos from the start of therapy and 22 (81%) achieved BCR-ABL/ABL levels <0.05%, with 11 (41%) having undetectable BCR-ABL by Q-PCR. Eleven 11 pts had Q-PCR at 6 mos and 10 (91%) achieved undetectable BCR-ABL. The most common grade ≥3 non-hematologic toxicity was fatigue (n=4, 11%), rash (n=3, 8%), nausea/vomiting (n=2, 6%), and musculoskeletal pain (n=2, 6%). Twelve patients developed grade ≥3 myelosuppression, including neutropenia (n= 5,14%), thrombocytopenia (n=5,14%), and anemia (n=2, 5%). Seventeen 17 (47%) patients required treatment interruptions and 16 of those (44%) have required dose reductions. Neupogen was administered to 8 (22%) pts with 3 (8%) pts for grade ≥3 neutropenia. Most common toxicities for dose reductions were fatigue (6, 17%), nausea/vomiting (9, 25%), and rash (5, 14%). Conclusions: High-dose imatinib is tolerable and effective for pts with newly diagnosed CP-CML in a multicenter setting. Compared to 400 mg daily of imatinib, pts at 800 mg daily achieve substantially higher rates of molecular response with majority having BCR-ABL/ABL ratios under 0.05% at 3 months and up to 41% having undetectable BCR-ABL on Q-PCR. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Novartis Novartis Novartis Novartis

Effect of a p210 multipeptide vaccine associated with imatinib or interferon in patients with chronic myeloid leukaemia and persistent residual disease: a multicentre observational trial

Background Although imatinib is the standard treatment for chronic myeloid leukaemia, not all patients reach complete cytogenetic remission (CCR) and most maintain detectable disease at the molecular level. We investigated whether a vaccine targeting the BCR-ABL-derived p210 fusion protein was an active and specific immunotherapy. Methods We recruited 16 patients who had chronic myeloid leukaemia (with the b3a2 fusion point of p210), stable residual disease, a minimum treatment of 12 months of imatinib or 24 months of interferon alfa, and no further reduction of residual disease for at least 6 months preceding enrolment. They were given six vaccinations with a peptide vaccine derived from the sequence p210-b3a2 plus molgramostim and QS-21 as adjuvants (CMLVAX100) before assessment of immunological and disease response, which included detecting amounts of b3a2 transcripts by standardised quantitative real-time reverse-transcriptase PCR. Results Of ten patients on imatinib, nine started CMLVAX100 having had a median of 10 months' stable cytogenetic disease (median 10% Philadelphia-chromosome-positive metaphases), whereas one started in stable CCR. All patients' cytogenetic responses improved after six vaccinations, with five reaching CCR. Notably, three of these five patients also had undetectable amounts of b3a2 transcript (BCR-ABL:β2 microglobulin ratio <0·00001). Six patients on interferon alfa treatment with a median of 17 months' stable residual disease (median 13% Philadelphia-chromosome-positive cells) were also vaccinated. All but one had improved cytogenetic responses, and two reached CCR. Overall, we recorded peptide-specific delayed-type hypersensitivity (in 11 of 16 patients), CD4 cell proliferation (13 of 14 assessed), and interferon γ production (five of five assessed). Interpretation Addition of CMLVAX100 to conventional treatment in patients with chronic myeloid leukaemia might favour further reduction of residual disease and increase the number of patients reaching a molecular response. Although imatinib is the standard treatment for chronic myeloid leukaemia, not all patients reach complete cytogenetic remission (CCR) and most maintain detectable disease at the molecular level. We investigated whether a vaccine targeting the BCR-ABL-derived p210 fusion protein was an active and specific immunotherapy. We recruited 16 patients who had chronic myeloid leukaemia (with the b3a2 fusion point of p210), stable residual disease, a minimum treatment of 12 months of imatinib or 24 months of interferon alfa, and no further reduction of residual disease for at least 6 months preceding enrolment. They were given six vaccinations with a peptide vaccine derived from the sequence p210-b3a2 plus molgramostim and QS-21 as adjuvants (CMLVAX100) before assessment of immunological and disease response, which included detecting amounts of b3a2 transcripts by standardised quantitative real-time reverse-transcriptase PCR. Of ten patients on imatinib, nine started CMLVAX100 having had a median of 10 months' stable cytogenetic disease (median 10% Philadelphia-chromosome-positive metaphases), whereas one started in stable CCR. All patients' cytogenetic responses improved after six vaccinations, with five reaching CCR. Notably, three of these five patients also had undetectable amounts of b3a2 transcript (BCR-ABL:β2 microglobulin ratio <0·00001). Six patients on interferon alfa treatment with a median of 17 months' stable residual disease (median 13% Philadelphia-chromosome-positive cells) were also vaccinated. All but one had improved cytogenetic responses, and two reached CCR. Overall, we recorded peptide-specific delayed-type hypersensitivity (in 11 of 16 patients), CD4 cell proliferation (13 of 14 assessed), and interferon γ production (five of five assessed). Addition of CMLVAX100 to conventional treatment in patients with chronic myeloid leukaemia might favour further reduction of residual disease and increase the number of patients reaching a molecular response. Vaccine development for chronic myelogenous leukaemiaThose familiar with the history of the development of tumour vaccines for chronic myelogenous leukaemia (CML), a myeloproliferative disease that accounts for 10–20% of chronic leukaemias, are often reminded of the labours of Sisyphus, who was condemned by the gods to perpetually roll a heavy boulder up a steep hill, only to helplessly watch it roll back before reaching the summit, and start over. In theory, CML should represent an ideal target for immunotherapy, and, indeed, in the arena of haemopoietic stem-cell transplantation, CML has long been recognised as one of the more responsive malignancies to immunotherapy. Full-Text PDF