Effects of imatinib on normal hematopoiesis and immune activation

A Rare Case of Metastatic Small Cell Carcinoma of Lung in a Follow-Up Patient of Chronic Myeloid Leukemia on Imatinib Treatment

Imatinib has an excellent long-term survival rate and significantly ameliorates the treatment of chronic myeloid leukaemia during the past few decades. There is now a concern that first-generation tyrosine kinase inhibitors can cause secondary neoplasms. Here, we describe a case of a 49-year-old non-smoker male who was diagnosed with chronic myeloid leukaemia and treated with imatinib. After 15 years of treatment, an incidental right cervical lymphadenopathy was noted. The fine needle aspiration cytology from the lymph node revealed the small round cell morphology. In order to identify the primary lesion, computerised tomography of the thorax and abdomen was advised, which revealed a diagnosis of small cell carcinoma lung. In the index case report, we will discuss the potential side effects of first-generation tyrosine kinase inhibitors on a long-term basis along with treatment protocols for metastatic small cell carcinoma lung in a disease-free follow-up case of chronic myeloid leukaemia.

Tyrosine kinase inhibitors can activate the NLRP3 inflammasome in myeloid cells through lysosomal damage and cell lysis

Inflammasomes are intracellular protein complexes that promote an inflammatory host defense in response to pathogens and damaged or neoplastic tissues and are implicated in inflammatory disorders and therapeutic-induced toxicity. We investigated the mechanisms of activation for inflammasomes nucleated by NOD-like receptor (NLR) protiens. A screen of a small-molecule library revealed that several tyrosine kinase inhibitors (TKIs)-including those that are clinically approved (such as imatinib and crizotinib) or are in clinical trials (such as masitinib)-activated the NLRP3 inflammasome. Furthermore, imatinib and masitinib caused lysosomal swelling and damage independently of their kinase target, leading to cathepsin-mediated destabilization of myeloid cell membranes and, ultimately, cell lysis that was accompanied by potassium (K⁺) efflux, which activated NLRP3. This effect was specific to primary myeloid cells (such as peripheral blood mononuclear cells and mouse bone marrow-derived dendritic cells) and did not occur in other primary cell types or various cell lines. TKI-induced lytic cell death and NLRP3 activation, but not lysosomal damage, were prevented by stabilizing cell membranes. Our findings reveal a potential immunological off-target of some TKIs that may contribute to their clinical efficacy or to their adverse effects.

Double Infection in a Patient with Chronic GVHD Post Allogeneic Transplant: “Hickam's Dictum” Trumps “Occam's Razor”!—A Case Report with Review of Literature

Double pneumonia with Pneumocystis jirovecii (PCP) and Mycobacterium tuberculosis (MTB) has been reported in patients with acquired immune deficiency syndrome. A similar immune-suppressed state exists in allogeneic transplant survivors treated for graft-versus-host disease (GVHD). The clinical features and imaging findings could be quite similar in both the etiologies. Reaching a timely diagnosis and initiation of appropriate therapy is essential to prevent complications. We report a patient who had concurrent PCP and MTB pneumonia while on treatment for chronic GVHD. We describe the diagnostic challenge, the treatment, and outcome of this patient. We intend to sensitize physicians to consider more than one etiology in this subset of patients.

Kaposi’s sarcoma associated with chronic myeloid leukemia and imatinib mesylate therapy

Kaposi's sarcoma is associated with immunosuppression and human herpesvirus 8 infection, while rarely described in myeloid malignancies. Here, we illustrate a rare case of chronic myeloid leukemia treated with imatinib, a tyrosine kinase inhibitor, who developed a human herpesvirus 8‐related Kaposi's sarcoma.

BCR::ABL1 tyrosine kinase inhibitors hamper the therapeutic efficacy of blinatumomab in vitro

PURPOSE

Acute B-lymphoblastic leukemia (B-ALL) is a malignant disease characterized by accumulation of clonal immature lymphocytes in the bone marrow and peripheral blood. The approval of BCR::ABL1 tyrosine kinase inhibitors (TKI) such as imatinib, dasatinib, nilotinib and ponatinib marked a milestone in targeted therapy only for a subset of patients carrying the translocation t(9;22)(q34;q11). Immunotherapy with the bispecific antibody (bsAb) blinatumomab targeting CD19xCD3 revolutionized treatment of all B-ALL cases. The combination of both TKI and bsAb, so-called "dual targeting", is currently under clinical investigation, although TKI might influence T cell effects.

METHODS

We here investigated the combination of different TKI and blinatumomab in BCR::ABL1⁺ and BCR::ABL1^- B-ALL cell lines and primary samples regarding T cell proliferation, differentiation, cytokine release and killing of tumor cells.

RESULTS

In vitro analysis revealed profound reduction of T cell proliferation, differentiation, cytokine release and killing of tumor cells upon application of BCR::ABL1 TKI with blinatumomab. Inhibition was more pronounced with dasatinib and ponatinib compared to nilotinib and imatinib. T cell signalling after CD3 stimulation was impaired by TKI mirrored by inhibition of LCK phosphorylation. This known off-target effect might influence the efficacy of bsAb therapy when combined with BCR::ABL1 TKI.

CONCLUSION

In conclusion, we propose that nilotinib and imatinib might also be suitable substances for combination with blinatumomab and suggest evaluation in clinical trials.

Second Cancer Onset in Myeloproliferative Neoplasms: What, When, Why?

The risk of developing a solid cancer is a major issue arising in the disease course of a myeloproliferative neoplasm (MPN). Although the connection between the two diseases has been widely described, the backstage of this complex scenario has still to be explored. Several cellular and molecular mechanisms have been suggested to link the two tumors. Sometimes the MPN is considered to trigger a second cancer but at other times both diseases seem to depend on the same source. Increasing knowledge in recent years has revealed emerging pathways, supporting older, more consolidated theories, but there are still many unresolved issues. Our work aims to present the biological face of the complex clinical scenario in MPN patients developing a second cancer, focusing on the main cellular and molecular pathways linking the two diseases.

Outcomes and toxicity of allogeneic hematopoietic cell transplantation in chronic myeloid leukemia patients previously treated with second-generation tyrosine kinase inhibitors: a prospective non-interventional study from the Chronic Malignancy Working Party of the EBMT

Allogeneic hematopoietic cell transplantation (allo-HCT) remains a treatment option for patients with chronic myeloid leukemia (CML) who fail to respond to tyrosine kinase inhibitors (TKIs). While imatinib seems to have no adverse impact on outcomes after transplant, little is known on the effects of prior use of second-generation TKI (2GTKI). We present the results of a prospective non-interventional study performed by the EBMT on 383 consecutive CML patients previously treated with dasatinib or nilotinib undergoing allo-HCT from 2009 to 2013. The median age was 45 years (18-68). Disease status at transplant was CP1 in 139 patients (38%), AP or >CP1 in 163 (45%), and BC in 59 (16%). The choice of 2GTKI was: 40% dasatinib, 17% nilotinib, and 43% a sequential treatment of dasatinib and nilotinib with or without bosutinib/ponatinib. With a median follow-up of 37 months (1-77), 8% of patients developed either primary or secondary graft failure, 34% acute and 60% chronic GvHD. There were no differences in post-transplant complications between the three different 2GTKI subgroups. Non-relapse mortality was 18% and 24% at 12 months and at 5 years, respectively. Relapse incidence was 36%, overall survival 56% and relapse-free survival 40% at 5 years. No differences in post-transplant outcomes were found between the three different 2GTKI subgroups. This prospective study demonstrates the feasibility of allo-HCT in patients previously treated with 2GTKI with a post-transplant complications rate comparable to that of TKI-naive or imatinib-treated patients.

