Patients Receiving Imatinib Mesylate Research Articles

BCR-ABL1 Doubling-Times and Halving-Times May Predict CML Response to Tyrosine Kinase Inhibitors.

In Chronic Myeloid Leukemia (CML), successful treatment requires accurate molecular monitoring to evaluate disease response and provide timely interventions for patients failing to achieve the desired outcomes. We wanted to determine whether measuring BCR-ABL1 mRNA doubling-times (DTs) could distinguish inconsequential rises in the oncogene's expression from resistance to tyrosine kinase inhibitors (TKIs). Thus, we retrospectively examined BCR-ABL1 evolution in 305 chronic-phase CML patients receiving imatinib mesylate (IM) as a first line treatment. Patients were subdivided in two groups: those with a confirmed rise in BCR-ABL1 transcripts without MR3.0 loss and those failing IM. We found that the DTs of the former patients were significantly longer than those of patients developing IM resistance (57.80 vs. 41.45 days, p = 0.0114). Interestingly, the DT values of individuals failing second-generation (2G) TKIs after developing IM resistance were considerably shorter than those observed at the time of IM failure (27.20 vs. 41.45 days; p = 0.0035). We next wanted to establish if decreases in BCR-ABL1 transcripts would identify subjects likely to obtain deep molecular responses. We therefore analyzed the BCR-ABL1 halving-times (HTs) of a different cohort comprising 174 individuals receiving IM in first line and observed that, regardless of the time point selected for our analyses (6, 12, or 18 months), HTs were significantly shorter in subjects achieving superior molecular responses (p = 0.002 at 6 months; p < 0.001 at 12 months; p = 0.0099 at 18 months). Moreover, 50 patients receiving 2G TKIs as first line therapy and obtaining an MR3.0 (after 6 months; p = 0.003) or an MR4.0 (after 12 months; p = 0.019) displayed significantly shorter HTs than individuals lacking these molecular responses. Our findings suggest that BCR-ABL1 DTs and HTs are reliable tools to, respectively, identify subjects in MR3.0 that are failing their assigned TKI or to recognize patients likely to achieve deep molecular responses that should be considered for treatment discontinuation.

Economic Impact of Imatinib Mesylate Withdraw: An Option for Third World Countries?

Introduction: The advent of tyrosine kinase inhibitors has changed the natural history of chronic myelogenous leukemia (CML), promoting molecular remission in a high number of patients. In 40-60% of the patients that reach deep molecular responses (RM4.5 or more) and are using imatinib mesylate for 24 months or longer, a molecular response can be maintained after the cessation of the drug. Besides improving life quality in those patients, to withdraw the medication could have a great economic impact in the health system, what is extremely important in third world countries.Objective: To estimate the economic impact of stopping imatinib mesylate in CML chronic phase patients, receiving treatment for at least 36 months and presenting deep molecular response, determinate by BCR-ABL transcripts with quantitative reverse transcriptase polymerase chain reaction (QRT-PCR), in the last 24 months.Patients and methods: A single center observational retrospective study, including all patients diagnosed with chronic phase CML, confirmed by cytogenetic or molecular exams receiving treatment at a tertiary hospital in Brazil. All patients received imatinib mesylate either in first or second line therapy. Patients presenting deep molecular response for at least 24 months, under imatinib mesylate for 36 months or more were considered eligible for discontinuation the drug. The annual coast with the treatment was estimated considering the coasts of the medication and the QRT-PCR molecular exams in the Brazilian public health system.Results: In this study, 169 patients date were analyzed, the median follow up time is 5 years (range 1-13 years), 26 (15%) of those patients are eligible for stopping imatinib mesylate according to the criteria previously mentioned. Considering the requirement of QRT-PCR exams every month in the first year of discotinuating the drug, these patients would coast proximally 1.550,00 dollars/ patients year for the public health system. This coast could be reduced to 800,00 and 520 dollars/patients year, after the second and third year of the medication withdraw, when monitoring molecular response can be done every 2 and 3 months respectively. The patients receiving imatinib mesylate, and having QTR-PCR exams every six months, in the other hand, would coast the Brazilian public health system over 31.000, 00dollars /patients year. Stopping imatinib mesylate could reduce CML chronic phase treatment coasts in up to 95%.Discussion: Discontinuating imatinib mesylate is something that must be done only in clinical trial. The economic impact projection shown in this study observed the eligibility criteria described in the literature. If stopping imatinib mesylate proves to be a safe option, studies promoting it should be done in Brazil and other third world countries, as a manner of saving resources in the health system. Furthermore, the impact in life quality free of adverse effects and the possibility of gestation in young woman is not to be ignored. DisclosuresNo relevant conflicts of interest to declare.

