ALBERT

Description: Mouse bone marrow erythropoiesis is homeostatic, whereas after acute anemia, bone morphogenetic protein 4 (BMP4)–dependent stress erythropoiesis develops in the spleen. The aim of this work was to compare spleen stress erythropoiesis and bone marrow erythropoiesis in a mouse model of zymosan-induced generalized inflammation, which induces long-lasting anemia and to evaluate the ability of erythropoietin (Epo) injections to correct anemia in this setting. The effects of zymosan and/or Epo injections on erythroid precursor maturation and apoptosis, serum interferon-γ levels, hematologic parameters, and spleen BMP4 expression were analyzed, as well as the effect of zymosan on red blood cell half-life. We found that bone marrow erythropoiesis is suppressed by inflammation and does not respond to Epo administration, despite repression of erythroblast apoptosis. On the contrary, a robust erythropoietic response takes place in the spleen after Epo injections in both control and zymosan-induced generalized inflammation mice. This specific response implies Epo-mediated induction of BMP4 expression by F4/80+ spleen macrophages, proliferation of stress burst-forming units-erythroid, and increased number of spleen erythroblasts. It allows only partial recovery of anemia, probably because of peripheral destruction of mature red cells. It is not clear whether similar BMP4-dependent stress erythropoiesis can occur in human bone marrow after Epo injections.

Description: Abstract 3544 The prognosis of patients with aggressive relapsed or refractory B- or T-cell lymphomas is poor with conventional chemotherapy. Therefore, high-dose chemotherapy followed by autologous or allogeneic transplantation is the treatment of choice in these patients. We investigated the outcome of patients with aggressive B- or T-cell lymphomas transplanted between 1998 and 2009 in one centre. A total of 104 patients with diffuse large B-cell lymphoma (DLBCL) (n=69) and T-lymphoblastic lymphoma (T-LBL) (n=35) received autologous (auto) (n=66; DLBCL: 68%; T-LBL: 32%) or allogeneic (allo) (n=38; DLBCL: 63%; T-LBL: 37%) HSCT. Patients ineligible for auto transplantation, who did not respond to prior chemotherapy or had bone marrow involvement, were assigned to allo transplantation. Allo HSCT recipients were more likely to have high risk disease (higher disease stage, more prior chemotherapy regimens, resistant disease). Recipients of auto HCT were more likely to have chemosensitive disease at HSCT compared to patients at allo HCT (70% vs. 30%). Median age at transplantation was 52 years for auto and 42 years for allo HSCT. Median follow up was 12.7 (0.2-106) months after auto and 6.4 (0.4-111) months after allo transplantion. All patients with auto HSCT received BEAM and patients with allo HSCT TBI-based preparative regimen (myeloablative: n=23; reduced intensity: n=15). In the cohort of 104 patients the estimated 5-years overall (OS) and progression free survival (PFS) were 38% and 44%, respectively. There was no difference in OS and PFS between DLBCL and T-LBL (p=0.44). The estimated OS and PFS after allo HCT were significant lower (25% and 37%) than after auto HCT (45% and 47%; p=0.008 and p=0.03) caused by outcome differences in patients with DLBCL (p=0.02). Interestingly, OS and PFS were not different in patients with T-LBL transplanted with auto or allo HSCT (p=0.55 [OS] and p=0.34 [PFS]). The estimated PFS was significantly better in chemosensitive than chemorefractory patients (p=0.0001), however the OS and PFS were similar in chemosensitive group of patients regardless auto or allo HSCT (PFS: 50% vs. 51%; p=0.57; OS: 49% (auto) vs 32% (allo); p=0.19). Treatment related mortality (TRM) at day 100 was 18% after allo HSCT compared to 8% after auto. In conclusion, allo HSCT in patients with aggressive B- or T-cell lymphoma ineligible for auto transplantation is an attractive treatment option for these patients with high risk of relapse with a considerably low TRM. The response status at the moment of HSCT is the most important parameter affecting either OS or PFS. Disclosures: Niederwieser: Bristol-Myers Squibb: Speakers Bureau; Novartis: Speakers Bureau.