Chronic Myeloid Leukemia in Children: Immune Function and Vaccinations

Children with CML need TKI treatment for many years, and the lack of knowledge about immune dysfunction with TKI has hindered routine immunizations. This review attempts to provide an overview of the effects of TKIs licensed for children (e.g., imatinib, dasatinib, and nilotinib) on immune function, as well as its implications on immunizations. We discuss surveillance strategies (e.g., immunoglobulin blood serum levels and hepatitis B reactivation) and immunizations. All inactivated vaccines (e.g., influenza, pneumococcal, and streptococcal) can be given during the treatment of CML in the chronic phase, although their efficacy may be lower. As shown in single cases of children and adults with CML, live vaccines (e.g., varicella, measles, mumps, rubella, and yellow fever) may be administered under defined circumstances with great precautions. We also highlight important aspects of COVID-19 in this patient population (e.g., the outcome of COVID-19 infection in adults with CML and in children with varying hemato-oncological diseases) and discuss the highly dynamic field of presently available different vaccination options. In conclusion, TKI treatment for CML causes humoral and cellular immune dysfunction, which is mild in most patients, and thus infectious complications are rare. Routine immunizations are important for health maintenance of children, but vaccinations for children with CML on TKI therapy should be carefully considered.

Prospective evaluation of variables affecting platelet function in patients with newly diagnosed chronic myeloid leukemia

: Platelet function in chronic myeloid leukemia (CML) could be affected by either hyperleucocytosis, clonal megakaryopoiesis, or tyrosine kinase inhibitors. However, these variables have never been prospectively evaluated. We conducted a prospective study over a period of 1.5 years in a tertiary care center of north India. Patients with CML in chronic phase, more than 18 years, and treated with imatinib were enrolled (n = 32). Age, and sex-matched controls were also included. Platelet function test was performed using two-channel Chrono-Log aggregometer 490 at four time-points: first, at diagnosis; second, after leucoreduction (total leucocyte count, <10 × 10/l) achieved with hydroxycarbamide; third, on-imatinib at BCR-ABL less than 1%; and fourth, in an independent cohort (off-imatinib) at deep molecular response (DMR) (BCR-ABL < 0.01%). Statistical analysis was performed using IBM SPSS statistics (version 22.0). Median age of patients was 42 years (15-65), and M : F ratio was 1 : 1. At diagnosis, platelet function correlated negatively with total leucocyte count, but not with platelet count. As compared with baseline, platelet aggregation with ADP (2.5 μl), and collagen (2.5 μl) improved significantly after leucoreduction (P = 0.05 and 0.009, respectively). Imatinib further caused significant impairment of aggregation with ADP (2.5 μl), collagen (2.5 μl), and collagen (1 μl) (P = 0.04, 0.008, and 0.02, respectively). Patients in DMR also demonstrated a significant impairment of platelet aggregation with all the agonists as compared with controls. While leucoreduction alone can improve the baseline platelet function derangement in CML, imatinib further impairs it. Residual CML stem cells, or effect of imatinib on normal common myeloid progenitors might account for platelet function derangement at DMR.

Kinase inhibitors developed for treatment of hematologic malignancies: implications for immune modulation in COVID-19

Tyrosine kinase inhibitors (TKIs) are used to target dysregulated signaling pathways in virtually all hematologic malignancies. Many of the targeted signaling pathways are also essential in nonmalignant immune cells. The current coronavirus severe acute respiratory syndrome coronavirus 2 pandemic catalyzed clinical exploration of TKIs in the treatment of the various stages of COVID-19, which are characterized by distinct immune-related complications. Most of the reported effects of TKIs on immune regulation have been explored in vitro, with different class-specific drugs having nonoverlapping target affinities. Moreover, many of the reported in vivo effects are based on artificial animal models or on observations made in symptomatic patients with a hematologic malignancy who often already suffer from disturbed immune regulation. Based on in vitro and clinical observations, we attempt to decipher the impact of the main TKIs approved or in late-stage development for the treatment of hematological malignancies, including inhibitors of Bruton's tyrosine kinase, spleen tyrosine kinase, BCR-Abl, phosphatidylinositol 3-kinase/ mammalian target of rapamycin, JAK/STAT, and FMS-like tyrosine kinase 3, to provide a rationale for how such inhibitors could modify clinical courses of diseases, such as COVID-19.

Targeted Therapies: Friends or Foes for Patient's NK Cell-Mediated Tumor Immune-Surveillance?

In the last 20 years there has been a huge increase in the number of novel drugs for cancer treatment. Most of them exploit their ability to target specific oncogenic mutations in the tumors (targeted therapies–TT), while others target the immune-checkpoint inhibitor molecules (ICI) or the epigenetic DNA modifications. Among them, TT are the longest established drugs exploited against a wide spectrum of both solid and hematological tumors, often with reasonable costs and good efficacy as compared to other innovative therapies (i.e., ICI). Although they have greatly improved the treatment of cancer patients and their survival, patients often relapse or develop drug-resistance, leading to the impossibility to eradicate the disease. The outcome of TT has been often correlated with their ability to affect not only tumor cells, but also the repertoire of immune cells and their ability to interact with cancer cells. Thus, the possibility to create novel synergies among drugs an immunotherapy prompted scientists and physicians to deeply characterize the effects of TT on immune cells both by in-vitro and by ex-vivo analyses. In this context, NK cells may represent a key issue, since they have been shown to exert a potent anti-tumor activity, both against hematological malignancies and solid tumors. In the present review we will discuss most recent ex-vivo analyses that clarify the effect of TT treatment on patient’s NK cells comparing them with clinical outcome and previous in-vitro data.

Incidence of Clinically Significant (≤10 g/dL) Late Anemia in Elderly Patients with Newly Diagnosed Chronic Myeloid Leukemia Treated with Imatinib

BACKGROUND

In elderly patients with chronic myeloid leukemia (CML) responsive to imatinib, the incidence of clinically significant (CS) late chronic anemia is still unknown.

MATERIALS AND METHODS

To highlight this issue, we revised retrospectively 81 CML patients aged >60 years treated at our Institution with front-line imatinib for at least 24 months in durable complete cytogenetic response (CCyR). CS late chronic anemia was defined as the presence of persistent (>6 months) and otherwise unexplained Hb levels ≤10 g/dL, which occurred >6 months from imatinib start.