Effects of imatinib mesylate on the levels of endocrine hormones

To measure the levels of hormones in chronic myelogenous leukemia (CML) patients receiving imatinib mesylate (IM) and evaluate the effects of IM on endocrine system. 69 patients with CML while taking IM were enrolled and a total of 86 peripheral blood samples were detected. The levels of total triiodothyronine (TT3), total tetraiodothyronine (TT4), thyroid stimulating hormone (TSH), testosterone, progesterone, estradiol (E2), plasma total cortisol (PTC) at 8:00-10:00 am measured. Concentration of hormones in different groups were measured to evaluate the effects of IM on endocrine system and relationships with its administration duration, plasma concentration and clinical symptoms. (1) Of the 7 types of hormones, an elevation of TSH level was found in 14 patients (20.3%), a decrease of TT3 and testosterone in 8 patients (11.6%) and 8 males (18.6%), respectively. (2) A significant decline of TT3 and testosterone was observed in all patients divided by different administration duration. Negative correlation was seen between TT3 level and duration of administration (r=-0.273, P=0.010), which was also found for testosterone (r=-0.302, P=0.025). (3) There was no correlation between serum levels of the seven hormones and concentration of IM. IM affect the levels of thyroid and sex hormones in some patients with clinical manifestations: a decrease of TT3, testosterone and testosterone, an increase of TSH, which have relationship with the duration of administration.

Hepatitis B reactivation in chronic myeloid leukemia patients receiving tyrosine kinase inhibitor

Hepatitis B virus (HBV) reactivation is a well-recognized complication in patients with chronic HBV infection receiving cytotoxic or immunosuppressive chemotherapy. Imatinib mesylate and nilotinib are selective Bcr/Abl tyrosine kinase inhibitors, which are now widely used in the treatment of patients with chronic myeloid leukemia. Although HBV reactivation induced by imatinib mesylate has been reported, nilotinib-related HBV reactivation has not been reported in the English literature. We report here 2 cases of HBV reactivation in chronic myeloid leukemia patients receiving imatinib mesylate and a novel case of nilotinib related HBV reactivation.

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.

Altered Bone and Mineral Metabolism in Patients Receiving Imatinib Mesylate

Altered Bone and Mineral Metabolism in Patients Receiving Imatinib Mesylate

Altered Bone and Mineral Metabolism in Patients Receiving Imatinib Mesylate

Altered Bone and Mineral Metabolism in Patients Receiving Imatinib Mesylate

Altered Bone and Mineral Metabolism in Patients Receiving Imatinib Mesylate

Altered Bone and Mineral Metabolism in Patients Receiving Imatinib Mesylate

High Levels of Tumor Load Reduction after Intensive Chemotherapy Favorably Affect the Prognosis of BCR/ABL+ ALL Adult Patients Receiving Imatinib Mesylate Alone as a Post-Consolidation Treatment According to the Italian GIMEMA LAL 0201/A Protocol.

