ALBERT

Description: B-cell chronic lymphocytic leukemia (CLL) is the most common human leukemia and dysregulation of the T-cell leukemia/lymphoma 1 (TCL1) oncogene is a contributing event in the pathogenesis of the aggressive form of this disease based on transgenic mouse studies. To determine a role of microRNAs on the pathogenesis of the aggressive form of CLL we studied regulation of TCL1 expression in CLL by microRNAs. We identified miR-3676 as a regulator of TCL1 expression. We demonstrated that miR-3676 targets three consecutive 28-bp repeats within 3′UTR of TCL1 and showed that miR-3676 is a powerful inhibitor of TCL1. We further showed that miR-3676 expression is significantly down-regulated in four groups of CLL carrying the 11q deletions, 13q deletions, 17p deletions, or a normal karyotype compared with normal CD19+ cord blood and peripheral blood B cells. In addition, the sequencing of 539 CLL samples revealed five germ-line mutations in six samples (1%) in miR-3676. Two of these mutations were loss-of-function mutations. Because miR-3676 is located at 17p13, only 500-kb centromeric of tumor protein p53 (Tp53), and is codeleted with Tp53, we propose that loss of miR-3676 causes high levels of TCL1 expression contributing to CLL progression.

Description: Background: Mutations of MAP2K1, which encodes MEK1, have been identified in up to half of patients with variant Hairy Cell Leukemia (vHCL).[Waterfall et al., Nat Gen 2014, Mason et al., Leukemia & Lymphoma 2016], and have been associated with vHCL with IGHV4-34 gene usage, which This form of HCL tends to have a worse prognosis than classic HCL or wild type vHCL (Arons et al., Blood 2009), with inferior responses to chemotherapy and shorter durations of remission. Trametinib, an oral inhibitor of MEK1 and MEK2, is FDA approved for treatment of patients with BRAF p.V600E mutant melanoma. We hypothesized that this MEK inhibitor would have activity in MAP2K1 mutant vHCL. Case Report: The patient is a 52 year old man with a history of CD25+, BRAF wildtype, IGHV4-34 usage vHCL diagnosed in 2005. His previous treatments included cladribine, BL22, pentostatin/rituximab, splenectomy, single agent rituximab, ibrutinib, bendamustine/rituximab, and allogeneic transplantation from a matched unrelated donor. The patient experienced disease relapse day +350 post transplant when he developed skin nodules as well as a generalized skin rash. The skin rash appeared clinically consistent with acute GVHD. However, when biopsies of both the skin nodules and skin rash were performed he was found to have relapsed vHCL. He was consented for paired tumor and germline next generation sequencing with a 25-gene amplicon panel which revealed a somatic MAP2K1 K57N mutation that has been shown to constitutively activate MEK [Marks et al., Cancer Res 2008]. As the patient had exhausted the majority of available treatment options, he was prescribed trametinib 2 mg po daily (commercial supply, according to approved melanoma dosing). Within a week of therapy initiation his skin nodules were markedly diminished in size and his generalized rash had resolved. He did develop a new acneiform rash over his face consistent with drug toxicity. This was managed with topical agents with improvement and did not require a dose reduction. Disease restaging following cycle 2 of therapy showed near complete resolution of skin nodules, with disappearance of visible skin rash. Repeat bone marrow biopsy showed unchanged hairy cell index. Skin biopsies were repeated and phospho-ERK (T202/Y204) staining of skin biopsies pre- and post-trametinib were performed (Figure 1). This showed diminished lymphocyte involvement on H&E staining with a decrease in p-ERK expression on immunostaining, indicative of decreased signaling downstream of MEK and consistent with on target trametinib effects. As of this writing, the patient has remained on trametinib for 12 weeks with no recurrence of leukemia cutis rash. Discussion: MEK inhibition with the oral MEKi trametinib is a well tolerated therapy with clinical activity in MAP2K1 mutant vHCL. Additional studies of this agent are warranted. Optimal dose and duration of therapy will need to be explored in prospective clinical trials. Figure 1 Skin biopsies pre- and post-trametinib. (A)(C) H&E staining shows diminished lymphocyte involvement. (B)(D) PhosphoERK immunostaining shows decrease of phosphoERK expression. Bar = 500 μm Figure 1. Skin biopsies pre- and post-trametinib. (A)(C) H&E staining shows diminished lymphocyte involvement. (B)(D) PhosphoERK