RESULTS

A condition of CS late chronic anemia occurred in 22 out of 81 patients (27.2%) at different intervals from imatinib start. Seven out of 22 patients (31.8%) needed packed red cell transfusions during the follow-up. At diagnosis, patients who developed CS late chronic anemia were significantly older and had a lower Hb median level. Six out of 22 patients with CS late chronic anemia received subcutaneous recombinant alpha-erythropoietin (EPO) at the standard dosage of 40,000 IU weekly: all 6 patients achieved an erythroid response. A significantly worse event-free survival (EFS) in patients with untreated CS late chronic anemia was observed (p = 0.012).

CONCLUSIONS

CS late chronic anemia during long-term treatment with imatinib is a common complication in responsive elderly patients, with worse EFS if untreated. Results with EPO are encouraging, but larger studies are warranted to define its role.

A case of primary gastric diffuse large B-cell lymphoma occurring in chronic myeloid leukemia

Chronic myeloid leukemia (CML) and Non-Hodgkin Lymphoma (NHL) are two different origins of hematological malignancies, which rarely occur at the same time. Moreover, NHL secondary to CML is common in T cell lymphoma, while NHL of B cell origin is rare. Since 1999, only 22 cases with B cell lymphoma have been reported, of which 4 cases have diffuse large B-cell lymphoma (DLBCL). The lesions of DLBCL were in lymph node, liver, jejunum, and soft palate. To our knowledge, it has no report for the primary gastric DLBCL (PG-DLBCL) occurring in CML. Here we reported a 63-year-old man of chronic phase (CP) CML associated with PG-DLBCL. The patient was diagnosed with CML nearly eight years ago and was treated with imatinib and nilotinib successively. However, gastroscopy found malignant lesions in the patient’s stomach in March 2018, and the masses were diagnosed as PG-DLBCL. Subsequently, with the treatment of the RCOP + lenalidomide regimen chemotherapy for 3 cycles, the patient achieved nearly complete remission (CR).

Demographics and Outcome of Philadelphia-positive ALL in a Pediatric Population in North India: a Single-center Experience

Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) in children had a worse outcome before the use of tyrosine kinase inhibitors. We have evaluated the demographics and outcome of Ph+ ALL patients treated with imatinib without blood marrow transplantation. Of the 206 children with ALL registered for treatment, the demographic data of 15 Ph+ ALL patients were compared with the remaining Ph- patients. Imatinib (340 mg/m) was started on day 5 (D5) of induction in Ph+ patients, and their overall survival was compared with Ph- high-risk patients treated on similar protocols. Statistical analysis was carried out by the Fisher exact test and the t test. The Kaplan-Meier test was used for survival analysis. Philadelphia positivity noted in 15/206 (7.28%) ALL patients was higher than reported earlier. Median initial total leukocyte count and central nervous system positivity were significantly higher in Ph+ patients. Myeloid markers, CD13 and CD33, were also positive in 33.3% Ph+ patients. D15 and D35 marrow showed remissions in a larger proportion of Ph+ ALL, as compared with Ph- patients, but chemotherapy interruptions and neutropenic deaths were significantly higher after starting imatinib, as compared with Philadelphia high-risk patients. Overall survival was similar in Ph+ and Ph- high-risk ALL patients. Ph+ ALL, noted in 7.28%, presented with high initial white blood cell counts, high central nervous system positivity, poor steroid response, and higher induction deaths, as compared with high-risk Ph- ALL, and raised the question about the appropriate dose and time of introduction of imatinib to prevent toxicity.

Risk and outcomes of second malignant neoplasms in chronic myeloid leukemia survivors

The risk of second malignant neoplasms (SMN) in chronic myeloid leukemia (CML) survivors remains unclear. We utilized the Surveillance, Epidemiology and End Results 18 (SEER 18) registries to evaluate the risk and subsequent outcomes of SMN in CML survivors. There were 3407 patients included. Of these, 170 (4.99%) developed a SMN with SIR of 1.40 (95% C.I. 1.19-1.62). An increased risk was noted for cancers of the respiratory tract, genitourinary (GU) tract and skin excluding basal cell and squamous cell carcinoma. Using 3:1 matching (3 de novo malignancies to 1 post-CML SMN case), we compared survival data for cancers of the respiratory, GU and gastrointestinal (GI) tract. Patients with GU malignancies developing after CML had worse overall survival than patients without prior CML diagnosis (P = 0.018). There was no difference in survival between post-CML and non-post-CML patients with respiratory or GI malignancies.

Renal dysfunction and anemia associated with long-term imatinib treatment in patients with chronic myelogenous leukemia

Knowledge of the toxicity profile of long-term treatment with imatinib is limited. In the present study, we sought to evaluate renal function and hemoglobin levels during long-term imatinib treatment. Eighty-two patients with chronic myelogenous leukemia in chronic phase who had been on imatinib for over 5 years were retrospectively analyzed. The mean estimated glomerular filtration rate (eGFR) was significantly decreased over 5 years (77 ± 17 to 62 ± 14 ml/min/1.73m², P < 0.001). Higher age and lower eGFR value at initiation of imatinib were significantly associated with development of renal dysfunction by multivariate analyses. Mean hemoglobin levels also significantly decreased over the 5-year period (12.9 ± 1.7 to 12.4 ± 1.3 g/dl, P < 0.01). The rate of decrease in eGFR correlated significantly with hemoglobin levels (correlation coefficient = - 0.249, P < 0.05). Serum erythropoietin (EPO) levels did not increase in 16 patients with both renal dysfunction and anemia (median, 31.9 mIU/ml). In patients who participated in a clinical trial of imatinib discontinuation, mean eGFR (50.0 ± 6.5 to 56.0 ± 10.2 ml/min/1.73m², P < 0.05) and hemoglobin levels (12.0 ± 1.7 to 14.0 ± 1.6 g/dl, P < 0.01) improved significantly at 1 year after discontinuation. These findings suggest that long-term imatinib results in a partially reversible continuous decline in renal function and decreased hemoglobin levels.

Incidence and outcome of second malignancies in patients with chronic myeloid leukemia during treatment with tyrosine kinase inhibitors

We performed a retrospective study to evaluate the incidence of second malignancies (SMs) in chronic myeloid leukemia (CML) patients treated with tyrosine kinase inhibitors (TKIs). We analyzed data from 339 patients with CML who were extracted from the CML Cooperative Study Group database. The standardized incidence ratio (SIR) was calculated to assess the risk of SMs using data from the Cancer Registries in Japan. The median follow-up was 65 months. SMs developed in 14 patients (4.1%, 10 men, 4 women) after the start of TKIs. The median age was 69 years at the time of the CML diagnosis and 72.5 years at the time of the SM diagnosis. Ten patients were treated with imatinib, three with dasatinib, and one with nilotinib as the initial treatment. The SIR for all malignancies was 1.05 (95% CI 0.50-1.93) for men and 1.08 (95% CI 0.29-2.76) for women. The difference in the overall survival (OS) of patients with or without SMs was not statistically significant (5-year OS: 82.5% vs. 92.9%; p = 0.343). A subgroup analysis of 166 patients treated with second-generation TKIs (92 dasatinib, 74 nilotinib) showed that the SIRs for all malignancies were 1.33 (95% CI 0.36-3.41) for men and 0 for women. In conclusion, the incidence of SMs in CML patients during TKI treatment was the same as that in the general Japanese population. There was no evidence of an increase in the incidence of SMs during second-generation TKI treatment. Furthermore, the occurrence of SMs during TKI treatment did not affect the survival or mortality in our cohort.

