ALBERT

Description: Abstract 1745 In classical Philadelphia-negative myeloproliferative neoplasms (MPN), JAK2V617F is considered as a driver mutation when the threshold of 1% JAK2V617F/JAK2total allele burden is reached. However a lower ratio is sometimes detected with highly sensitive assays. We investigated the clinical significance of such minor clones by describing the characteristics of 27 patients with a low JAK2V617F allele burden ranging from 0.1% to 0.99%. Material and Methods A commercially available quantitative ASO-PCR assay of 0.1% sensitivity (MutaQuant® kit, Ipsogen) was used. Two thousand five hundred consecutive blood samples were sent to our lab for JAK2V617F mutation between 2009 and 2012. Total blood DNA was extracted by an automated standardized procedure (Qiasymphony®, Qiagen). All samples were tested in duplicate. The 27 samples of our cohort were controlled using a second assay of 0.01% sensitivity (Larsen et al, BJH 2007). Thirty samples from healthy donors were also tested. High resolution melting curve (HRM) analysis of JAK2 exon 14 ruled out the possibility of an additional mutation hampering the annealing of a primer. Patients with a known classical MPN clinical phenotype were also tested for JAK2 exons 12–17 (entire pseudo-kinase domain) or for MPL exon 10 depending on the context. Results Laboratory Findings Among the 2500 samples, 735 (29.4%) were positive above 1%, 27 (1.1%) had low JAK2V617F allele burden ranging from 0.12 to 0.99%. The patient with the lowest ratio (0.12%) was not confirmed by the second assay and therefore was excluded from the study. This allowed the median to settle at 0.40%. No associated mutations were found in the JAK2 pseudo-kinase domain in patients with polycythemia vera (PV) and in MPL exon 10 in patients with essential thrombocytosis (ET) and primary myelofibrosis (PMF). Healthy patients were all tested JAK2V617F negative. Clinical Aspects The cohort included 19 men and 7 women ranging from 28 to 95 years of age (median 63 years old). Two patients had secondary acute myeloid leukaemia following JAK2V617F positive MPN indicating the presence of residual JAK2V617F cells and the negativity of the myeloblastic population. Thirteen patients (50%) had a classical MPN with a median ratio of 0.36%: 7 ET, 5 PV and 1 PMF according to WHO 2008 criteria. However a bone marrow biopsy was available for only two patients (1 ET, 1 PMF). None of them had received pegylated interferon alpha-2a. Four patients had a prior history of thrombosis: two strokes, one pulmonary embolism, two portal vein thrombosis (PVT). For one PV patient, a 6 months follow-up blood and bone marrow sample confirmed a low allele burden in the same range (0.4%) and in vitro Epo-independant erythroid colonies were observed. Five patients had other chronic myeloid neoplasms (two myelodysplastic/myeloproliferative neoplasms, one chronic eosinophilic leukaemia, one chronic myeloid leukaemia, one refractory anaemia with ring sideroblasts). Among these five, four had an abnormal karyotype. We did not observe any thrombotic event in these patients. We cannot conclude on hematological diagnosis for the last six patients: four patients were screened for JAK2 mutation because of PVT. One patient had chronic polycythemia in a context of alcohol and tobacco abuse. One patient had homozygous hemochromatosis with a normal haemoglobin level in spite of repeated phlebotomies. Discussion In this single centre study low JAK2V617F allele burden represented 1% of all samples sent for JAK2V617F study and 3.5% of JAK2V617F positive patients. Seventeen patients (65%) had classical MPN or splanchnic vein thrombosis. To our knowledge PV patients with such low JAK2V617F allele burden have not been reported in the absence of associated JAK2 pseudo-kinase domain mutation. A larger screen for cooperating mutations responsible for the PV phenotype is under process. In the context of other chronic myeloid neoplasms, the JAK2V617F mutation is thought to belong to a more complex clonal architecture mostly implicating chromatin remodeling genes. Here, the presence of a JAK2 mutation could argue in favour of clonal haematopoiesis. In conclusion the clinical phenotype of low JAK2V617F patients overlaps with classical JAK2V617F MPN. The technical implications might be challenging for molecular diagnostic platforms. More data are needed to further characterize these patients. Disclosures: No relevant conflicts of interest to declare.