Description: Abstract 3378 Chronic Myelogenous Leukemia (CML) originates in the Philadelphia chromosome, a reciprocal translocation creating the fusion oncogene BCR-ABL. In 1–2% of CML cases, breakpoints fall outside the M-BCR gene on chromosome 22, leading to the synthesis of a variety of atypical BCR-ABL transcripts [shortened: e1a2 (m-BCR), e6a2, e8a2, b2a3 (e13a3), b3a3 (e14a3), or elongated transcripts: e19a2 (m-BCR)] and to the synthesis of different molecular weight BCR-ABL proteins that might have different tyrosine kinase activities. Thus, clinical phenotypes and BCR-ABL inhibition by tyrosine kinase inhibitors might be different and lead to different prognostic features. We retrospectively analysed at the national level, the clinical characteristics and the responses to imatinib (IM) of 63 patients with CML harbouring atypical BCR-ABL transcripts: 22 e1a2 [Group 1 (G1)], 20 e19a2 [Group 2 (G2)], 5 e8a2 [Group 3 (G3)], 4 e6a2 [Group 4 (G4)], 5 b2a3 [Group 5 (G5)], and 3 b3a3 [Group 6 (G6)] BCR-ABL transcripts. The general characteristics of the patients and their best response to IM are depicted in Table 1: Table 1 Group 1(e1a2) Group 2 (e19a2) Group 3 (e8a2) Group 4 (e6a2) Group 5 (b2a3) Group 6 (b3a3) n 22 20 5 8 5 3 M/F 7/15 6/14 4/1 4/4 5/0 0/3 Median age (years) 70 69 43 57 62 47 CP/AccP/MBC 20/0/2 17/1/2 5/0/0 4/1/3 4/1/0 2/1/0 Sokal (L/H/I/Ukn)* 6/8/2/4 1/3/9/4 3/1/0/1 1/2/1/0 1/2/0/1 0/2/0/0 Leukocytes (G/l, median) 60.85 28.3 55 28.4 93 82.4 Hemoglobin (g/dl, median) 12 10.2 11.7 10.95 11.1 10.2 Platelets (G/l, median) 303 848 253 259 167 363 Monocytes (G/l median) 4.8 0.8 2.34 0.05 1.08 0.825 Additional Clonal Abnormalities at diag (% of patients) 20 28 0 29 25 0 IM duration (median, years) 1.55 1.38 1.58 0.8 1.13 1.42 Interval Diagnosis-IM (median, years) 1.31 1.48 1 1.17 0.87 1.66 Best response to IM* No response 20 0 0 0 0 0 CHR (%) 13 32 0 0 0 0 Minor CyR (%) 47 0 0 0 0 0 PCyR (%) 0 10 20 10 25 67 CCyR (%) 13 32 60 50 0 0 MMR (%) 7 26 20 40 75 33 Follow-up since diag (median, years) 3.24 1.57 1.6 3.82 1.5 1.68 (CP states for Chronic phase, AccP for accelerated phase, MBC for myeloid blast crisis, L for Low, I for intermediate, H for High, Ukn for Unknown, * For CP patients only) Surprisingly, e1a2 and e19a2 transcripts seem significantly more frequent in females than in males conversely to typical BCR-ABL transcripts (p=0.01) and occurring more often in the elderly (p=0.05). The majority of the patients presented with typical cytological CML features, however, a significant monocytosis was observed in e1a2 and e8a2 atypical transcripts (p=0.0002). The median time on IM and the interval between diagnosis and IM were not statistically different between the 6 groups. Overall, there was no significant difference in the (hematologic, cytogenetic, molecular) responses to IM, but e1a2 transcripts seem less sensitive to this agent. The overall survival since diagnosis or since IM initiation was not different between atypical transcripts (p=0.55 and p=0.73 respectively), however, the progression-free survival (PFS) since diagnosis with e1a2 transcripts was significantly worse than for all other atypical transcripts (p=0.02) as shown in Figure 1: The PFS since IM initiation was somewhat worse for e1a2 transcripts, but close to significance (p=0.09), but the follow-up is not very long yet. Fifteen patients among 63 had second generation TKIs (TKI2), 7 in group 1, 3 in group 2, 1 in groups 3, 4, 5, and 2 in group 6. Only one patient (b3a3 transcript) developed a MBC being on IM. Two patients developed a T315I BCR-ABL mutation (1 e1a2, and 1 e6a2). Two patients got allo-transplanted (1 e1a2 alive and well at last follow-up, 1 e19 a2 died from GVHD). In conclusion, atypical BCR-ABL transcripts induce a particular molecular and subsequent clinical phenotypes, particularly e1a2 transcripts showing in this study poor prognosis features. The response of atypical BCR-ABL transcripts to IM might vary from that what it is for classical M-BCR transcripts, but a longer follow-up is needed. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 3986 Background: P-glycoprotein (P-gp or ABCB1) is a common cause of multidrug resistance (MDR) in cancer and leukemia that serves to extrude amphipathic drugs from the plasma membrane. P-gp is an ATP-binding cassette (ABC) transporter that exports a wide range of anti-neoplastics that are structurally or functionally unrelated. The vast majority of P-gp inhibitors tested clinically act as competitive export channel inhibitors to promote antineoplastic retention. We investigated the in vitro and in vivo effects of a novel substituted quinoline P-gp modulator, HG-829, in MDR cell lines and xenograft models. Methods: In vitro activity of HG-829 was evaluated in the K562-daunomycin-selected (K562-R) cell line and the ABCB1-transfected human embryonic kidney-293 cell line (HEK-293-B1) using a variety of P-gp substrates (daunomycin, doxorubicin, taxol, etoposide, vincristine) in a 72h MTT proliferation assay, and results compared to the effects of cyclosporine-A (CsA). Rhodamine 123 export and retention was assessed by flow cytometry. Flank injections of K562-R and parental K562-S cells in female SCID beige mice were performed for xenograft models. ANOVA and Turkey's multiple comparison tests were used to determine significant differences between groups in the proliferation assay and xenograft studies. Differences in rhodamine intracellular retention and efflux were assessed by Student's t-test. Results: Treatment with HG-829 at 0.5uM and 1uM completely reversed resistance to each of the antineoplastics studied in both the K562-R and HEK-293-B1 cell lines, but did not sensitize parental cells. HG-829 sensitized K562-R cells to daunomycin 57-fold and 97-fold at concentrations of 0.5uM and 1uM, respectively (p