Immunological effects of nilotinib prophylaxis after allogeneic stem cell transplantation in patients with advanced chronic myeloid leukemia or philadelphia chromosome-positive acute lymphoblastic leukemia

Allogeneic stem cell transplantation remains the standard treatment for resistant advanced chronic myeloid leukemia and Philadelphia chromosome–positive acute lymphoblastic leukemia. Relapse is the major cause of treatment failure in both diseases. Post-allo-SCT administration of TKIs could potentially reduce relapse rates, but concerns regarding their effect on immune reconstitution have been raised. We aimed to assess immune functions of 12 advanced CML and Ph+ ALL patients who received post-allo-SCT nilotinib. Lymphocyte subpopulations and their functional activities including T-cell response to mitogens, NK cytotoxic activity and thymic function, determined by quantification of the T cell receptor (TCR) excision circles (TREC) and TCR repertoire, were evaluated at several time points, including pre-nilotib-post-allo-SCT, and up to 365 days on nilotinib treatment. NK cells were the first to recover post allo-SCT. Concomitant to nilotinib administration, total lymphocyte counts and subpopulations gradually increased. CD8 T cells were rapidly reconstituted and continued to increase until day 180 post SCT, while CD4 T cells counts were low until 180−270 days post nilotinib treatment. T-cell response to mitogenic stimulation was not inhibited by nilotinib administration. Thymic activity, measured by TREC copies and surface membrane expression of 24 different TCR Vβ families, was evident in all patients at the end of follow-up after allo-SCT and nilotinib treatment. Finally, nilotinib did not inhibit NK cytotoxic activity. In conclusion, administration of nilotinib post allo-SCT, in attempt to reduce relapse rates or progression of Ph+ ALL and CML, did not jeopardize immune reconstitution or function following transplantation.

An observational study on risk of secondary cancers in chronic myeloid leukemia patients in the TKI era in the United States

Introduction

The treatment with tyrosine kinase inhibitors (TKIs) has drastically improved the outcome of chronic myeloid leukemia (CML) patients. This study was conducted to examine the risk of secondary cancers (SCs) in the CML patients who were diagnosed and treated in the TKI era in the United States.

Methods

The surveillance epidemiology and end results (SEER) database was used to identify CML patients who were diagnosed and received treatment during January 2002–December 2014. Standardized incidence ratios (SIRs) and absolute excess risks (AER) were calculated.

Results

Overall, 511 SCs (excluding acute leukemia) developed in 9,200 CML patients followed for 38,433 person-years. The risk of developing SCs in the CML patients was 30% higher than the age, sex and race matched standard population (SIR 1.30, 95% CI: 1.2–1.40; p < 0.001). The SIRs for CLL (SIR 3.4, 95% CI: 2–5.5; p < 0.001), thyroid (SIR 2.2, 95% CI: 1.2–3.5; p < 0.001), small intestine (SIR 3.1, 95% CI: 1.1–7; p = 0.004), gingiva (SIR 3.7, 95% CI: 1.2–8.7; p = 0.002), stomach (SIR 2.1, 95% CI: 1.1–3.5; p = 0.005), lung (SIR 1.4, 95% CI: 1.1–1.7; p = 0.006) and prostate (SIR 1.3, 95% CI: 1.02–1.6; p = 0.026) cancer among CML patients were significantly higher than the general population. The risk of SCs was higher irrespective of age and it was highest in the period 2–12 months after the diagnosis of CML. The risk of SCs in women was similar to that of the general population.

Conclusion

CML patients diagnosed and treated in the TKI era in the United States are at an increased risk of developing a second malignancy. The increased risk of SCs in the early period after CML diagnosis suggests that the risk of SCs may be increased due to the factors other than TKIs treatment.

Secondary breast carcinoma after completely remitted chronic myeloid leukemia following targeted tyrosine kinase inhibitor therapy

We describe a rare case of secondary breast carcinoma after chronic myeloid leukemia (CML) in a 56-year-old woman. The patient was treated with hydroxyurea and imatinib for CML and achieved complete remission (she has since been taking imatinib as the maintenance therapy). Four years later, the patient noticed a firm and painless lump in the left breast, which was diagnosed as ductal carcinoma in situ based on a percutaneous biopsy of the mass. Simple resection and sentinel lymph node biopsy of the left breast were then performed. Pathological studies revealed a medium-grade intraductal carcinoma, with local infiltration associated with invasive micropapillary carcinoma. She received adjuvant endocrine therapy with imatinib after surgery. Breast cancer secondary to CML (treated with imatinib and completely remitted) is extremely rare. This report provides evidence to assist in the diagnosis and treatment for this rare manifestation.

Incidence of second primary malignancies and related mortality in patients with imatinib-treated chronic myeloid leukemia

The majority of patients with chronic myeloid leukemia are successfully managed with life-long treatment with tyrosine kinase inhibitors. In patients in chronic phase, other malignancies are among the most common causes of death, raising concerns on the relationship between these deaths and the off-target effects of tyrosine kinase inhibitors. We analyzed the incidence of second primary malignancies, and related mortality, in 514 chronic myeloid leukemia patients enrolled in clinical trials in which imatinib was given as first-line treatment. We then compared the observed incidence and mortality with those expected in the age- and sex-matched Italian general population, calculating standardized incidence and standardized mortality ratios. After a median follow-up of 74 months, 5.8% patients developed second primary malignancies. The median time from chronic myeloid leukemia to diagnosis of the second primary malignancies was 34 months. We did not find a higher incidence of second primary malignancies compared to that in the age- and sex-matched Italian general population, with standardized incidence ratios of 1.06 (95% CI: 0.57–1.54) and 1.61 (95% CI: 0.92–2.31) in males and females, respectively. Overall, 3.1% patients died of second primary malignancies. The death rate in patients with second primary malignancies was 53% (median overall survival: 18 months). Among females, the observed cancer-related mortality was superior to that expected in the age- and sex-matched Italian population, with a standardized mortality ratio of 2.41 (95% CI: 1.26 – 3.56). In conclusion, our analysis of patients with imatinib-treated chronic myeloid leukemia did not reveal a higher incidence of second primary malignancies; however, the outcome of second primary malignancies in such patients was worse than expected. Clinicaltrials.gov: NCT00514488, NCT00510926.