immunostaining shows decrease of phosphoERK expression. Bar = 500 μm Disclosures Andritsos: Hairy Cell Leukemia Foundation: Research Funding. Anghelina:Hairy Cell Leukemia Foundation: Research Funding. Lozanski:Boehringer Ingelheim: Research Funding; Beckman Coulter: Research Funding; Genentech: Research Funding; Stemline Therapeutics Inc.: Research Funding. Jones:Pharmacyclics, LLC, an AbbVie Company: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Description: Ibrutinib is a promising targeted therapy for chronic lymphocytic leukemia (CLL). However, a small subset of patients progress on ibrutinib either through progressive CLL or Richter's transformation. Patients responding to ibrutinib and then progressing with Richter's transformation do so most commonly within the first 2 years of treatment and have an extremely poor prognosis. Identifying biomarkers associated with this transformation is of utmost importance. Near-tetraploidy (4 copies of most chromosomes within a cell) has been reported in various lymphomas; however, its incidence in CLL has not been described. We investigated the prevalence of near-tetraploidy in CLL patients prior to starting ibrutinib and identified it as a pre-treatment biomarker for Richter's transformation. We examined near-tetraploidy in a large series of CLL patients enrolled across four ibrutinib clinical trials at the Ohio State University, for which extensive correlative studies and follow up data are available (previously described by Maddocks et al., JAMA Oncol, 2015). We identified this abnormality in 9 of 300 patients (3.0%, 95% CI: 1.4-5.6) in blood or bone marrow samples taken prior to starting therapy. Near-tetraploidy was detected by the presence of four signals with four or more fluorescence in situ hybridization (FISH) probes and confirmed in the metaphase karyotype of each patient in at least one cell. Near-tetraploidy was associated with aggressive disease characteristics including: Rai stage 3/4 (p=0.03), deletion 17p (p=0.03), and complex karyotype (p=0.01), as well as trisomy 12 (p=0.05). With a median follow-up time of 40.5 months, in patients positive with near-tetraploidy, one patient (11%) progressed with CLL on ibrutinib, six patients (67%) progressed with Richter's transformation, and two patients (22%) were still on treatment. Cumulative incidence of Richter's transformation was significantly higher in patients with near-tetraploidy (Figure; p

Description: Key Points Cytoreduction with obinutuzumab and ibrutinib followed by the addition of venetoclax has acceptable safety with no tumor lysis syndrome. This combination has preliminary activity including complete remissions with undetectable residual disease in relapsed or refractory CLL.

Description: Eradication of minimal residual disease (MRD) during the first months of treatment for patients (pts) with ALL is associated with improved disease-free survival (DFS). We hypothesized that Alemtuzumab, a humanized monoclonal antibody directed against CD52, might be an effective, novel agent for eradication of MRD in ALL based on data demonstrating strong CD52 expression in other lymphoid malignancies and in several ALL cell lines, and from case reports of clinical activity in advanced ALL. In CALGB 10102, to define the percentage of CD52+ cases and to demonstrate feasibility, we tested dose escalation of Alemtuzumab in sequential cohorts to a target dose of 30 mg administered sc 3X/week for 4 weeks (12 doses) during post-remission therapy. Pts are eligible to receive Alemtuzumab if lymphoblast CD52 expression at diagnosis is ≥ 10% as determined in a CALGB reference laboratory. The 10102 therapy is composed of monthly treatment modules outlined below: Treatment module sequence is: A,B,C, D, A, B, C followed by maintenance therapy for a total of 2 years. Antimicrobial prophylaxis for cytomegalovirus (CMV) (e.g. acyclovir 800 mg qid) and pneumocystis carinii is mandated. Weekly quantitative monitoring for CMV viremia is performed. 150 pts with untreated ALL have enrolled: Median age is 48 yrs. 124 (83%) pts have precursor-B; 19(13%) have precursor T-ALL and 7 (4%) have biphenotypic or bilineal ALL. Of 139 evaluable pts, 95 (68%) had CD52 ≥ 10%. By immunophenotype, 72% of precursor B and 61% of precursor T pts were eligible to receive Alemtuzumab. Phase I dose escalation was recently completed. Dose limiting toxicity (DLT) for Phase I was defined as the inability to proceed with protocol treatment within 6 weeks of the last dose of Alemtuzumab. Non-heme toxicities have been mild and sc Alemtuzumab administration was well tolerated. Hematologic and infectious toxicities are summarized below: Myelosuppression was transient and use of G-CSF was permitted during Module D. 2 pts were treated for CMV viremia due to rising CMV titers in 2 sequential assays. 