ALBERT

Description: Eradication of Helicobacter pylori may lead to improvement of chronic immune thrombocytopenic purpura (ITP), although its efficacy over time is uncertain. We report the results of H pylori screening and eradication in 75 consecutive adult patients with ITP. We also used molecular methods to investigate lymphocyte clonality and H pylori genotypes in the gastric biopsies from 10 H pylori–positive patients with ITP and 19 H pylori–positive patients without ITP with chronic gastritis. Active H pylori infection was documented in 38 (51%) patients and successfully eradicated in 34 (89%) patients. After a median follow-up of 60 months, a persistent platelet response in 23 (68%) of patients with eradicated infection was observed; 1 relapse occurred. No differences in mucosal B- or T-cell clonalities were observed between patients with ITP and control participants. Of note, the frequency of the H pylori cagA gene (P = .02) and the frequency of concomitant H pylori cagA, vacAs1, and iceA genes (triple-positive strains; P = .015) resulted statistically higher in patients with ITP than in control participants. All asymptomatic H pylori–positive patients with ITP were suffering from chronic gastritis. Our data suggest a sustained platelet recovery in a proportion of patients with ITP by H pylori eradication alone. Overrepresentation of specific H pylori genotypes in ITP suggests a possible role for bacterium-related factors in the disease pathogenesis.

Description: Abstract 2829 Background: Peripheral T/NK cell lymphomas (PTCL) have a dismal prognosis with an overall 5yr survival 〈 30% and of 21% and 6% for intermediate-high and high IPI scores, respectively. The incorporation of new agents and transplant procedures in upfront strategies is a present challenge to investigators, due to the advanced age of the patient population and to the unsatisfactory results achieved with anthracyclines- based standard or intensified regimens. The nucleoside analog gemcitabine has shown high single agent activity in recurrent disease, but very little data are available on the upfront efficacy of gemcitabine-based combinations. We assessed activity, toxicity and stem cells (SCs) mobilizing capacity of a dose-dense combination of gemcitabine (G) with ifosfamide (Ifo) and oxaliplatin (Ox) (GIFOX regimen) for front-line therapy of PTCL other than anaplastic large cell subtypes and with 3–5 IPI scores. Methods: Patients had to receive 6 GIFOX courses at biweekly intervals; SCs mobilization and consolidation of chemosensitive response with autologous transplantation (ASCT) were planned after the 3rd and the 6th course, respectively. GIFOX consisted of G 1200 mg/m2 D1, Ox 120 mg/m2 D2 and Ifo 5 g/m2 D2, as a 24h single infusion in pts aged ≤ 65 years, or fractionated over days 2, 3 and 4 in pts aged 〉 65 years, G-CSF 5 mcg/kg/d DD 7–11 (10 mcg/kg/d, 3rd course until SCs mobilization). No dose reductions were planned in case of inadequate bone marrow recovery, and treatment was delayed until the absolute neutrophil count was more than 1000/μL and the platelet count more than 50000/μL. For patients 〉 65 years the agents dosing was determined according to the nadir neutrophil or platelet counts with reduction to 75% of the planned dose for gemcitabine in case of CTCAE v.3 grade 3 toxicity, and for all the three drugs in case of grade 4 toxicity. A strict monitoring of Clcr was required and Ifo doses were reduced according to Kintzel (Cancer Treat Rev, 1995, 21(1):33-64). Results: Twenty-one pts (M/F=15/6; median age 63 yrs, r 42–80) with PTCL [angioimmunoblastic (n=6), PTCL,nos (n=8), extranasal NK (n=2), Sezary syndrome (n=5)] were prospectively accrued. Fifteen pts (71%) had stage IV disease, nine (43%) had 〉1 extranodal site, 71% had abnormal LDH, 29% had ECOG PS 〉1, 43% B-symptoms. A total of 105 courses were delivered (median 6, r 2–6) with only three patients receiving less than 4 courses due to disease progression (n=2) and early death (n=1). This latter event occurred in a 76 yr-old man succumbing to septic shock after the 2nd cycle of treatment. In two elderly patients Ifo was omitted from the 4th course onward due to signs of encephalopathy. Grade 4 thrombocytopenia occurred in 8 pts (38%), grade 4 anemia and grade 3 infection were found in 24% and 33%, respectively. The ORR according to FDG-PET/IWC criteria after the first 3 courses was 86% (95%CI: +/− 15), with 4 partial and 14 complete responses (8CR+6 CRu= 67%; 95%CI: 47–87). Bone marrow tumor clearance after full completion of GIFOX eventually converted 6 CRu in full CR. Among the eight pts eligible for ASCT, 6 had effective CD34+ cells harvest and 4 proceeded to transplant. The 5-year Event-Free Survival was 49%, median survival 30.5 months. For complete responders the probability of relapse was 36.5 % at a median follow-up of 24 months (Figure). Conclusions: GIFOX retains an attractive therapeutic potential as upfront strategy in PTCL, enabling cytoreduction and SCs mobilization for ASCT consolidation, and allows the safe delivery of a full induction program also to patients aged or unfit for high dose therapy. Disclosures: No relevant conflicts of interest to declare.