CML as Part of Dual Malignancies-A Retrospective Analysis: Possible Mechanisms and Review of Literature

Introduction of imatinib has changed the outlook of chronic myeloid leukaemia (CML) patients with overall survival approaching general population. Long term survival in CML patients has provided an opportunity to better study natural history and long term complications of disease as well as the treatment modalities. To study the occurrence and association of other malignancies with their outcomes in patients with CML. This is a single centre retrospective study. All CML patients case records registered with haematology clinic of a tertiary care centre in North India from 2001 to 2014 were perused and evaluated for dual malignancies. Those patients with dual malignancies were personally examined and interviewed if alive. Out of 1677 patients, 15 cases had co-existent malignancies. Four of fifteen cases of dual malignancies had CML as secondary cancer. Three had synchronous and rest 12 patients had metachronous malignancies. Only one patient was in accelerated phase, rest all were in chronic phase. Median age of the dual malignancy cases was 50 years (25-66 years), much younger than reported in west. The initial dose of imatinib was 400 mg OD in all except one. We did not find any causal association between CML or imatinib therapy with development of secondary tumours. Interestingly in this series, incidence of CML as secondary or synchronous malignancy was higher than earlier published studies.

Secondary malignancies in chronic myeloid leukemia patients after imatinib-based treatment: long-term observation in CML Study IV

Treatment of chronic myeloid leukemia (CML) has been profoundly improved by the introduction of tyrosine kinase inhibitors (TKIs). Long-term survival with imatinib is excellent with a 8-year survival rate of ∼88%. Long-term toxicity of TKI treatment, especially carcinogenicity, has become a concern. We analyzed data of the CML study IV for the development of secondary malignancies. In total, 67 secondary malignancies were found in 64 of 1525 CML patients in chronic phase treated with TKI (n=61) and interferon-α only (n=3). The most common malignancies (n⩾4) were prostate, colorectal and lung cancer, non-Hodgkin's lymphoma (NHL), malignant melanoma, non-melanoma skin tumors and breast cancer. The standardized incidence ratio (SIR) for all malignancies excluding non-melanoma skin tumors was 0.88 (95% confidence interval (0.63-1.20)) for men and 1.06 (95% CI 0.69-1.55) for women. SIRs were between 0.49 (95% CI 0.13-1.34) for colorectal cancer in men and 4.29 (95% CI 1.09-11.66) for NHL in women. The SIR for NHL was significantly increased for men and women. An increase in the incidence of secondary malignancies could not be ascertained. The increased SIR for NHL has to be considered and long-term follow-up of CML patients is warranted, as the rate of secondary malignancies may increase over time.

Platelet Dysfunction in Patients with Chronic Myeloid Leukemia: Does Imatinib Mesylate Improve It?

Objective:

The aim of this study was to investigate the effects of imatinib mesylate on platelet aggregation and adenosine triphosphate (ATP) release in chronic myeloid leukemia patients.

Materials and Methods:

Platelet aggregation and ATP release induced by 5.0 mM adenosine diphosphate, 0.5 mM arachidonic acid, 1.0 mg/mL ristocetin, and 2 µg/mL collagen were studied by whole blood platelet lumi-aggregometer in 20 newly diagnosed chronic myeloid leukemia patients before and after imatinib mesylate treatment.

Results:

At the time of diagnosis, 17/20 patients had abnormal platelet aggregation results; 8 (40%) had hypoactivity, 6 (30%) had hyperactivity, and 3 (15%) had mixed hypo- and hyperactivity. Repeat platelet aggregation studies were performed after a mean of 19 months (min: 5 months-max: 35 months) in all patients who received imatinib mesylate during this period. After therapy, 18/20 (90%) patients had abnormal laboratory results; 12 (60%) had hypoactive platelets, 4 (20%) had mixed hypo- and hyperactive platelets, and 2 (10%) had hyperactive platelets. Three of the 8 patients with initial hypoactivity remained hypoactive, while 2 developed a mixed picture, 2 became hyperactive, and 1 normalized. Of the 6 patients with initial hyperactivity, 4 became hypoactive and 2 developed a mixed pattern. All of the 3 patients with initial hypo- and hyperactivity became hypoactive. Finally, 2 of the 3 patients with initial normal platelets became hypoactive while 1 remained normal. There was a significant decrease in ristocetin-induced platelet aggregation after therapy (p<0.001), while platelet aggregation and secretion induced by other agonists showed no difference after treatment (p>0.05).

Conclusion:

These findings indicate that a significant proportion of chronic myeloid leukemia patients have different patterns of platelet function abnormalities and imatinib mesylate has no effect on these abnormalities, with a significant impairment in ristocetin-induced platelet aggregation.

Interferon gamma modulates sensitivity of CML cells to tyrosine kinase inhibitors

Immune effector cells such as T and NK cells can efficiently eliminate tumor cells. However, when activating oncogenic signaling pathways or protective mechanisms against cell death are active, immune cells can also confer therapy resistance. Here, we analyzed the role of activated T and NK cells and released cytokines on tyrosine kinase inhibitors imatinib and nilotinib - mediated apoptosis induction and proliferation of chronic myelogenous leukemia (CML) cells. Incubation of CML cells with activated, but not with resting CD3⁺ T cells or with activated NK cells significantly inhibited TKI-induced apoptosis induction in CML cells as quantified by nuclear fragmentation assays. Transwell experiments revealed a critical role for T or NK cell-derived cytokines for CML cell protection. Accordingly, CML cells treated with IFNγ also showed a clearly reduced sensitivity to TKI-mediated cell death induction and inhibition of proliferation. In contrast, IFNα or other pro-inflammatory mediators and cytokines, such as TNFα and GM-CSF did not impair TKI-induced apoptosis in CML cells. On a molecular level, IFNγ-exposed CML cells showed a significantly reduced caspase-3 activation and PARP-1 cleavage as well as an increased expression of anti-apoptotic molecule xIAP. Finally, IFNγ diminished TKI-induced downregulation of Jak-2 and STAT-5 phosphorylation and increased nuclear expression of RUNX-1, which may at least in part contribute to the reduced sensitivity to TKI effects. Our results demonstrate that IFNγ released by activated T or NK cells may interfere with the therapeutic effects of TKI in CML. Our findings may have important implications for the understanding of inflammation-mediated BCR-ABL independent resistance mechanisms.

Change of health-related profiles after Imatinib cessation in chronic phase chronic myeloid leukemia patients

The aim of this study was to investigate the changes in health-related profiles including quality-of-life (HRQoL) in the chronic myeloid leukemia (CML) patients who discontinued imatinib (IM). An HRQoL survey composed of 43 parameters about IM-related adverse events (AEs), physical health-related and mental health-related was provided at baseline and 6 months post-discontinuation. A total of 55 patients with a sustained UMRD over 6 months were analyzed. Although the majority of IM-related AEs were significantly improved, unexpectedly pruritus and musculoskeletal pain worsen or newly develop in 29.1% and 21.8% of patients, respectively. The improvements in physical and mental health condition were variable in individual patients. In addition, rapid restorations of the hematological and biochemical parameters were observed. The results showed the changes of HRQoL and laboratory tests in treatment-off patients and the necessity of continuing physical and mental support for some patients in tyrosine kinase inhibitor (TKI)-off studies.

