Charalambos Andreadis

ATP citrate lyase is an important component of cell growth and transformation

Cell proliferation requires a constant supply of lipids and lipid precursors to fuel membrane biogenesis and protein modification. Cytokine stimulation of hematopoietic cells directly stimulates glucose utilization in excess of bioenergetic demand, resulting in a shift from oxidative to glycolytic metabolism. A potential benefit of this form of metabolism is the channeling of glucose into biosynthetic pathways. Here we report that glucose supports de novo lipid synthesis in growing hematopoietic cells in a manner regulated by cytokine availability and the PI3K/Akt signaling pathway. The net conversion of glucose to lipid is dependent on the ability of cells to produce cytosolic acetyl CoA from mitochondria-derived citrate through the action of ATP citrate lyase (ACL). Stable knockdown of ACL leads to a significant impairment of glucose-dependent lipid synthesis and an elevation of mitochondrial membrane potential. Cells with ACL knockdown display decreased cytokine-stimulated cell proliferation. In contrast, these cells resist cell death induced by either cytokine or glucose withdrawal. However, ACL knockdown significantly impairs Akt-mediated tumorigenesis in vivo. These data suggest that enzymes involved in the conversion of glucose to lipid may be targets for the treatment of pathologic cell growth.

Treatment of PTLD with Rituximab or Chemotherapy

Information regarding treatment of post‐transplant lymphoproliferative disease (PTLD) beyond reduction in immunosuppression (RI) is limited. We retrospectively evaluated patients receiving rituximab and/or chemotherapy for PTLD for response, time to treatment failure (TTF) and overall survival (OS). Thirty‐five patients met inclusion criteria. Twenty‐two underwent rituximab treatment, with overall response rate (ORR) 68%. Median TTF was not reached at 19 months and estimated OS was 31 months. In univariable analysis, Epstein‐Barr virus (EBV) positivity predicted response and TTF. LDH elevation predicted shorter OS. No patient died of rituximab toxicity and all patients who progressed underwent further treatment with chemotherapy. Twenty‐three patients received chemotherapy. ORR was 74%, median TTF was 10.5 months and estimated OS was 42 months. Prognostic factors for response included stage, LDH and allograft involvement by tumor. These factors and lack of complete response (CR) predicted poor survival. Twenty‐six percent of the patients receiving chemotherapy died of toxicity. Rituximab and chemotherapy are effective in patients with PTLD who fail or do not tolerate RI. While rituximab is well tolerated, toxicity of chemotherapy is marked. PTLD patients requiring therapy beyond RI should be considered for rituximab, especially with EBV‐positive disease. Chemotherapy should be reserved for patients who fail rituximab, have EBV‐negative tumors or need a rapid response.

A phase 1/2 study of an adjuvanted varicella-zoster virus subunit vaccine in autologous hematopoietic cell transplant recipients

Recombinant herpes zoster (HZ) vaccines may be an alternative to the live-attenuated HZ vaccine for immunocompromised individuals. This was a phase 1/2, randomized, observer-blind, placebo-controlled study in adults with multiple myeloma, non-Hodgkin lymphoma (B- or T-cell), Hodgkin lymphoma, or acute myeloid leukemia who had undergone autologous hematopoietic stem-cell transplant 50 to 70 days earlier. Subjects (N = 121) were randomized 1:1:1:1 to receive (at months 0, 1, 3) three doses of 50 μg varicella-zoster virus glycoprotein E (gE) adjuvanted with AS01B, 3 doses of gE adjuvanted with AS01E, 1 dose of saline followed by 2 doses of gE/AS01B, or 3 doses of saline. One month after the last dose (6 months after transplant), frequencies of CD4(+) T cells expressing ≥2 activation markers after induction with gE and anti-gE antibody concentrations were higher with all gE/AS01 regimens than with saline. Both responses persisted up to 1 year in subjects vaccinated with gE/AS01. Immune responses were higher in the gE/AS01B 3-dose group than in the gE/AS01B 2-dose group but not higher than in the gE/AS01E 3-dose group. One serious adverse event (pneumonia) was considered vaccine related. Both formulations and both schedules were immunogenic and well tolerated in this population. This study was registered at www.clinicaltrials.gov as #NCT00920218.

Regression of advanced non-splenic marginal zone lymphoma after treatment of hepatitis C virus infection.

We describe a patient with chronic hepatitis C virus (HCV) infection who presented with extranodal (right salivary gland and bone marrow) marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). Within a year, the lymphoma progressed to involve peripheral lymph nodes and the liver. After treatment of HCV with peginterferon and ribavirin, he achieved complete radiographic response and remains in remission two years later. This is an example of a patient in whom treatment of HCV infection led to regression of non-splenic, extranodal marginal zone lymphoma. It suggests that HCV testing and treatment should be considered in all patients with marginal zone lymphomas, including non-splenic types.

Long-term event-free survivors after high-dose therapy and autologous stem-cell transplantation for low-grade follicular lymphoma

Summary:Although follicular lymphoma (FL) is generally responsive to conventional-dose chemotherapy, improved survival in patients with this disease has been difficult to demonstrate. High-dose chemo/radiotherapy followed by autologous stem-cell transplantation (ASCT) can improve response rates, although its effects on survival remain controversial. Between 1990 and 2003, we transplanted 49 patients with low-grade FL at our institution. Twenty-two patients (45%) had undergone histologic transformation at the time of ASCT. In all, 44 patients (90%) had relapsed disease and five patients (10%) were resistant to chemotherapy at the time of transplantation. After ASCT, 30 patients (61%) were in complete remission (CR). The median overall survival (OS) has not been reached, while the median event-free survival (EFS) is 2.4 years. At a median follow-up of 5.5 years (longest 12.4 years), a plateau has been reached with 56% of patients remaining alive, and 35% event-free. ASCT was well tolerated except for two (4%) treatment-related deaths. In multivariable analysis, CR after ASCT and age less than 60 years are the best predictors of EFS and OS. ASCT is thus a safe therapeutic approach in FL, resulting in long-term EFS and OS for some patients, even with transformed disease.