6 other pts had transient CMV elevations during or immediately following completion of Alemtuzumab that did not require treatment. 22/24 phase I pts received all 12 doses of Alemtuzumab. There were 2 DLTs reported: 1 pt in cohort 2 due to CMV viremia requiring gancyclovir following completion of Alemtuzumab; and 1 pt in cohort 3 due to ANC 〈 1500 six weeks after Alemtuzumab (pt was not given G-CSF). Based on these Phase I data, the targeted dose of 30 mg Alemtuzumab was recommended for further study in the ongoing Phase II study. In summary, we report for the first time that CD52 is expressed in the majority of ALL cases and demonstrate the feasibility of employing Alemtuzumab in front-line therapy. Ongoing accrual to the phase II study will evaluate the efficacy of Alemtuzumab in eradication of MRD in adult ALL. Module A Module B Module C Module D (Alemtuzumab) Maintenance Cytoxan Cytoxan Methotrexate (IV, PO, IT) 10 mg* cohort 1 Vincristine Daunorubicin Cytarabine Vincristine 20 mg* cohort 2 Dexamethasone Vincristine Vincrisitne 6-MP 30 mg* cohort 3 6-MP Dexamethasone L-asparaginase *Phase I dose escalation Methotrexate L-asparaginase IT-Methotrexate Alemtuzumab cohorts N Myelosuppression (grades 3 or 4) Lymphopenia CMV viremia 10 mg 6 2 1 2 20 mg 10 1 1 4 30 mg 8 1 0 2

Description: Introduction: The Bruton's Tyrosine Kinase (BTK) inhibitor ibrutinib (IB) is a standard therapy for previously untreated CLL patients. While therapy is currently indicated only for patients with progressive, symptomatic disease, the introduction of targeted therapies in CLL has re-opened the question of whether asymptomatic high risk patients would benefit from early intervention. As well, even in early stages CLL is associated with profound cellular, humoral and innate immune suppression and patients with CLL respond poorly to routine vaccinations. IB has been shown to reverse disease mediated immune dysfunction partly through Th1 skewing. We undertook a phase 2 study of IB in asymptomatic high risk CLL patients who did not otherwise require therapy to evaluate: 1) the safety and efficacy of 2 years of IB in this clinical setting and 2) ability of IB to improve the efficacy of routine vaccines. Methods: This is a single-stage phase II study of IB in previously untreated asymptomatic, genetically high-risk patients with CLL, who did not meet IWCLL treatment criteria. High risk genomics were defined as del(11)(q22.3), del(17)(p13.1), unmutated IGHV, and/or complex karyotype (≥3 cytogenetic abnormalities). Patients were randomized to receive IB 420mg PO daily either concurrent with the pneumococcal (PCV13), influenza and TdaP vaccines (Arm A) or following vaccination (Arm B) for a total of 27 cycles (2 years). The primary objective of the study was to determine the safety and 2-year progression-free survival (PFS) of asymptomatic, high-risk CLL patients treated with IB. Secondary objectives include determination of safety and immune responses to vaccines in relation to IB administration, development of resistance, and quality-of-life (QOL). QOL measures assessed general QOL (SF-12, EORTC), anxiety (GAD-7) and depression (PHQ-9). Results: Forty-four patients (pts; 21 in Arm A, 23 in Arm B) were enrolled from 1/2016 to 6/2017, with a median age of 58 (range 35-82). Sixty-six percent of pts were male and all were high-risk: 91% with unmutated IGHV, 14% with del(17)(p13.1), 34% with del(11)(q22.3), and 24% with complex karyotype (≥ 3 abnormalities). Median follow-up is 2.6 years (range: 0.2-3.2). Excluding 2 patients in Arm B who progressed prior to receipt of IB, 2-year PFS was 92%. From a landmark of 2-years and including 33 patients who reached this point and discontinued IB, 6-month PFS was 87% (95% CI: 69-95%; Figure 1). Of 9 pts who progressed after IB discontinuation, 3 have not required further treatment, 5 restarted IB or acalabrutinib, and 1 started venetoclax/rituximab, and all responded. For PCV13, in Arm A, 15/16 patients showed a significant increase in antibody titer 2 cycles following vaccination, but response disappeared by cycle 12. In Arm B, 3/13 patients had an increase in antibody titer, with no increase following second vaccination. For influenza, patients in Arm B showed a significant response to influenza A vaccination, while