Description: Background: The highly unfavorable outcome of patients with recurrent HL, who progress after stem cell transplantation or are ineligible for such procedure make the development of new active agents an impellent medical need in this clinical setting. EDO-S101 is fusion molecule combining the DNA damaging effects of bendamustine (BDM) with the pan-histone deacetylase (HDAC) inhibitor, vorinostat. Given that BDM and HDAC inhibitors are active agents in recurrent HL we investigated the preclinical activity of EDO-S101 in this malignancy. Methods: We assessed the patterns of EDO-S101 cytotoxicity (0.39 to 50 µmol/L) in a panel of HL-derived cell lines (L1236, L428, KMH2, HDLM2, L540) and its regulatory effects on genes involved in DNA-damage/repair response, apoptosis and cell cycle checkpoints. As a further model we exploited an L1236 cell clone (R100) selected for resistance (R) to BDM through continuous exposure to increasing concentrations of the agent. R100 cells display a growth pattern indistinguishable from parental L1236 cells when cultured in the presence of BDM (100 µmol/L). Clonal identity of R100 cells with parental L1236 was confirmed by sequencing of V3-21 (FR2/FR3) and JH3-JH4 Ig DNA regions. Results: EDO-S101 induced a significant time- and dose-dependent inhibition of growth and survival in all HL cell lines. L1236 cells displayed the highest sensitivity to the agent with an IC50, at 48 hrs, of 1.88 µmol/L, as opposed to KMH2, L428, L540 and HDLM2 cells with IC50 of 2.06, 2.53, 2.26 and 16.2 µmol/L, respectively. These values were about 10-fold lower than the IC50 of BDM in the same cell lines. While exposure of L1236 cells to EDO-S101 caused cell accumulation in S-phase, qRT-PCR disclosed that cell death was mainly dependent on triggering of apoptosis, as shown by the early (24 hrs) and sustained (48 hrs) upregulation of NOXA, p21 and p27 genes. Data were confirmed by the significant increase (〉150%) of Annexin V-expressing L1236 cells. In contrast, expression levels of PLK1, AKA and cyclin B1 genes remained unchanged or were increased. This excluded induction of the mitotic catastrophe (MC) as a major determinant of cytotoxic activity for EDO-S101 in L1236 cells. Exposure to EDO-S101 induced a strong DNA stress/repair response as shown by the activation of pATR/pATM and increase of the downstream DNA damage checkpoint proteins pCHK1-/-2 and CCNB1, along with the upregulation of the EXO1 gene. Most intriguingly, BDM-resistant L1236 cells (R100) were highly sensitive to EDO-S101, with an IC50 of only 4.56 µmol/L, but less responsive to vorinostat (IC50: 6.17 µmol/L) than parental L1236 cells (IC50: 0.58 µmol/L). Differently from native cells, EDO-S101 induced a late downregulation of transcripts for PLK1 and AKA genes and of cyclin B1 gene and protein in R100 cells, along with the early induction of NOXA and p21, but not p27 genes. In both L1236 and R100 cells, expression of MC-genes was unaffected by exposure to vorinostat. This suggests a more complex mechanism for EDO-S101 in BDM-resistant HL cells involving activation of the both apoptotic and MC pathways. Notably, we documented that EDO-S101 corrected the constitutive ATM/ATR unbalance of R100 cells by triggering the early (24 hrs) upregulation of ATR and a late (48 hrs) downregulation of ATM transcripts and proteins, along with increased levels of EXO1 and MGMT at 24 hrs. Vorinostat induced a similar effect. Finally, while baseline expression levels of HDAC isoforms were comparable among HL cell lines, EDO-S101 caused a significant (〉40%) late downregulation of transcripts for all HDAC isoforms (HDAC-1 to -8) in R100 cells but only of HDAC-6 in native L1236. This pattern diverged from results obtained in both L1236, i.e. increase of all HDAC isoform transcripts except HDAC-6, and R100 cells, i.e. upregulation of all isoforms and reduction of HDAC-6, with vorinostat and BDM as single agents. Conclusions: We have described for the first time that EDO-S101 is effective in preclinical models of HL including cells resistant to BDM. The combined functions of in one molecule of a bifunctional alkylator and panHDAC inhibitor confer this agent unique antitumor property different from both of its single drug components. Following a strong DNA damage response, triggering of apoptosis and/or MC may take place in HL cells according to their sensitivity status to BDM. A phase 1/2 study in recurrent HL, including patients pretreated with BDM, is next to be launched. Disclosures Mehrling: 4Mundipharma-EDO GmbH, Basel, Switzerland: Employment. Pinto:Takeda, Celgene, Roche, TEVA: Honoraria; Takeda: Research Funding.