A Phase I Study of Bexarotene, a Retinoic X Receptor Agonist, in Non-M3 Acute Myeloid Leukemia

Purpose: Bexarotene is a retinoic X receptor agonist that has been shown in vitro to inhibit growth and induce differentiation of myeloid leukemic cell lines. We therefore conducted a phase I dose escalation study to assess the maximum tolerated dose, toxicities, and activity of bexarotene in patients with non-M3 acute myeloid leukemia (AML). Experimental Design: We enrolled patients with active non-M3 AML who had either relapsed or refractory disease or were not eligible for standard cytotoxic chemotherapy. Cohorts of three to six patients received escalating doses of daily oral bexarotene ranging from 100 to 400 mg/m2 until evidence of disease progression or unacceptable adverse events occurred. Results: Twenty-seven patients, with median age of 69 years (range, 51-82 years), were treated. Twenty-four (89%) patients had undergone prior chemotherapy. At the highest dose level tested (400 mg/m2), three of six patients had to reduce their dose of bexarotene due to grade 3 adverse events. The maximum tolerable dose of bexarotene was determined to be 300 mg/m2. Clinical activity was manifested by 4 (15%) patients with reduction in bone marrow blasts to ≤5%, 11 (41%) patients with improved platelet counts, and 7 (26%) patients with improved neutrophil counts. Three patients with relapsed AML survived >1 year while taking bexarotene. Leukemic blast differentiation was suggested by the presence of the leukemic cytogenetic abnormality in mature circulating granulocytes and the occurrence of differentiation syndrome. Conclusions: The recommended dose of bexarotene for future studies is 300 mg/m2/d. Bexarotene is well tolerated in patients with non-M3 AML and has evidence of antileukemic activity.

Impact of polymorphisms in drug pathway genes on disease-free survival in adults with acute myeloid leukemia

Acute myeloid leukemia (AML) is a clinically heterogeneous disease, with a 5-year disease-free survival (DFS) ranging from under 10% to over 70% for distinct groups of patients. At our institution, cytarabine, etoposide and busulfan are used in first or second remission patients treated with a two-step approach to autologous stem cell transplantation (ASCT). In this study, we tested the hypothesis that polymorphisms in the pharmacokinetic and pharmacodynamic pathway genes of these drugs are associated with DFS in AML patients. A total of 1659 variants in 42 genes were analyzed for their association with DFS using a Cox-proportional hazards model. One hundred and fifty-four genetically European patients were used for the primary analysis. An intronic single nucleotide polymorphism (SNP) in ABCC3 (rs4148405) was associated with a significantly shorter DFS (hazard ratios (HR)=3.2, P=5.6 × 10−6) in our primary cohort. In addition, a SNP in the GSTM1-GSTM5 locus, rs3754446, was significantly associated with a shorter DFS in all patients (HR=1.8, P=0.001 for 154 European ancestry; HR=1.7, P=0.028 for 125 non-European patients). Thus, for the first time, genetic variants in drug pathway genes are shown to be associated with DFS in AML patients treated with chemotherapy-based autologous ASCT.

Primary cardiac lymphoma: Utility of multimodality imaging in diagnosis and management

Primary cardiac lymphoma (PCL) is an extremely rare disease defined as a lymphoma strictly confined to the heart or pericardium without dissemination. We present the case of an 82 yr old male with newly diagnosed PCL and two years of subsequent follow up. This report highlights the utility of a multimodality imaging approach in the diagnosis and management of PCL.

Clinical Characterization Might Help in Preventing Osteonecrosis of the Jaw

To the Editors: We read with considerable interest the article by Raje et al. ([1][1]) shedding light on clinical, radiographic, and biochemical markers concerning biphosphonate osteonecrosis of the jaw (ONJ). The investigators highlight that most information regarding ONJ has been from case series

Delayed hematopoietic recovery after auto-SCT in patients receiving arsenic trioxide-based therapy for acute promyelocytic leukemia: a multi-center analysis.

A potential link between arsenic (ATO)-based therapy and delayed hematopoietic recovery after autologous hematopoietic SCT (HSCT) for acute promyelocytic leukemia (APL) has previously been reported. We retrospectively reviewed the clinical histories of 58 patients undergoing autologous HSCT for APL at 21 institutions in the United States and Japan. Thirty-three (56%) of the patients received ATO-based therapy prior to stem cell collection. Delayed neutrophil engraftment occurred in 10 patients (17%): 9 of the 10 patients (90%) received prior ATO (representing 27% of all ATO-treated patients), compared with 1 of the 10 patients (10%) not previously treated with ATO (representing 4% of all ATO-naïve patients; P<0.001). Compared with ATO-naïve patients, ATO-treated patients experienced significantly longer times to ANC recovery (median 12 days vs 9 days, P<0.001). In multivariate analysis, the only significant independent predictor of delayed neutrophil engraftment was prior treatment with ATO (hazard ratio 4.87; P<0.001). Of the available stem cell aliquots from APL patients, the median viable post-thaw CD34+ cell recovery was significantly lower than that of cryopreserved autologous stem cell products from patients with non-APL AML. Our findings suggest that ATO exposure prior to CD34+ cell harvest has deleterious effects on hematopoietic recovery after autologous HSCT.