Imatinib-induced agranulocytosis in patients with gastrointestinal stromal tumors

Agranulocytosis is a rare but serious side effect of imatinib in gastrointestinal stromal tumor (GIST) patients. Imatinib is an inhibitor of the proto-oncogene tyrosine kinase (c-kit) and the first-line agent in patients with locally advanced and metastatic GIST. Little evidence is available on the management of this adverse event, and consensus-based guidelines are lacking. In this article, we describe 4 patients with agranulocytosis after starting imatinib. In addition, an overview of the available literature concerning the underlying mechanisms is given, and therapeutic strategies for overcoming this adverse event are discussed. In our experience it appears safe to restart imatinib after normalization of neutrophil count. In case of relapse of agranulocytosis, reintroduction combined with prednisolone, with treatment with granulocyte colony-stimulating factor or dose reduction can be considered.

Incidence of persistent/late chronic anemia in newly diagnosed patients with chronic myeloid leukemia responsive to imatinib

In patients with chronic myeloid leukemia (CML) responsive to imatinib, it is still unknown whether the long-lasting treatment could induce the appearance of a persistent/late chronic anemia. To highlight this issue, we revised 128 patients with CML (M/F 64/64, median age at diagnosis 56.9 years, interquartile range 43.0-69.3) treated at our Institution with 1st line imatinib for at least 36 months and in stable complete cytogenetic response. At the 36th month of imatinib, a chronic anemia (Hb < 12 g/dl for > 6 months) was present in 38/128 patients (29.6%): the anemia was moderate (Hb > 8 ≤ 10 g/dl) in 12 patients (9.3%) and mild (Hb > 10 < 12 g/dl) in 26 patients (20.3%). All patients with persistent/late chronic anemia had a low reticulocyte count and 8/38 a condition of iron deficiency without clinical and instrumental signs of chronic blood loss. Four out of 38 patients (10.5%) needed red cell transfusions during the follow-up. At a landmark analysis from the 36th month of imatinib treatment, cumulative 4-year overall survival (OS) for patients with chronic anemia was 94.4% (CI 95% 83.8-100) compared to 93.5% (CI 95% 87.2-99.8) for patients without chronic anemia (P = 0.617). In conclusion, the occurrence of a late chronic anemia during long-lasting treatment with imatinib has been observed in about 30% of our responsive patients: its occurrence does not seem to affect OS, but its real impact should be evaluated on a larger cohort of patients.

Avian influenza viruses inhibit the major cellular signalling integrator c-Abl

The non-structural protein 1 (NS1) of influenza A viruses (IAV) encodes several src homology (SH) binding motifs (bm) (one SH2bm, up to two SH3bm), which mediate interactions with host cell proteins. In contrast to NS1 of human IAV, NS1 of avian strains possess the second SH3bm (SH3(II)bm) consensus sequence. Since our former studies demonstrated an NS1-CRK interaction, mediated by this motif, here, we addressed the regulatory properties of this SH3bm for cellular signalling. Initially, we observed a reduced basal CRK phosphorylation upon infection with avian IAV harbouring an NS1 with an SH3(II)bm in contrast to human IAV. Reduced activity of the tyrosine kinase c-Abl was identified to be responsible for reduced CRK phosphorylation. Further, binding of NS1 to c-Abl was determined, and mutational manipulation of the SH3(II)bm illustrated the necessity of this motif for c-Abl inhibition. Interestingly, Abl kinase inhibition resulted in impaired avian IAV propagation and pathogenicity and mutational analysis linked the pronounced inhibition of c-Abl to cytopathogenic cell alterations upon avian IAV infections. Taken together, NS1 proteins of avian IAV interfere with the kinase activity of c-Abl, a major cellular signalling integrator that controls multiple signalling processes and cell fate regulations apparently including IAV infections.

Immune consequences of kinase inhibitors in development, undergoing clinical trials and in current use in melanoma treatment

Metastatic malignant melanoma is a frequently fatal cancer. In recent years substantial therapeutic progress has occurred with the development of targeted kinase inhibitors and immunotherapeutics. Targeted therapies often result in rapid clinical benefit however responses are seldom durable. Immune therapies can result in durable disease control but responses may not be immediate. Optimal cancer therapy requires both rapid and durable cancer control and this can likely best be achieved by combining targeted therapies with immunotherapeutics. To achieve this, a detailed understanding of the immune consequences of the various kinase inhibitors, in development, clinical trial and currently used to treat melanoma is required.

Relative increase in lymphocytes from as early as 1 month predicts improved response to dasatinib in chronic-phase chronic myelogenous leukemia

Lymphocytosis in response to dasatinib for chronic myelogenous leukemia (CML) may be associated with favorable response. However, it occurs at varying times and in a limited subset of patients. To identify early clinical markers for favorable responses applicable to all patients with or without lymphocytosis, we prospectively analyzed lymphocyte profiles of 50 Japanese CML patients treated with dasatinib after intolerance/resistance to imatinib. Although absolute lymphocyte counts did not differ significantly until 3 months between patients with complete molecular response (CMR) at 12 months and those without it, relative increases in lymphocyte compared with baselines differed significantly from 1 month. Patients with relative lymphocyte counts >150 % at 1 month or >200 % at 3 months had higher CMR rates at 12 months than others (57.9 vs. 23.3 %, P = 0.015, and 76.5 vs. 16.1 %, P < 0.0001, respectively). A relative increase in lymphocyte subset of CD57(+)CD14(-), CD8(+)T, or NK cells >200 % at 1 month was also significantly associated with a higher CMR rate. There were significant negative correlations between relative lymphocyte increases and BCR/ABL transcript levels. CD57(+)CD14(-) cells were a highly specific focus of proliferation. Relative increases in lymphocyte count and its subsets from 1 month are reliable early markers of favorable responses to dasatinib.

Src-kinase inhibitors sensitize human cells of myeloid origin to Toll-like-receptor-induced interleukin 12 synthesis

Src-kinase inhibitors hold great potential as targeted therapy against malignant cells. However, such inhibitors may also affect nonmalignant cells and cause pronounced off-target effects. We investigated the role of the dual kinase inhibitor dasatinib on human myeloid cells. Dasatinib is clinically used for the treatment of bcr/abl⁺ leukemias because it blocks the mutated tyrosine kinase abl. To understand its effect on the development of antigen-specific T-cell responses, we assessed antigen-specific priming of human, naïve T cells. In surprising contrast to the direct inhibition of T-cell activation by dasatinib, pretreatment of maturing dendritic cells (DCs) with dasatinib strongly enhanced their stimulatory activity. This effect strictly depended on the activating DC stimulus and led to enhanced interleukin 12 (IL-12) production and T-cell responses of higher functional avidity. Src-kinase inhibitors, and not conventional tyrosine kinase inhibitors, increased IL-12 production in several cell types of myeloid origin, such as monocytes and classical or nonclassical DCs. Interestingly, only human cells, but not mouse or macaques DCs, were affected. These data highlight the potential immunostimulatory capacity of a group of novel drugs, src-kinase inhibitors, thereby opening new opportunities for chemoimmunotherapy. These data also provide evidence for a regulatory role of src kinases in the activation of myeloid cells.