Description: Background Autoimmune cytopenia (AIC) are well-known complications of chronic lymphocytic leukemia, occurring in approximately 4 to 10% of patients. The management of CLL-associated AIC is not consensual and patient with uncontrolled AIC are systematically excluded from clinical trials. Few data evaluating the efficacy of BCR inhibitors on CLL-related AIC are available. If some preliminary data focusing on patients included in clinical trials with controlled AIC suggested that ibrutinib was able to control AIC, the duration of responses were unknown. Moreover, no data regarding the ability of idelalisib to control AIC have been currently reported. The aim of this study was to retrospectively analyze the outcome of CLL patients suffering from autoimmune hemolytic anemia (AIHA), immune thrombocytopenia (ITP), Evans syndrome or pure red cell anemia (PRCA) and treated with ibrutinib or idelalisib. Results Forty-four patients from 15 FILO centers were included in this study. First kinase inhibitor (KI) was ibrutinib for 25 patients and idelalisib for 19 patients. Among the ibrutinib treated patients, diagnosis of AIC was AIHA for 16 patients (64%), ITP for 5 patients (20%), Evans syndrome for 3 patients (12%) and PRCA for one patient (4%). In the idelalisib group, 12 patients were treated for AIHA (63%), 6 patients for ITP (32%) and one patient for an Evans syndrome (5%). Most patients presented with adverse prognostic factors such as 11q or 17p deletion by FISH and unmutated IgHV. Most patients had previously been treated either for CLL progression, autoimmune cytopenia or both and median number of prior therapies was 1 (0 to 6). Before starting ibrutinib or idelalisib, 34 patients (77%) had a history of AIC and had previously received corticosteroid monotherapy (N=15), rituximab monotherapy (N=15), a combination of rituximab, cyclophosphamide and dexamethasone (N=23) or rituximab and bendamustine (N=15). At the time of KI initiation, 66% of patients were receiving concomitant AIC therapy, consisting in corticosteroids in 26 patients (59%) or TPO (thrombopoietin) receptor agonists in 3 patients (7%). Overall response rates (ORRs) to ibrutinib and idelalisib on AIC were 92% and 95% respectively, and were not correlated to the AIC type. On ibrutinib therapy, 87.5% of patients with AIHA and 100% of patients with ITP or Evans syndrome achieved at least partial response (PR). In the idelalisib group, the ORR was 92% for AIHA patients and 100% for patients with ITP or PRCA. Considering CLL, Ibrutinib ORR and bone marrow unconfirmed complete response (CR) were 100% and 24% respectively. ORR and BM unconfirmed CR on CLL were 95% and 37% respectively the idelalisib group. KI therapy allowed discontinuing corticosteroids in 86% of ibrutinib patients and in 67% of idelalisib patients. Fifteen patients (34%) of the whole cohort experienced progression of CLL, CAI or both during the follow-up. Among them, nine (20%) experienced relapses of the CAI, and all of them were AIHA. In the ibrutinib arm, 1 patient withdrew ibrutinib shortly after initiation because of uncontrolled AIHA and 2 patients experienced relapse of AIHA while on therapy. In the idelalisib group, treatment failed to control AIHA in one case, but for responding patients, no AIHA relapse was described during idelalisib treatment. Five patients experienced relapse of AIHA after idelalisib discontinuation. With a median follow-up of the entire cohort of 26.8 months, the estimated two years overall survival (2y-OS) of the whole cohort was 88%, while the estimated two years progression free survival (2y-PFS) were 75.3% for CLL and 65.1% for AIC. In the ibrutinib cohort, 2y-OS was 95% and 2y-PFS were 81% for AIC and 94.4% for CLL. In the idelalisib arm, 2y-OS was 80%. Median PFS was 19 months for AIC and 25.7 months for CLL. Conclusion Our results demonstrate that kinase inhibitors are able to induce long-term control of both AIC and CLL and represent new therapeutics options for patients with AIC associated with CLL. Disclosures Quinquenel: Jansen Cilag: Honoraria, Research Funding; Abbvie: Honoraria. Ysebaert:Roche: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy, Research Funding; Janssen: Consultancy, Research Funding.

Description: Background: High dose melphalan (HDM) followed by autologous hematopoietic stem cell transplantation (ASCT) is widely used in multiple myeloma (MM) patients as upfront and salvage therapy. However, the safety and efficacy of ASCT in patients with renal insufficiency (RI) is controversial, which have led to an inconsistent arbitrary cut-off for creatinine clearance (CrCl) for performing ASCT. Here we analyzed prospectively the outcomes of MM patients with severe RI who underwent ASCT. Methods: We enrolled prospectively 50 newly diagnosed MM patients who had a serum CrCl of