patients in both arms responded to influenza B vaccination. IB was generally well tolerated, and only one pt discontinued treatment due to toxicity (atrial fibrillation). Grade 3+ toxicities that occurred in 〉2% of patients included anemia (7%), atrial fibrillation (11%), dental caries (7%), hyperglycemia (7%), hypertension (43%), and neutropenia (7%). At baseline, patients' reports of physical health-related (M=48.52, SD=7.96) and mental health-related quality of life (M=52.20, SD=8.57) similar to U.S population norms, along with moderately high global health (M=78.49 of 100, SD = 20.51). Additionally, patients' anxiety (M=3.56, SD=4.71) and depressive symptom reports (M=3.65, SD=4.46) were in the "none/mild" range. There was no significant change in the latter measure from baseline to 12 months (p〉0.25), excepting anxiety which slightly decreased (M=1.31, SD=2.33; F(3,44)=5.94, p

Description: Abstract 1737 Poster Board I-763 We previously reported the efficacy and B-cell selectivity of the natural product silvestrol in acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL), using both primary cells and B-cell lines. We also showed that silvestrol inhibits translation, resulting in rapid depletion of the short half-life protein Mcl-1 followed by mitochondrial damage and apoptosis. Cencic et al. reported that silvestrol directly blocks translation initiation by aberrantly promoting interaction of eIF4A with capped mRNA (PLoS One 2009; 4(4):e5223). However, the loss of Mcl-1 in breast and prostate cancer cell lines is delayed relative to what we observe in B-leukemias (48 hr vs. 4-6 hr in CLL and ALL cells). Additionally, silvestrol does not reduce Mcl-1 expression in normal T-cells to the same extent that it does in B-cells, potentially explaining in part the relative resistance of T-cells to this agent. We therefore investigated cell-type differences, as well as the importance of Mcl-1, in silvestrol-mediated cytotoxicity. We incubated the ALL cell line 697 with gradually increasing concentrations of silvestrol to generate a cell line (697-R) with resistance to 30 nM silvestrol (IC50 of parental 697 〈 5 nM). No differences between 697-R and the parental line were detected upon detailed immunophenotyping. However, cytogenetic analysis revealed a balanced 7q;9p translocation in 697-R not present in the parental 697 cell line that may be related to the emergence of a resistant clone. We also detected no difference in expression of multi-drug resistance proteins MDR-1 and MRP, which can contribute to resistance to complex amphipathic molecules such as silvestrol. In contrast, we found that baseline Mcl-1 protein expression is strikingly increased in 697-R cells relative to the parental line, although these cells still show similar percent-wise reduction in Mcl-1 upon re-exposure to 80 nM silvestrol. To investigate whether this resistance to silvestrol is reversible, 697-R cells were maintained without silvestrol for 6 weeks (∼18 passages). During this time, viability remained near 99%. Cells were then treated with 30 nM silvestrol. Viability was 94% at 48 hr post-treatment and returned to 99% within a week, while parental 697 cells with the same treatment were completely dead. Baseline Mcl-1 levels remained elevated in 697-R even with prolonged silvestrol-free incubation. These results indicate that the resistance phenotype is not rapidly reversible, as is seen with transient upregulation of multi-drug resistance or stress-response proteins. Additionally, silvestrol moderately induces the transcription of several pro-apoptotic Bcl-2 family members and results in elevated levels of these proteins despite its translation inhibitory activity. Interestingly, no such activity is detected in silvestrol-treated normal T-cells. Together, these results support the hypothesis that in B-cells, silvestrol induces cell death by altering the balance of pro- and anti-apoptotic factors, and that increased Mcl-1 protein can force the balance back toward survival. This work further underscores the importance of Mcl-1 in silvestrol-mediated cytotoxicity. We are now investigating the mechanism of Mcl-1 upregulation in 697-R cells to identify a factor or pathway that can be targeted therapeutically to circumvent resistance. Silvestrol is currently undergoing preclinical pharmacology and toxicology investigation by the U.S. National Cancer Institute Drug Development Group at the Stage IIA level to facilitate its progression to Phase I clinical testing. Disclosures No relevant conflicts of interest to declare.