In vitro inhibitory effects of imatinib mesylate on stromal cells and hematopoietic progenitors from bone marrow

Imatinib mesylate (IM) is used to treat chronic myeloid leukemia (CML) because it selectively inhibits tyrosine kinase, which is a hallmark of CML oncogenesis. Recent studies have shown that IM inhibits the growth of several non-malignant hematopoietic and fibroblast cells from bone marrow (BM). The aim of the present study was to evaluate the effects of IM on stromal and hematopoietic progenitor cells, specifically in the colony-forming units of granulocyte/macrophage (CFU-GM), using BM cultures from 108 1.5- to 2-month-old healthy Swiss mice. The results showed that low concentrations of IM (1.25 µM) reduced the growth of CFU-GM in clonogenic assays. In culture assays with stromal cells, fibroblast proliferation and α-SMA expression by immunocytochemistry analysis were also reduced in a concentration-dependent manner, with a survival rate of approximately 50% with a dose of 2.5 µM. Cell viability and morphology were analyzed using MTT and staining with acrydine orange/ethidium bromide. Most cells were found to be viable after treatment with 5 µM IM, although there was gradual growth inhibition of fibroblastic cells while the number of round cells (macrophage-like cells) increased. At higher concentrations (15 µM), the majority of cells were apoptotic and cell growth ceased completely. Oil red staining revealed the presence of adipocytes only in untreated cells (control). Cell cycle analysis of stromal cells by flow cytometry showed a blockade at the G0/G1 phases in groups treated with 5-15 µM. These results suggest that IM differentially inhibits the survival of different types of BM cells since toxic effects were achieved.

A review of pneumatosis intestinalis in the setting of systemic cancer treatments, including tyrosine kinase inhibitors

PURPOSE

Pneumatosis intestinalis is a radiologic diagnosis that manifests in a variety of clinical settings. We report 4 cases of pneumatosis intestinalis in patients undergoing cancer treatments that included cytotoxic agents and/or tyrosine kinase inhibitors. These reports aim to provide insight into the clinical interpretation and pathogenesis of pneumatosis intestinalis in the setting of cancer treatments and demonstrate a potential association with tyrosine kinase inhibitors.

METHODS

Radiologists responsible for the interpretation of adult imaging at our tertiary care centre were surveyed to identify cases of pneumatosis intestinalis arising in the midst of cancer treatment. The case histories were reviewed by physicians with expertise in cancer treatment.

RESULTS

Four cases of chemotherapy-related pneumatosis intestinalis were identified. The diagnosis was made in 1 patient during investigations undertaken for non-life-threatening abdominal symptoms and incidentally in 2 patients by abdominal imaging used to measure chemotherapy response. A fourth patient presented in a life-threatening manner, and abdominal imaging was symptom guided. Interestingly, 3 of the 4 patients were receiving treatments that included a tyrosine kinase inhibitor, and this agent was the only identifiable potential etiology in 1 patient.

CONCLUSIONS

The significance of pneumatosis intestinalis arising during cancer treatments is difficult to interpret because of the complex nature of the diseases and the treatments that often include combinations of cytotoxic agents and/or novel therapies. These reports demonstrate the importance of classifying this radiologic finding according clinical severity rather than etiology and underscore the need for continued observation for unexplained adverse effects when using novel therapies.

Challenges for allogeneic hematopoietic stem cell transplantation in chronic myeloid leukemia in the era of tyrosine kinase inhibitors

Following the introduction of the tyrosine kinase inhibitor (TKI) imatinib in the treatment of chronic myeloid leukemia (CML) patients, the allogeneic hematopoietic stem cell transplantation (HSCT) scene in CML has changed dramatically. The number of patients receiving HSCT in first chronic phase (CP) has declined rapidly, as allogeneic HSCT in CP is now performed in these patients only in case of failure or intolerance of TKIs. Second, those CML patients who undergo allogeneic HSCT represent a selection of high-risk patients due to more advanced disease with high rates of accelerated or blast phase (being associated with an increased relapse risk), advanced age and relevant co-morbidities. Efforts at meeting these special challenges are being developed: treatment with TKIs aims to improve the pre-transplant remission status before HSCT. Dose-reduced conditioning protocols were introduced to decrease transplant-related mortality in patients with co-morbidities or older age. In the post-transplant period, TKIs may be administered for prophylaxis and for treatment of post-transplant relapse. Still, the outcome of patients in advanced CML phases remains guarded, and requires an improvement in current transplant strategies.

The BCR/ABL-inhibitors imatinib, nilotinib and dasatinib differentially affect NK cell reactivity

In chronic myeloid leukemia (CML), BCR/ABL-mediated oncogenic signaling can be targeted with the BCR/ABL-inhibitors Imatinib, Nilotinib and Dasatinib. However, these agents may also affect anti-tumor immunity. Here, we analyzed the effects of the 3 BCR/ABL-inhibitors on natural killer (NK) cell reactivity. Exposure of CML cells (K562, Meg-01) to pharmacological concentrations of Imatinib, Nilotinib and Dasatinib diminished expression of ligands for the activating immunoreceptor NKG2D to a similar extent. This resulted in comparably reduced NK cell cytotoxicity and IFN-gamma production. When direct effects on NK cell responses to K562 and primary CML cells as well as activating cytokines were studied, Dasatinib was found to abrogate NK cytotoxicity and cytokine production. Nilotinib did not alter cytotoxicity but, at high levels, impaired NK cytokine production, while Imatinib had no direct influence on NK cell reactivity. Of note, Nilotinib, but not the other BCR/ABL-inhibitors increased cell death within the preferentially cytokine-secreting CD56(bright)CD16(-) NK cell subset, which may, at least in part, serve to explain the effect of Nilotinib on NK cytokine production. Analysis of NK cell signaling revealed that Dasatinib inhibited proximal signaling events leading to decreased phosphorylation of PI3K and ERK that are crucial for NK cell reactivity. Imatinib and Nilotinib, in contrast, showed no relevant effect on NK cell PI3K or ERK activity. In light of the potential role of NK cells in the immunesurveillance of residual leukemia and for future combinatory immunotherapeutic approaches, our data indicate that choice and dosing of the most suitable BCR/ABL-inhibitor for a given patient require careful consideration.

Anti-inflammatory M2 type macrophages characterize metastasized and tyrosine kinase inhibitor-treated gastrointestinal stromal tumors

We have made a detailed inventory of the immune infiltrate of gastrointestinal stromal tumors (GISTs), which originate from mesenchymal cells in the intestinal tract. These sarcomas are heavily infiltrated with macrophages and T cells, while immune cells of other lineages were much less abundant. Dissecting the functional subtypes of T cells with multicolor fluorescent microscopy revealed substantial populations of cytotoxic T cells, helper T cells and FoxP3(+) regulatory T cells. The balance of cytotoxic T cells and FoxP3(+) T cells was toward immune suppression. Analysis of the macrophage population also showed a dominance of anti-inflammatory cells, as the M2 type scavenger receptor CD163 was abundantly present. Other subsets of macrophages (CD14(+)CD163(-)) were occasionally detected. M2 type CD163(+) macrophages were associated with the number of infiltrating FoxP3(+) regulatory T cells and twice as many macrophages were found in metastatic GIST compared to primary lesions. Most metastatic GISTs had been treated with the tyrosine kinase inhibitors imatinib and sunitinib, but the high macrophage infiltrate was not related to this treatment. However, imatinib and sunitinib did induce secretion of anti-inflammatory IL-10 in macrophage cultures, indicating that treatment with these inhibitors might contribute to an immune suppressive microenvironment in GIST. Overall, our data reveal a picture of GIST as an active site of tumor-immune interaction in which suppressive mechanisms overrule potential antitumor responses. Tyrosine kinase inhibitors might promote this negative balance.