Thirty-six adult patients aged between 20 and 60 years (median age: 44) with BCR-ABL+ ALL were prospectively monitored by Q-RT-PCR between December 2001 to November 2005. All patients were treated according to the GIMEMA LAL 0201/A protocol, in which Imatinib alone, was administered as post-consolidation therapy, in responding patients after high-dose induction and consolidation treatment, at the dosage of 400 mg x 2 daily for at least six months and continued on the basis of the opinion of physicians. Twenty-three (64%) were p190+ and 13 (36%) p210+. At presentation, the median BCR-ABL/ABL ratio was 1.33 (range 0.23 to 7.8). Before Imatinib, all patients were in 1st CR (34 after the first induction and consolidation course; 2 after a salvage treatment). At this time point, the median reduction from baseline in BCR-ABL transcripts, calculated for each individual patients, was 2.1 log (range: 0 to 6.1). In particular, 18 of the 36 cases showing a log reduction of the BCR-ABL/ABL ratio > 2.1 (p190=14 cases; p210 = 4 cases) were considered as good responders to the antecedent chemotherapies, whereas 18 cases (p190=9; p210=9 cases) showing a log reduction ≤2.1 were considered as bad responders. The median reduction from baseline in BCR-ABL levels was 2.49 log (range: 0.00–6.1) and 1.45 log ( range: 0.19–5.34) in p190 and p210 positive cases, respectively (p=.16). During Imatinib treatment, 10 (56%) of the 18 poor responders patients presented a relapse of disease versus 5 (28%) ( 3 =BM; 2=CNS) of the 18 good responders.At last follow-up 16 patients were in first CR; of these patients, only 4 were allo-transplanted (2 good, 2 bad responders), therefore 12 (9 good, 3 bad responders) persisted in first CR maintained by Imatinib alone after a median follow-up of 24 months (range: 7–48). At 24 months, the cumulative incidence of relapse was 29% vs 44% for good and bad responders (p=.034), respectively, whereas, the DFS and OS rates were 65% vs 33% ( p=.0032) and 76% vs 32% (p=.0056) for good and poor responder patients, respectively. Monitoring of MRD was prospectively evaluated at the starting of Imatinib therapy and afterwards at the 3rd, 5th and 6th month. At these time points, the median BCR-BCR/ABL ratio were 0.015, −0.006, −0.008 and −0.009, respectively. In addition to the classification as good/ bad responders, the current variation of BCR-ABL ratio (used as time-dependent covariate in a Cox model), was associated with an increase of the hazard of failure (hazard ratio of an increase by 2 log of the BCR-ABL levels compared to a constant ratio equal to 2.1). In conclusion, Imatinib mesylate is a highly effective post-consolidation treatment for adult Ph+ ALL patients. However, the clinical outcome after Imatinib was significantly affected by the level of molecular response evaluated before the starting of Imatinib, resulting excellent for the good responders but remaining dismal for patients who responded poorly to the initial chemotherapy.

Altered Bone and Mineral Metabolism in Patients Receiving Imatinib Mesylate

Imatinib mesylate inhibits several tyrosine kinases, including BCR-ABL, the C-KIT receptor, and the platelet-derived growth factor receptors alpha and beta, all of which are associated with disease. We observed that hypophosphatemia developed in some patients with either chronic myelogenous leukemia or gastrointestinal stromal tumors who were receiving imatinib. We identified 16 patients who had low serum phosphate levels and 8 patients who had normal serum phosphate levels, all of whom were receiving imatinib. We performed the following biochemical measurements: whole-blood levels of ionized calcium, plasma levels of intact parathyroid hormone, and serum levels of total calcium, phosphate, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, magnesium, and markers of bone formation (bone alkaline phosphatase and osteocalcin) and bone resorption (N-telopeptide of collagen cross-links); urinalysis; and phosphate, calcium, and creatinine levels in "spot" urine specimens. Patients in the low-phosphate group (median serum phosphate level, 2.0 mg per deciliter [0.6 mmol per liter]; normal level, >2.5 mg per deciliter [0.8 mmol per liter]) had elevated parathyroid hormone levels and low-to-normal serum calcium levels, were younger, and were receiving a higher dose of imatinib than patients in the normal-phosphate group (median level, 3.2 mg per deciliter [1.0 mmol per liter]). Both groups had high levels of phosphate excreted in the urine and markedly decreased serum levels of osteocalcin and N-telopeptide of collagen cross-links. Hypophosphatemia, with associated changes in bone and mineral metabolism, develops in a proportion of patients taking imatinib for either chronic myelogenous leukemia or gastrointestinal stromal tumors. The drug may inhibit bone remodeling (formation and resorption), even in patients with normal serum phosphate levels.