Description: Background: Donor grafts with more naive T cells and plasmacytoid dendritic cells were associated with improved overall survival after unrelated donor bone marrow, but not peripheral blood stem cell (PBSC) transplants (Waller, E JCO 2014). Here we present results on influence of innate and adaptive immune subsets in G-CSF mobilized allografts on incidence of acute GVHD (aGVHD) and chronic GVHD (cGVHD) in 238 patients (pts). Methods: We analyzed the absolute numbers and percentages of T, NK, NKT and B cells along with an extensive immunophenotypic characterization of their activation status in consecutive PBSC allografts obtained from sibling and unrelated donors between 2010 - 2014 and studied their association with the incidence of aGVHD and cGVHD. Wilcoxon rank sum tests were used to screen differential marker expression between those who did vs. did not develop aGVHD and similarly for cGVHD. Significant markers were evaluated in the multivariable (m.v.) setting along with known prognostic factors, including: recipient age, related vs. unrelated donor, female donor vs. not, Anti-thymocyte globulin (ATG) use (yes vs. no), and Reduced-intensity conditioning (RIC) vs. not. Cutpoints for markers were generated using recursive partitioning algorithms and evaluated in m.v. models. Results: Of the 238 alloSCT pts evaluated, most (71%) had unrelated donors, 64% received ATG, where most pts with unrelated donors received ATG (83%), and 78% received RIC. The incidence of aGVHD and cGVHD was 58% and 38% respectively. A total of 107 pts had grade II-IV aGVHD reported (71 II, 28 III, 8 IV), and 92 of 192 evaluable for cGVHD (at least 100 days of f/u) had reported cGVHD. Median follow-up in living pts was 21 months (range: 1.4 to 41.1 months). Table 1 shows dichotomized markers most influential on aGVHD. Higher absolute numbers of T cells, activated T cells, CD8+ cells, CD8+ cells expressing IL-7 receptor and CD27 were associated with higher incidence of aGVHD. Higher number of Stage 4 NK cells expressing stem cell factor receptor, and T-regs were associated with a lower incidence of aGVHD. Similar analyses were done for cGVHD (Table 2). Higher absolute numbers of activated T lymphocytes, activated B lymphocytes, KIR expressing CD3+ cells, CD8+ lymphocytes and activated NK cells were associated with higher incidence of cGVHD. When the percent of these makers in relation to total lymphocytes was evaluated regarding association with aGVHD, higher percent of T-regs (OR: 0.204, p=0.0018), effector memory T cells (OR: 0.45, p=0.024) and NKG2D positive NK cells (OR: 0.38, p=0.0008) conferred protection from aGVHD . Similar analysis for cGVHD showed higher percent of naïve CD4+ T cells conferred protection from cGVHD (OR: 0.44; p=0.0062) while higher percent of CD8+ cells (OR: 3.93; p=0.0032) and activated NK cells (OR: 2.08; p=0.024) was associated with cGVHD. Conclusions: These results show a protective role of donor T-regs, CD4+ T cells and Stage 4 NK cells from aGVHD. Additionally, higher content of activated T cells, CD8+ cells and B lymphocytes are associated with higher incidence of cGVHD. Higher content of activated NK cells seems to protect from aGVHD, but not from cGVHD. Updated results including multivariable analyses will be presented. These findings showing the influence of specific subsets in the allograft on aGVHD and cGVHD may provide opportunities for therapeutic interventions for graft engineering or pharmacologic methods for targeting specific immune subsets to decrease incidence of aGVHD and cGVHD. Table 1 Univariate model results for aGVHD with dichotomized markers using cutpoints: Marker Absolute OR p-value CD3+/CD5616- (T lymphocytes) 3.07 0.0013 CD3+/HLA DR+ (Activated T lymphocytes) 3.26 0.012 CD8+/CD45RA- (CD 8+ lymphocytes) 2.56 0.012 CD8+/CD27+ (Effector Memory CD8 cells) 3.25 0.0082 CD8+/CD127+ ( CD8 cells expressing IL-7 receptor) 2.92 0.073 CD4+/CD25+/CD127-(T regs) 0.43 0.057 CD3-/CD16-/CD56+/CD117+ (Stage 4 NK cells expressing Stem cell factor receptor) 0.12 0.0007 Table 2 Univariate model results for cGVHD with dichotomized markers using cutpoints: Marker Absolute OR p-value CD3+/HLA DR+ (Activated T lymphocytes) 4.41