Description: 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.

Description: Abstract 5168 Background: Myeloproliferative neoplasms (MPNs) are a group of diseases characterized by clonal expansion of single or multiple lineages of myeloid subset (i.e. granulocytic, erythroid, megakaryocytic and mast cell). Since 2008, the WHO included the detection of JAK2 mutations (the common V617F and the less common exon 12 mutations), into the diagnostic criteria of MPNs. The specific pathogenic implication of JAK2 mutations in MPNs is still under investigation. Preliminary data emerging from the treatment of Idiopathic Myelofibrosis patients with JAK2 inhibitors have shown only clinically significant benefits (improvement of splenomegaly and constitutional symptoms) but not a clear evidence of disease-modifying activity. Several techniques (e.g. ASO-PCR, ARMS-PCR, Direct sequencing, HRM, DHPLC, etc) have been used to detect the JAK2 V617F mutation, but all of them were low sensitive and time-consuming. We developed a PNA-clamping competitive PCR assay able to detect JAK2 V617F mutation with a very high level of sensitivity and specificity. Methods: In order to promote the selective amplification of the JAK2 V617F mutant allele, a specific PNA oligonucleotide, full matching with the wild-type (wt) sequence of the portion of JAK2 gene containing the V617F mutation, was designed to compete with the reverse primer used in the PCR assay. It was experimentally demonstrated that a PNA concentration of 6 μmol/L occurred for the complete clamping of 100 ng of wt genomic DNA used as template for the PCR reaction. The sensitivity of the assay was determined by a serial dilution (100% through 0.01%) of genomic DNA containing JAK2 V617F mutation, obtained from HEL cell line, with wt DNA obtained from healthy donors. The specificity of PCR products was assessed by sequencing in both forward and reverse directions. The thermal dissociation profile of PNA/DNA and DNA/DNA duplexes was studied by monitoring the Enthalpy as function of the temperature (range 20–100°C), with an heating/cooling rate of 1°C/min. Results: PNA-clamping competitive PCR was able to detect JAK2 V617F mutation with a sensitivity of 0.01%. Thermodynamic studies clearly showed that the melting temperature (Tm) of fully matched PNA/DNA duplex is always higher than Tm of the corresponding DNA/DNA duplex. The enthalpy values for the hybrid PNA/DNA are always greater than the corresponding DNA/DNA duplex and a single mismatch has an energetic cost higher in a PNA/DNA than in DNA/DNA duplex. This energetic cost is more evident in the melting temperature with a ΔTm of 16°C and 7°C for the PNA/DNA and DNA/DNA duplex, respectively. In the PCR assay the PNA complementary to the JAK2 wild type sequence strongly compete with the primer resulting in a complete knock out of the wild type allele. In a blind screening of samples obtained from 308 MPN patients, PNA clamping competitive PCR was able to detect JAK2 V617F mutation in 61.4% cases of Polycythemia Vera, 54.4% of Essential Thrombocythemia, 57.9% of Idiopathic Myelofibrosis and in 21.4% of Ph negative-MPNs, respectively. In 40 unselected patients, PNA clamping PCR results were confirmed by other techniques such as ASO-PCR, ARMS-PCR and direct sequencing. Conclusions: The PNA-clamping competitive PCR assay could be used as convenient, high-sensitive and reliable diagnostic test for detection of JAK2 V617F mutation both on genomic DNA and cDNA samples. As suggested from the thermodynamic studies, a similar technique could be developed for the detection of any known single point mutation, widely contributing to the improvement of molecular diagnostic tests usable in clinical practice. Disclosures: No relevant conflicts of interest to declare.