U.S. Food and Drug Administration Drug Approval Summary: Conversion of Imatinib Mesylate (STI571; Gleevec) Tablets from Accelerated Approval to Full Approval

Imatinib mesylate (Gleevec, Novartis Pharmaceuticals East Manruer, NJ) received accelerated approval on May 10, 2001 for the treatment of patients with chronic myeloid leukemia (CML) in (a) chronic phase after failure of IFN-alpha therapy, (b) accelerated phase, and (c) blast crisis. The accelerated approval was accompanied by a postmarketing commitment by Novartis Pharmaceuticals to continue patient follow-up to determine duration of treatment response and survival. The present review, based on a safety and efficacy report submitted on December 20, 2002, summarizes data applicable to the conversion of these three CML indications to full approval status. Chronic phase CML: Five hundred thirty-two chronic phase CML patients who had not benefited from prior IFN therapy were treated at a starting imatinib mesylate dose of 400 mg p.o. qd; dose escalation to 800 mg p.o. qd was allowed. Patients had received a median of 14 months of IFN therapy at doses > or =25 million IU/wk and were all in late chronic phase, with a median time from diagnosis of 32 months. Median duration of imatinib mesylate treatment was 29 months, with 81% of patients treated for > or =24 months (maximum 31.5 months). Initial favorable treatment responses were sustained. An estimated 87.8% of patients who had a major cytogenetic response maintained their response 2 years after their initial response. After 2 years of treatment, an estimated 85.4% of patients were free of progression to accelerated phase or blast crisis, and the estimated overall survival was 90.8% (95% confidence interval, 88.3-93.2). Accelerated phase CML: Patients enrolled totaled 293: 235 with CML accelerated phase, 48 with relapsed/refractory acute lymphocytic leukemia, 2 with relapsed/refractory acute myelocytic leukemia, and 8 with relapsed/refractory CML in lymphoid blast crisis. Patients received imatinib mesylate 400 or 600 mg p.o. qd. Dose escalation was permitted, to a maximum of 800 mg/d, taken as 400 mg bid. Efficacy results were improved in patients receiving imatinib mesylate 600 mg qd versus patients receiving 400 mg qd. The median duration of hematologic response was 29 versus 17 months and the estimated 24-month maintained hematologic response rate was 61% versus 42%. The median survival of patients treated with imatinib mesylate 600 mg qd was not reached versus 20.9 months for patients receiving 400 mg qd. Estimated 24-month survival rate was 66% versus 46%. The median survival in the advanced leukemia population (acute lymphocytic leukemia, acute myelocytic leukemia, and lymphoid blast crisis) was only 5 months, and only two patients are still on treatment. Blast crisis CML: A total of 260 patients were recruited. The imatinib mesylate dose was initially 400 mg qd (37 patients) but was subsequently increased to 600 mg qd (223 patients). Patients receiving imatinib mesylate 600 mg qd had a higher hematologic response rate than did patients receiving 400 mg (33% versus 16%). Major cytogenetic responses occurred in 15% of the 260 study patients. The overall median survival was 6.9 months: 7.1 months for patients treated with imatinib mesylate 600 mg and 4.7 months for patients receiving imatinib mesylate 400 mg. Estimated 12-month survival rate for all study patients was 32.1% and estimated 24-month survival rate was 18.3%. Imatinib mesylate was generally well tolerated, but relatively frequent reports of common toxicity criteria grade 3/4 neutropenia and thrombocytopenia were encountered. The most frequently reported adverse events included gastrointestinal disturbances, edema, rash, and musculoskeletal complaints. These rarely led to discontinuation of therapy. The results confirm those of the interim analysis and suggest that imatinib mesylate represents an effective therapeutic agent for the treatment of patients with CML in chronic phase after failure of IFN-alpha therapy, in blast crisis, and in accelerated phase.