Emergence of BCR-ABL–specific cytotoxic T cells in the bone marrow of patients with Ph+ acute lymphoblastic leukemia during long-term imatinib mesylate treatment

Imatinib mesylate has been demonstrated to allow the emergence of T cells directed against chronic myeloid leukemia cells. A total of 10 Philadelphia chromosome–positive acute lymphoblastic leukemia patients receiving high-dose imatinib mesylate maintenance underwent long-term immunological monitoring (range, 2-65 months) of p190BCR-ABL–specific T cells in the bone marrow and peripheral blood. p190BCR-ABL–specific T lymphocytes were detected in all patients, more frequently in bone marrow than in peripheral blood samples (67% vs 25%, P < .01) and resulted significantly associated with lower minimal residual disease values (P < .001), whereas absent at leukemia relapse. Specific T cells were mainly effector memory CD8+ and CD4+ T cells, producing interferon-γ, tumor necrosis factor-α, and interleukin-2 (median percentage of positive cells: 3.34, 3.04, and 3.58, respectively). Cytotoxic subsets able to lyse BCR-ABL–positive leukemia blasts also were detectable. Whether these autologous p190BCR-ABL–specific T cells may be detectable under other tyrosine-kinase inhibitors, expanded ex vivo, and exploited for immunotherapy remains to be addressed.

Allogeneic hematopoietic cell transplantation (allogeneic HCT) for treatment of pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL)

BACKGROUND

Allogeneic hematopoietic cell transplant (HCT) with best available donor for children with Philadelphia positive (Ph+) acute lymphoblastic leukemia (ALL) has previously been considered standard practice. Since the introduction of imatinib into the treatment of this disease, the role of allogeneic HCT is more uncertain.

PROCEDURE

We investigated the impact of remission status, graft source, and imatinib use on transplant outcomes for 37 children with Ph+ ALL who received an allogeneic HCT at the University of Minnesota between 1990 and 2006. The median age at HCT was 7.47 (range; 1.4-16.4) years. Thirteen patients received imatinib therapy pre- and/or post-HCT (imatinib group) and 24 patients, received either no imatinib (n = 23) or only post-HCT relapse (n = 1) (non-imatinib group).

RESULTS

There was no difference in disease-free survival (DFS) or relapse between the imatinib and non-imatinib groups at 3 years (62%/15% vs. 53%/26%; P = 0.99; 0.81, respectively). There was no significant difference in transplant outcomes between matched related donor or unrelated donor (umbilical cord blood or matched unrelated marrow) recipients whereas patients receiving allogeneic HCT in first remission (CR1) had superior DFS and less relapse compared to patients transplanted in >or=CR2 (71%/16% vs. 29%/36%; P = 0.01; P = 0.05).

CONCLUSIONS

Based on this retrospective analysis at a single institution, the use of imatinib either pre- and/or post-transplant does not appear to significantly impact outcomes for children with Ph+ ALL and allogeneic HCT with the best available donor should be encouraged in CR1.

Chronic myeloid leukemia patient manifesting fatal hepatitis B virus reactivation during treatment with imatinib rescued by liver transplantation: case report and literature review

Imatinib mesylate (imatinib) is now a standard treatment for patients with chronic myeloid leukemia (CML). Although imatinib is known to have a potential impact on various infectious organisms by altering the T-cell mediated immune response, only two cases of hepatitis B virus (HBV) reactivation during imatinib treatment have actually been reported. The role of liver transplantation (LT) after fatal HBV reactivation in patients with potentially treatable or curable hematologic malignancy is also unknown. Therefore, this report presents a case of fatal HBV reactivation during imatinib treatment for CML, where the patient is rescued by LT. Following a successful living donor LT, the liver function improves rapidly and the patient remains in complete cytogenetic remission after retreatment with imatinib for 6 months. The present report also covers the role of tyrosine kinase inhibitor in triggering HBV reactivation and a literature review of fulminant hepatic failure in CML patients taking imatinib.

Selective reduction of JAK2V617F-dependent cell growth by siRNA/shRNA and its reversal by cytokines

The JAK(V617F) mutation is responsible for the majority of breakpoint cluster region (BCR)/Abelson (ABL)-negative myeloproliferative disorders. Ongoing clinical trials of Janus kinase 2 (JAK2) inhibitors in myeloproliferative disorder patients use small molecules targeting both wild-type and mutated JAK2. To selectively target malignant cells, we developed JAK2(V617F)-specific small interfering RNAs or short hairpin RNAs. Expression of these RNAs in cell lines or CD34(+) cells from patients reduced JAK2(V617F)-driven autonomous cell proliferation. Mechanisms of inhibition involved selective JAK2(V617F) protein down-regulation, and consequently, decrease in signal transducer and activator of transcription 5 phosphorylation, cell-cycle progression, and cell survival. However, the addition of high concentrations of cytokines to cell lines or erythropoietin to patient cells greatly reduced growth inhibition. Similarly, the efficacy of a JAK2 small molecule inhibitor on cell line and patient cell proliferation dose dependently decreased with the addition of cytokines. Our results demonstrate that it is possible to specifically target JAK2(V617F) by RNA interference (RNAi) strategies. In addition, cytokines partially reverse the inhibition induced by both RNAi and small molecule approaches. This strongly suggests that patient cytokine levels in current JAK2 inhibitor clinical trials modulate the outcome of these therapies.

Evaluation of ARG protein expression in mature B cell lymphomas compared to non-neoplastic reactive lymph node

The participation of Abl-Related Gene (ARG) is demonstrated in pathogenesis of different human malignancies. However there is no conclusive evidence on ARG expression level in mature B cell lymphomas. In this study we evaluated ARG protein expression in Follicular Lymphoma (FL), Burkitt's Lymphoma (BL) and Diffused Large B Cell Lymphoma (DLBCL) in comparison with non-neoplastic lymph nodes. Semi-quantitative fluorescent ImmunoHistoChemistry was applied on 14, 7 and 4 patients with DLBCL, FL and BL respectively, adding to 4 normal and 4 reactive lymph nodes. The mean ratio of ARG/GAPDH expression was significantly different (p<0.00) between lymphomas and control samples, with DLBCL having the highest ARG expression amongst all. Over expression of ARG was seen in FL and BL, with FL expressing statistically more ARG than BL. Moreover, the ARG/GAPDH expression ratio increased from DLBCL stage I towards stage VI, all showing significantly more ARG expression than FL and BL (in all cases p<0.00).